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Schöbel T, Gemkow M, Wendler T, Schleifenbaum S, Löffler S, Theopold J, Hepp P. Primary stability in locking plate fixation for proximal humeral fractures may be increased by using an additional nail osteosynthesis in combination with locking plate osteosynthesis-A biomechanical comparison. Clin Biomech (Bristol, Avon) 2024; 114:106235. [PMID: 38552372 DOI: 10.1016/j.clinbiomech.2024.106235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Stability is regarded as an important factor for proper healing and avoiding secondary dislocation in osteoporotic fractures of the proximal humerus. Several surgical techniques have been proposed for treatment, including intramedullary nail osteosynthesis and locking plate fixation. This study introduces a novel approach that combines both techniques and compares its primary stability with conventional methods. METHODS The study involved 25 osteoporotic humeri with two-part fracture models, which were randomly assigned to locking-plate fixation, intramedullary nailing, or a combination of both techniques. The specimens were subjected to sinusoidal loading at 250 N in 20° abduction for 5000 cycles and then to quasi-static loading until failure. Fracture movement, failure mode, and failure load were measured and compared among the groups. FINDINGS The groups fixated with intramedullary nailing and the groups fixated with intramedullary nailing and locking plate fixation showed significantly lower fracture motion than the group using locking plate fixation only (p < 0.005) and significantly higher load to failure (p = 0.007 and p = 0.0062, respectively). There was no significant difference between the group using intramedullary nailing and the group using locking-plate fixation and intramedullary nailing in fracture movement or load-to-failure (p > 0.005). INTERPRETATION The results indicate that locking plate fixation provides less primary stability than intramedullary nailing or the combined of both techniques. This combined approach may offer advantages as a treatment for complex proximal humeral fractures in osteoporotic bone, and specific implants should be developed to ensure optimal treatment.
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Affiliation(s)
- Tobias Schöbel
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
| | - Maximilian Gemkow
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
| | - Toni Wendler
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany; ZESBO - Center for Research on Musculoskeletal Systems, Semmelweisstraße 14, 04103 Leipzig, Germany.
| | - Stefan Schleifenbaum
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany; ZESBO - Center for Research on Musculoskeletal Systems, Semmelweisstraße 14, 04103 Leipzig, Germany; Fraunhofer Institute for Machine Tools and Forming Technology, Nöthnitzer Straße 44, 01187 Dresden, Germany.
| | - Sabine Löffler
- Institute of Anatomy, University of Leipzig, Liebigstraße 13, 04103 Leipzig, Germany.
| | - Jan Theopold
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
| | - Pierre Hepp
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
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Zdero R, Brzozowski P, Schemitsch EH. Biomechanical design optimization of proximal humerus locked plates: A review. Injury 2024; 55:111247. [PMID: 38056059 DOI: 10.1016/j.injury.2023.111247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/15/2023] [Accepted: 11/24/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Proximal humerus locked plates (PHLPs) are widely used for fracture surgery. Yet, non-union, malunion, infection, avascular necrosis, screw cut-out (i.e., perforation), fixation failure, and re-operation occur. Most biomechanical investigators compare a specific PHLP configuration to other implants like non-locked plates, nails, wires, and arthroplasties. However, it is unknown whether the PHLP configuration is biomechanically optimal according to some well-known biomechanical criteria. Therefore, this is the first review of the systematic optimization of plate and/or screw design variables for improved PHLP biomechanical performance. METHODS The PubMed website was searched for papers using the terms "proximal humerus" or "shoulder" plus "biomechanics/biomechanical" plus "locked/locking plates". PHLP papers were included if they were (a) optimization studies that systematically varied plate and screw variables to determine their influence on PHLP's biomechanical performance; (b) focused on plate and screw variables rather than augmentation techniques (i.e., extra implants, bone struts, or cement); (c) published after the year 2000 signaling the commercial availability of locked plate technology; and (d) written in English. RESULTS The 41 eligible papers involved experimental testing and/or finite element modeling. Plate variables investigated by these papers were geometry, material, and/or position, while screw variables studied were number, distribution, angle, size, and/or threads. Numerical outcomes given by these papers included stiffness, strength, fracture motion, bone and implant stress, and/or the number of loading cycles to failure. But, no paper fully optimized any plate or screw variable for a PHLP by simultaneously applying four well-established biomechanical criteria: (a) allow controlled fracture motion for early callus generation; (b) reduce bone and implant stress below the material's ultimate stress to prevent failure; (c) maintain sufficient bone-plate interface stress to reduce bone resorption (i.e., stress shielding); and (d) increase the number of loading cycles before failure for a clinically beneficial lifespan (i.e., fatigue life). Finally, this review made suggestions for future work, identified clinical implications, and assessed the quality of the papers reviewed. CONCLUSIONS Applying biomechanical optimization criteria can assist biomedical engineers in designing or evaluating PHLPs, so orthopaedic surgeons can have superior PHLP constructs for clinical use.
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Affiliation(s)
- Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada
| | - Pawel Brzozowski
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada; Division of Orthopaedic Surgery, Western University, London, ON, Canada
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Karslioglu B, Dedeoglu SS, Imren Y, Yerli M, Guler Y, Keskin A. Pectoralis major pedicle bone grafting vs. tricortical iliac grafting for Neer 4-part proximal humerus fractures: a randomized controlled trial. J Shoulder Elbow Surg 2024; 33:14-22. [PMID: 37625692 DOI: 10.1016/j.jse.2023.07.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 07/13/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023]
Abstract
BACKGROUND The risk of avascular necrosis, nonunion, or malunion is high in osteoporosis-related 4-part fractures. We evaluated the results of patients who underwent plate osteosynthesis with a vascularized pectoralis major graft compared with tricortical iliac grafting to treat 4-part proximal humerus fractures. MATERIAL AND METHODS Thirty-four patients aged 50-75 years with Neer 4-part proximal humerus fractures were studied. Group A (n = 17) underwent osteotomy of a 2.5 ± 1 cm pectoralis major pedicle bone graft and plate application, whereas group B (n = 17) underwent plate osteosynthesis using iliac autogenous grafts. Final follow-up assessments included evaluation using Constant and American Shoulder and Elbow Surgeons scoring systems, humeral neck-shaft angle (HNSA), humeral head height, and humeral head avascular necrosis. RESULTS Reduction loss was observed in 3 patients (17.6%) in group A, whereas it was observed in 10 patients (58.8%) in group B (P = .013). Humeral head avascular necrosis was found in 1 patient (5.8%) in group A, whereas it was found in 5 patients (29.4%) in the other group (P = .071). The HNSA was normal in 12 (70.5%) of group A patients, whereas it was normal in 6 (35.2%) of group B patients. The HNSA was weak or bad (<1200) in 29.4% of group A patients, whereas this rate was 64.7% in group B patients. Humeral head height was 2.64 ± 1.45 mm in group A and 3.66 ± 1.65 mm in group B. There were no statistically significant differences between the 2 groups in terms of Constant and American Shoulder and Elbow Surgeons scoring systems. CONCLUSION Pectoralis major bone pedicle graft in Neer 4-part proximal humerus fractures reduces the risk of avascular necrosis and nonunion rates. Our technique yielded excellent clinical and radiological results. We achieved recovery without creating additional donor site morbidity.
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Affiliation(s)
- Bulent Karslioglu
- Department of Orthopedics and Traumatology, Prof. Cemil Tascioglu City Hospital, University of Health Sciences, Istanbul, Turkey
| | - Suleyman Semih Dedeoglu
- Department of Orthopedics and Traumatology, Metin Sabanci Baltalimani Bone Diseases Training and Research Hospital, Istanbul, Turkey.
| | - Yunus Imren
- Department of Orthopedics and Traumatology, Metin Sabanci Baltalimani Bone Diseases Training and Research Hospital, Istanbul, Turkey
| | - Mustafa Yerli
- Department of Orthopedics and Traumatology, Prof. Cemil Tascioglu City Hospital, University of Health Sciences, Istanbul, Turkey
| | - Yasin Guler
- Department of Orthopedics and Traumatology, Metin Sabanci Baltalimani Bone Diseases Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Keskin
- Department of Orthopedics and Traumatology, Kartal Dr. Lütfi Kırdar City Hospital, Istanbul, Turkey
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Halbauer C, Capanni F, Bertusch I, Paech A, Merkle T, Da Silva T. Biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures - a systematic literature review. BIOMED ENG-BIOMED TE 2023; 68:553-561. [PMID: 37406349 DOI: 10.1515/bmt-2023-0039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/27/2023] [Indexed: 07/07/2023]
Abstract
Proximal humeral shaft fractures can be treated with helically deformed bone plates to reduce the risk of iatrogenic nerve lesion. Controversially to this common surgical technique that was first established in 1999, no biomechanical investigation on humeral helical plating is recorded by other reviews, which focus on proximal fractures exclusively. Does an additional scope for shaft fractures reveal findings of helical testing? The present systematic literature review was performed based on guidelines by Kitchenham et al. to systematically search and synthesize literature regarding biomechanical testing of osteosynthetic systems for proximal humeral shaft fractures. Therefore, a systematic approach to search and screen literature was defined beforehand and applied on the findings of the database PubMed®. Synthesized information of the included literature was categorized, summarized and analyzed via descriptive statistics. Out of 192 findings, 22 publications were included for qualitative synthesis. A wide range of different test methods was identified, leading to a suboptimal comparability of specific results between studies. Overall, 54 biomechanical test scenarios were identified and compared. Physiological based boundary conditions (PB-BC) were referenced in 7 publications only. One study of testing straight and helical dynamic compression plates without PB-BCs was identified, showing significant differences under compressional loading. The absence of test standards of specific fields like humeral fractures lead to a high variance in biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures. Physiological approaches offer realistic test scenarios but need to be uniformed for enhanced comparability between studies. The impact of helically deformed locking plates under PB-BC was not identified in literature.
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Affiliation(s)
- Christian Halbauer
- Department of Mechatronics and Medical Engineering, Biomechatronics Research Group, Ulm, University of Applied Sciences, Ulm, Germany
| | - Felix Capanni
- Department of Mechatronics and Medical Engineering, Biomechatronics Research Group, Ulm, University of Applied Sciences, Ulm, Germany
| | - Isabel Bertusch
- Department of Mechatronics and Medical Engineering, Biomechatronics Research Group, Ulm, University of Applied Sciences, Ulm, Germany
| | - Andreas Paech
- Department for Orthopedic and Trauma Surgery, University Medical Center Schleswig-Holstein, Lübeck, Germany
| | - Tobias Merkle
- Department of Trauma Surgery and Orthopedics, Clinical Centre Stuttgart-Katharinenhospital, Stuttgart, Germany
| | - Tomas Da Silva
- Department of Trauma Surgery and Orthopedics, Clinical Centre Stuttgart-Katharinenhospital, Stuttgart, Germany
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Kotler JA, Zuppke JN, Abraham VM, Sanville JA, Nabet AC, Carofino B, Gardner MJ, Smith CS. Biomechanical Analysis of Combined Medial Calcar and Lateral Locked Plating Versus Isolated Lateral Locked Plating of Proximal Humerus Fractures. J Orthop Trauma 2023; 37:e355-e360. [PMID: 37074819 DOI: 10.1097/bot.0000000000002619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/10/2023] [Indexed: 04/20/2023]
Abstract
OBJECTIVE Medial calcar buttress plating combined with lateral locked plating is biomechanically tested against isolated lateral locked plating in synthetic humeri models for the treatment of proximal humerus fractures. METHODS Proximal humerus fractures (OTA/AO type 11-A2.1) were manufactured in 10 pairs of Sawbones humeri models (Sawbones, Pacific Research Laboratories, Vashon Island, WA). Specimen were randomly assigned and instrumented with either medial calcar buttress plating combined with lateral locked plating (CP) or isolated lateral locked plating (LP). Nondestructive torsional and axial load tests were performed to evaluate construct stiffness. Large-cycle axial tests were conducted followed by destructive ramp-to-failure tests. Cyclic stiffness was compared in both nondestructive and ultimate failure loads. Failure displacement was recorded and compared between groups. RESULTS The addition of medial calcar buttress plating to lateral locked plating constructs significantly increased the axial ( P < 0.01) and torsional ( P < 0.01) stiffness of the construct compared with isolated lateral locked plating by 95.56% and 37.46%, respectively. All models demonstrated greater axial stiffness ( P < 0.01) after 5000 cycles of axial compression, not dependent on the fixation method. During destructive testing, the CP construct withstood 45.35% larger load ( P < 0.01) and congruently exhibited 58% less humeral head displacement ( P = 0.02) before failure when compared with the LP construct. CONCLUSION This study demonstrates the biomechanical superiority of medial calcar buttress plating when combined with lateral locked plating as compared with isolated lateral locked plating of OTA/AO type 11-A2.1 proximal humerus in synthetic humeri models.
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Affiliation(s)
- Joshua A Kotler
- 3d Medical Battalion, 3D Marine Logistics Group, III Marine Expeditionary Force, Okinawa, Japan
| | - Julia N Zuppke
- Bone and Joint/Sports Medicine Institute, Naval Medical Readiness and Training Center, Portsmouth, VA
| | - Vivek M Abraham
- Bone and Joint/Sports Medicine Institute, Naval Medical Readiness and Training Center, Portsmouth, VA
| | - Jennifer A Sanville
- Bone and Joint/Sports Medicine Institute, Naval Medical Readiness and Training Center, Portsmouth, VA
| | - Austin C Nabet
- Bone and Joint/Sports Medicine Institute, Naval Medical Readiness and Training Center, Portsmouth, VA
| | | | - Michael J Gardner
- Department of Orthopaedic Surgery, Stanford University, Redwood City, CA
| | - Christopher S Smith
- Bone and Joint/Sports Medicine Institute, Naval Medical Readiness and Training Center, Portsmouth, VA
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Fu H, Wu J, Wu X. Intramedullary Nail for Treatment of Proximal Humeral Fracture: A Credible Fixation in Comminuted Calcar. Orthop Surg 2023; 15:2007-2015. [PMID: 36514186 PMCID: PMC10432444 DOI: 10.1111/os.13616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/31/2022] [Accepted: 11/04/2022] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Restoration of the medial support is especially important for the treatment of proximal humeral fractures. The objective of this study was to investigate the radiographic and clinical outcomes of intramedullary nail fixation with a special focus on the presence of calcar comminution. METHODS In this retrospective study of patients with displaced proximal humeral fractures that were treated by intramedullary nail between January 2018 and July 2021, fracture morphology and the calcar integrity were noted on preoperative radiographs. Patients were divided into two groups according to calcar integrity. During follow-up, radiological assessment and functional outcome, including the deltoid tuberosity index (DTI), neck shaft angle (NSA), visual analog scale (VAS), the American Shoulder and Elbow Surgeons (ASES) score, the Simple Shoulder Test (SST) score, active and passive range of motion, were performed. A Student t-test and univariate logistic regression analysis was used. RESULTS A total of 83 patients (54 female, 29 male) had complete follow-up (average, 12.8 months; range, 10 to 33 months) and functional assessment in our study. The average age was 58.6 years (range, 20 to 89 years). The mean loss of NSA was 4° (range, 0°-12°) and no significant difference was found between two groups (p = 0.27). DTI had an average of 1.50 ± 0.19 (range 1.13-2.04). Patients with intact calcar achieved greater range of forward elevation (129.06 ± 11.91 vs. 121.05 ± 11.97, p = 0.01), and higher SST scores (8.61 ± 1.85 vs. 7.37 ± 2.22, p = 0.02). Two groups showed similar outcomes in VAS, ASES score, and range of abduction. One patient demonstrated a proximal interlocking screw cutting through and osteonecrosis of the humeral head, who underwent a second surgery for screw removal. There were no cases of infection, malunion, nonunion, nerve injury, subacromial impingement, or rotator cuff tear during the study period. CONCLUSION Intramedullary nail can favorably be used to manage proximal humeral fractures with good early radiographic and functional outcomes, even for those with comminuted calcar.
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Affiliation(s)
- Huichao Fu
- Department of Orthopaedic Traumatology, Trauma Center, Shanghai General HospitalShanghaiChina
| | - Jianhong Wu
- Department of Orthopaedic Traumatology, Trauma Center, Shanghai General HospitalShanghaiChina
| | - Xiaoming Wu
- Department of Orthopaedic Traumatology, Trauma Center, Shanghai General HospitalShanghaiChina
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Wendler T, Fischer B, Schleifenbaum S, Theopold J, Hepp P. Dynamic biomechanical investigation of a novel sulcus bicipitalis plate in combination with a conventional locking plate for the treatment of complex proximal humerus fractures. Clin Biomech (Bristol, Avon) 2023; 105:105984. [PMID: 37156192 DOI: 10.1016/j.clinbiomech.2023.105984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/28/2023] [Accepted: 05/01/2023] [Indexed: 05/10/2023]
Abstract
BACKGROUND Complex proximal humerus fractures place high demands on osteosynthetic treatment. In some cases, double plating has already been used to increase primary stability of the osteosynthesis. This approach was advanced in the present study by developing an additive plate for the sulcus bicipitalis. To demonstrate the superior primary stability of the newly developed plate osteosynthesis, a biomechanical comparison against a conventional locking plate with an additional calcar screw was performed. METHODS Ten pairs of cadaveric humeri were treated proximally with a locking plate (PENTA plate small fragment, INTERCUS). Each had a two-part fracture model with a fracture gap of 10 mm. All right humeri were treated with an additive novel plate that extends along the bicipital sulcus and encircles the lesser tuberosity proximally. First, the specimens were loaded sinusoidally at 250 N in 20° abduction for 5000 cycles. Afterwards quasi-static loading until failure was applied. FINDINGS The movement at the fracture gap due to the cyclic loading occurred mainly as rotation around the z-axis, corresponding to a tilt medially and distally. The double plate osteosynthesis reduces the rotation by approximately 39%. For all load cycles observed, except 5000 cycles, medial and distal rotation of the head was significantly reduced by the double plate. The failure loads showed no significant differences between the groups. INTERPRETATION In the tested scenario under cyclic loading, the novel double plate osteosynthesis showed a significant superiority of primary stability over the conventional treatment with one locking plate. Furthermore, the study showed the advantages of cyclic load application over quasi-static load application until failure.
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Affiliation(s)
- Toni Wendler
- ZESBO - Centre for Research on Musculoskeletal Systems, Leipzig University, Leipzig, Germany; Institute of Anatomy, Leipzig University, Leipzig, Germany.
| | - Benjamin Fischer
- ZESBO - Centre for Research on Musculoskeletal Systems, Leipzig University, Leipzig, Germany; Institute of Anatomy, Leipzig University, Leipzig, Germany
| | - Stefan Schleifenbaum
- ZESBO - Centre for Research on Musculoskeletal Systems, Leipzig University, Leipzig, Germany; Department of Orthopaedic, Trauma and Plastic Surgery, Leipzig University, Leipzig, Germany
| | - Jan Theopold
- Department of Orthopaedic, Trauma and Plastic Surgery, Leipzig University, Leipzig, Germany
| | - Pierre Hepp
- ZESBO - Centre for Research on Musculoskeletal Systems, Leipzig University, Leipzig, Germany; Department of Orthopaedic, Trauma and Plastic Surgery, Leipzig University, Leipzig, Germany
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Double Plating for Complex Proximal Humeral Fractures: Clinical and Radiological Outcomes. J Clin Med 2023; 12:jcm12020696. [PMID: 36675625 PMCID: PMC9860712 DOI: 10.3390/jcm12020696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/19/2022] [Accepted: 01/09/2023] [Indexed: 01/17/2023] Open
Abstract
Double plating for proximal humeral fractures (PHF) is an option to increase the primary fixation stability. Clinical data is missing for assessment of clinical and radiological outcome, as well as complications. We retrospectively examined 35 patients with unilateral PHF, who were treated with double plating for PHF between 2013 and 2019. The mean age was 59.5 ± 12 years and the leading fracture type was a varus dislocation (Resch type IV in 55.3%). A head-split was present in 22.9% of the cases. The primary outcome measurement was the radiological neck shaft angle (NSA). The radiological follow-up was 21 ± 16.6 months and the NSA did not differ between the intraoperative and follow-up time point (131.5 ± 6.9° vs. 136.6 ± 13.7°; p = 0.267). The clinical follow-up was 29.5 ± 15.3 months. The Constant-score was 78.5 ± 17 points, the simple-shoulder-test (SST) was 9.3 ± 3.2 points and the subjective shoulder value (SSV) was 78.8 ± 19.5%. The over-all complication rate was 31.4%, and without stiffness 14.3%. An avascular necrosis occurred in two patients (5.7%). In conclusion, this study shows good radiological and functional outcomes after double plating of highly complex proximal humeral fractures, while the complication rate is comparable to the literature. Double plating is a viable option especially for younger patients with complex fractures as a potential alternative to fracture arthroplasty.
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Patel R, Brown JR, Miles JW, Dornan GJ, Bartolomei C, Dey Hazra RO, Vidal LB, Millett PJ. Preventing varus collapse in proximal humerus fracture fixation: 90-90 dual plating versus endosteal fibular allograft strut. Arch Orthop Trauma Surg 2023:10.1007/s00402-022-04738-1. [PMID: 36598604 DOI: 10.1007/s00402-022-04738-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/13/2022] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Screw cut out and varus collapse are the most common complication of locked plate fixation of proximal humerus fractures. The purpose of this study was to compare dual plating and endosteal fibular allograft struts as augmentation strategies to prevent varus collapse. MATERIALS AND METHODS A trapezoidal osteotomy was created at the metaphysis to create a 2-part proximal humerus model in 18 paired shoulder specimens. Each specimen was assigned to group A, B, or C and was fixed with either a lateral locking plate, a lateral locking plate and anterior one-third tubular plate in an orthogonal 90/90 configuration, or a lateral locking plate with intramedullary fibular strut, respectively. The specimens were stressed in axial compression to failure. Displacement, elastic limit, ultimate load, and stiffness were recorded and calculated. RESULTS There was no difference in mean cyclic displacement between the three groups (0.71 mm vs 0.89 mm vs 0.61 mm for Group A, B, C, respectively). Lateral plating demonstrated the greatest absolute and relative displacement at the elastic limit (5.3 mm ± 1.5 and 4.4 mm ± 1.3) without significance. The elastic limit or yield point was greatest for fibular allograft, Group C (1223 N ± 501 vs 1048 N ± 367 for Group B and 951 N ± 249 for Group A) without significance. CONCLUSIONS Dual plating of proximal humerus fractures in a 90-90 configuration demonstrates similar biomechanical properties as endosteal fibular strut allograft. Both strategies demonstrate superior stiffness to isolated lateral locked plating.
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Affiliation(s)
- Ravi Patel
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA
| | - Justin R Brown
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA
| | - Jon W Miles
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA
| | - Grant J Dornan
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA
| | | | - Rony-Orijit Dey Hazra
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA
| | - Leslie B Vidal
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA
| | - Peter J Millett
- Steadman Philippon Research Institute, 181 W. Meadow Dr. Ste 1000, Vail, CO, 81657, USA.
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Zhu Z, Chang Z, Zhang W, Nie S, Qi L, Tang P, Chen H, Liu Y. How to improve the biomechanical stability of endosteal augmentation for proximal humerus fracture with osteopenia? A cadaveric study. Clin Biomech (Bristol, Avon) 2023; 101:105850. [PMID: 36493692 DOI: 10.1016/j.clinbiomech.2022.105850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
BACKGROUND Endosteal augmentation enhances the stability of osteoporotic proximal humeral fracture fixation, but the optimal configuration is unknown. The purpose of this study was to compare the biomechanical properties of different lengths of fibula with or without calcar screw in osteoporotic proximal humeral fracture. METHODS Three-part proximal humeral fractures with osteopenia were created on 20 pairs of fresh-frozen humeri specimens and allocated to four groups: (1) locking plate with a 6-cm fibular strut allograft, (2) locking plate with a 6-cm fibular strut allograft and additional calcar screws, (3) locking plate with a 12-cm fibular strut allograft,and (4) locking plate with a 12-cm fibular strut allograft and additional calcar screws. Specimens were loaded to simulate the force at 25° abduction. Thereafter, an axial stiffness test and a compound cyclic load to failure test were applied. Structural stiffness, number of cycles loaded to failure and relative displacement values for 5000 cycles at predetermined measurement points were recorded using a testing machine and a synchronized 3D video tracking system. FINDINGS In terms of initial stiffness, number of cycles loaded to failure, and relative displacement values, the groups with 12-cm fibular strut showed obvious improvement compared to the groups with 6-cm fibular strut irrespective of the influence of calcar screw implementation. Further, the groups implemented with calcar screws also showed promising biomechanical stability irrespective of fibular length. INTERPRETATION Lateral locking plate with longer endosteal fibular augmentation and calcar screw can significantly improve biomechanical stability for elderly proximal humeral fractures with posteromedial comminution.
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Affiliation(s)
- Zhengguo Zhu
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China
| | - Zuhao Chang
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China
| | - Wei Zhang
- AI Sports Engineering Lab, School of Sports Engineering, Beijing Sport University, Beijing, China
| | - Shaobo Nie
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China
| | - Lin Qi
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China
| | - Peifu Tang
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China
| | - Hua Chen
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China.
| | - Yujie Liu
- The Department of Orthopaedic Trauma, Chinese PLA General hospital (301 Hospital), 28 Fuxing Road, Wukesong, Beijing 100853, China.
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Comparison of fibula strut and calcium phosphate cement augmentation of the medial buttress in 2-part proximal humerus fractures reconstruction: a biomechanical study. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY & TRAUMATOLOGY : ORTHOPEDIE TRAUMATOLOGIE 2023; 33:67-72. [PMID: 34739600 DOI: 10.1007/s00590-021-03147-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 10/11/2021] [Indexed: 01/11/2023]
Abstract
PURPOSE Augmentation strategies for surgical fixation of proximal humerus fractures (PHF) are available to address their relatively high failure rate. The purpose of this study was to compare two medial-buttress augmentation strategies for PHF fixation. METHODS A two-part PHF model with loss of medial buttress was created in 16 synthetic bones. The PHFs were fixed with locking plates and either calcium phosphate cement (CPC) or fibula strut (FS) augmentation. After cadaveric validations, the fixation constructs were subjected to nondestructive axial compression tests, followed by a cyclic test. Construct stiffness and angular displacement of the humerus head were recorded. RESULTS Humeral head angular displacement was statistically greater in the CPC group than in the FS group at the applied force of 300 N and higher (p < 0.05). Axial stiffness was statistically greater in the FS fixation group than in the CPC group at initial and final phases of cyclic loading protocol (p < 0.05). CONCLUSIONS In an osteoporotic cadaveric model of a 2-part PHF with loss of a medial buttress, locked plate constructs augmented with FS have a higher resistance to varus collapse compared to those augmented with CPC.
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Hung CY, Yeh CY, Wen PC, Yeh WL, Lin SJ. The effect of medial calcar support on proximal humeral fractures treated with locking plates. J Orthop Surg Res 2022; 17:467. [PMID: 36307815 PMCID: PMC9617439 DOI: 10.1186/s13018-022-03337-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/28/2022] [Indexed: 11/10/2022] Open
Abstract
Background Studies have reported mixed results on the importance of medial calcar support for the treatment of proximal humeral fractures. The purpose of this study was to compare radiographic and functional outcomes of patients who had displaced proximal humeral fractures with varying levels of medial support. Methods We performed a retrospective comparative cohort study. The study was conducted at a Level III trauma center in Taiwan. Seventy patients with proximal humeral fractures were collected retrospectively from 2015 to 2019. Only patients with two-, three-, or four-part types (Neer type I, II, or III) of displaced proximal humeral fractures were included in this study. However, patients with head-split fracture patterns, shoulder dislocation, prior shoulder trauma, and poor fracture reduction present in postoperative films were excluded. We assessed the radiographic outcomes, including the reduction score and amount of impaction in the humeral head. The functional outcome was evaluated based on the Constant score. Results Patients were grouped into the intact medial calcar group and the medial calcar deficiency group. In a subgroup analysis, the group with intact medial support had a significantly lower amount of impaction and a higher Constant score compared with the medial calcar deficiency group. Additionally, the groups with intact medial support had a nonsignificant difference in the Constant score between the affected side and the contralateral side. Conclusion The amount of impaction and the reduction score in the humeral head at the 12-month radiographic follow-up were significantly higher in the group with medial support deficiency. However, the reduction score after surgery exhibited no difference. This implies that the inherent nature of medial comminution of proximal humeral fracture may lead to inferior radiographic outcomes.
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Affiliation(s)
- Chun-Yu Hung
- Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Yunlin, Taiwan.,Department of Orthopaedic Surgery, Jen-Ai Hospital, Taichung, Taiwan
| | - Chia-Yi Yeh
- Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Po-Chong Wen
- Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Yunlin, Taiwan
| | - Wen-Ling Yeh
- Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan.,Department of Orthopaedic Surgery, Lotung Poh-Ai Hospital, Yilan, Taiwan
| | - Shih-Jie Lin
- Department of Orthopaedic Surgery, New Taipei Municiple TuCheng Hospital, Chang Gung Memorial Hospital, New Taipei City, Taiwan. .,Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan.
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Ott N, Hackl M, Prescher A, Scaal M, Lanzerath F, Müller LP, Wegmann K. The effect of long calcar screws on the primary stability of 3-part, varus impacted proximal humeral fractures compared to short calcar screws: a real fracture simulation study. Arch Orthop Trauma Surg 2022; 143:2485-2491. [PMID: 35635575 PMCID: PMC10110638 DOI: 10.1007/s00402-022-04473-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 04/27/2022] [Indexed: 11/02/2022]
Abstract
BACKGROUND Complex proximal humeral fracture ranks among the most common fracture types, especially in elderly patients. In locked plate fixation of proximal humerus fractures, the calcar is deciding for screws providing further medial column support. To date, the biomechanical effect of the length of these calcar screws is not well known. The purpose of this study was to analyze the effect of long calcar screws on fresh frozen prefractured cadaveric specimens. METHODS In the present biomechanical study, 8 pairs of cadaveric proximal humeri were fractured identically using a custom-made fracture simulator. ORIF was performed using a locking plate (PHILOS; Fa. Synthes). The specimens were tested in a biomechanical setup under increased axial load without any calcar screws installed, with short calcar screws and long calcar screws installed. Strain gages (4-wire-120 Ohm, Fa. Vishay) mounted on the locking plate were used to evaluate the fixation strain and to give an estimate for primary stability.. RESULTS The measured strain of the locking plate without calcar screws (804,64 µm/m) at maximum load (200 N) was significantly higher than with short (619,07 µm/m; p = 0.02) or long calcar screws (527,31 µm/m; p = 0.007). Additionally, strain with short calcar screws was noticeably higher in comparison to long calcar screws (619,07 µm/m vs. 527,31 µm/m; p = 0.03). CONCLUSION Use of calcar screws improves the stability of realistically impacted 3-part varus humeral fractures. Long calcar screws that are positioned as close as possible to the joint provide further primary stability compared to short calcar screws. LEVEL OF EVIDENCE Basic science study.
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Affiliation(s)
- Nadine Ott
- Department of Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Kerpener Street 62, 50937, Cologne, Germany.
| | - Michael Hackl
- Department of Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Kerpener Street 62, 50937, Cologne, Germany
| | - Andreas Prescher
- Institute of Molecular and Cellular Anatomy -Prosektur, RWTH Aachen, Aachen, Germany
| | - Martin Scaal
- Department of Anatomy, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Fabian Lanzerath
- Department of Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Kerpener Street 62, 50937, Cologne, Germany
| | - Lars Peter Müller
- Department of Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Kerpener Street 62, 50937, Cologne, Germany
| | - Kilian Wegmann
- Department of Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Kerpener Street 62, 50937, Cologne, Germany.,Orthopädische Chirurgie München, OCM Clinic, Steinerstrasse 6, 81369, Munich, Germany
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Xu J, Zhan S, Ling M, Jiang D, Hu H, Sheng J, Ding J. How can medial support for proximal humeral fractures be achieved when positioning of regular calcar screws is challenging? Slotting and off-axis fixation strategies. J Shoulder Elbow Surg 2022; 31:782-791. [PMID: 34619347 DOI: 10.1016/j.jse.2021.08.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/21/2021] [Accepted: 08/29/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND Achieving medial support for proximal humeral fractures (PHFs) by regular calcar screw positioning is challenging when the humeral head is small or locking plates are placed distally, as there are unable inserted calcar screws into the humeral head. We aimed to investigate the suitability of the 2 strategies, slotting calcar screw (SCS) and off-axis calcar screw (OCS), to achieve medial support for PHFs. METHODS Regular calcar screw (RCS), SCS, OCS, and noncalcar screw (NCS) were tested via mechanical experiments and finite element analysis (FEA), using synthetic bones for biomechanical comparisons. All PHFs treated in our hospital from March 2017 to March 2019 were reviewed. The patients were divided into 3 groups based on the calcar screw fixation: RCS, SCS, and OCS. The postoperative varus collapse (neck-shaft angle changed to less than 120°) and Disabilities of the Arm, Shoulder and Hand (DASH) scores were recorded. RESULTS The properties of RCS, SCS, and OCS against the torsion and varus force were superior to those of NCS, whereas the stiffness of SCS, OCS, and RCS were similar. FEA predicted lower peri-screw strains in the OCS and SCS than in the RCS, indicating a lower risk of cut-out. Patients (n = 125; 75 female, 50 male) aged 55.9 ± 13.0 years were evaluated. Compared with the RCS (5/55), varus collapse incidences were not significantly higher following SCS (0/29, P = .094) or OCS (3/41, P = .756), and neither were DASH scores (P = .867 and .736, respectively). CONCLUSIONS This study is a preliminary study demonstrating that the SCS and OCS fixation strategies could be useful alternatives when regular calcar fixation is not possible using the plate at hand.
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Affiliation(s)
- Jian Xu
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Shi Zhan
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Ming Ling
- Department of Orthopedics, Fudan University Affiliated Huadong Hospital, Shanghai, China
| | - Dajun Jiang
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Hai Hu
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China; Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Jiagen Sheng
- Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Jian Ding
- Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China.
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Schöbel T, Schleifenbaum S, Nitsch V, Hepp P, Theopold J. Primary stability of cement augmentation in locking plate fixation for proximal humeral fractures: A comparison of absorbable versus non-absorbable cement. Clin Biomech (Bristol, Avon) 2022; 91:105516. [PMID: 34814041 DOI: 10.1016/j.clinbiomech.2021.105516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/25/2021] [Accepted: 11/01/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Cement augmentation has been suggested to increase the stability of screw anchoring in osteoporotic humeral fractures. Initial results are promising but may be jeopardized by cement leakage into the joint and difficult implant removal. Absorbable cement might have advantages in this regard, but it is unclear if the primary stability of both techniques is equivalent to each other. Therefore, this study aimed to compare its primary stability with that of non-absorbable cement augmentation. METHODS Nineteen cadaveric humeri with two-part fracture models were treated with locking plate osteosynthesis and cement augmentation using either absorbable calcium phosphate cement (group 1) or polymethylmethacrylate (group 2). Fracture movement, stiffness, failure mode, and ultimate load under cyclic compressive loading were examined and compared between the groups. FINDINGS The absolute and relative stiffness values in group 1 were significantly smaller than those in group 2 after 50 cycles (group 1: 114 ± 38 N/mm and 94 ± 8% vs. group 2: 188 ± 71 N/mm and 106 ± 9%; p50 = 0.022), 2000 cycles (group 1: 97 ± 34 N/mm and 81 ± 15% vs. group 2: 153 ± 47 N/mm and 88 ± 15%; p2000 = 0.028), and 5000 cycles (group 1: 98 ± 40 N/mm and 81 ± 22% vs. group 2: 158 ± 40 N/mm and 92 ± 16%; p5000 = 0.028). The failure load was not statistically significantly different between the groups. INTERPRETATION Although the PMAA group showed higher values for absolute and relative stiffness, no statistically significant difference was found in the primary stability between absorbable and non-absorbable cement augmentation supporting plate osteosynthesis in proximal humeral fractures. In view of the potential advantages of bio-absorbable cement during the healing process, its use should be considered for the augmentation and stabilization of osteoporotic fractures.
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Affiliation(s)
- Tobias Schöbel
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
| | - Stefan Schleifenbaum
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany; ZESBO - Center for Research on Musculoskeletal Systems, Semmelweisstrasse 14, 04103 Leipzig, Germany; Fraunhofer Institute for Machine Tools and Forming Technology, Nöthnitzer Straße 44, 01187 Dresden, Germany.
| | - Viktoria Nitsch
- ZESBO - Center for Research on Musculoskeletal Systems, Semmelweisstrasse 14, 04103 Leipzig, Germany.
| | - Pierre Hepp
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
| | - Jan Theopold
- Department of Orthopedic, Trauma, and Plastic Surgery, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
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The forgotten fragment: additional lesser tuberosity fixation of 4-part proximal humeral fractures-a biomechanical investigation. J Shoulder Elbow Surg 2021; 30:2852-2861. [PMID: 34022364 DOI: 10.1016/j.jse.2021.04.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/12/2021] [Accepted: 04/28/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND Fractures of the proximal humerus are common. The most frequent surgical treatment option is open reduction and locking plate fixation. Multifragmentary fractures, including 3- and 4-part fractures, are especially challenging to treat because they correlate with an increased risk of fixation failure. In the past, several mechanisms of additional fixation were investigated, but none directly addressed the lesser tuberosity (LT). The goal of this study was to investigate the biomechanical impact of additional anterior fracture fixation in lateral locked plating (LLP) of 4-part proximal humeral fractures (PHFs). METHODS Twenty-seven fresh frozen human shoulder specimens (mean age, 80 years) with intact rotator cuffs (RCs) were randomized into 4 groups: 3-part PHF with LLP and RC cerclage (n = 6); 4-part PHF with LLP and RC cerclage as standard of care (n = 7); 4-part PHF with LLP, RC cerclage, and 2 anterior 3.5-mm cortical screws (n = 7); and 4-part PHF with LLP, RC cerclage, and additional anterior one-third tubular plate (additional anterior plating [AAP], n = 7). Static load of the RC was simulated with weights. A force-controlled cyclic loading test was performed with a servo-hydraulic testing machine, followed by load-to-failure testing. An optical motion capture system recorded humeral head range of motion. RESULTS LLP of a 4-part PHF showed more humeral head motion than LLP of a 3-part PHF without fracture of the LT (P < .001). Fixing the LT to the humeral head with two 3.5-mm screws significantly reduced humeral head motion compared with LLP with RC cerclage alone (P < .006). Using AAP significantly increased the construct stiffness compared with the standard of care (P = .03). CONCLUSION LLP of a 4-part PHF is biomechanically less stable than LLP of a 3-part PHF without fracture of the LT. Additional screw fixation of the LT in 4-part PHFs improves stability compared with LLP alone. In case of metaphyseal comminution, AAP is favorable from a biomechanical perspective.
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Biomechanical study of Proximal humeral fracture fixation: Locking plate with medial support screw vs. locking plate with intramedullary fibular graft. Clin Biomech (Bristol, Avon) 2021; 90:105510. [PMID: 34673363 DOI: 10.1016/j.clinbiomech.2021.105510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND The purpose of this study was to evaluate the biomechanical properties of two different fixation constructs in varus collapse proximal humerus fracture, locking plate with medial support screw and locking plate with intramedullary fibular graft. METHODS We used 8 pairs of undamaged fresh-frozen humen cadaveric humeri and fibula from patients ranging in age from 62 to 81 years. We simulated a proximal humerus fracture with medial comminution using wedge shaped osteotomy. One group was fixed with locking plate with medial support screws, the other group with locking plate with intramedullary fibular graft. Biomechanical test was carried out using servohydraulic material testing system. We measured displacement of specimens under cyclic load test, maximum failure load, initial stiffness, and mode of failure under increasing load test. FINDINGS Under cyclic loading, the displacement of the specimen was significantly less in the locking plate with fibular strut graft group than in the locking plate with medial support screws group. (p = 0.012) Under increasing load test, the Locking plate with fibular strut graft group showed higher values in both maximum failure load and initial stiffness than the Locking plate with medial support screws group, and this was statistically significant. (p = 0.012, p = 0.001). INTERPRETATION In biomechanical study, the locking plate with fibular strut graft showed significantly better results in all of the maximum failure load, initial stiffness, and gap depletion compared to the locking plate with medial support screws. LEVEL OF EVIDENCE Level IV.
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Shin MJ, Kim H, Kim DM, Park D, Jeon IH, Koh KH. Role of inferomedial supporting screws for secondary varus deformity in non-osteoporotic proximal humerus fracture: A biomechanical study. Arch Orthop Trauma Surg 2021; 141:1517-1523. [PMID: 33051712 DOI: 10.1007/s00402-020-03627-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 09/30/2020] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The purpose of this study was to evaluate the effect of a medial support screw through a proximal humerus fracture. For this purpose, we verified whether the biomechanics are different according to the position of the screw while using the same number of screws. In addition, we tried to verify whether the insertion of additional inferomedial screws would make a difference in stability. MATERIALS AND METHODS Twenty-four proximal humerus bones were included in the study. A two-part fracture was created and fixed using a locking plate. Cyclic loading and load-to-failure test were applied to three groups: group A (proximal 6 screws + calcar screws), group B (proximal 6 screws), and group C (proximal 4 screws + calcar screws). Interfragmentary gaps were measured following cyclic loading and compared. The failure was defined when the bone breakage or medial gap closing was observed during ultimate failure load applied. The load-to-failure, maximum displacement, stiffness, and yield load were recorded and compared. RESULTS The interfragmentary gap was differently reduced by 0.29 ± 0.14 mm, 0.73 ± 0.25 mm, and 0.53 ± 0.09 mm following 1000 cyclic loading for groups A, B, and C, respectively. The load-to-failure was 945.22 ± 101.02 N, 941.40 ± 148.90 N, and 940.58 ± 91.78 N in groups A, B, and C, respectively. The stiffness of group A (214.76 ± 34.0 N/mm) was superior when compared to that of group C (171.12 ± 23.0 N/mm; p = 0.025). The maximum displacement prior to failure, yield load, showed no significant difference between comparative groups. CONCLUSION Our study did not show any additional biomechanical effects with the use of inferomedial supporting screws in non-osteoporotic proximal humerus fracture, besides making the fracture-plate construct stiff. The role of the inferomedial supporting screw was also unclear. However, the groups that used increased screw fixation and inferomedial screw insertion seemed to be more resistant to cyclic loading.
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Affiliation(s)
- Myung Jin Shin
- Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
| | - Hyojune Kim
- Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
| | - Dong Min Kim
- Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
| | - Dongjun Park
- Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
| | - In-Ho Jeon
- Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
| | - Kyoung Hwan Koh
- Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea.
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Double plating - surgical technique and good clinical results in complex and highly unstable proximal humeral fractures. Injury 2021; 52:2285-2291. [PMID: 34148652 DOI: 10.1016/j.injury.2021.05.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 02/02/2023]
Abstract
INTRODUCTION A stable fixation of highly unstable proximal humerus fractures remains challenging and complication rates, especially secondary varus dislocation, remains high. Different techniques of double plate osteosynthesis have been suggested for the treatment of complex proximal humeral fractures as they are well established for other fractures. The aim of this study was to evaluate an operative technique using an angular stable lateral plate supported by a one-third tubular plate positioned anteriorly at the lesser tuberosity for unstable proximal humeral fractures. PATIENTS AND METHODS Retrospectively, patients treated with a double plate osteosynthesis were included between January 2014 and December 2017. Out of 31, 25 patients (80.6%) with an average age of 53.1 years ± 12.5 were available for follow-up. 60% of the patients were male. The clinical evaluation consisted of a physical examination and standardised questionnaire including subjective and objective shoulder scores like the Constant-Murley Shoulder Score, Simple Shoulder Score, and Subjective Shoulder Value. RESULTS After a mean follow-up of 30.9 months (range, 12-76 months) eighteen patients (72%) had either excellent or good results regarding the Constant-Murley Shoulder Score with a mean value of 77 points ± 17. Average Simple Shoulder Score was 76% ± 0.2 and Subjective Shoulder Value 72% ± 0.2%. Mean NSA at time of follow-up 135° ± 13°. Nine patients had an implant-removal, five in combination with arthrolysis after a mean of 7.2 months. Three patients underwent surgery for secondary arthroplasty. The study shows a complication rate of 16%. No revision-surgery because of secondary varus dislocation was reported. DISCUSSION Arthroplasty is the less favourable treatment for a younger, active cohort of patients with highly unstable proximal humeral fractures as results are not as good and options for revision are limited. Double plate osteosynthesis can be used in addition to calcar screws, bone graft augmentation, cement augmentation and additional free screws for more multidirectional stability and shows good clinical results despite a higher rate of avascular necrosis and high primary stability with comparable complication-rates to single plate osteosynthesis. It seems to be a valid alternative to primary fracture arthroplasty and can prevent secondary varus displacement.
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Tilton M, Lewis GS, Hast MW, Fox E, Manogharan G. Additively manufactured patient-specific prosthesis for tumor reconstruction: Design, process, and properties. PLoS One 2021; 16:e0253786. [PMID: 34260623 PMCID: PMC8279401 DOI: 10.1371/journal.pone.0253786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 06/12/2021] [Indexed: 01/20/2023] Open
Abstract
Design and processing capabilities of additive manufacturing (AM) to fabricate complex geometries continues to drive the adoption of AM for biomedical applications. In this study, a validated design methodology is presented to evaluate AM as an effective fabrication technique for reconstruction of large bone defects after tumor resection in pediatric oncology patients. Implanting off-the-shelf components in pediatric patients is especially challenging because most standard components are sized and shaped for more common adult cases. While currently reported efforts on AM implants are focused on maxillofacial, hip and knee reconstructions, there have been no reported studies on reconstruction of proximal humerus tumors. A case study of a 9-year-old diagnosed with proximal humerus osteosarcoma was used to develop a patient-specific AM prosthesis for the humerus following tumor resection. Commonly used body-centered cubic (BCC) structures were incorporated at the surgical neck and distal interface in order to increase the effective surface area, promote osseointegration, and reduce the implant weight. A patient-specific prosthesis was fabricated using electron beam melting method from biocompatible Ti-6Al-4V. Both computational and biomechanical tests were performed on the prosthesis to evaluate its biomechanical behavior under varying loading conditions. Morphological analysis of the construct using micro-computed tomography was used to compare the as-designed and as-built prosthesis. It was found that the patient-specific prosthesis could withstand physiologically-relevant loading conditions with minimal permanent deformation (82 μm after 105 cycles) at the medial aspect of the porous surgical neck. These outcomes support potential translation of the patient-specific AM prostheses to reconstruct large bone defects following tumor resection.
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Affiliation(s)
- Maryam Tilton
- Department of Mechanical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Gregory S. Lewis
- Department of Mechanical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Orthopaedics and Rehabilitation, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Michael W. Hast
- Biedermann Lab for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Edward Fox
- Department of Orthopaedics and Rehabilitation, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Guha Manogharan
- Department of Mechanical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States of America
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Kim H, Shin MJ, Kholinne E, Seo J, Ahn D, Kim JW, Koh KH. How Many Proximal Screws Are Needed for a Stable Proximal Humerus Fracture Fixation? Geriatr Orthop Surg Rehabil 2021; 12:2151459321992744. [PMID: 33623724 PMCID: PMC7876747 DOI: 10.1177/2151459321992744] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/11/2021] [Indexed: 11/16/2022] Open
Abstract
Purpose This biomechanical study investigates the optimal number of proximal screws for stable fixation of a 2-part proximal humerus fracture model with a locking plate. Methods Twenty-four proximal humerus fracture models were included in the study. An unstable 2-part fracture was created and fixed by a locking plate. Cyclic loading and load-to-failure tests were used for the following 4 groups based on the number of screws used: 4-screw, 6-screw, 7-screw, and 9-screw groups. Interfragmentary gaps were measured following cyclic loading and compared. Consequently, the load to failure, maximum displacement, stiffness, and mode of failure at failure point were compared. Results The interfragmentary gaps for the 4-screw, 6-screw, 7-screw, and 9-screw groups were significantly reduced by 0.24 ± 0.09 mm, 0.08 ± 0.06 mm, 0.05 ± 0.01 mm, and 0.03 ± 0.01 mm following 1000 cyclic loading, respectively. The loads to failure were significantly different between the groups with the 7-screw group showing the highest load to failure. The stiffness of the 7-screw group was superior compared with the 6-screw, 9-screw, and 4-screw groups. The maximum displacement before failure showed a significant difference between the comparative groups with the 4-screw group having the lowest value. The 7-screw group had the least structural failure rate (33.3%). Conclusion At least 7 screws would be optimal for proximal fragment fixation of proximal humerus fractures with medial comminution to minimize secondary varus collapse or fixation failure. Level of Evidence Basic science study.
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Affiliation(s)
- Hyojune Kim
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea.,Depart of Orthopedic Surgery, Eulji University Hospital, Daejeon, Korea
| | - Myung Jin Shin
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
| | - Erica Kholinne
- Department of Orthopedic Surgery, Faculty of Medicine, St. Carolus Hospital, Trisakti University, Jakarta, Indonesia
| | | | | | - Ji Wan Kim
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
| | - Kyoung Hwan Koh
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
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22
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YI JINWOONG, KIM JONGUN, CHA HYUNJAE, YI JINBOK, TAE KISIK. ESTIMATION OF THE OPTIMAL FIBULAR GRAFT ANGLE FOR PROXIMAL HUMERUS FRACTURES USING FINITE ELEMENT ANALYSIS. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420400291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Proximal humerus fracture is a common injury and is usually treated using an internal fixation. However, clinical studies have reported that such treatments are associated with problems such as varus deformity and screw penetration. Therefore, to solve these problems, a surgical method using fibular allografts (FAs) is recently reported. Thus, this study is aimed to confirm the effective insertion angle ([Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]) of the FA. We applied axial and shear loads to finite element models used in our study. Finite element simulations using these models were repeated five times for each fibular insertion angle. We evaluated the construct stiffness, stress distribution on the plate and fibula, and fracture micromotion. Results showed that the method using the FA caused less stress on the plate and provided higher structural stability than the method without using the FA. In particular, the axis perpendicular condition yielded significantly greater construct stiffness and caused less von Mises stresses than the other conditions. In conclusion, the finite element analysis results showed that the FA inserted horizontally was effective in the treatment of proximal humerus fracture with an unstable medial support.
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Affiliation(s)
- JIN WOONG YI
- Department of Orthopedic Surgery, Konyang University Hospital, 158 Gwanjeodong-ro, Seo-gu Daejeon, Republic of Korea
| | - JONG UN KIM
- Department of Biomedical Engineering, Konyang University, 158 Gwanjeodong-ro, Seo-gu Daejeon, Republic of Korea
| | - HYUN JAE CHA
- Department of Orthopedic Surgery, Konyang University Hospital, 158 Gwanjeodong-ro, Seo-gu Daejeon, Republic of Korea
| | - JINBOK YI
- Department of Biomedical Engineering & Welfare Technology, Hanseo University, 46 Hanseo 1 Road, Chungcheongnam-do, Republic of Korea
| | - KI SIK TAE
- Department of Biomedical Engineering, Konyang University, 158 Gwanjeodong-ro, Seo-gu, Daejeon, Republic of Korea
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23
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Deng XY, Fan ZY, Yu BF, Ni BB, Wang W, Lu H, Shen H. Use of a locking intramedullary nail for the treatment of initial varus proximal humeral fracture: a prospective pilot study. J Int Med Res 2020; 48:300060520935286. [PMID: 32588694 PMCID: PMC7323304 DOI: 10.1177/0300060520935286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective To evaluate the feasibility of locked intramedullary nailing, rather than locking plate fixation combined with fibular allograft augmentation, for initial varus proximal humeral fractures. Methods This prospective pilot study enrolled patients with initial varus proximal humeral fractures that were treated with a locking intramedullary nail. Radiography was performed to evaluate fracture healing. Data about the visual analogue scale (VAS) pain score, Constant Shoulder Score (CSS), Disabilities of the Arm, Shoulder and Hand (DASH) score, American Shoulder and Elbow Surgeons (ASES) score and shoulder range of motion (ROM) were recorded. Results Twenty patients, including eight with Neer two-part and 12 with three-part fractures, were followed-up, with a mean time of 12.3 months. All patients sustained fractures that healed without re-varus. During the last follow-up, the shoulder function of the patients had recovered well, with a mean VAS pain score of 1.4, a mean CSS of 83.1, a mean DASH score of 80.8, a mean ASES score of 84.0 and a satisfactory ROM. In one patient, the proximal locking screw came out and was removed via a second surgery. Conclusions The use of a locking intramedullary nail alone for initial varus proximal humeral two-/three-part fractures was feasible. This treatment has advantages, such as preventing re-varus and causing milder surgical trauma, than that seen with a locking plate.
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Affiliation(s)
- Xiang-Yi Deng
- Department of Orthopaedic Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhi-Yuan Fan
- Department of Orthopaedic Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Bao-Fu Yu
- Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Bin-Bin Ni
- Department of Orthopaedic Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wei Wang
- Department of Orthopaedic Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hua Lu
- Department of Orthopaedic Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hao Shen
- Department of Orthopaedic Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
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24
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Mechanical Effects of Bone Substitute and Far-Cortical Locking Techniques in 2-Part Proximal Humerus Fracture Reconstruction: A Cadaveric Study. J Orthop Trauma 2020; 34:199-205. [PMID: 32197036 DOI: 10.1097/bot.0000000000001668] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To make direct comparisons of the biomechanical properties of a control (CTL) group and implants that were augmented with far cortical locking (FCL), bone substitute material (BSM), and a combination of both (ALL) to determine which fixation is most effective in reducing implant failure. METHODS The constructs were tested with osteopenic cadaveric specimens in a two-part fracture model. Specimens were subjected to a battery of nondestructive torsion and axial compression tests, followed by a cyclic test. Construct stiffness and cycles to failure were documented, pre- and post-test fluoroscopy was performed, and implant and bone kinematics were quantified. RESULTS During nondestructive testing, the BSM group exhibited significantly increased torsional and axial stiffness compared with the FCL (P = 0.006, P < 0.001) group and ALL group (P < 0.001, P = 0.006). There were no significant differences in resistance to cyclic loading between groups. Fluoroscopic analysis indicated significant differences in the motions of nonlocked cannulated screws (used in BSM and ALL) versus locked screws (used in CTL and FCL). CONCLUSIONS Patients with poor bone quality and proximal humerus fracture may necessitate added compliance or rigidity to achieve fixation. Both have exhibited favorable biomechanical characteristics in this cadaveric 2-part proximal humerus fracture model.
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25
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Tilton M, Armstrong A, Sanville J, Chin M, Hast MW, Lewis GS, Manogharan GP. Biomechanical Testing of Additive Manufactured Proximal Humerus Fracture Fixation Plates. Ann Biomed Eng 2019; 48:463-476. [PMID: 31555983 DOI: 10.1007/s10439-019-02365-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/12/2019] [Indexed: 01/24/2023]
Abstract
Achieving satisfactory fracture fixation in osteoporotic patients with unstable proximal humerus fractures remains a major clinical challenge. Varus collapse is one of the more prominent complications that may lead to screw cutout. This aim of this study was to compare the fixation provided by conventional locking plates with novel design concepts that are only feasible through additive manufacturing (AM) techniques. In addition to reversed engineered implants, two novel implant designs with integrated struts were included in the study to provide medial support to humeral head. The medial strut was either solid or included a porous lattice structure intended to promote bone ingrowth. Biomechanical tests were performed using low density synthetic bones with simulated 3-part comminuted fractures. Nondestructive torsion and compression were performed, followed by increasing cyclic loading. The relative displacements between the bone fragments were determined using a 3D motion capture system. The AM manufactured implants with medial strut showed significant reduction of varus displacement during the increasing cyclic loading when compared to conventional designs. AM reversed-engineered locking plates showed similar mechanical behavior to conventional plates with identical geometry. This study demonstrates the feasibility and potential of employing alternative design via AM for fixation of unstable comminuted proximal humerus fractures to reduce fragment displacement.
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Affiliation(s)
- Maryam Tilton
- Department of Mechanical Engineering, Pennsylvania State University, 232 Reber Bldg, University Park, PA, 16802, USA
| | - April Armstrong
- Department of Orthopaedics and Rehabilitation, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Jennifer Sanville
- Biedermann Lab for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew Chin
- Biedermann Lab for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael W Hast
- Biedermann Lab for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Gregory S Lewis
- Department of Orthopaedics and Rehabilitation, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Guha P Manogharan
- Department of Mechanical Engineering, Pennsylvania State University, 232 Reber Bldg, University Park, PA, 16802, USA.
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26
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Augmentation of plate osteosynthesis for proximal humeral fractures: a systematic review of current biomechanical and clinical studies. Arch Orthop Trauma Surg 2019; 139:1075-1099. [PMID: 30903343 DOI: 10.1007/s00402-019-03162-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Secondary dislocation due to loss of fixation is the most common complication after plate fixation of proximal humeral fractures. A wide range of different techniques for augmentation has been described to improve the primary and secondary stability. Nevertheless, comparative analyses on the specific advantages and limitations are missing. Therefore, the aim of the present article was to systematically review and evaluate the current biomechanical and clinical studies. MATERIALS AND METHODS The databases of PubMed and EMBASE were comprehensively searched for studies on augmentation techniques for proximal humeral fractures using defined search terms. Subsequently, all articles identified were screened for eligibility and subdivided in either clinical or biomechanical studies. Furthermore, the level of evidence and study quality were assessed according the Oxford Centre for Evidence-Based Medicine and the Coleman Methodology Score, respectively. RESULTS Out of 2788, 15 biomechanical and 30 clinical studies were included. The most common techniques were structural allogenic or autologous bone grafting to enhance the medial support, metaphyseal void filling utilizing synthetic bone substitutes or bone grafts, and screw-tip augmentation with bone cement. Biomechanical data were available for structural bone grafting to enhance the medial support, void filling with synthetic bone substitutes, as well as for screw-tip augmentation. Clinical evidence ranged from level II-IV and study quality was 26-70/100 points. Only one clinical study was found investigating screw-tip augmentation. All studies included revealed that any kind of augmentation positively enhances mechanical stability, reduces the rate of secondary dislocation, and improves patients' clinical outcome. None of the studies showed relevant augmentation-associated complication rates. CONCLUSIONS Augmentation of plate fixation for proximal humeral fractures seems to be a reliable and safe procedure. All common techniques mechanically increase the constructs' stability. Clinically evaluated procedures show reduced complication rates and improved patient outcomes. Augmentation techniques seem to have the highest significance in situations of reduced bone mineral density and in high-risk fractures, such as 4-part fractures. However, more high-quality and comparative clinical trials are needed to give evidence-based treatment recommendations.
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27
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Fletcher JWA, Windolf M, Richards RG, Gueorguiev B, Buschbaum J, Varga P. Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations. J Orthop Res 2019; 37:957-964. [PMID: 30690786 DOI: 10.1002/jor.24235] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/21/2019] [Indexed: 02/04/2023]
Abstract
Multifragmented proximal humeral fractures frequently require operative fixation. The locking plates commonly used are often placed relative to the greater tuberosity, however no quantitative data exists regarding the effect of positional changes. The aim of the study was to establish the effects from variations in proximal-distal PHILOS humeral plate positioning on predicted fixation failure risk. Twenty-one left-sided low-density virtual humeri models were created with a simulation framework from CT data of elderly donors and osteotomized to mimic an unstable three-part malreduced AO/OTA 11-B3.2 fracture with medial comminution. A PHILOS plate with either four or six proximal screws was used for fixation. Both configurations were modelled with plate repositioning 2 and 4 mm distally and proximally to its baseline position. Applying a validated computational model, three physiological loading situations were simulated and fixation failure predicted using average strain around the proximal screws-an outcome established as a surrogate for cycles to failure. Varying the craniocaudal plate position affected the peri-implant strain for both four and six-screw configurations. Even though significant changes were seen only in the latter, all tests suggested that more proximal plate positioning results in decreased peri-screw strains whereas distalizing creates increases in strain. These results suggest that even a small distal PHILOS plate malpositioning may reduce fixation stability. Plate distalization increases the probability of being unable to insert all screws within the humeral head, which dramatically increases the forces acting on the remaining screws. Proximal plate shifting may be beneficial, especially for constructs employing calcar screws. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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Affiliation(s)
- James W A Fletcher
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland.,Department for Health, University of Bath, Bath, UK
| | - Markus Windolf
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland
| | - R Geoff Richards
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland
| | - Boyko Gueorguiev
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland
| | - Jan Buschbaum
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland
| | - Peter Varga
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland
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Abstract
Proximal humerus fractures in the setting of osteoporosis can be technically challenging. Intraoperative challenges include comminution, thin cortical bone, and crushed cancellous bone that lead to difficulties in obtaining and maintaining a reduction and hardware fixation. Loss of fixation and varus collapse continue to be problems despite the utilization of modern locking plate fixation. A clearer understanding of predictors of fixation failure and the encouraging early results of reverse total shoulder arthroplasty (RTSA) have resulted in increased utilization of RTSA for the primary treatment of proximal humerus fractures.
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29
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Rusimov L, Zderic I, Ciric D, Barcik JP, Enchev D, Rashkov M, Hadzhinikolova M, Richards G, Gueorguiev B, Baltov A. Does Supplemental Intramedullary Grafting Increase Stability of Plated Proximal Humerus Fractures? J Orthop Trauma 2019; 33:196-202. [PMID: 30570617 DOI: 10.1097/bot.0000000000001376] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To investigate the biomechanical competence of locked plating augmented with supplemental intramedullary graft in comparison to conventional locked plate fixation in proximal humerus fractures (PHF). METHODS Complex four-part PHFs were set in 30 artificial humeri assigned to 3 study groups (n = 10 in each group). Group 1 was characterized by loss of medial support, group 2 by simulated severe cancellous bone damage due to osteoporosis, and group 3 by combination of the 2 features. After locked plating, each specimen underwent nondestructive quasi-static mechanical testing in 25 degrees lateral angulation under axial loading between 150 and 400 N in 50-N increments, accompanied by consecutive anteroposterior x-ray imaging. Subsequently, an additional 3D-printed intramedullary graft was inserted into each specimen and all tests were repeated. RESULTS Grafting resulted in significantly higher axial stiffness compared with no graft in groups 1 and 3 (P < 0.01) but not in group 2 (P = 0.12). Nongrafted specimens represented significantly higher stiffness in group 2 compared with groups 1 and 3 (P < 0.01), whereas no significant differences were detected among the 3 groups in the grafted state (P > 0.99). Varus deformation decreased significantly in each group after graft insertion (P ≤ 0.04). Nongrafted specimens in group 2 showed significantly lower varus deformation compared with groups 1 and 3 (P ≤ 0.04). No significant differences were registered among the 3 groups after grafting (P ≥ 0.65). CONCLUSIONS From a biomechanical perspective, locked plating augmented with intramedullary graft has the potential to increase significantly the stability against varus collapse in unstable PHFs when compared with conventional locked plate fixation.
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Affiliation(s)
- Lyubomir Rusimov
- AO Research Institute Davos, Davos, Switzerland.,Department of Trauma Surgery, University Multiprofile Hospital for Active Treatment and Emergency Medicine "N. I. Pirogov," Sofia, Bulgaria
| | - Ivan Zderic
- AO Research Institute Davos, Davos, Switzerland
| | - Daniel Ciric
- AO Research Institute Davos, Davos, Switzerland.,Flinders University, Tonesly, South Australia
| | | | - Dian Enchev
- Department of Trauma Surgery, University Multiprofile Hospital for Active Treatment and Emergency Medicine "N. I. Pirogov," Sofia, Bulgaria
| | - Mihail Rashkov
- Department of Trauma Surgery, University Multiprofile Hospital for Active Treatment and Emergency Medicine "N. I. Pirogov," Sofia, Bulgaria
| | - Mariya Hadzhinikolova
- AO Research Institute Davos, Davos, Switzerland.,Department of Trauma Surgery, University Multiprofile Hospital for Active Treatment and Emergency Medicine "N. I. Pirogov," Sofia, Bulgaria
| | | | | | - Asen Baltov
- Department of Trauma Surgery, University Multiprofile Hospital for Active Treatment and Emergency Medicine "N. I. Pirogov," Sofia, Bulgaria
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30
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Schliemann B, Risse N, Frank A, Müller M, Michel P, Raschke MJ, Katthagen JC. Screws with larger core diameter and lower thread pitch increase the stability of locked plating in osteoporotic proximal humeral fractures. Clin Biomech (Bristol, Avon) 2019; 63:21-26. [PMID: 30784787 DOI: 10.1016/j.clinbiomech.2019.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/04/2019] [Accepted: 02/12/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Little is known about the screw design as a factor for stability of the bone-implant interface in locking plate fixation of proximal humeral fractures. Aim of the present study was to analyze if locking screws with a large core diameter and a low thread pitch provide increased stability when compared to conventional locking screws. METHODS 3-Part proximal humeral fractures were created in ten pairs of osteoporotic human cadaveric humeri and fixed with a locking plate. Head fixation was performed with screws with a large core diameter (soft bone screws) in one humerus and with conventional cancellous locking screws in the other humerus of each donor. Specimens were loaded in the varus bending position. Stiffness, failure loads, plate bending and motion at the bone-implant interface were evaluated using mechanical sensors and an optical motion capture system. FINDINGS The stiffness of the construct for the soft bone screws was 299.8 N/mm (IR, 72.1 N/mm) and 203.9 N/mm (IR, 37.3 N/mm) for the conventional locking screws (p = 0.005). Plate bending did not differ between the two groups. Motion at the bone-implant interface was significantly reduced in the soft bone screw group (p < 0.05). The median load-to-failure was significantly higher in the soft bone screw group (358 N vs. 313 N; p = 0.012). INTERPRETATION The use of soft bone screws is associated with less motion at the bone-implant interface and therefore greater fixation strength when compared to fixation with conventional locking screws. Clinical studies are needed to prove these biomechanical findings in the in vivo situation. LEVEL OF EVIDENCE Controlled laboratory study.
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Affiliation(s)
- Benedikt Schliemann
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany.
| | - Nadine Risse
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany
| | - Andre Frank
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany
| | - Marcus Müller
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany
| | - Philipp Michel
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany
| | - Michael J Raschke
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany
| | - J Christoph Katthagen
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, building W1, 48149 Münster, Germany
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Theopold J, Schleifenbaum S, Müller M, Werner M, Hammer N, Josten C, Hepp P. Biomechanical evaluation of hybrid double plate osteosynthesis using a locking plate and an inverted third tubular plate for the treatment of proximal humeral fractures. PLoS One 2018; 13:e0206349. [PMID: 30372476 PMCID: PMC6205804 DOI: 10.1371/journal.pone.0206349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 10/11/2018] [Indexed: 01/31/2023] Open
Abstract
Background Treating proximal humerus fractures can be challenging because of large metaphyseal defects that conceal anatomical landmarks. In such cases, medial cortical support with, for example, calcar screws, is mandatory. Nevertheless, varus dislocations and implant failures in patients with impaired bone quality persist. Thus, the need for effective treatment of these patients exists. Hybrid double plate osteosynthesis was introduced as an alternative, yielding similar results as calcar screws. However, a biomechanical comparison of the stability of these two techniques is pending. Methods Cadaveric humeral specimens were treated with plate osteosynthesis and calcar screws (group 1, n = 9) or hybrid double plate osteosynthesis (group 2, n = 9) using a proximal humerus fracture model with a two-part fracture. Displacement, stiffness, failure mode, and ultimate load were examined biomechanically in a cyclic compressive-loading scenario. Results Although the hybrid double plate osteosynthesis (group 2) tended to confer higher stiffnesses than the medial support screws at higher cycles (group 1), this trend was below the level of significance. The displacement revealed non-significantly lower values for group 1 as compared with group 2 for cycles 50 and 2000, but at 5000 cycles, group 2 offered non-significantly lower displacement values than group 1. The ultimate load tended to be non-significantly higher in the hybrid double plate osteosynthesis group (group 2: 1342±369 N, group 1: 855±408 N). Both groups yielded similar failure rates, with the majority of failures in group 2 being gap closures (n = 8), whereas those in group 1 being plate dislocations (n = 4). Conclusions The use of an additive plate osteosynthesis in the region of the bicipital groove may be a potential alternative to the previously-established method of using calcar screws. The biomechanical data obtained in this study suggests that hybrid double plate osteosynthesis is as rigid and robust as calcar screws.
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Affiliation(s)
- Jan Theopold
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany
- * E-mail:
| | - Stefan Schleifenbaum
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany
- ZESBO–Zentrum zur Erforschung der Stuetz- und Bewegungsorgane, Leipzig, Germany
| | - Mirijam Müller
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany
| | - Michael Werner
- Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany
| | - Niels Hammer
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Christoph Josten
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany
| | - Pierre Hepp
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany
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32
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Katthagen JC, Dey Hazra RO, Raschke MJ, Heilmann L, Michel P, Lill H, Schliemann B. Innovationen bei der Behandlung der proximalen Humerusfraktur. ARTHROSKOPIE 2018. [DOI: 10.1007/s00142-018-0243-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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33
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Kuang GM, Wong TM, Wu J, Ouyang J, Guo H, Zhou Y, Fang C, Leung FKL, Lu W. Augmentation of a Locking Plate System Using Bioactive Bone Cement-Experiment in a Proximal Humeral Fracture Model. Geriatr Orthop Surg Rehabil 2018; 9:2151459318795312. [PMID: 30305979 PMCID: PMC6176529 DOI: 10.1177/2151459318795312] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/10/2018] [Accepted: 07/21/2018] [Indexed: 12/17/2022] Open
Abstract
Introduction: The purpose of this study was to test whether local filling of a novel
strontium-containing hydroxyapatite (Sr-HA) bone cement can augment the fixation of a
locking plate system in a cadaveric proximal humeral facture model. Materials and Methods: Twelve pairs of formalin-treated cadaveric humeri were used. One side in each pair was
for cemented group, while the other side was for the control group. The bone mineral
density (BMD) of the samples was tested. A 3-part facture model was created and then
reduced and fixed by a locking plate system. In the cemented group, the most proximal 4
screw holes were filled with 0.5 mL bone cement. In the control group, the screw holes
were not filled by cement. Locking screws were inserted in a standard manner before the
cement hardened. X-ray was taken before all the specimens being subjected to mechanical
study, in which 6 pairs were used for axial loading (varus bending) test, while other 6
pairs were used for axial rotational test. Results: There is no difference in BMD between the cemented side and the control side. The X-ray
shows that the implant is in position. Cement filling was noted in the most proximal 4
screws in the cemented group. Better mechanical outcome was seen in the cemented groups,
in terms of less maximal displacement per cycle and higher failure point and stiffness
in varus bending test. However, no difference was found between the
cemented group and the control group in the axial rotation test. Discussion: In similarity with the previous studies, our results showed better mechanical results
in the cemented group. However, due to the limitations (e.g. sample size, fracture
model, testing protocol, etc), we still cannot directly extrapolate current mechanical
results to clinical practice at the present moment. Furthermore, it is still unknown
whether better primary outcome may lead to better long-term results, even though the
local release of strontium may enhance the local bone formation. Conclusion: The local filling of Sr-HA bone cement augments the fixation of the locking plate
system in current proximal humeral fracture model.
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Affiliation(s)
- Guan-Ming Kuang
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Shenzhen Hospital, Shenzhen, China.,Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Tak Man Wong
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - Jun Wu
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Shenzhen Hospital, Shenzhen, China.,Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Jun Ouyang
- Department of Anatomy and Medical Biomechanical Key Laboratory of Guangdong Province, Southern Medical University, Guangzhou, China
| | - Haihua Guo
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Shenzhen Hospital, Shenzhen, China.,Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Yapeng Zhou
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Shenzhen Hospital, Shenzhen, China.,Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Christian Fang
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - Frankie K L Leung
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - William Lu
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Shenzhen Hospital, Shenzhen, China
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Which additional augmented fixation procedure decreases surgical failure after proximal humeral fracture with medial comminution: fibular allograft or inferomedial screws? J Shoulder Elbow Surg 2018; 27:1852-1858. [PMID: 29735375 DOI: 10.1016/j.jse.2018.03.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 03/14/2018] [Accepted: 03/18/2018] [Indexed: 02/01/2023]
Abstract
BACKGROUND The purpose of this study was to compare clinical and radiologic results between treatment with locking plate fixation and fibular allograft augmentation (FA) and treatment with locking plate fixation and additional inferomedial screws (IMSs) in 3- or 4-part proximal humeral fractures with medial comminution in geriatric patients. METHODS We enrolled 164 patients with 3- or 4-part proximal humeral fractures with medial comminution who were treated with locking plates. The patients were divided into 2 groups according to additional augmented fixation procedures. The IMS group was composed of patients treated with additional IMSs (80 patients), whereas the FA group was treated with an additional fibular allograft (84 patients). On the basis of fracture classification, the IMS group was subdivided into those with 3-part fractures (52 patients) and those with 4-part fractures (28 patients) and the FA group was subdivided into those with 3-part fractures (55 patients) and those with 4-part fractures (29 patients). Clinical and radiographic results were compared and analyzed. RESULTS In patients with 3-part fractures, no differences in clinical outcomes were found regardless of additional procedures. However, the FA group showed superior clinical outcomes in patients with 4-part fractures (P = .038 for Constant score and P = .045 for visual analog scale score). The postoperative neck-shaft angle was maintained in the FA group compared with the IMS group with both fracture types at the last follow-up (P = .048 for IMS vs FA with 3-part fractures and P = .023 for IMS vs FA with 4-part fractures). The number of complications was significantly higher in the IMS group (5.5%) than in the FA group (1.2%) (P = .001). CONCLUSION An FA technique is considered a primary additional procedure for medial support in patients with 4-part proximal humeral fractures involving medial metaphyseal comminution when treated with locking plate fixation.
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35
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Oppebøen S, Wikerøy AKB, Fuglesang HFS, Dolatowski FC, Randsborg PH. Calcar screws and adequate reduction reduced the risk of fixation failure in proximal humeral fractures treated with a locking plate: 190 patients followed for a mean of 3 years. J Orthop Surg Res 2018; 13:197. [PMID: 30092807 PMCID: PMC6085712 DOI: 10.1186/s13018-018-0906-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/02/2018] [Indexed: 12/14/2022] Open
Abstract
Background Fixation of proximal humeral fractures (PHF) with locking plates has gained popularity over conservative treatment, but surgery may be complicated with infection, non-union, avascular necrosis (AVN) of the humeral head and fixation failure. Failure to achieve structural support of the medial column has been suggested to be an important risk factor for fixation failure. The aims of this study were to examine the effect of calcar screws and fracture reduction on the risk of fixation failure and to assess long-term shoulder pain and function. Methods This was a single-centre retrospective study of 190 adult PHF patients treated with a locking plate between 2011 and 2014. Reoperations due to fixation failure were the primary outcome. Risk factors for fixation failure were assessed using the Cox regression analysis. Postoperative shoulder pain and function were assessed by the Oxford Shoulder Score (OSS). Results Thirty-one of 190 (16%) patients underwent a reoperation: 14 (7%) due to fixation failure, 10 (5%) due to deep infection and 2 (1%) due to AVN. The absence of calcar screws and fixation with residual varus malalignment (head-shaft angle < 120°) both increased the risk of fixation failure with an adjusted hazard ratio (95% CI) of 8.6 (1.9–39.3; p = 0.005) and 4.9 (1.3–17.9; p = 0.02), respectively. The median (interquartile range) OSS was 40 (27–46). Conclusion The use of calcar screws, as well as the absence of postoperative varus malalignment, significantly reduced the risk of fixation failure. We, therefore, recommend the use of calcar screws and to avoid residual varus malalignment to improve the medial support of proximal humeral fractures treated with a locking plate.
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Affiliation(s)
- Sjur Oppebøen
- Department of Orthopaedic Surgery, Akershus University Hospital, Lørenskog, Norway.
| | - Annette K B Wikerøy
- Department of Orthopaedic Surgery, Akershus University Hospital, Lørenskog, Norway
| | - Hendrik F S Fuglesang
- Department of Orthopaedic Surgery, Akershus University Hospital, Lørenskog, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Filip C Dolatowski
- Department of Orthopaedic Surgery, Akershus University Hospital, Lørenskog, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Per-Henrik Randsborg
- Department of Orthopaedic Surgery, Akershus University Hospital, Lørenskog, Norway
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Biomechanical analysis of plate systems for proximal humerus fractures: a systematic literature review. Biomed Eng Online 2018; 17:47. [PMID: 29703261 PMCID: PMC5923007 DOI: 10.1186/s12938-018-0479-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 04/18/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Proximal humerus fractures are the third most common in the human body but their management remains controversial. Open reduction and internal fixation with plates is one of the leading modes of operative treatment for these fractures. The development of technologies and techniques for these plates, during the recent decades, promise a bright future for their clinical use. A comprehensive review of in vitro biomechanical studies is needed for the comparison of plates' mechanical performance and the testing methodologies. This will not only guide clinicians with plate selection but also with the design of future in vitro biomechanical studies. This review was aimed to systematically categorise and review the in vitro biomechanical studies of these plates based on their protocols and discuss their results. The technologies and techniques investigated in these studies were categorised and compared to reach a census where possible. METHODS AND RESULTS Web of Science and Scopus database search yielded 62 studies. Out of these, 51 performed axial loading, torsion, bending and/or combined bending and axial loading while 11 simulated complex glenohumeral movements by using tendons. Loading conditions and set-up, failure criteria and performance parameters, as well as results for each study, were reviewed. Only two studies tested four-part fracture model while the rest investigated two- and three-part fractures. In ten studies, synthetic humeri were tested instead of cadaveric ones. In addition to load-displacement data, three-dimensional motion analysis systems, digital image correlation and acoustic emission testing have been used for measurement. CONCLUSIONS Overall, PHILOS was the most tested plate and locking plates demonstrated better mechanical performance than non-locking ones. Conflicting results have been published for their comparison with non-locking blade plates and polyaxial locking screws. Augmentation with cement [calcium phosphate or poly(methyl methacrylate)] or allografts (fibular and femoral head) was found to improve bone-plate constructs' mechanical performance. Controversy still lies over the use of rigid and semi-rigid implants and the insertion of inferomedial screws for calcar region support. This review will guide the design of in vitro and in silico biomechanical tests and also supplement the study of clinical literature.
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Mehta S, Chin M, Sanville J, Namdari S, Hast MW. Calcar screw position in proximal humerus fracture fixation: Don't miss high! Injury 2018; 49:624-629. [PMID: 29452734 PMCID: PMC7413303 DOI: 10.1016/j.injury.2018.02.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/06/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION In locked plate fixation of proximal humerus fractures, the calcar is an important anchor point for screws providing much-needed medial column support. Most locking plate implants utilize a fixed-trajectory locking screw to achieve this goal. Consequently, adjustments of plate location to account for patient-specific anatomy may result in a screw position outside of the calcar. To date, little is known about the consequences of "missing" the calcar during plate positioning. This study sought to characterize the biomechanics associated with proximal and distal placement of locking plates in a two-part fracture model. MATERIALS AND METHODS This experiment was performed twice, first with elderly cadaveric specimens and again with osteoporotic sawbones. Two-part fractures were simulated and specimens were divided to represent proximal, neutral, and distal plate placements. Non-destructive torsional and axial compression tests were performed prior to an axial fatigue test and a ramp to failure. Torsional stiffness, axial stiffness, humeral head displacement and stiffness during fatigue testing, and ultimate load were compared between groups. RESULTS Cadavers: Proximal implant placement led to trends of decreased mechanical properties, but there were no significant differences found between groups. Sawbones: Distal placement increased torsional stiffness in both directions (p = 0.003, p = 0.034) and axial stiffness (p = 0.018) when compared to proximal placement. Distal placement also increased torsional stiffness in external rotation (p = 0.020), increased axial stiffness (p = 0.024), decreased humeral head displacement during fatigue testing, and increased stiffness during fatigue testing when compared to neutral placement. DISCUSSION The distal and neutral groups had similar mechanical properties in many cadaveric comparisons while the proximal group trended towards decreased construct stiffness. RESULTS from the Sawbones model were more definitive and provided further evidence that proximal calcar screw placements are undesirable and distal implant placement may provide improved construct stability. CONCLUSION Successful proximal humerus fracture reconstruction is inherent upon anatomic fracture reduction coupled with medial column support. Results from this experiment suggest that missing the calcar proximally is deleterious to fixation strength, while it is safe, and perhaps even desirable, to aim slightly distal to the intended target.
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Affiliation(s)
- Samir Mehta
- Biedermann Lab for Orthopaedic Research, University of Pennsylvania, Department of Orthopaedic Surgery, Philadelphia, PA, United States
| | - Matthew Chin
- Biedermann Lab for Orthopaedic Research, University of Pennsylvania, Department of Orthopaedic Surgery, Philadelphia, PA, United States
| | - Jennifer Sanville
- Biedermann Lab for Orthopaedic Research, University of Pennsylvania, Department of Orthopaedic Surgery, Philadelphia, PA, United States
| | - Surena Namdari
- Rothman Institute, Thomas Jefferson University, Department of Orthopaedic Surgery, Philadelphia, PA, United States
| | - Michael W. Hast
- Biedermann Lab for Orthopaedic Research, University of Pennsylvania, Department of Orthopaedic Surgery, Philadelphia, PA, United States,Corresponding author at: Biedermann Laboratory for Orthopaedic Research, University of Pennsylvania, 3737 Market Street, Suite 1050,10th Floor, Philadelphia, PA 19104, United States. (M.W. Hast)
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38
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Qiang M, Jia X, Chen Y, Zhang K, Li H, Jiang Y, Zhang Y. Assessment of Screw Length of Proximal Humerus Internal Locking System (PHILOS) Plate for Proximal Humeral Fractures Using Three-Dimensional Computed Tomography Scan. Med Sci Monit 2018; 24:1158-1165. [PMID: 29478073 PMCID: PMC5836538 DOI: 10.12659/msm.906355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Screw perforation and varus collapse are common complications of treatment with a PHILOS (proximal humerus internal locking system) plate for proximal humerus fractures, which are associated with improper screw length selection and lack of medial column support. The purposes of this study were: (1) to measure the proper length of periarticular screws of the PHILOS plate in the humeral head, and (2) to determine what factors influence the screw length and implantation of the inferomedial support screw. Material/Methods Computed tomography (CT) images of the normal proximal humerus in 134 cases were retrospectively reviewed. The length of periarticular screws was measured using three-dimensional (3D) techniques. Intraobserver and interobserver reliability of measurement were evaluated using intraclass correlation coefficients (ICCs). Sex and body height influences on screw length and implantation of the inferomedial screw were analyzed. Results All measurements had excellent agreement (ICC>0.75). The screw length and implantation rate of the inferomedial screw were greater in males than in females. Positive correlations were observed between body height and screw length and implantation of the inferomedial screw (all P<0.001). Conclusions The screws were longer and the implantation rate was higher for inferomedial screws in males than in females, and were positively correlated with body height. Our data can be used as a reference for surgeons to reduce the number of times screws are changed intraoperatively and to reduce operation duration and minimize use of intraoperative fluoroscopy for proximal humerus fractures treated with the PHILOS plate.
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Affiliation(s)
- Minfei Qiang
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
| | - Xiaoyang Jia
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
| | - Yanxi Chen
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
| | - Kun Zhang
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
| | - Haobo Li
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
| | - Yuchen Jiang
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
| | - Yijie Zhang
- Department of Orthopedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China (mainland)
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Figaredo VM, Pons-Villanueva J. How many cephalic locked screws are needed in valgus proximal humeral fractures? Injury 2017; 48:2370-2372. [PMID: 28789777 DOI: 10.1016/j.injury.2017.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 07/30/2017] [Indexed: 02/02/2023]
Affiliation(s)
| | - Juan Pons-Villanueva
- Orthopedic Surgery and Traumatology Department, Clínica Universidad de Navarra, Spain.
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40
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Laux CJ, Grubhofer F, Werner CML, Simmen HP, Osterhoff G. Current concepts in locking plate fixation of proximal humerus fractures. J Orthop Surg Res 2017; 12:137. [PMID: 28946902 PMCID: PMC5613450 DOI: 10.1186/s13018-017-0639-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 09/17/2017] [Indexed: 12/27/2022] Open
Abstract
Despite numerous available treatment strategies, the management of complex proximal humeral fractures remains demanding. Impaired bone quality and considerable comorbidities pose special challenges in the growing aging population. Complications after operative treatment are frequent, in particular loss of reduction with varus malalignment and subsequent screw cutout. Locking plate fixation has become a standard in stabilizing these fractures, but surgical revision rates of up to 25% stagnate at high levels. Therefore, it seems of utmost importance to select the right treatment for the right patient. This article provides an overview of available classification systems, indications for operative treatment, important pathoanatomic principles, and latest surgical strategies in locking plate fixation. The importance of correct reduction of the medial cortices, the use of calcar screws, augmentation with bone cement, double-plate fixation, and auxiliary intramedullary bone graft stabilization are discussed in detail.
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Affiliation(s)
- Christoph J Laux
- Department of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland.
| | - Florian Grubhofer
- Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Clément M L Werner
- Department of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Hans-Peter Simmen
- Department of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Georg Osterhoff
- Department of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
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41
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Touloupakis G, Stuflesser W, Ferrara F, Maione A, Antonini G, Crippa C. Early-stage radiological critical analysis of unsuccessful cases following a four-part fracture osteosynthesis of the proximal humerus: focus on the "P" sign. ACTA BIO-MEDICA : ATENEI PARMENSIS 2017; 88:178-184. [PMID: 28845833 PMCID: PMC6166154 DOI: 10.23750/abm.v88i2.5295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 04/11/2016] [Indexed: 11/23/2022]
Abstract
Radiological evaluation of complex intra-articular fractures of the proximal humerus is still challenging. Here, we describe the post-operative "P" sign as a reproducible radiographical mark of a varus reduction, performed by assembling a head-shaft angulation of less than 130 degrees. Our retrospective study was conducted in a group of subjects who previously suffered from proximal humerus four-part fractures. We evaluated the post-operative evolution of specific radiographical parameters that are of crucial prognostic significance: Cervix-diaphysis angle (HHSA), quality level of the orthopaedic reduction (insufficient, sufficient and good) based on a radiological generalized subjective overview, presence of calcar screws through the Philos plate. The final cohort included a group of 39 patients of 70.76 ± 8.3 years of age and an average follow-up of 7.2 months. The post-operative mean HHSA was 131.5 ± 9.4. Interestingly, a positive correlation was detected between presence of the radiographical "P" sign in the post-operative period and the number of surgical complications coming up in the post-operative period (OR: 3.68 - I.C. 95%: 0.7984255-19.2532430), although not statistically significant. In our study, the high number of complications corresponds to literature database. Presence of the "P" sign could be a useful tool for assessing the quality of reduction during intra and post-operative radiological evaluation. We underline the importance of the "P" sign as a "quality of reduction" factor and strongly recommend its intra-operative monitoring as an additional tool together with a standard subjective evaluation of the reduction.
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Affiliation(s)
- Georgios Touloupakis
- Department of Orthopedics and Traumatology, San Carlo Borromeo Hospital, Milan, Italy.
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42
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PEEK versus titanium locking plates for proximal humerus fracture fixation: a comparative biomechanical study in two- and three-part fractures. Arch Orthop Trauma Surg 2017; 137:63-71. [PMID: 28005168 DOI: 10.1007/s00402-016-2620-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 02/09/2023]
Abstract
INTRODUCTION The high rigidity of metal implants may be a cause of failure after fixation of proximal humerus fractures. Carbon fiber-reinforced polyetheretherketone (PEEK) plates with a modulus similar to human cortical bone may help to overcome this problem. The present study assesses the biomechanical behavior of a PEEK plate compared with a titanium locking plate. MATERIALS AND METHODS Unstable two- and three-part fractures were simulated in 12 pairs of cadaveric humeri and were fixed with either a PEEK or a titanium locking plate using a pairwise comparison. With an optical motion capture system, the stiffness, failure load, plate bending, and the relative motion at the bone-implant interface and at the fracture site were evaluated. RESULTS The mean load to failure for two- and three-part fracture fixations was, respectively, 191 N (range 102-356 N) and 142 N (range 102-169 N) in the PEEK plate group compared with 286 N (range 191-395 N) and 258 N (range 155-366 N) in the titanium locking plate group. The PEEK plate showed significantly more bending in both the two- and three-part fractures (p < 0.05), an increased relative motion at the bone-implant interface and lower stiffness values (p < 0.05). CONCLUSION In this biomechanical study on unstable proximal humerus fractures, fixation with a PEEK plate showed lower fixation strength and increased motion at the bone-implant interface compared with a titanium locking plate.
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43
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Schnetzke M, Bockmeyer J, Porschke F, Studier-Fischer S, Grützner PA, Guehring T. Quality of Reduction Influences Outcome After Locked-Plate Fixation of Proximal Humeral Type-C Fractures. J Bone Joint Surg Am 2016; 98:1777-1785. [PMID: 27807109 DOI: 10.2106/jbjs.16.00112] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The aim of this study was to determine if fracture reduction, fracture pattern, and patient-related factors influence clinical outcome after locked-plate fixation of displaced proximal humeral fractures. METHODS Ninety-eight patients (mean age, 61.1 ± 11.2 years) with a proximal humeral fracture involving the anatomical neck (type C according to the OTA/AO classification system) were included. Clinical outcome was determined by age and sex-adjusted Constant score (CS%) and the Disabilities of the Arm, Shoulder and Hand (DASH) score. Fracture reduction was quantitatively determined by 3 parameters (head-shaft displacement, head-shaft alignment, and cranialization of the greater tuberosity), and patients were divided into groups according to anatomical reduction, acceptable reduction, or malreduction. Relative risk (RR) for complications, revision surgery, and inferior clinical outcome (CS of <50%) was determined according to the quality of fracture reduction and fracture pattern (disruption of the medial hinge; type-C3 fracture) and patient-related factors (age; comorbidities). RESULTS After a mean of 3.1 ± 1.5 years, the mean CS% and DASH score were 54.8% ± 28.0% and 31.9 ± 24.8, respectively. The complication rate was 32.7% (n = 32), and 27 patients (27.6%) required revision surgery. Anatomical or acceptable fracture reduction was achieved in 40 (40.8%) of the patients. This resulted in a significantly lower complication rate (20.0% compared with 41.4% among the patients with malreduction; p = 0.027), a trend of lower revision rate (20% compared with 32.8%; p = 0.165), and better clinical outcome (mean CS% of 65.4% ± 28.2% compared with 47.6% ± 25.7%; p = 0.002) without a higher risk for osteonecrosis of the humeral head (5% compared with 10.3%). Cranialization of the greater tuberosity of >5 mm (n = 25), head-shaft displacement of >5 mm (n = 50), and valgus head-shaft alignment (n = 12) all increased the RR for inferior clinical outcome by twofold to threefold. Conversely, a patient age of >65 years (n = 31) and an OTA/AO type-C3 fracture pattern (n = 38) were not significantly associated with complications and inferior clinical outcome (RR, 0.9 to 1.8). CONCLUSIONS Anatomical fracture reduction with a locked plate significantly improved the clinical outcome of unstable and displaced proximal humeral fractures involving the anatomical neck. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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Affiliation(s)
- Marc Schnetzke
- Department of Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen at the University of Heidelberg, Ludwigshafen on the Rhine, Germany
| | - Julia Bockmeyer
- Department of Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen at the University of Heidelberg, Ludwigshafen on the Rhine, Germany
| | - Felix Porschke
- Department of Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen at the University of Heidelberg, Ludwigshafen on the Rhine, Germany
| | - Stefan Studier-Fischer
- Department of Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen at the University of Heidelberg, Ludwigshafen on the Rhine, Germany
| | - Paul-Alfred Grützner
- Department of Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen at the University of Heidelberg, Ludwigshafen on the Rhine, Germany
| | - Thorsten Guehring
- Department of Trauma and Orthopaedic Surgery, BG Trauma Center Ludwigshafen at the University of Heidelberg, Ludwigshafen on the Rhine, Germany
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Katthagen JC, Schwarze M, Warnhoff M, Voigt C, Hurschler C, Lill H. Influence of plate material and screw design on stiffness and ultimate load of locked plating in osteoporotic proximal humeral fractures. Injury 2016; 47:617-24. [PMID: 26804939 DOI: 10.1016/j.injury.2016.01.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 12/18/2015] [Accepted: 01/09/2016] [Indexed: 02/02/2023]
Abstract
INTRODUCTION The main purpose was to compare the biomechanical properties of a carbon-fibre reinforced polyetheretherketone (CF-PEEK) composite locking plate with pre-existing data of a titanium-alloy plate when used for fixation of an unstable 2-part fracture of the surgical neck of the humerus. The secondary purpose was to compare the mechanical behaviour of locking bolts and conventional locking cancellous screws. METHODS 7 pairs of fresh frozen human humeri were allocated to two equal groups. All specimens were fixed with the CF-PEEK plate. Cancellous screws (PEEK/screw) were compared to locking bolts (PEEK/bolt) for humeral head fixation. Stiffness, fracture gap deflection and ultimate load as well as load before screw perforation of the articular surface were assessed. Results were compared between groups and with pre-existing biomechanical data of a titanium-alloy plate. RESULTS The CF-PEEK plate featured significantly lower stiffness compared to the titanium-alloy plate (P<0.001). In ultimate load testing, 6 out of 14 CF-PEEK plates failed due to irreversible deformation and cracking. No significant difference was observed between results of groups PEEK/screw and PEEK/bolt (P>0.05). DISCUSSION The CF-PEEK plate has more elastic properties and significantly increases movement at the fracture site of an unstable proximal humeral fracture model compared to the commonly used titanium-alloy plate. The screw design however does neither affect the constructs primary mechanical behaviour in the constellation tested nor the load before screw perforation.
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Affiliation(s)
- Jan Christoph Katthagen
- Department of Trauma and Reconstructive Surgery, Diakoniekrankenhaus Friederikenstift gGmbH, Humboldtstr. 5, 30169 Hannover, Germany.
| | - Michael Schwarze
- Laboratory of Biomechanics and Biomaterials, Medizinische Hochschule Hannover (MHH), Anna-von-Borries-Str. 1-7, 30625 Hannover, Germany
| | - Mara Warnhoff
- Department of Trauma and Reconstructive Surgery, Diakoniekrankenhaus Friederikenstift gGmbH, Humboldtstr. 5, 30169 Hannover, Germany
| | - Christine Voigt
- Department of Trauma and Reconstructive Surgery, Diakoniekrankenhaus Friederikenstift gGmbH, Humboldtstr. 5, 30169 Hannover, Germany
| | - Christof Hurschler
- Laboratory of Biomechanics and Biomaterials, Medizinische Hochschule Hannover (MHH), Anna-von-Borries-Str. 1-7, 30625 Hannover, Germany
| | - Helmut Lill
- Department of Trauma and Reconstructive Surgery, Diakoniekrankenhaus Friederikenstift gGmbH, Humboldtstr. 5, 30169 Hannover, Germany
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Screw augmentation reduces motion at the bone-implant interface: a biomechanical study of locking plate fixation of proximal humeral fractures. J Shoulder Elbow Surg 2015; 24:1968-73. [PMID: 26255200 DOI: 10.1016/j.jse.2015.06.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 06/08/2015] [Accepted: 06/22/2015] [Indexed: 02/01/2023]
Abstract
BACKGROUND Shear forces at the bone-implant interface lead to a loss of reduction after locking plate fixation of proximal humeral fractures. The aim of the study was to analyze the roles of medial support screws and screw augmentation in failure loads and motion at the bone-implant interface after locking plate fixation of proximal humeral fractures. METHODS Unstable 3-part fractures were simulated in 6 pairs of cadaveric humeri and were fixed with a DiPhos-H locking plate (Lima Corporate, Udine, Italy). An additional medial support screw was implanted in 1 humerus of every donor. The opposite humerus was stabilized with a medial support screw and additional bone cement augmentation of the 2 anteriorly directed head screws. Specimens were loaded in the varus bending position. Stiffness, failure loads, plate bending, and the motion at the bone-implant interface were evaluated using an optical motion capture system. RESULTS The mean load to failure was 669 N (standard deviation [SD], 117 N) after fixation with medial support screws alone and 706 N (SD, 153 N) after additional head screw augmentation (P = .646). The initial stiffness was 453 N/mm (SD, 4.16 N/mm) and 461 N/mm (SD, 64.3 N/mm), respectively (P = .594). Plate bending did not differ between the 2 groups. However, motion at the bone-implant interface was significantly reduced after head screw augmentation (P < .05). CONCLUSION The addition of bone cement to augment anteriorly directed head screws does not increase stiffness and failure loads but reduces motion at the bone-implant interface. Thus, the risk of secondary dislocation of the head fragment may be reduced.
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How to enhance the stability of locking plate fixation of proximal humerus fractures? An overview of current biomechanical and clinical data. Injury 2015; 46:1207-14. [PMID: 25978864 DOI: 10.1016/j.injury.2015.04.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/24/2015] [Accepted: 04/13/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND The complication rate after locking plate fixation of proximal humerus fractures is high. In addition to low bone mineral density, a lack of medial support has been identified as one of the most important factors accounting for mechanical instability. As a result of the high failure rate, different strategies have been developed to enhance the mechanical stability of locking plate fixation of proximal humerus fractures. The aim of the present article is to give an overview of the current biomechanical and clinical studies that focus on how to increase the stability of locking plate fixation of proximal humerus fractures. METHODS A comprehensive search of the Medline databases using specific search terms with regard to the stability of locking plate fixation of proximal humerus fractures was performed. After screening of the articles for eligibility, they were subdivided according to clinical and biomechanical aspects. RESULTS Medial support screws, filling of bone voids and screw-tip augmentation with bone cement as well as the application of bone grafts are currently the most frequently assessed and performed methods. Although the evidence is weak, all of the mentioned strategies appear to have a positive effect on achieving and maintaining a stable reduction even of complex fractures. CONCLUSION Further clinical studies with a higher number of patients and a higher level of evidence are required to develop a standardised treatment algorithm with regard to cement augmentation and bone grafting. Although these measures are likely to have a stabilising effect on locking plate fixation, its general use cannot be fully recommended yet.
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