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Beneš J, Kunz L, Liška J, Šrám J, Krbec M, Džupa V, Křivohlávek M, Návrat T. Determination of stress and displacement on human composite pelvis under static and dynamic loading. Proc Inst Mech Eng H 2022; 236:951-959. [DOI: 10.1177/09544119221099805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This case study describes the experimental determination of displacements and stresses on a composite model of a pelvis that was modified to represent a healthy intact pelvic ring. The modified model was stressed statically up to 1750 N to simulate standing on one leg and also cyclically to model walking. For two different model settings in the loading machine the values of displacements and stresses at the pelvic ring were determined. The two different settings correspond to two different loading vectors applied on the pelvic ring, boundary conditions and degrees of freedom. The experimentally determined values of displacements in both settings are very similar and in accordance with the knowledge on the behaviour of a real human pelvis. The modified model is thus suitable for testing of newly developed implants for pelvis treatment and experimental determination of displacements and stresses in pelvic ring which are caused by application of implants.
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Affiliation(s)
- Jan Beneš
- BT Medical Engineering, Inc., Rozsochy, Czech Republic
| | - Ludvík Kunz
- Institute of Physics of Materials, Czech Academy of Sciences, Brno, Czech Republic
| | | | | | - Martin Krbec
- Department of Orthopaedics and Traumatology, Third Faculty of Medicine of Charles University and University Hospital Kralovske Vinohrady, Prague, Czech Republic
| | - Valér Džupa
- Department of Orthopaedics and Traumatology, Third Faculty of Medicine of Charles University and University Hospital Kralovske Vinohrady, Prague, Czech Republic
| | | | - Tomáš Návrat
- Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic
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Zderic I, Wagner D, Schopper C, Lodde M, Richards G, Gueorguiev B, Rommens P, Acklin YP. Screw-in-screw fixation of fragility sacrum fractures provides high stability without loosening-biomechanical evaluation of a new concept. J Orthop Res 2021; 39:761-770. [PMID: 33098585 DOI: 10.1002/jor.24895] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 09/20/2020] [Accepted: 10/21/2020] [Indexed: 02/04/2023]
Abstract
Surgical treatment of fragility sacrum fractures with percutaneous sacroiliac (SI) screw fixation is associated with high failure rates. Turn-out is detected in up to 20% of the patients. The aim of this study was to evaluate a new screw-in-screw implant prototype for fragility sacrum fracture fixation. Twenty-seven artificial hemipelvises were assigned to three groups (n = 9) for instrumentation of an SI screw, the new screw-in-screw implant prototype, ora transsacral screw. Before implantation, a vertical osteotomy was set in zone 1 after Denis. All specimens were biomechanically tested to failure in upright position. Validated setup and test protocol were used for complex axial and torsional loading applied through the S1 vertebral body to promote turn-out of the implants. Interfragmentary movements were captured via optical motion tracking. Screw motions were evaluated by means of triggered anteroposterior X-rays. Interfragmentary movements and implant motions were significantly higher for SI screw fixation compared to both transsacral and screw-in-screw fixations. In addition, transsacral screw and screw-in-screw fixations revealed similar construct stability. Moreover, screw-in-screw fixation successfully prevented turn-out of the implant that remained during testing at 0° rotation for all specimens. From biomechanical perspective, fragility sacrum fracture fixation with the new screw-in-screw implant prototype provides higher stability than an SI screw, being able to successfully prevent turn-out. Moreover, it combines the higher stability of transsacral screw fixation with the less risky operational procedure of SI screw fixation and can be considered as their alternative treatment option.
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Affiliation(s)
- Ivan Zderic
- Biomechanical Department, AO Research Institute Davos, Davos, Switzerland
| | - Daniel Wagner
- Department of Orthopaedic and Trauma Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Clemens Schopper
- Biomechanical Department, AO Research Institute Davos, Davos, Switzerland
| | - Moritz Lodde
- Biomechanical Department, AO Research Institute Davos, Davos, Switzerland
| | - Geoff Richards
- Biomechanical Department, AO Research Institute Davos, Davos, Switzerland
| | - Boyko Gueorguiev
- Biomechanical Department, AO Research Institute Davos, Davos, Switzerland
| | - Pol Rommens
- Department of Orthopaedic and Trauma Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Yves P Acklin
- Biomechanical Department, AO Research Institute Davos, Davos, Switzerland.,Department of Orthopaedic and Trauma Surgery, University Hospital Basel, Basel, Switzerland
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Jeong JH, Leasure JM, Park J. Assessment of Biomechanical Changes After Sacroiliac Joint Fusion by Application of the 3-Dimensional Motion Analysis Technique. World Neurosurg 2018; 117:e538-e543. [DOI: 10.1016/j.wneu.2018.06.072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/09/2018] [Accepted: 06/11/2018] [Indexed: 10/28/2022]
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Grüneweller N, Raschke MJ, Zderic I, Widmer D, Wähnert D, Gueorguiev B, Richards RG, Fuchs T, Windolf M. Biomechanical comparison of augmented versus non-augmented sacroiliac screws in a novel hemi-pelvis test model. J Orthop Res 2017; 35:1485-1493. [PMID: 27564231 DOI: 10.1002/jor.23401] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 08/19/2016] [Indexed: 02/04/2023]
Abstract
Operative treatment of sacral insufficiency fractures is frequently being complicated by osteopenic bone properties. Cement augmentation of implanted sacroiliac screws may lead to superior construct stability and prevent mechanical complications. A novel hemi-pelvis test model with dissected symphysis was developed. Five fresh-frozen cadaveric pelvises were vertically osteotomized at the sacrum on both sides and fixed with sacroiliac screws in both corridors of the first sacral vertebral body. One side was randomly augmented with bone cement. Cyclic testing consisting of torsional loading (±2.5 Nm) combined with progressively increasing axial loading (+50 N compression, -10 N traction, ±0,01 N/cycle) was performed until failure; simulated physiological loads derived from inverse dynamic calculations. The fixation was analyzed fluoroscopically quantifying screw migrations and assessing failure mechanisms. Failure modes were cut-out, pull-out, screw-out, and washer penetration. Motion at fracture site was analyzed via optical motion tracking. Unscrewing was provoked four times with non-augmented and twice with augmented screws. When focusing on the sacral region only, cement augmentation significantly improved screw fixation in terms of increased number of cycles to failure (p = 0.043). However, when considering overall construct stability, there was no significant difference between augmented and non-augmented state due to washer penetration at the iliac bone. The generated hemi-pelvis model was found to be valid due to the reproduction of the clinically observed failure mode (unscrewing). Unscrewing was not fully prevented by cement augmentation. Augmentation effects stability at the screw tip, but particularly in porotic bone, failure may shift to the next weak point. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1485-1493, 2017.
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Affiliation(s)
- Niklas Grüneweller
- AO Research Institute Davos, Clavadelerstraße 8, 7270 Davos, Switzerland.,Department for Trauma-, Hand- and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, Building W1, Münster, 48149, Germany
| | - Michael J Raschke
- Department for Trauma-, Hand- and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, Building W1, Münster, 48149, Germany
| | - Ivan Zderic
- AO Research Institute Davos, Clavadelerstraße 8, 7270 Davos, Switzerland
| | - Daniel Widmer
- AO Research Institute Davos, Clavadelerstraße 8, 7270 Davos, Switzerland
| | - Dirk Wähnert
- Department for Trauma-, Hand- and Reconstructive Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, Building W1, Münster, 48149, Germany
| | - Boyko Gueorguiev
- AO Research Institute Davos, Clavadelerstraße 8, 7270 Davos, Switzerland
| | | | - Thomas Fuchs
- Department for Trauma and Reconstructive Surgery, Vivantes Hospital Friedrichshain, Landsberger Allee 49, Berlin, 10249, Germany
| | - Markus Windolf
- AO Research Institute Davos, Clavadelerstraße 8, 7270 Davos, Switzerland
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Liu D, Hua Z, Yan X, Jin Z. Biomechanical analysis of a novel hemipelvic endoprosthesis during ascending and descending stairs. Proc Inst Mech Eng H 2016; 230:962-75. [PMID: 27587536 DOI: 10.1177/0954411916663970] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 07/21/2016] [Indexed: 11/16/2022]
Abstract
In this study, the biomechanical characteristic of a newly developed adjustable hemipelvic prosthesis under dynamic loading conditions was investigated using explicit finite element method. Both intact and reconstructed pelvis models, including pelvis, femur and soft tissues, were established referring to human anatomic data using a solid geometry of a human pelvic bone. Hip contact forces during ascending stairs and descending stairs were imposed on pelvic models. Results showed that maximum von Mises stresses in reconstructed pelvis were 421.85 MPa for prostheses and 109.12 MPa for cortical bone, which were still within a low and elastic range below the yielding strength of Ti-6Al-4V and cortical bone, respectively. Besides, no significant difference of load transferring paths along pelvic rings was observed between the reconstructed pelvis and natural pelvis models. And good agreement was found between the overall distribution of maximum principal stresses in trabecular bones of reconstructed pelvis and natural pelvis, while at limited stances, principal stresses in trabecular bone of reconstructed pelvis were slightly lower than natural pelvis. The results indicated that the load transferring function of pelvis could be restored by this adjustable hemipelvic prosthesis. Moreover, the prosthesis was predicted to have a reliable short- and long-term performance. However, due to the occurrence of slightly lower principal stresses at a few stances, a porous structure applied on the interface between the prosthesis and bone would be studied in future work to obtain better long-term stability.
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Affiliation(s)
- Dongxu Liu
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, P.R. China
| | - Zikai Hua
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, P.R. China
| | - Xinyi Yan
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, P.R. China
| | - Zhongmin Jin
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, P.R. China School of Mechanical Engineering, University of Leeds, Leeds, UK
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Camino Willhuber G, Zderic I, Gras F, Wahl D, Sancineto C, Barla J, Windolf M, Richards RG, Gueorguiev B. Analysis of sacro-iliac joint screw fixation: does quality of reduction and screw orientation influence joint stability? A biomechanical study. INTERNATIONAL ORTHOPAEDICS 2015; 40:1537-43. [DOI: 10.1007/s00264-015-3007-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/17/2015] [Indexed: 12/01/2022]
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Vigdorchik JM, Jin X, Sethi A, Herzog DT, Oliphant BW, Yang KH, Vaidya R. A biomechanical study of standard posterior pelvic ring fixation versus a posterior pedicle screw construct. Injury 2015; 46:1491-6. [PMID: 25986670 DOI: 10.1016/j.injury.2015.04.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 01/29/2015] [Accepted: 04/25/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The purpose of this study was to biomechanically test a percutaneous pedicle screw construct for posterior pelvic stabilisation and compare it to standard fixation modalities. METHODS Utilizing a sacral fracture and sacroiliac (SI) joint disruption model, we tested 4 constructs in single-leg stance: an S1 sacroiliac screw, S1 and S2 screws, the pedicle screw construct, and the pedicle screw construct+S1 screw. We recorded displacement at the pubic symphysis and SI joint using high-speed video. Axial stiffness was also calculated. Values were compared using a 2-way ANOVA with Bonferroni adjustment (p<0.05). RESULTS In the sacral fracture model, the stiffness was greatest for the pedicle screw+S1 construct (p<0.001). There was no significant difference between the pedicle screw construct and S1 sacroiliac screw (p=1). For the SI joint model, the S1+S2 SI screws had the largest overall load and stiffness (p<0.001). The S1 screw was significantly stronger than pedicle screw construct (p=0.001). CONCLUSIONS The pedicle screw construct biomechanically compares to currently accepted methods of fixation for sacral fractures when the fracture is uncompressible. It should not be used for SI joint disruptions as one SI or an S1+S2 are significantly stiffer and cheaper.
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Affiliation(s)
- Jonathan M Vigdorchik
- Department of Orthopedic Surgery, Detroit Receiving Hospital, Detroit Medical Center, 4201 St. Antoine Blvd., Suite 4G, Detroit, MI 48201, United States
| | - Xin Jin
- Department of Biomedical Engineering, Wayne State University, 818 West Hancock, Detroit, MI 48201, United States
| | - Anil Sethi
- Department of Orthopedic Surgery, Detroit Receiving Hospital, Detroit Medical Center, 4201 St. Antoine Blvd., Suite 4G, Detroit, MI 48201, United States.
| | - Darren T Herzog
- Department of Orthopedic Surgery, Detroit Receiving Hospital, Detroit Medical Center, 4201 St. Antoine Blvd., Suite 4G, Detroit, MI 48201, United States
| | - Bryant W Oliphant
- Department of Orthopedic Surgery, Detroit Receiving Hospital, Detroit Medical Center, 4201 St. Antoine Blvd., Suite 4G, Detroit, MI 48201, United States
| | - King H Yang
- Department of Biomedical Engineering, Wayne State University, 818 West Hancock, Detroit, MI 48201, United States
| | - Rahul Vaidya
- Department of Orthopedic Surgery, Detroit Receiving Hospital, Detroit Medical Center, 4201 St. Antoine Blvd., Suite 4G, Detroit, MI 48201, United States
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Symphyseal internal rod fixation versus standard plate fixation for open book pelvic ring injuries: a biomechanical study. Eur J Trauma Emerg Surg 2015; 42:197-202. [PMID: 26038047 DOI: 10.1007/s00068-015-0529-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 03/30/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE This study investigates the biomechanical stability of a novel technique for symphyseal internal rod fixation (SYMFIX) using a multiaxial spinal screw-rod implant that allows for direct reduction and can be performed percutaneously and compares it to standard internal plate fixation of the symphysis. METHODS Standard plate fixation (PLATE, n = 6) and the SYMFIX (n = 6) were tested on pelvic composite models with a simulated open book injury using a universal testing machine. On a previously described testing setup, 500 consecutive cyclic loadings were applied with sinusoidal resulting forces of 200 N. Displacement under loading was measured using an optoelectronic camera system and construct rigidity was calculated as a function of load and displacement. RESULTS The rigidity of the PLATE construct was 122.8 N/mm (95 % CI: 110.7-134.8), rigidity of the SYMFIX construct 119.3 N/mm (95 % CI: 105.8-132.7). Displacement in the symphyseal area was mean 0.007 mm (95 % CI: 0.003-0.012) in the PLATE group and 0.021 mm (95 % CI: 0.011-0.031) in the SYMFIX group. Displacement in the sacroiliac joint area was mean 0.156 mm (95 % CI: 0.051-0.261) in the PLATE group and 0.120 mm (95 % CI: 0.039-0.201) in the SYMFIX group. CONCLUSIONS In comparison to standard internal plate fixation for the stabilization of open book pelvic ring injuries, symphyseal internal rod fixation using a multiaxial spinal screw-rod implant in vitro shows a similar rigidity and comparable low degrees of displacement.
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Anterior internal fixator versus a femoral distractor and external fixation for sacroiliac joint compression and single stance gait testing: a mechanical study in synthetic bone. INTERNATIONAL ORTHOPAEDICS 2013; 37:1341-6. [PMID: 23645004 DOI: 10.1007/s00264-013-1890-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 03/29/2013] [Indexed: 01/13/2023]
Abstract
PURPOSE The purpose of this study was to evaluate the biomechanical stability and compressive forces across the sacroiliac (SI) joint of an anterior internal fixator compared to the femoral distractor and external fixator for vertically unstable pelvic fractures. METHODS Five composite pelvises with a simulated APC type III injury fixed with a femoral distractor, external fixator, or anterior internal fixator were tested. A pressure-sensitive film (Tekscan) was placed in the disrupted SI joint recording the magnitude of force. Then, in a single-leg stance model (Instron machine), a load was applied through the sacrum. We recorded displacement at the pubic symphysis and SI joint using high-speed video. Peak load and displacement were measured, and axial stiffness was calculated. Values were compared using a Student's t-test (p < 0.05). RESULTS The SI joint was compressed significantly (p < 0.001) more using the anterior internal fixator (18.9 N) and femoral distractor (18.6 N) than the two-pin external fixator (2.5 N). There was no significant difference between the anterior internal fixator and the femoral distractor in displacement at the SI joint. The pubic symphysis displaced less with the femoral distractor than the anterior internal fixator (5.5 mm vs. 4.1 mm; p < 0.05). CONCLUSIONS The anterior pedicle screw internal fixator allows for indirect compression across the sacroiliac joint that is superior to two-pin external fixation and comparable to the femoral distractor. The anterior internal fixator may be an option for temporary anterior pelvic fixation in situations where external fixation or the femoral distractor have otherwise been used.
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Pizanis A, Garcia P, Santelmann M, Culemann U, Pohlemann T. Reduction and fixation capabilities of different plate designs for pubic symphysis disruption: a biomechanical comparison. Injury 2013; 44:183-8. [PMID: 23068141 DOI: 10.1016/j.injury.2012.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 06/05/2012] [Accepted: 09/24/2012] [Indexed: 02/02/2023]
Abstract
BACKGROUND Typical stabilisation of pelvic open book injuries consists in plate fixation of the symphysis, leading to many different plate designs and procedures that have evolved. However, implant loosening and development of chronic instability are still evident and represent major complications after plate fixation of the symphysis. The aim of this study was to analyse reduction and fixation capabilities of different classical plate techniques with dynamic compression (DC), prebending or modern interlocking screws. METHODS Compression injuries (OTA B1.1) were simulated on synthetic composite pelvises. Sensor films placed in the disrupted symphysis allowed assessment of reduction and compression forces, as well as contact characteristics by implants at defined time points under static non loaded conditions. The commercially available steel plates used in our study differed in curved design, prebending and DC- or locking screw capabilities, as narrow large fragment (4.5) or small fragment plates (3.5). RESULTS DC procedure clearly increased the compressive force in the symphysis and improved the reduction by enhanced contact areas. These effects were preserved to the end of the experiments only when the plates were prebended (10°). Anatomically contoured and prebended 3.5 plates had a similar effect, but the contact area was even more pronounced. Best results were observed using the "3.5 symphyseal plate" with DC-effect medially and locking screws laterally. Purely interlocking screw plates by themselves allowed an optimal contact area, yet failed to preserve the initial compressive reduction force. CONCLUSIONS The experimental results suggest a biomechanical advantage in using prebended plates for symphysis fixation compared to non-bended plates. Best results with regard to compression and increased contact area can be achieved by anatomically contoured plates with combined DC and locking screw capabilities. These findings are of special interest in pelvic surgery for choosing the right implant in severe displacements, obese patients and symphysiodesis techniques.
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Affiliation(s)
- Antonius Pizanis
- Department of Trauma-, Hand- and Reconstructive Surgery, University Hospital of Saarland, D-66424 Homburg/Saar, Germany.
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