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Su KC, Yen YC, Wang CH, Wang YL, Wang SP. Biomechanical comparisons of F.E.R.I. techniques with different type of intramedullary screws fixation for Jones fractures. Front Bioeng Biotechnol 2024; 12:1389127. [PMID: 38751865 PMCID: PMC11094221 DOI: 10.3389/fbioe.2024.1389127] [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: 02/21/2024] [Accepted: 04/18/2024] [Indexed: 05/18/2024] Open
Abstract
Introduction: Jones fractures frequently fail to unite, and adequate fixation stability is crucial. This study aimed to elucidate the biomechanical stability of various intramedullary screw fixation constructs. Methods: Jones fracture model over the proximal 5th metatarsal of artificial bone was created in all specimens. Six groups were divided based on varied screw constructs with different screw lengths, either 30 or 40 mm, including cannulated screws-C30 and C40 groups, one high-resistance suture combined with intramedullary cannulated screws (F.E.R.I. technique)-CF30 and CF40 groups, and second-generation headless compression screws (SG-HCS) -HL30 and HL40 groups. Mechanical testing was conducted sequentially, and the maximal force (N) and stiffness (N/mm) of all constructs were recorded. Results: The maximal force (N) at 1.0 mm downward displacement in C30, C40, CF30, CF40, HL30, and HL40 groups were 0.56 ± 0.02, 0.49 ± 0.02, 0.65 ± 0.02, 0.49 ± 0.01, 0.68 ± 0.02, and 0.73 ± 0.02, respectively, and the stiffness (N/mm) in subgroups were 0.49 ± 0.01, 0.43 ± 0.01, 0.67 ± 0.01, 0.42 ± 0.01, 0.61 ± 0.01, and 0.58 ± 0.02, respectively. SG-HCS subgroups exhibited greater maximal force and stiffness than conventional cannulated screws. Screws of 30 mm in length demonstrated better stability than all 40 mm-length screws in each subgroup. In C30 fixation, the stiffness and maximum force endured increased by 1.16 and 1.12 times, respectively, compared with the C40 fixation method. There were no significant differences between CF30 and SG-HCS groups. Only the F.E.R.I technique combined with the 4.5 mm cannulated screw of 30 mm in length increased the biomechanical stability for Jones fractures. Discussion: These biomechanical findings help clinicians decide on better screw fixation options for greater stability in Jones fractures, especially when large-diameter screws are limited in use. However, this biomechanical testing of intramedullary screw fixation on Jones fracture model lacks clinical validation and no comparisons to extramedullary plate fixations. Moving forward, additional clinical and biomechanical research is necessary to validate our findings.
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Affiliation(s)
- Kuo-Chih Su
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
- Department of Medical Equipment Development and Application, HungKuang University, Taichung, Taiwan
| | - Yu-Chun Yen
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chun-Hsiang Wang
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Yi-Lun Wang
- Stella Matutina Girls’ High School, Taichung, Taiwan
| | - Shun-Ping Wang
- Department of Orthopaedics, Taichung Veterans General Hospital, Taichung, Taiwan
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung, Taiwan
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Mandala M, Shaunak S, Kreitmair P, Phadnis J, Guryel E. Biomechanical comparison of headless compression screws versus independent locking screw for intra-articular fractures. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY & TRAUMATOLOGY : ORTHOPEDIE TRAUMATOLOGIE 2024; 34:1319-1325. [PMID: 38112781 PMCID: PMC10980631 DOI: 10.1007/s00590-023-03792-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 11/15/2023] [Indexed: 12/21/2023]
Abstract
PURPOSE Headless compression screws (HCS) have a variable thread pitch and headless design enabling them to embed below the articular surface and generate compression force for fracture healing without restricting movement. Locking screws have greater variety of dimensions and a threaded pitch mirroring the design of the HCS. The objective of this study is to determine whether locking screws can generate compression force and compare the compressive forces generated by HCS versus locking screws. METHOD A comparison between 3.5-mm HCS versus 3.5-mm locking screws and 2.8-mm HCS versus 2.7-mm locking screws was performed using a synthetic foam bone model (Synbone) and FlexiForce sensors to record the compression forces (N). The mean peak compression force was calculated from a sample of 3 screws for each screw type. Statistical analysis was performed using the one-way ANOVA test and statistical significance was determined to be p = < 0.05. RESULTS The 3.5-mm Synthes and Smith and Nephew locking screws generated similar peak compression forces to the 3.5-mm Acutrak 2 headless compression screws with no statistically significant difference between them. The smaller 2.7-mm Synthes and Smith and Nephew locking screws initially generated similar compressive forces up to 1.5 and 2 revolutions, respectively, but their peak compression force was less compared to the 2.8-mm Micro Acutrak 2 HCS. CONCLUSION Locking screws are able to generate compressive forces and may be a viable alternative to headless compressive screws supporting their use for intra-articular fractures.
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Affiliation(s)
| | - Shalin Shaunak
- University Hospitals Sussex NHS Foundation Trust, Brighton, UK
| | | | - Joideep Phadnis
- University Hospitals Sussex NHS Foundation Trust, Brighton, UK
| | - Enis Guryel
- University Hospitals Sussex NHS Foundation Trust, Brighton, UK.
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Heineman N, Do DH, Ahn J, Sammer DM, Koehler DM. Biomechanical Analysis of Headless Compression Screw Versus Tension Band Wiring for Proximal Interphalangeal Joint Arthrodesis. J Hand Surg Am 2024:S0363-5023(24)00023-6. [PMID: 38416093 DOI: 10.1016/j.jhsa.2024.01.007] [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: 09/21/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 02/29/2024]
Abstract
PURPOSE Proximal interphalangeal (PIP) joint arthrodesis is a procedure employed to address arthritis, instability, and deformity. Multiple fixation methods are available to maintain stability across the arthrodesis interval, including headless compression screws (HCSs), tension band wiring (TBW), plating, and Kirschner wire constructs. The purpose of this study was to compare the biomechanical properties of the HCS and TBW techniques. METHODS Thirty-two nonthumb digits from the paired upper limbs of four fresh frozen cadavers were divided into pairs, matching contralateral digits from the same specimen. One PIP joint of each pair was fused with an antegrade 3.5 mm HCS, and the second was fused with TBW using 0.035 in. Kirschner wires with 24-gauge dental wire. Each construct was then stressed to 10 N in the radial deviation, ulnar deviation, flexion, and extension planes, and stiffness (N/mm) was calculated. The fingers were stressed to failure in extension with the ultimate load and mode of failure recorded. RESULTS When stressed in extension, the HCS construct had a significantly greater mean stiffness than the TBW construct (16.4 N/mm vs 10.8 N/mm). The stiffness in all other planes of motion were similar between the two constructs. The mean ultimate load to failure in extension was 91.4 N for the HCS and 41.9 N for the TBW. The most common mode of failure was fracture of the dorsal lip of the proximal phalanx (13/16) for the HCS and bending of the K-wires (15/16) for TBW. CONCLUSIONS Arthrodesis of the PIP joint using a HCS resulted in a construct that was significantly stiffer in extension with greater than double the load to failure compared to TBW. CLINICAL RELEVANCE Although the stiffness required to achieve successful PIP joint arthrodesis has not been well quantified, the HCS proved to be the most favorable construct with respect to initial strength and stability.
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Affiliation(s)
- Nathan Heineman
- Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Dang-Huy Do
- Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Junho Ahn
- Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Douglas M Sammer
- Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Daniel M Koehler
- Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas.
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Chatain GP, Oldham A, Uribe J, Duhon B, Gardner MJ, Witt JP, Yerby S, Kelly BP. Biomechanics of sacroiliac joint fixation using lag screws: a cadaveric study. J Orthop Surg Res 2023; 18:807. [PMID: 37898818 PMCID: PMC10613391 DOI: 10.1186/s13018-023-04311-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 10/22/2023] [Indexed: 10/30/2023] Open
Abstract
BACKGROUND Iliosacral screw placement is ubiquitous and now part of the surgeon's pelvic trauma armamentarium. More recent evidence supports sacroiliac arthrodesis for treating sacroiliac joint (SIJ) dysfunction in select patients. Regardless of the surgical indication, there are currently no studies examining lag screw compression biomechanics across the SIJ. The objective of this biomechanical investigation was to quantify iliosacral implant compressive loads and to examine the insertion torque and compressive load profile over time. METHODS Eight human cadaveric pelvic specimens underwent SIJ fixation at S1 and S2 using 11.5 and 10.0 mm iFuse-TORQ Lag implants, respectively, and standard 7.3 mm trauma lag screws. Load decay analysis was performed, and insertion and removal torques were measured. RESULTS For both implants at S1 and S2 levels, the load relaxed 50% in approximately 67 min. Compressive load decay was approximately 70% on average occurring approximately 15 h post-insertion. Average insertion torque for the 11.5 mm TORQ implant at S1 was significantly greater than the trauma lag screw. Similarly, at S2, insertion torque of the 10.0 mm TORQ implant was greater than the trauma lag screw. At S1, removal torque for the 11.5 mm TORQ implant was higher than the trauma lag screw; there was no significant difference in the removal torque at S2. CONCLUSIONS In this study, we found that a novel posterior pelvic implant with a larger diameter, roughened surface, and dual pitch threads achieved improved insertion and removal torques compared to a standard screw. Load relaxation characteristics were similar between all implants.
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Affiliation(s)
- Grégoire P Chatain
- Department of Neurosurgery, University of Colorado School of Medicine, 12605 E 16Th Ave, Aurora, CO, 80045, USA.
| | - Alton Oldham
- Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Juan Uribe
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Bradley Duhon
- Department of Neurosurgery, University of Colorado School of Medicine, 12605 E 16Th Ave, Aurora, CO, 80045, USA
| | - Michael J Gardner
- Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, CA, USA
| | - Jens-Peter Witt
- Department of Neurosurgery, University of Colorado School of Medicine, 12605 E 16Th Ave, Aurora, CO, 80045, USA
| | | | - Brian P Kelly
- Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
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Hanna T, Smith N, Akalonu C, Simmons J, Nehete PV, Dodson M. Decreased Complication Rate Using Partially Threaded Compared With Fully Threaded Compression Screws in 4 Corner Arthrodesis: A Retrospective Study. Hand (N Y) 2023:15589447231167883. [PMID: 37128854 DOI: 10.1177/15589447231167883] [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] [Indexed: 05/03/2023]
Abstract
BACKGROUND Scapho-lunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) of the wrist are the most common types of wrist arthritis. We compared the union rate and complication profile of patients with SLAC and SNAC wrist undergoing 4 corner arthrodesis with partially threaded or fully threaded headless compression screws. METHODS A single-center retrospective review was conducted to identify all patients treated for SLAC and SNAC with 4 corner fusion using headless compression screws from 2016 to 2021. A total of 33 patients undergoing surgery on 35 wrists were identified and included in the study. Demographics, comorbidities, complication profile, and radiographs were collected and compared between groups. RESULTS One hundred percent (16/16) of partially threaded and 84.2% (16/19) of fully threaded screws demonstrated union by minimum 10-week follow-up. The total complication rate (avascular necrosis of lunate, screw loosening, etc.) was 31.4%; 52.6% of wrists implanted with fully threaded screws experienced complications compared with a 6.3% complication rate with partially threaded screws. The difference was statistically significant between the 2 groups (P = .004). CONCLUSIONS Four corner arthrodesis using antegrade compression screws is an effective, reproducible method to achieve fusion in the wrist. The use of fully threaded screws was associated with more complications than with partially threaded screws, although union rate was not significantly different. Future studies with larger sample sizes would be useful to fully elucidate differences between these 2 constructs.
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Affiliation(s)
- Tammam Hanna
- The University of Mississippi Medical Center, Jackson, USA
| | - Nathan Smith
- Penn State College of Medicine, Hershey, PA, USA
| | | | - Jack Simmons
- The University of Mississippi Medical Center, Jackson, USA
| | | | - Mark Dodson
- The University of Mississippi Medical Center, Jackson, USA
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Çetin A, Bircan DA. 3D pull-out finite element simulation of the pedicle screw-trabecular bone interface at strain rates. Proc Inst Mech Eng H 2021; 236:134-144. [PMID: 34479459 DOI: 10.1177/09544119211044560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Biomedical experimental studies such as pull-out (PO), screw loosening experience variability mechanical properties of fresh bone, legal procedures of cadaver bone samples and time-consuming problems. Finite Element Method (FEM) could overcome experimental problems in biomechanics. However, material modelling of bone is quite difficult, which has viscoelastic and viscoplastic properties. The study presents a bone material model which is constructed at the strain rates with the Johnson-Cook (JC) material model, one of the robust constitutive material models. The JC material constants of trabecular bone are determined by the curve fitting method at strain rates for the 3D PO finite element simulation, which defines the screw-bone interface relationship. The PO simulation is performed using the Abaqus/CAE software program. Bone fracture mechanisms are simulated with dynamic/explicit solutions during the PO phenomenon. The paper exposes whether the strain rate has effects on the PO performance. Moreover, simulation reveals the relationship between pedicle screw diameter and PO performance. The results obtained that the maximum pull-out force (POF) improves as both the screw diameter and the strain rate increase. For 5.5 mm diameter pedicle screw POFs were 487, 517 and 1708 N at strain rate 0.00015, 0.015 and 0.015 s-1, respectively. The FOFs obtained from the simulation of the other screw were 730, 802 and 2008 N at strain rates 0.00015, 0.0015 and 0.015, respectively. PO phenomenon was also simulated realistically in the finite element analysis (FEA).
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Affiliation(s)
- Ahmet Çetin
- Department of Mechanical Engineering, Cukurova University, Adana, Turkey
| | - Durmuş Ali Bircan
- Department of Mechanical Engineering, Cukurova University, Adana, Turkey
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Ilyas AM, Mahoney JM, Bucklen BS. A Mechanical Comparison of the Compressive Force Generated by Various Headless Compression Screws and the Impact of Fracture Gap Size. Hand (N Y) 2021; 16:604-611. [PMID: 31565968 PMCID: PMC8461202 DOI: 10.1177/1558944719877890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: There is evidence that interfragmentary fracture gap size may affect the compression achievable with a modern headless compression screw (HCS). This mechanical study compared the compression achieved by 3 commercial HCS systems through various fracture gaps: CAPTIVATE Headless (Globus Medical, Inc, Audubon, Pennsylvania), Synthes (DePuy Synthes, Westchester, Pennsylvania), and Acumed Acutrak 2 (Acumed LLC, Hillsboro, Oregon). Methods: Screws were inserted into a custom test fixture composed of polyurethane synthetic bone foam fragments, separated by a layer of easily compressible polyurethane foam simulating a fracture gap. Compression was measured after final insertion and countersinking. The effect of the interfragmentary fracture gap size on the compression generated was also investigated. Results: The CAPTIVATE Headless 3.0 mm screw (70.1 ± 5.7 N) and the Synthes 3.0 mm screw (64.9 ± 7.3 N) achieved similar compressive forces after final countersink. Similar comparisons were found for the CAPTIVATE Headless 2.5 mm and Synthes 2.4 mm screws, and the CAPTIVATE Headless 4.0 mm and Acutrak 2 Standard screws. The final compression of the CAPTIVATE Headless 2.5 mm and Synthes 2.4 mm screws was not significantly affected when the fracture gap was doubled from 2 to 4 mm, but was reduced significantly by 95.9% with the Acutrak 2 Micro screw. Conclusion: When comparing like-sized screws, the CAPTIVATE, Synthes, and Acutrak 2 HCS systems demonstrated similar potential compressive forces. However, compared with the CAPTIVATE Headless and Synthes HCS systems, which are inserted with a compression sleeve that is not gap distance-dependent, the Acutrak 2 HCS system demonstrated less compression when the simulated fracture gap size was increased to 4 mm.
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Affiliation(s)
| | - Jonathan M. Mahoney
- Globus Medical Inc, Audubon, PA, USA,Jonathan M. Mahoney, Musculoskeletal Education and Research Center, Globus Medical, Inc, 2560 General Armistead Avenue, Audubon, PA 19403, USA.
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Kılıç B, Çalışkan M, Agar A, Uzun B, Ertem F, Gülabi D, Ertürk C. Comparison of two different screw trajectories in the treatment of oblique scaphoid fractures: A mechanical study on composite bone models. Jt Dis Relat Surg 2021; 32:377-382. [PMID: 34145814 PMCID: PMC8343848 DOI: 10.52312/jdrs.2021.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/17/2021] [Indexed: 11/22/2022] Open
Abstract
Objectives
In this mechanical study, we aimed to compare two different screw trajectories in terms of durability against axial loads on oblique scaphoid fractures using composite bone models. Materials and methods
Oblique osteotomies were made along the dorsal sulcus of 14 composite scaphoid bone models. Following this, all bone models were randomly classified. One group of bones were fixed with a screw placed perpendicular to the osteotomy line and the other group was fixed with a screw placed centrally down the long axis of the scaphoid bone. Each scaphoid bone model was positioned on a mechanical testing machine. Subsequently, axial loading tests were applied on each bone model to measure the amount of loading required to cause 2-mm displacement and failure on the osteotomy side and maximum displacement at the time of failure on scaphoid bone models. Results
There was no statistically significant difference in load to 2-mm displacement and failure between the two groups (p>0.05). Also, there was no statistically significant difference between the two groups in terms of maximum displacement seen on failure (p>0.05). Conclusion
In our study, we found that the stability of the screws which laid perpendicular to the fracture line and parallel to the long axis of the scaphoid was the same in fixing oblique scaphoid fractures.
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Affiliation(s)
- Bülent Kılıç
- SBÜ, Kanuni Sultan Süleyman Eğitim ve Araştırma Hastanesi, Ortopedi ve Travmatoloji Kliniği, 34303 Küçükçekmece, İstanbul, Türkiye.
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Vishwanathan K, Patel R, Talwalkar S. Which Headless Compression Screw Produces the Highest Interfragmentary Compression Force in Scaphoid Fracture? Indian J Orthop 2020; 54:548-564. [PMID: 32850017 PMCID: PMC7429644 DOI: 10.1007/s43465-020-00107-5] [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: 12/27/2019] [Accepted: 04/04/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND Interfragmentary compression at the fracture site facilitates healing. Headless compression screws used to treat scaphoid fractures can be grouped as shank screws, conical tapered screws and double component screws. There has been no meta-analysis of biomechanical studies to compare interfragmentary compression produced by the above screws. METHODS A computerised search of Pubmed, Embase and OVID database was undertaken to identify the studies. We estimated the weighted mean difference of interfragmentary compression (in Newton) with 95% confidence intervals. Random effects model was selected for meta-analysis. RESULTS The pooled estimate of nine studies demonstrated that conical tapered screw produced significantly higher interfragmentary compression force compared to the shank screw (WMD 19.96, 95% CI 11.2-28.8, p < 0.0001, I 2 = 99%). The pooled estimate of four studies demonstrated that dual component screw produced significantly higher interfragmentary compression force compared to the shank screw (WMD 16.93, 95% CI 12.3-21.6, p < 0.0001, I 2 = 97.7%). The pooled estimate of four studies showed that there was no significant difference in the interfragmentary compression force generated by either conical tapered screw or dual component screw (WMD 3.93, 95% CI - 8.3 to 16.2, p = 0.53, I 2 = 99.7%). There was evidence of minimal publication bias. CONCLUSION Conical tapered screws and dual component screws produced statistically significant higher interfragmentary compression force at the scaphoid fracture site compared to shank screws. There was no difference in the compression force generated by either conical tapered screw or dual component screw.
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Affiliation(s)
- Karthik Vishwanathan
- Department of Orthopaedics, Parul Institute of Medical Sciences and Research, P.O Limda, Waghodia, Vadodara, 391760 India
| | - Ravi Patel
- Pramukhswami Medical College, Charutar Arogya Mandal, Gokal Nagar, Karamsad, 388325 India
| | - Sumedh Talwalkar
- Department of Orthopaedics, Wrightington, Wigan and Leigh NHS Trust, Wrightington, WN6 9EP UK
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Addevico F, Morandi M, Scaglione M, Solitro GF. Screw insertion torque as parameter to judge the fixation. Assessment of torque and pull-out strength in different bone densities and screw-pitches. Clin Biomech (Bristol, Avon) 2020; 72:130-135. [PMID: 31864036 DOI: 10.1016/j.clinbiomech.2019.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/27/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Pull-out strength is a critical parameter to judge screw fixation in orthopaedic implants. However, the insertion torque is the main feeling in the hand of a surgeon relating to the strength of synthesis. The correlation between pull-out strength and torque is not completely understood. This creates uncertainty about the key-question: Should the torque be considered a valid parameter to judge the quality of fixation? METHODS Using the ASTM F543 as reference, three screws differing only in pitch (1.5, 2.1, 2.8 mm pitches) were tested in three foam-block densities (10, 15, and 20 pcf). The correlation was investigated by assessing the role of density and screw geometry. FINDINGS Torque was related to pull-out strength in all configurations (R = 0.979, P = 0.000). No difference in pull-out strength was found when screws were tightened to a range of 71.6%, SD = 7.6, of torque to fail (P > 0.05). Torque and pull-out strength were stratified according to density that influenced the two parameters up to 524% (P < 0.000). Pitch determined pull-out strength up to 33% (P < 0.000) while the 2.1 mm screw pitch showed the highest pull-out strength and torque in all configurations. INTERPRETATION Insertion torque was demonstrated to be a valid parameter to judge the quality of bone under fixation and therefore, the strength of the synthesis. Surgeons should not tighten the screws to values approaching torque to fail to obtain the highest pull-out strength. Density was the main factor influencing pull-out strength and torque. Pitch is another parameter deciding screw holding capacity.
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Affiliation(s)
| | - Massimo Morandi
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, Louisiana State University Health, Science Center Shreveport, LA, USA
| | | | - Giovanni F Solitro
- Biomechanics Laboratory, Department of Orthopaedic Surgery, Louisiana State University Health, Science Center Shreveport, LA, USA
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11
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Cheng RZ, Wegner AM, Behn AW, Amanatullah DF. Headless compression screw for horizontal medial malleolus fractures. Clin Biomech (Bristol, Avon) 2018; 55:1-6. [PMID: 29604557 DOI: 10.1016/j.clinbiomech.2018.03.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 03/21/2018] [Accepted: 03/26/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Horizontal medial malleolus fractures are caused by the application of rotational force through the ankle joint in several orientations. Multiple techniques are available for the fixation of medial malleolar fractures. METHODS Horizontal medial malleolus osteotomies were performed in eighteen synthetic distal tibiae and randomized into two fixation groups: 1) two parallel unicortical cancellous screws or 2) two Acutrak 2 headless compression screws. Specimens were subjected to offset axial tension loading. Frontal plane interfragmentary motion was monitored. FINDINGS The headless compression group (1699 (SD 947) N/mm) had significantly greater proximal-distal stiffness than the unicortical group (668 (SD 298) N/mm), (P = 0.012). Similarly, the headless compression group (604 (SD 148) N/mm) had significantly greater medial-lateral stiffness than the unicortical group (281 (SD 152) N/mm), (P < 0.001). The force at 2 mm of lateral displacement was significantly greater in the headless compression group (955 (SD 79) N) compared to the unicortical group (679 (SD 198) N), (P = 0.003). At 2 mm of distal displacement, the mean force was higher in the headless compression group (1037 (SD 122) N) compared to the unicortical group (729 (SD 229) N), but the difference was not significant (P = 0.131). INTERPRETATION A headless compression screw construct was significantly stiffer in both the proximal-distal and medial-lateral directions, indicating greater resistance to both axial and shear loading. Additionally, they had significantly greater load at clinical failure based on lateral displacement. The low-profile design of the headless compression screw minimizes soft tissue irritation and reduces need for implant removal.
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Affiliation(s)
- Robin Z Cheng
- Stanford University School of Medicine, Stanford, CA, USA
| | - Adam M Wegner
- University of California Davis Medical Center, Sacramento, CA, USA
| | - Anthony W Behn
- Stanford University School of Medicine, Stanford, CA, USA
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12
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Donald SM, Niu R, Jones CW, Smith BJ, Clarke EC, Lawson RD. Effects of Removal and Reinsertion of Headless Compression Screws. J Hand Surg Am 2018; 43:139-145. [PMID: 29137829 DOI: 10.1016/j.jhsa.2017.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/30/2017] [Accepted: 10/02/2017] [Indexed: 02/02/2023]
Abstract
PURPOSE This study investigates the loss of compression when 3 commonly used headless compression screws are backed out (reversed), and assesses the ability to re-establish compression with screws of greater diameter. METHODS Two investigators tested 3 screw designs (Acutrak 2, Synthes HCS, Medartis SpeedTip CCS) in 2 diameters and lengths. Each design had 10 test cycles in a polyurethane foam bone model with compression recorded using a washer load cell. A 28-mm screw of the narrower diameter was inserted until 2 mm recessed and then reversed 30°, 60°, 90°, 180°, 270°, 360°, and 720°. After this the screw was removed completely and a 24-mm screw of greater diameter inserted until recessed 2 mm with the compressive force again recorded. RESULTS All screws showed an immediate, statistically significant loss of compression at 30° of reversing. The Acutrak 2 Micro screw demonstrated not only the greatest mean compressive force, but also the fastest compressive loss. Insertion of the shorter screw of greater diameter was associated with re-establishment of compression to levels comparable with the original screw. CONCLUSIONS This study reaffirms the importance of establishing the correct screw length before insertion due to the immediate loss of compression with reversal of these devices. CLINICAL RELEVANCE If a headless compression screw penetrates the far joint surface, the screw should be completely removed and replaced with a shorter screw of greater diameter.
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Affiliation(s)
- Simon M Donald
- Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, University of Sydney, Sydney, Australia
| | - Rui Niu
- Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, University of Sydney, Sydney, Australia
| | - Christopher W Jones
- Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, University of Sydney, Sydney, Australia
| | - Belinda J Smith
- Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, University of Sydney, Sydney, Australia
| | - Elizabeth C Clarke
- Murray Maxwell Biomechanics Laboratory, Kolling Institute, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Richard D Lawson
- Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, University of Sydney, Sydney, Australia.
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Swanstrom MM, Morse KW, Lipman JD, Hearns KA, Carlson MG. Effect of Screw Perpendicularity on Compression in Scaphoid Waist Fractures. J Wrist Surg 2017; 6:178-182. [PMID: 28725497 PMCID: PMC5515612 DOI: 10.1055/s-0036-1596059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/25/2016] [Indexed: 10/20/2022]
Abstract
Background Central and perpendicular (PERP) screw orientations have each been described for scaphoid fracture fixation. It is unclear, however, which orientation produces greater compression. Questions/Purposes This study compares compression in scaphoid waist fractures with screw fixation in both PERP and pole-to-pole (PTP) configurations. PERP orientation was hypothesized to produce greater compression than PTP orientation. Methods Ten preoperative computed tomography scans of scaphoid waist fractures were classified by fracture type and orientation in the coronal and sagittal planes. Three-dimensional models of each scaphoid and fracture plane were created. Simulated Acutrak 2 (Acumed, Hillsboro, OR) screws were placed into the models in both PERP and PTP orientations. Engagement length and screw angle relative to the fracture were measured. Compression strength was calculated from the shear area, average density, and angle acuity. Results The PTP angle between screw and fracture ranged from 36 to 84 degrees. By definition, the PERP screw-to-fracture angle was 90 degrees. Perpendicularity of the PTP screw to the fracture was positively correlated to compression strength. PERP screws had greater compression than PTP screws when the PTP screw-to-fracture angle was < 80 degrees (106 vs. 80 N), but there was no difference in compression when the PTP screw-to-fracture angle was > 80 degrees, approximating the PERP screw. Conclusion Increasing screw perpendicularity resulted in higher compression when the screw-to-fracture angle of the PTP screw was < 80 degrees. Maximum compression was obtained with a screw PERP to the fracture. The increased compression gained from PERP screw placement offsets the decreased engagement length. Clinical Relevance These results provide guidelines for optimal screw placement in scaphoid waist fractures.
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Affiliation(s)
- Morgan M. Swanstrom
- Division of Hand and Upper Extremity Surgery, Hospital for Special Surgery, New York, New York
| | - Kyle W. Morse
- Division of Hand and Upper Extremity Surgery, Hospital for Special Surgery, New York, New York
| | - Joseph D. Lipman
- Department of Biomechanics, Hospital for Special Surgery, New York, New York
| | - Krystle A. Hearns
- Division of Hand and Upper Extremity Surgery, Hospital for Special Surgery, New York, New York
| | - Michelle G. Carlson
- Division of Hand and Upper Extremity Surgery, Hospital for Special Surgery, New York, New York
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14
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Interfragmentary compression and pull-out properties of 6.5-mm AO cancellous lag screws in a uniform synthetic material during tightening procedures. Med Eng Phys 2017; 42:116-120. [DOI: 10.1016/j.medengphy.2017.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 09/23/2016] [Accepted: 01/08/2017] [Indexed: 12/15/2022]
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15
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Osteosynthesis using cannulated headless Herbert screws in mandibular angle fracture treatment: A new approach? J Craniomaxillofac Surg 2017; 45:526-539. [PMID: 28256384 DOI: 10.1016/j.jcms.2017.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/18/2016] [Accepted: 01/20/2017] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION Fractures of the mandibular angle are a common type of facial skull fracture. Although operative treatment includes a wide range of fixation techniques, a definite gold standard method has yet to be established. Headless, cannulated Herbert screws, often used in many forms of minimally invasive trauma surgery, provide functional and stable fracture fixation. MATERIALS AND METHODS In a prospective, double-randomised, controlled, parallel-group - designed, in vitro trial, the biomechanical behaviour of the Herbert bone screw system was compared to that of a conventional locking plate system in 40 mandibular angle fractures of human mandible cadaver phantoms. RESULTS The mean stress values were 250 (±68.0) N in the plate subgroup and 200 (±61.0) N in the screw subgroup. The respective mean strain values were 7.90 (±2.7) mm and 6.90 (±2.2) mm, and the respective mean stiffness were values 1.10 (±0.61) N/m and 0.78 (±0.40) N/m. The differences in the results obtained using the two treatments were not significant (p = 0.55). CONCLUSIONS The biomechanical behaviour of the two fixation systems within the tested loads did not significantly differ with respect to postoperative parameters clinically relevant in osteosynthesis. Both systems met the mandibular angle assessment criterion, which is considered to be sufficient for clinical use. The results indicate the potential clinical utility of these two systems, and recommend further testing.
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Hart A, Harvey EJ, Rabiei R, Barthelat F, Martineau PA. Fixation strength of four headless compression screws. Med Eng Phys 2016; 38:1037-43. [DOI: 10.1016/j.medengphy.2016.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/25/2016] [Accepted: 06/19/2016] [Indexed: 11/28/2022]
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17
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Rowe-Guthrie KM, Markel MD, Bleedorn JA. Mechanical Evaluation of Locking, Nonlocking, and Hybrid Plating Constructs Using a Locking Compression Plate in a Canine Synthetic Bone Model. Vet Surg 2015; 44:838-42. [DOI: 10.1111/vsu.12368] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kathleen M. Rowe-Guthrie
- Department of Surgical Sciences; University of Wisconsin, School of Veterinary Medicine; Madison Wisconsin
| | - Mark D. Markel
- Department of Surgical Sciences; University of Wisconsin, School of Veterinary Medicine; Madison Wisconsin
| | - Jason A. Bleedorn
- Department of Surgical Sciences; University of Wisconsin, School of Veterinary Medicine; Madison Wisconsin
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18
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Göksel F, Ermutlu C, Gölge UH, Kaymaz B. Treatment of juvenile hallux valgus interphalangeus with a double compression headless bone screw. BMJ Case Rep 2015; 2015:bcr-2015-210204. [PMID: 26243744 DOI: 10.1136/bcr-2015-210204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A 14-year-old girl presented with idiopathic valgus deformity of her left great toe at the interphalangeal joint (IPJ). The deformity, which had been present but asymptomatic for the past 4 years, began to enlarge and cause discomfort. The measured IPJ angle on anteroposterior standing X-ray was 26°. We treated the toe by medial closing wedge osteotomy and fixation with a double compression headless bone screw (DCHBS). Postoperative hallux valgus interphalangeus (HVI) angle was 14°.
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Affiliation(s)
- Ferdi Göksel
- Department of Orthopaedics and Traumatology, Çanakkale Onsekiz Mart University School of Medicine, Çanakkale, Turkey
| | - Cenk Ermutlu
- Department of Orthopaedics and Traumatology, İstanbul Training Hospital, Istanbul, Turkey
| | - Umut Hatay Gölge
- Department of Orthopaedics and Traumatology, Çanakkale Onsekiz Mart University School of Medicine, Çanakkale, Turkey
| | - Burak Kaymaz
- Department of Orthopaedics and Traumatology, Çanakkale Onsekiz Mart University School of Medicine, Çanakkale, Turkey
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19
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Tonosu J, Watanabe K, Abe H, Higashikawa A, Kato S, Yamada K. Anterior screw fixation for an odontoid fracture using an Acutrak 4/5 screw: a case report. Arch Orthop Trauma Surg 2013; 133:1681-6. [PMID: 24121624 DOI: 10.1007/s00402-013-1870-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Indexed: 10/26/2022]
Abstract
The direct anterior screw fixation of odontoid fractures by a single cancellous screw, especially for osteoporotic vertebrae, has a potential risk of leading to insufficient stability and implant failures. We experienced good results following surgery using a single Acutrak 4/5 screw to obtain sufficient stability for an odontoid fracture in a patient with osteopenia. The screw is a cannulated self-tapping headless screw and has a tapered profile and full threads with variable pitches, and it can yield sufficient compression force as the screw is inserted. The preoperative severe neck pain of the patient was diminished immediately after the surgery. The patient achieved bone union in a short time and had a good clinical result for at least 3 years. Some biomechanical studies showed that the compression force of Acutrak standard screws was stronger than that of both 4.0-mm cancellous screws inserted with the lag screw technique and Herbert screws, and other studies showed that the compression force of Acutrak 4/5 screws was equivalent to that of 4.5-mm cortical screws. However, there has been no clinical report of surgery using an Acutrak 4/5 screw for odontoid fractures. This is the first clinical report of fixation by an Acutrak 4/5 screw.
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20
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Hart A, Harvey EJ, Lefebvre LP, Barthelat F, Rabiei R, Martineau PA. Insertion profiles of 4 headless compression screws. J Hand Surg Am 2013; 38:1728-34. [PMID: 23809468 PMCID: PMC3823572 DOI: 10.1016/j.jhsa.2013.04.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 04/20/2013] [Accepted: 04/23/2013] [Indexed: 02/02/2023]
Abstract
PURPOSE In practice, the surgeon must rely on screw position (insertion depth) and tactile feedback from the screwdriver (insertion torque) to gauge compression. In this study, we identified the relationship between interfragmentary compression and these 2 factors. METHODS The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple implants were tested using a polyurethane foam scaphoid model. A specialized testing jig simultaneously measured compression force, insertion torque, and insertion depth at half-screw-turn intervals until failure occurred. RESULTS The peak compression occurs at an insertion depth of -3.1 mm, -2.8 mm, 0.9 mm, and 1.5 mm for the Acutrak Mini, Acutrak Standard, Herbert-Whipple, and Synthes screws respectively (insertion depth is positive when the screw is proud above the bone and negative when buried). The compression and insertion torque at a depth of -2 mm were found to be 113 ± 18 N and 0.348 ± 0.052 Nm for the Acutrak Standard, 104 ± 15 N and 0.175 ± 0.008 Nm for the Acutrak Mini, 78 ± 9 N and 0.245 ± 0.006 Nm for the Herbert-Whipple, and 67 ± 2N, 0.233 ± 0.010 Nm for the Synthes headless compression screws. CONCLUSIONS All 4 screws generated a sizable amount of compression (> 60 N) over a wide range of insertion depths. The compression at the commonly recommended insertion depth of -2 mm was not significantly different between screws; thus, implant selection should not be based on compression profile alone. Conically shaped screws (Acutrak) generated their peak compression when they were fully buried in the foam whereas the shanked screws (Synthes and Herbert-Whipple) reached peak compression before they were fully inserted. Because insertion torque correlated poorly with compression, surgeons should avoid using tactile judgment of torque as a proxy for compression. CLINICAL RELEVANCE Knowledge of the insertion profile may improve our understanding of the implants, provide a better basis for comparing screws, and enable the surgeon to optimize compression.
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Affiliation(s)
- Adam Hart
- Division of Orthopedic Surgery, McGill University Health Centre, McGill University, Montreal, Canada.
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21
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Wähnert D, Hofmann-Fliri L, Schwieger K, Brianza S, Raschke MJ, Windolf M. Cement augmentation of lag screws: an investigation on biomechanical advantages. Arch Orthop Trauma Surg 2013; 133:373-9. [PMID: 23263012 DOI: 10.1007/s00402-012-1676-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Indexed: 11/26/2022]
Abstract
BACKGROUND In trauma surgery, lag screws are commonly used. However, in osteoporotic bone, anchorage can be considerably compromised. This study investigates the biomechanical potential of cement augmentation in terms of improved fixation. METHODS 36 Surrogate osteoporotic bone specimens were utilised in three biomechanical experiments, each comparing 6 augmented with 6 non-augmented samples. Standard partially-threaded lag screws (Synthes) were placed following surgical standard. For the augmented groups, 0.4 ml of polymethylmethacrylate was injected into the pre-drilled hole prior to screw placement. Interfragmentary compression was determined using a cannulated ring compression sensor. Maximum torque was recorded with a torque wrench. Compressive relaxation after 24 h, relaxation after loosening and re-tightening the screw as well as maximum compression and torque at failure were measured. FINDINGS Mean relaxation was significantly lower for the augmented group (p < 0.01). After 24 h, a remaining fragmental compression of 62 % for the augmented and 52 % for the non-augmented specimens was found. Loosening and re-tightening of the screw did not affect the compressive relaxation when augmentation was applied (p = 0.529), compared to an increased relaxation after re-tightening in the non-augmented group (p = 0.04). The mean maximum compression and torque until failure were significantly higher for the augmented group (p < 0.001). INTERPRETATION Cement augmentation of lag screws can improve fixation stability in terms of installing and maintaining interfragmentary compression. Effects of relaxation can be reduced and re-tightening of screws is possible without compromising the fixation. Particularly in reduced bone mass, augmentation of lag screws can markedly increase the security of the technique.
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Affiliation(s)
- D Wähnert
- AO Foundation, AO Research Institute, Clavadelerstrasse 8, Davos, Switzerland.
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22
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Gardner AW, Yew YT, Neo PY, Lau CC, Tay SC. Interfragmentary compression profile of 4 headless bone screws: an analysis of the compression lost on reinsertion. J Hand Surg Am 2012; 37:1845-51. [PMID: 22854254 DOI: 10.1016/j.jhsa.2012.05.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE To evaluate the interfragmentary compression force generated by 4 different types of headless compression screws and to examine the effects of removal and reinsertion of the screw. METHODS We chose foot bones rather than scaphoids for the model because they were larger and would enable comparison of 2 screw designs in the same bone, thereby controlling for the effect of interspecimen variability. A transverse osteotomy was made in 10 fresh-frozen cadaveric navicular bones and 10 medial cuneiforms. A load cell was used to measure compression between the 2 fragments as a screw was inserted across the fracture. Each bone was tested twice, with an Acutrak Mini (Acumed, Hillsboro, OR; n = 10) and an SBi AutoFIX screw (SBi, Morrisville, PA; n = 10) or an Extremifix (Osteomed, Addison, TX; n = 10) and a Barouk screw (Depuy, Warsaw, IN; n = 10). Compression was recorded at initial insertion and on removal and reinsertion of the screw twice to the same position. Compression was also measured after one additional full turn further than the initial position. RESULTS The mean interfragmentary compression generated by the Acutrak Mini screw was greater than that of the SBi AutoFIX screw (96 N vs 22 N). There was a trend toward a greater mean compression generated by the Extremifix screw compared to the Barouk screw (85 N vs 22 N). There was a significant loss of compression upon removal and reinsertion of the screws. An additional full turn of the screw was able to re-establish a large proportion of the original compression. CONCLUSIONS The compression forces achieved by headless screw systems appeared to vary according to the screw design, depth of insertion, and the quality of the bone. Substantial compression was lost if the screw was removed and replaced. Some screw designs appeared to require a greater depth of insertion to achieve effective compression, and the number of additional turns required to re-establish compression might vary according to the thread design. CLINICAL RELEVANCE Surgeons should be aware of the compression profile of each screw design and the effect of screw removal and reinsertion in the clinical setting of small bone fixation.
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Affiliation(s)
- A W Gardner
- Department of Hand Surgery, Singapore General Hospital, Singapore
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Assari S, Darvish K, Ilyas AM. Biomechanical analysis of second-generation headless compression screws. Injury 2012; 43:1159-65. [PMID: 22482931 DOI: 10.1016/j.injury.2012.03.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/23/2011] [Accepted: 03/11/2012] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Headless Compression Screws (HCS) are commonly utilized for the fixation of small bone and articular fractures. Recently several new second generation HCS (SG-HCS) have been introduced with the purported benefits of improved biomechanical characteristics. We sought to determine and compare the biomechanical efficiencies of these screws. MATERIAL AND METHODS Five HCS including four second generation (Mini-Acutrak 2 (Acumed), Twinfix (Stryker), Kompressor Mini (Integra), HCS 3.0 (Synthes)) and one first generation (Herbert-Whipple) were studied. Polyurethane foam blocks that represented osteoporotic cancellous bone (0.16 g/cc) with a simulated transverse fracture at the waist were utilized and five screws of each brand were tested for the generated compression force and fastening torque during insertion with and without pre-drilling. RESULTS The generated compression force was highest for Mini-Acutrak 2 (45.41 ± 0.88 N) and lowest for Herbert-Whipple (13.44 ± 2.35 N) and forces of Twinfix, Kompressor Mini, HCS 3.0 were in between in descending order. The compression force of SG-HCS increased slightly without pre-drilling but it was not statistically significant while the fastening torque increased significantly. Slight over-fastening beyond the recommended stage significantly reduced the compression force in Twinfix and Kompressor and had no or moderate effect in other screws. CONCLUSION All SG-HCS demonstrated greater biomechanical characteristics than the first generation Herbert-Whipple screw. The Mini-Acutrak 2 with a variable pitch design generated the maximum compression force and showed the most reliability and sustainability. Screws with independently rotating trailing heads (Twinfix and Kompressor Mini) demonstrated loss of compression with extra turns. The increase of fastening torque due to over-fastening and loss of compression at the same time in some screw designs, demonstrated how the fastening torque (applied by the surgeon) can be a misleading measure of the compression force. Application of SG-HCS in osteoporotic bone without pre-drilling can slightly increase the compression force.
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Affiliation(s)
- Soroush Assari
- Department of Mechanical Engineering, Temple University, Philadelphia, PA 19122, USA
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24
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Gruszka DS, Burkhart KJ, Nowak TE, Achenbach T, Rommens PM, Müller LP. The durability of the intrascaphoid compression of headless compression screws: in vitro study. J Hand Surg Am 2012; 37:1142-50. [PMID: 22624783 DOI: 10.1016/j.jhsa.2012.03.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 03/08/2012] [Accepted: 03/08/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE To test a new generation of compression screws: the Acumed Acutrak 2 Mini (AA; Acumed, Hillsboro, OR), the Stryker TwinFix (ST; Stryker, Kalamazoo, MI), and the Synthes 3.0 headless compression screw (SH; Synthes, Solothurn, Switzerland). METHODS We used 40 fresh-frozen human scaphoids for this study. Bone density was measured. A K-wire was inserted centrally. A perpendicular osteotomy was created in the middle third (Herbert B2 fracture). A custom-made load sensor was placed between the bone fragments. All screws were implanted according to the manufacturers' instructions. The Synthes 2.0 cortical screw (SC), implanted as a lag screw, was used as a reference. The compression force during each experiment was digitally monitored for 12 hours while the data were acquired. The data were analyzed using analysis of variance with the Bonferroni correction. RESULTS Immediately after screw insertion, ST reached 226 N, followed by AA with 191 N, SH with 137 N, and SC with 72 N. After 12 hours, ST displayed the highest residual compression force, 141 N, followed by AA with 121 N, SH with 78 N, and SC with 32 N. The differences were significant for ST and AA compared to SC. The loss of compression force over 12 hours was 39% for ST, 42% for AA, 49% for SH, and 55% for SC. CONCLUSIONS The new generation of headless compression screws, especially ST and AA, provided significantly higher compression forces after 12 hours, as well as the least loss of compression force over time, in comparison to a classic cortical lag screw. CLINICAL RELEVANCE A new generation of headless compression screws, by producing higher compression forces, increase stability at the fracture site and might thereby promote bone healing.
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Affiliation(s)
- D S Gruszka
- Department of Trauma Surgery, Centre for Musculoskeletal Surgery, The University Medical Center Mainz, Mainz, Germany.
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25
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Crawford LA, Powell ES, Trail IA. The fixation strength of scaphoid bone screws: an in vitro investigation using polyurethane foam. J Hand Surg Am 2012; 37:255-60. [PMID: 22154719 DOI: 10.1016/j.jhsa.2011.10.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 10/08/2011] [Accepted: 10/13/2011] [Indexed: 02/02/2023]
Abstract
PURPOSE To compare the compression strength and pull-apart resistance of 5 single-piece scaphoid bone compression screws (Acutrak, Asnis, Herbert, Herbert-Whipple, and Little Grafter), with those of 2 dual-component screws (Kompressor and TwinFix). METHODS Two blocks of polyurethane foam were compressed with a screw while held in a tension test machine, with the force measured at full insertion of the screw. The 2 blocks were then pulled apart, and the maximum resistive force was measured. RESULTS The dual-component screws (Kompressor and TwinFix) gave greater compression force than the single-component screws, with the Kompressor screw giving statistically significantly greater compression than the TwinFix. The pull-apart resistance forces did not show such clear differences. CONCLUSIONS The Kompressor screw achieves the greatest compressive forces and has one of the highest pull-apart forces. CLINICAL RELEVANCE When compression and pull-apart resistance are considered, the Kompressor screw has advantages over other methods of scaphoid fixation.
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Sugathan HK, Kilpatrick M, Joyce TJ, Harrison JWK. A biomechanical study on variation of compressive force along the Acutrak 2 screw. Injury 2012; 43:205-8. [PMID: 21839443 DOI: 10.1016/j.injury.2011.07.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/10/2011] [Accepted: 07/15/2011] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Acutrak 2 screws are commonly used for scaphoid fracture fixation. To our knowledge, the variation in compressive force along the screw has not been investigated before. The objectives of our study were to measure variance in compression along the length of the standard Acutrak 2 screw, to identify the region of the screw which produces the greatest compression and to discuss the clinical relevance of this to the placement of the screw for scaphoid fractures. MATERIALS AND METHODS A laboratory model was set up to test the compressive force at 2mm intervals along the screw, using solid polyurethane foam (Sawbone) blocks of varying width. The Acutrak 2 screws were introduced in the standard method. Forces were measured using a custom-made load cell washer introduced between the Sawbone blocks and were plotted as a graph along the whole length of the screw. RESULTS Maximum compression was at the mid-point of the screw. Overall compressive forces were higher in the proximal half of the screw by 19% when compared with the distal half. Minimum compression was seen at 4mm or less from either end of the screw. CONCLUSIONS There is variation in compression along the length of the standard Acutrak 2 screw and the maximum compression was obtained at the mid-point of the screw. From this study, we would recommend when using an Acutrak 2 screw for internal fixation of scaphoid fractures, to attain maximum compressive force, place the fracture at the mid-point of the Acutrak screw. If this is not possible, then place the fracture towards the proximal half of the screw.
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Gokce V, Oflaz H, Dulgeroglu A, Bora A, Gunal I. Kirschner wire fixation for scaphoid fractures: an experimental study in synthetic bones. J Hand Surg Eur Vol 2011; 36:325-8. [PMID: 21282225 DOI: 10.1177/1753193410394525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have studied the biomechanical stability in vitro of three different Kirschner (K) wire configurations in three types of simulated scaphoid waist fractures. The fractures were created with a saw in Sawbones models. There were three fracture patterns: perpendicular to the long axis of the scaphoid model; and 30° and 20° oblique to that. Two 1.2 mm. K-wires were used in each scaphoid. The three configurations were: parallel; 20° oblique; and crossing. The oblique or crossing configurations of K-wires were the most stable depending on the fracture pattern.
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Affiliation(s)
- V Gokce
- Department of Orthopedics, State Hospital; the Departments of Biomechanics and Orthopedics, Dokuz Eylul University Hospital, Izmir, Turkey
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Gereli A, Nalbantoglu U, Sener IU, Kocaoglu B, Turkmen M. Comparison of headless screws used in the treatment of proximal nonunion of scaphoid bone. INTERNATIONAL ORTHOPAEDICS 2010; 35:1031-5. [PMID: 20890757 DOI: 10.1007/s00264-010-1129-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/12/2010] [Accepted: 09/12/2010] [Indexed: 12/21/2022]
Abstract
Screws with different levels of compression force are available for scaphoid fixation and it is known that the Acutrak screw generates greater compression than the Herbert screw. We retrospectively compared two types of headless compression screw for their effectiveness in the repair of scaphoid nonunion. Twenty-nine cases of proximal scaphoid nonunion were surgically treated with non-vascularised bone graft: the Acutrak screw was used in 17 patients and the cannulated Herbert screw in 12 patients. Wrist range of motion, Mayo wrist score, grip strength and QuickDASH scores were indicators used for the functional evaluation. Radiographic findings were assessed for consolidation of nonunion and signs of arthrosis. The mean follow-up time was 49.2 months (range 12-96). Statistically, there was no significant difference between the Acutrak and Herbert screw types in terms of functional evaluation and time required for consolidation. Greater compression did not influence the functional outcome, consolidation rate or time to consolidation. The need for greater compression in the treatment of proximal scaphoid nonunions is thus questionable because it may increase the risk of proximal fragment communition.
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Affiliation(s)
- Arel Gereli
- Department of Orthopaedics and Traumatology, Acibadem University Faculty of Medicine, Acibadem Kadikoy Hospital, Tekin sok. No:8 Acibadem, 34718, Istanbul, Turkey.
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Burkhart KJ, Nowak TE, Appelmann P, Sternstein W, Rommens PM, Mueller LP. Screw fixation of radial head fractures: compression screw versus lag screw--a biomechanical comparison. Injury 2010; 41:1015-9. [PMID: 20347084 DOI: 10.1016/j.injury.2010.03.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 02/25/2010] [Accepted: 03/01/2010] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Secondary loss of reduction and pseudarthrosis due to unstable fixation methods remain challenging problems of surgical stabilisation of radial head fractures. The purpose of our study was to determine whether the 3.0mm Headless Compression Screw (HCS) provides superior stability to the standard 2.0 mm cortical screw (COS). MATERIALS AND METHODS Eight pairs of fresh frozen human cadaveric proximal radii were used for this paired comparison. A standardised Mason II-Fracture was created with a fragment size of 1/3 of the radial head's articular surface that was then stabilised either with two 3.0 mm HCS (Synthes) or two 2.0 mm COS (Synthes) according to a randomisation protocol. The specimens were then loaded axially and transversely with 100 N each for 4 cycles. Cyclic loading with 1000 cycles as well as failure load tests were performed. The Wilcoxon test was used to assess statistically significant differences between the two groups. RESULTS No statistical differences could be detected between the two fixation methods. Under axial loads the COS showed a displacement of 0.32 mm vs. 0.49 mm for the HCS. Under transverse loads the displacement was 0.25 mm for the COS vs. 0.58 mm for the HCS group. After 1000 cycles of axial loading there were still no significant differences. The failure load for the COS group was 291 N and 282 N for the HCS group. CONCLUSION No significant differences concerning the stability achieved by 3.0 mm HCS and the 2.0 mm COS could be detected in the experimental setup presented.
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Affiliation(s)
- Klaus J Burkhart
- Department of Trauma Surgery, Center for Muskuloskeletal Surgery, Johannes Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany.
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Abstract
Scaphoid fractures carry significant long-term morbidity and short-term socioeconomic difficulty in the young and active patient population in which they most commonly occur. While cast immobilization results in high rates of radiographic union in nondisplaced scaphoid fractures, internal fixation with headless compression screws has been recommended in cases of displaced fractures. Internal fixation has led to high rates of union in both nondisplaced and displaced fractures with the added benefits of earlier mobilization and return to work and sports. Multiple manufacturers are now offering "second generation" headless compression screws for the internal fixation of scaphoid fractures. The few biomechanical studies that exist demonstrate improved compression forces and load to failure for the newer generation of headless compression screws when compared with the first generation headless compression screw, although it is unclear if these differences are clinically significant.
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Affiliation(s)
- John R Fowler
- Temple University Hospital, 3401 North Broad Street, Philadelphia, PA, USA
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Ramaswamy R, Evans S, Kosashvili Y. Holding power of variable pitch screws in osteoporotic, osteopenic and normal bone: are all screws created equal? Injury 2010; 41:179-83. [PMID: 19747678 DOI: 10.1016/j.injury.2009.08.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 08/17/2009] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Biomechanical properties of four different commercially available small fragment cannulated screws (Twin fix (Stryker, Freiburg, Germany), Herbert, (Zimmer, Warsaw, USA), Omnitech (Unimedical, Torino, Italy), Barouk (Depuy, Warsaw, USA)), with variable pitch, used for fracture fixation were compared. MATERIALS AND METHODS Polyurethane foam blocks of three different densities with mechanical properties similar to osteoporotic, osteopenic and normal bones were used to conduct the tests. Each screw was tested for pushout and pullout holding power after a primary insertion and for pullout after a repeated insertion into the respective foam blocks. RESULTS The mean pullout and pushout strengths of all screws correlated to the foam density, and were significantly (p<0.001 and <0.001, respectively) better in foam with higher density. The mean pullout strength of each screw was consistently lower after reinsertion into the osteoporotic, osteopenic and normal bone densities by 4-30%, when compared to the index insertion (Fig. 4b). Yet, this difference was not found to be statistically significant (p=0.23). The Barouk screw performed significantly (p<0.0001) better than the other screws in all three different densities of foam for both for pushout and pullout after index insertion as well as for pullout tests after reinsertion. CONCLUSION The holding power of screws is directly correlated to bone density, thread design and number of threads engaging the bone. Reinsertion through the same hole could reduce the ultimate pullout strength. The surgeon should consider the advantages and disadvantages of each implant, depending on the clinical situation and choose accordingly.
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Affiliation(s)
- Rajesh Ramaswamy
- Holland Orthopaedic and Arthritic Campus, Sunnybrook Medical Health Sciences Centre, University of Toronto, Ontario, Canada
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