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Oldhoff MGE, Kamal Z, Ten Duis K, Wubs FW, de Vries JPPM, Kraeima J, IJpma FFA. Semi-automated finite element analyses of surgically treated acetabular fractures to investigate the biomechanical behaviour of patient-specific compared to conventional implants. J Orthop Surg Res 2024; 19:541. [PMID: 39237975 DOI: 10.1186/s13018-024-04957-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 07/29/2024] [Indexed: 09/07/2024] Open
Abstract
BACKGROUND In acetabular fracture surgery, understanding the biomechanical behaviour of fractures and implants is beneficial for clinical decision-making about implant selection and postoperative (early) weightbearing protocols. This study outlines a novel approach for creating finite element models (FEA) from actual clinical cases. Our objectives were to (1) create a detailed semi-automatic three-dimensional FEA of a patient with a transverse posterior wall acetabular fracture and (2) biomechanically compare patient-specific implants with manually bent off-the-shelf implants. METHODS A computational study was performed in which we developed three finite element models. The models were derived from clinical imaging data of a 20-year-old male with a transverse posterior wall acetabular fracture treated with a patient-specific implant. This implant was designed to fit the patient's anatomy and fracture configuration, allowing for optimal placement and predetermined screw trajectories. The three FEA models included an intact hemipelvis for baseline comparison, one with a fracture fixated with a patient-specific implant, and another with a conventional implant. Two loading conditions were investigated: standing up and peak walking forces. Von Mises stress and displacement patterns in bone, implants and screws were analysed to assess the biomechanical behaviour of fracture fixation with either a patient-specific versus a conventional implant. RESULTS The finite element models demonstrated that for a transverse posterior wall type fracture, a patient-specific implant resulted in lower peak stresses in the bone (30 MPa and 56 MPa) in standing-up and peak walking scenario, respectively, compared to the conventional implant model (46 MPa and 90 MPa). The results suggested that patient-specific implant could safely withstand standing-up and walking after surgery, with maximum von Mises stresses in the implant of 156 MPa and 371 MPa, respectively. The results from the conventional implant indicate a likelihood of implant failure, with von Mises stresses in the implant (499 MPa and 1000 MPa) exceeding the yield stress of stainless steel. CONCLUSION This study presents a workflow for conducting finite element analysis of real clinical cases in acetabular fracture surgery. This concept of personalized biomechanical fracture and implant assessment can eventually be applied in clinical settings to guide implant selection, compare conventional implants with innovative patient-specific ones, optimizing implant designs (including shape, size, materials, screw positions), and determine whether immediate full weight-bearing can be safely permitted.
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Affiliation(s)
- M G E Oldhoff
- Department of Trauma Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
- 3D Lab/Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Z Kamal
- 3D Lab/Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - K Ten Duis
- Department of Trauma Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - F W Wubs
- Bernoulli Institute for Mathematics, Computer Science and Artificial Intelligence, University of Groningen, Groningen, The Netherlands
| | - J P P M de Vries
- Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - J Kraeima
- 3D Lab/Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - F F A IJpma
- Department of Trauma Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Zhu Y, Babazadeh-Naseri A, Brake MRW, Akin JE, Li G, Lewis VO, Fregly BJ. Evaluation of finite element modeling methods for predicting compression screw failure in a custom pelvic implant. Front Bioeng Biotechnol 2024; 12:1420870. [PMID: 39234264 PMCID: PMC11372789 DOI: 10.3389/fbioe.2024.1420870] [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: 04/21/2024] [Accepted: 08/05/2024] [Indexed: 09/06/2024] Open
Abstract
Introduction: Three-dimensional (3D)-printed custom pelvic implants have become a clinically viable option for patients undergoing pelvic cancer surgery with resection of the hip joint. However, increased clinical utilization has also necessitated improved implant durability, especially with regard to the compression screws used to secure the implant to remaining pelvic bone. This study evaluated six different finite element (FE) screw modeling methods for predicting compression screw pullout and fatigue failure in a custom pelvic implant secured to bone using nine compression screws. Methods: Three modeling methods (tied constraints (TIE), bolt load with constant force (BL-CF), and bolt load with constant length (BL-CL)) generated screw axial forces using functionality built into Abaqus FE software; while the remaining three modeling methods (isotropic pseudo-thermal field (ISO), orthotropic pseudo-thermal field (ORT), and equal-and-opposite force field (FOR)) generated screw axial forces using iterative physics-based relationships that can be implemented in any FE software. The ability of all six modeling methods to match specified screw pretension forces and predict screw pullout and fatigue failure was evaluated using an FE model of a custom pelvic implant with total hip replacement. The applied hip contact forces in the FE model were estimated at two locations in a gait cycle. For each of the nine screws in the custom implant FE model, likelihood of screw pullout failure was predicted using maximum screw axial force, while likelihood of screw fatigue failure was predicted using maximum von Mises stress. Results: The three iterative physics-based modeling methods and the non-iterative Abaqus BL-CL method produced nearly identical predictions for likelihood of screw pullout and fatigue failure, while the other two built-in Abaqus modeling methods yielded vastly different predictions. However, the Abaqus BL-CL method required the least computation time, largely because an iterative process was not needed to induce specified screw pretension forces. Of the three iterative methods, FOR required the fewest iterations and thus the least computation time. Discussion: These findings suggest that the BL-CL screw modeling method is the best option when Abaqus is used for predicting screw pullout and fatigue failure in custom pelvis prostheses, while the iterative physics-based FOR method is the best option if FE software other than Abaqus is used.
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Affiliation(s)
- Yuhui Zhu
- Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - Ata Babazadeh-Naseri
- Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - Matthew R W Brake
- Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - John E Akin
- Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - Geng Li
- Department of Mechanical Engineering, Rice University, Houston, TX, United States
| | - Valerae O Lewis
- Department of Orthopedic Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Benjamin J Fregly
- Department of Mechanical Engineering, Rice University, Houston, TX, United States
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Zhao G, Wang L, Wang H, Li C, Yuan S, Sun J, Tian Y, Liu X. Biomechanical Effects of Multi-segment Fixation on Lumbar Spine and Sacroiliac Joints: A Finite Element Analysis. Orthop Surg 2024. [PMID: 39118238 DOI: 10.1111/os.14187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 07/15/2024] [Accepted: 07/21/2024] [Indexed: 08/10/2024] Open
Abstract
OBJECTIVE Spine fixation surgery affects the biomechanical environment in the sacroiliac joint (SIJ), which may lead to the SIJ pain or degeneration after surgery. The purpose of this study is to determine the impact of the number and position of fixed segments on the SIJs and provide references for surgeons to plan fixation levels and enhance surgical outcomes. METHODS The intact lumbar-pelvis finite element (FE) models and 11 fixation FE models with different number and position of fixed segments were developed based on CT images. A 400N follower load and 10° range of motion (ROM) of the spine were applied to the superior endplate of L1 to simulate the flexion, extension, bending and torsion motion after surgery. The peak stress on the SIJs, lumbar intervertebral discs, screws and rods were calculated to evaluate the biomechanical effects of fixation procedures. RESULTS With the lowermost instrumented vertebra (LIV) of L5 or S1, the peak stress on SIJs increased with the number of fixed segments increasing. The flexion motion led to the greater von Mises stress on SIJ compared with other load conditions. Compared with the intact model, peak stress on all fixed intervertebral discs was reduced in the models with less than three fixed segments, and it increased in the models with more than three fixed segments. The stress on the SIJ was extremely high in the models with all segments from L1 to L5 fixed, including L1-L5, L1-S1 and L1-S2 fixation models. The stress on the segment adjacent to the fixed segments was significant higher compared to that in the intact model. The peak stress on rods and screws also increased with the number of fixed segments increasing in the flexion, extension and bending motion, and the bending and flexion motions led to the greater von Mises stress on SIJs. CONCLUSION Short-term fixation (≤2 segments) did not increase the stress on the SIJs significantly, while long-term segment fixation (≥4 segments) led to greater stress on the SIJs especially when all the L1-L5 segments were fixed. Unfixed lumbar segments compensated the ROM loss of the fixed segments, and the preservation of lumbar spine mobility would reduce the risks of SIJ degeneration.
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Affiliation(s)
- Geng Zhao
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Lianlei Wang
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Hongwei Wang
- Collage of Artificial Intelligence and Big Data for Medical Sciences, Shandong First Medical University, Jinan, China
| | - Chao Li
- Department of Orthopedics, Peking University First Hospital, Beijing, China
| | - Suomao Yuan
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Junyuan Sun
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yonghao Tian
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xinyu Liu
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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Xia W, Jiang H, Tao E, Ye J, Wang F, Wang X, Cai L, Feng Y. Comparison of ESIN and other minimally invasive techniques for anterior pelvic ring injury: a finite element analysis and case-control study. Int J Surg 2024; 110:2636-2648. [PMID: 38320104 DOI: 10.1097/js9.0000000000001137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/25/2024] [Indexed: 02/08/2024]
Abstract
OBJECT A novel technique, percutaneous elastic stable intramedullary nail fixation (ESIN), proposed by our team for the treatment of anterior pelvic ring injury. Finite element analysis and retrospective case-control study were used to compare biomechanical properties and clinical outcomes between ESIN and other techniques. METHODS Four groups of finite element models of pelvic anterior ring injury were simulated, including ESIN (model A), retrograde transpubic screw fixation (RTSF, model B), subcutaneous internal fixator (model C), and external fixator (model D), and a vertical downward load of 500 N was applied to the S1 vertebral endplate. Stress and displacement distributions of intact pelvis, displacement distributions of pubic fracture fragments, and stress distributions of fixation devices were analysed. Then 31 patients with anterior pelvic ring injury (15 in the ESIN group and 16 in the RTSF group) were reviewed. Clinical outcomes were evaluated at the final follow-up. Postoperative complications were also recorded. RESULTS Under 500N loading, the intact stability of the pelvis was compared as follows: model B (20.58 mm, 121.82 MPa), model A (20.80 mm, 129.97 MPa), model C (22.02 mm, 141.70 MPa), and model D (22.57 mm, 147.06 MPa). The regional stability of superior pubic ramus was compared as follows: model B (9.48 mm), model A (10.16 mm), model C (10.52 mm), and model D (10.76 mm). All 31 patients received follow-up at least 12 months postsurgery (range 12-20 months). Age, sex, injury mechanism, fracture type, time between the injury and operation, American Society of Anesthesiologists score, intraoperative blood loss, hospital stay, follow-up period, time to union, and Majeed scores did not differ significantly between the two groups ( P >0.05). However, the differences in the duration of unilateral surgery, unilateral intraoperative fluoroscopy and one-time success rate were significant ( P <0.05). CONCLUSIONS With sufficient biomechanical stability and minimally invasive advantage, the percutaneous technique using ESIN can be used to successfully treat anterior pelvic ring injuries. In addition, advantages over RTSF include a shorter duration of surgery, reduced requirement for intraoperative fluoroscopy, and a higher one-time success rate. ESIN therefore constitutes a good alternative to RTSF.
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Affiliation(s)
- Weijie Xia
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
| | - Hongyi Jiang
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
| | - Endong Tao
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
| | - Jianjun Ye
- West China Hospital of Sichuan University, Chengdu, People's Republic of China
| | - Fulin Wang
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
| | - Xianyu Wang
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
| | - Leyi Cai
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
| | - Yongzeng Feng
- Department of Orthopaedics Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang
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Lei D, Lei J, Xu H. Biomechanical characteristics of arteries during pelvic fracture reduction and dynamic simulation analysis. Comput Methods Biomech Biomed Engin 2024:1-14. [PMID: 38439667 DOI: 10.1080/10255842.2024.2324880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/24/2024] [Indexed: 03/06/2024]
Abstract
During robot-assisted reduction of pelvic fracture, blood vessels are susceptible to tensile and shear forces, making them prone to injury. Considering the impact of pelvic reduction on the risk of arterial injury, the biomechanical characteristics of arteries during the pelvic fracture reduction process are studied, and a refined coupled composite model of the damaged pelvic structure is established. Dynamic simulations of pelvic fracture reduction are conducted based on the planned reduction path. The simulation results show that during the reduction process, when the affected side is rotated, the stress and strain of the artery are maximum, particularly at the locations of the iliac common artery, internal iliac artery, and the superior gluteal artery arch endure significant stress and strain. After reduction, the maximum stress is observed in the right superior gluteal artery, and the maximum strain occurs at the intersection of the right iliac common artery. The stretch ratio of both the left and right iliac common arteries is considerable. Therefore, it can be concluded that the superior gluteal artery and the internal iliac artery are prone to injury, particularly the segment from the origin of the superior gluteal artery to its passage around the greater sciatic notch. After reduction, substantial traction on the iliac common artery, which makes it more susceptible to deformation, carries a risk of arterial rupture and aneurysm formation. This study provides a reference for planning the safe reduction path of pelvic fracture surgery and improving safety.
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Affiliation(s)
- Dongwei Lei
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Jingtao Lei
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Haifei Xu
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
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Kou W, Liang Y, Wang Z, Liang Q, Sun L, Kuang S. An Integrated Method of Biomechanics Modeling for Pelvic Bone and Surrounding Soft Tissues. Bioengineering (Basel) 2023; 10:736. [PMID: 37370667 DOI: 10.3390/bioengineering10060736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
The pelvis and its surrounding soft tissues create a complicated mechanical environment that greatly affects the success of fixing broken pelvic bones with surgical navigation systems and/or surgical robots. However, the modeling of the pelvic structure with the more complex surrounding soft tissues has not been considered in the current literature. The study developed an integrated finite element model of the pelvis, which includes bone and surrounding soft tissues, and verified it through experiments. Results from the experiments showed that including soft tissue in the model reduced stress and strain on the pelvis compared to when it was not included. The stress and strain distribution during pelvic loading was similar to what is typically seen in research studies and more accurate in modeling the pelvis. Additionally, the correlation with the experimental results from the predecessor's study was strong (R2 = 0.9627). The results suggest that the integrated model established in this study, which includes surrounding soft tissues, can enhance the comprehension of the complex biomechanics of the pelvis and potentially advance clinical interventions and treatments for pelvic injuries.
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Affiliation(s)
- Wei Kou
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou 215137, China
| | - Yefeng Liang
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou 215137, China
| | - Zhixing Wang
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou 215137, China
| | - Qingxi Liang
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou 215137, China
| | - Lining Sun
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou 215137, China
| | - Shaolong Kuang
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou 215137, China
- College of Health Science and Environment Engineering, Shenzhen Technology University, Shenzhen 518118, China
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Duan P, Ding X, Xiong M, Wang P, Xu S, Du W. Biomechanical evaluation of a healed acetabulum with internal fixators: finite element analysis. J Orthop Surg Res 2023; 18:251. [PMID: 36973727 PMCID: PMC10044380 DOI: 10.1186/s13018-023-03736-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND Treatment of complicated acetabular fracture with internal fixation usually has high risk of failure because of unbefitting fixation. However, evaluation of the biomechanical effect of internal fixation under physiological loading for fracture healing is still generally rarely performed. The purpose of this study is to analyze the biomechanical characteristics of a healed acetabulum with designed internal fixators under gait and to explore the biomechanical relationship between the healed bone and the internal fixator. METHODS A patient-specific finite element model of whole pelvis with designed internal fixators was constructed based on the tomographic digital images, in which the spring element was used to simulate the main ligaments of the pelvis. And the finite element analysis under both the combination loading of different phases and the individual loading of each phase during the gait cycle was carried out. The displacement, von Mises stress, and strain energy of both the healed bone and the fixation were calculated to evaluate the biomechanical characteristics of the healed pelvis. RESULTS Under the combination loading of gait, the maximum difference of displacement between the left hip bone with serious injury and the right hip bone with minor injury is 0.122 mm, and the maximum stress of the left and right hemi-pelvis is 115.5 MPa and 124.28 MPa, respectively. Moreover, the differences of average stress between the bone and internal fixators are in the range of 2.3-13.7 MPa. During the eight phases of gait, the stress distribution of the left and right hip bone is similar. Meanwhile, based on the acetabular three-column theory, the strain energy ratio of the central column is relatively large in stance phases, while the anterior column and posterior column of the acetabular three-column increase in swing phases. CONCLUSIONS The acetabular internal fixators designed by according to the anatomical feature of the acetabulum are integrated into the normal physiological stress conduction of the pelvis. The design and placement of the acetabular internal fixation conforming to the biomechanical characteristics of the bone is beneficial to the anatomical reduction and effective fixation of the fracture, especially for complex acetabular fracture.
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Affiliation(s)
- Pengyun Duan
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, People's Republic of China
| | - Xiaohong Ding
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, People's Republic of China.
| | - Min Xiong
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, People's Republic of China
| | - Panfeng Wang
- Department of Orthopaedics, Changhai Hospital, Naval Medical University, Shanghai, People's Republic of China
| | - Shipeng Xu
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, People's Republic of China
| | - Wei Du
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, People's Republic of China
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Fallahnezhad K, O'Rourke D, Bahl JS, Thewlis D, Taylor M. The role of muscle forces and gait cycle discretization when assessing acetabular cup primary stability: A finite element study. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107351. [PMID: 36709556 DOI: 10.1016/j.cmpb.2023.107351] [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: 06/27/2022] [Revised: 12/18/2022] [Accepted: 01/10/2023] [Indexed: 06/18/2023]
Abstract
UNLABELLED The aim of this study was to investigate the influence of the muscle force contribution and loading cycle discretization on the predicted micromotion and interfacial bone strains in the implanted acetabulum. To this end, a patient specific finite element model of the hemipelvis was developed, based on the CT-scan and gait analysis results, collected as part of the authors' previous work. Outcomes of this study suggests that the acetabular cup micromotion and interfacial bone strains can be predicted just using the joint contact force. This helps to reduce the complexity of the finite element models by ignoring the contribution of muscle forces and the associated challenges of mapping these forces to the pelvis. However, the gait cycle needs to be adequately discretised to capture the micromotion at the bone-implant interface. BACKGROUND AND OBJECTIVE The Dalstra load case, which includes muscle forces, has been widely adopted in the literature for studying the mechanical environment in the intact and implanted acetabulum. To simplify the modelling approach, some researchers ignore the contribution of muscle forces. The Dalstra load case is also divided into eight separate load steps (five in the stance phase and three in the swing phase), however, it is unclear whether this adequately captures the micromotions, for a cementless acetabular cup, during a simulated activity. The aim of this study was to investigate the influence of the muscle force contribution and loading cycle discretization on the predicted micromotion and interfacial bone strains. METHODS In this work, a patient specific finite element model of the hemipelvis was developed, based on the CT-scan and gait analysis results, collected as part of the authors' previous work. Finite element simulations were performed using the joint contact and muscle forces derived from two sources. The first approach was used the load case proposed by Dalstra et al. The second approach used joint contact and muscle forces predicted by a musculoskeletal model. Additionally, the musculoskeletal load case was discretised into 50 equal load steps and the results compared with the equivalent Dalstra load steps. RESULTS The results showed that the contribution of the muscle forces resulted in minor differences in both the magnitude and distribution of the predicted acetabular micromotion (up to 4.01% in the mean acetabular micromotion) and interfacial bone strains (up to 10.34% in the mean interfacial bone strains). The degree of gait cycle discretisation had a significant influence on the acetabular micromotion with a difference of 20.89% in the mean acetabular micromotion. CONCLUSION Outcomes of this study suggests that the acetabular cup micromotion and interfacial bone strains can be predicted just using the joint contact force. This helps to reduce the complexity of the finite element models by ignoring the contribution of muscle forces and the associated challenges of mapping these forces to the pelvis. However, the gait cycle needs to be adequately discretised to capture the micromotion at the bone-implant interface.
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Affiliation(s)
- Khosro Fallahnezhad
- Medical Device Research Institute, College of Science and Engineering, Flinders University, 1284 South Road, Clovelly Park, South Australia 5042, Australia.
| | - Dermot O'Rourke
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Gardens Point campus, 2 George St, Brisbane, Brisbane, QLD 4000, Australia
| | - Jasvir S Bahl
- Centre for Orthopaedics and Trauma Research (COTR), The University of Adelaide, 4 North Terrace, Adelaide SA 5000, Australia
| | - Dominic Thewlis
- Centre for Orthopaedics and Trauma Research (COTR), The University of Adelaide, 4 North Terrace, Adelaide SA 5000, Australia
| | - Mark Taylor
- Medical Device Research Institute, College of Science and Engineering, Flinders University, 1284 South Road, Clovelly Park, South Australia 5042, Australia
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Modeling the debonding process of osseointegrated implants due to coupled adhesion and friction. Biomech Model Mechanobiol 2023; 22:133-158. [PMID: 36284076 PMCID: PMC9957925 DOI: 10.1007/s10237-022-01637-7] [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: 03/20/2022] [Accepted: 09/06/2022] [Indexed: 11/02/2022]
Abstract
Cementless implants have become widely used for total hip replacement surgery. The long-term stability of these implants is achieved by bone growing around and into the rough surface of the implant, a process called osseointegration. However, debonding of the bone-implant interface can still occur due to aseptic implant loosening and insufficient osseointegration, which may have dramatic consequences. The aim of this work is to describe a new 3D finite element frictional contact formulation for the debonding of partially osseointegrated implants. The contact model is based on a modified Coulomb friction law by Immel et al. (2020), that takes into account the tangential debonding of the bone-implant interface. This model is extended in the direction normal to the bone-implant interface by considering a cohesive zone model, to account for adhesion phenomena in the normal direction and for adhesive friction of partially bonded interfaces. The model is applied to simulate the debonding of an acetabular cup implant. The influence of partial osseointegration and adhesive effects on the long-term stability of the implant is assessed. The influence of different patient- and implant-specific parameters such as the friction coefficient [Formula: see text], the trabecular Young's modulus [Formula: see text], and the interference fit [Formula: see text] is also analyzed, in order to determine the optimal stability for different configurations. Furthermore, this work provides guidelines for future experimental and computational studies that are necessary for further parameter calibration.
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A novel anatomical self-locking plate fixation for both-column acetabular fractures. Chin J Traumatol 2022; 25:345-352. [PMID: 35478088 PMCID: PMC9751769 DOI: 10.1016/j.cjtee.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 03/08/2022] [Accepted: 03/26/2022] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To compare the stability of the posterior anatomic self-locking plate (PASP) with two types of popular reconstruction plate fixation, i.e. double reconstruction plate (DRP) and cross reconstruction plate (CRP), and to explore the influence of sitting and turning right/left on implants. METHODS PASP, DRP and CRP were assembled on a finite element model of both-column fractures of the left acetabulum. A load of 600 N and a torque of 8 N·m were loaded on the S1 vertebral body to detect the change of stress and displacement when sitting and turning right/left. RESULTS The peak stress and displacement of the three kinds of fixation methods under all loading conditions were CRP > DRP > PASP. The peak stress and displacement of PASP are 313.5 MPa and 1.15 mm respectively when turning right; and the minimal was 234.0 Mpa and 0.619 mm when turning left. CONCLUSION PASP can provide higher stability than DRP and CRP for both-column acetabular fractures. The rational movement after posterior DRP and PASP fixation for acetabular fracture is to turn to the ipsilateral side, which can avoid implant failure.
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Effects of Loading Conditions on the Pelvic Fracture Biomechanism and Discrimination of Forensic Injury Manners of Impact and Run-Over Using the Finite Element Pelvic Model. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12020604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study aimed to systematically simulate the responses of pelvic fracture under impact and run-over to clarify the effects of boundary and loading conditions on the pelvic fracture mechanism and provide complementary quantitative evidence for forensic practice. Based on the THUMS finite element model, we have validated the simulation performance of the model by a real postmortem human pelvis side impact experiment. A total of 54 simulations with two injury manners (impact and run-over), seven loading directions (0°, 30°, 60°, 90°, 270°, 300°, 330°), and six loading velocities (10, 20, 30, 40, 50, and 60 km/h) were conducted. Criteria of effective strain, Von-Mises stress, contact force, and self-designed normalized eccentricity were used to evaluate the biomechanism of pelvic fracture. Based on our simulation results, it’s challenging to distinguish impact from run-over only rely on certain characteristic fractures. Loads on the front and back were less likely to cause pelvic fractures. In the 30°, 60°, 300° load directions, the overall deformation caused a “diagonal” pelvic fracture. The higher is the velocity (kinetic energy), the more severe is the pelvic fracture. The contact force will predict the risk of fracture. In addition, our self-designed eccentricity will distinguish the injury manner of impact and run-over under the 90° loads. The “biomechanical fingerprints” based on logistic regression of all biomechanical variables have an AUC of 0.941 in discriminating the injury manners. Our study may provide simulation evidence and new methods for the forensic community to improve the forensic identification ability of injury manners.
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Salem M, Westover L, Adeeb S, Duke K. Prediction of fracture initiation and propagation in pelvic bones. Comput Methods Biomech Biomed Engin 2021; 25:808-820. [PMID: 34587835 DOI: 10.1080/10255842.2021.1981883] [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: 10/20/2022]
Abstract
The objective is developing an XFEM model that is capable of predicting different types of fracture in the pelvic bone under various loading conditions. Previously published mechanical and failure characteristics of cortical and cancellous tissues were implemented and assigned to an intact pelvic bone with specified cortical and cancellous tissues. Various loading conditions, including combined load directions, were applied to the acetabulum to model different types of fracture (e.g., anterior/posterior wall fracture and transverse fracture) in the pelvic bone. The predicated types of fracture and the maximum force at fracture were compared to those acquired from previously published experimental tests. Anterior/posterior wall fracture and transverse fracture were the most common types of fractures determined in the simulations. The XFEM simulations were able to predict similar fractures to those reported in the experimental tests. The maximum fracture force in the XFEM model was found to be 18.6 kN compared to 8.85 kN reported in the previous experimental tests. The results revealed that different types of fracture in the pelvic bones can be caused by the various loading conditions in unstable high-rate impact loads. Using proper mechanical and failure behaviors of cortical and cancellous tissues, XFEM modeling of pelvic bone is capable of predicting bone fracture. In future work, the XFEM models of cancellous and cortical tissues can be assigned to other bones in human body skeleton so that the failure mechanism in such bones can be investigated.
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Affiliation(s)
- Mohammad Salem
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Lindsey Westover
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Samer Adeeb
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Kajsa Duke
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
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Henyš P, Kuchař M, Hájek P, Hammer N. Mechanical metric for skeletal biomechanics derived from spectral analysis of stiffness matrix. Sci Rep 2021; 11:15690. [PMID: 34344907 PMCID: PMC8333423 DOI: 10.1038/s41598-021-94998-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 07/19/2021] [Indexed: 02/07/2023] Open
Abstract
A new metric for the quantitative and qualitative evaluation of bone stiffness is introduced. It is based on the spectral decomposition of stiffness matrix computed with finite element method. The here proposed metric is defined as an amplitude rescaled eigenvalues of stiffness matrix. The metric contains unique information on the principal stiffness of bone and reflects both bone shape and material properties. The metric was compared with anthropometrical measures and was tested for sex sensitivity on pelvis bone. Further, the smallest stiffness of pelvis was computed under a certain loading condition and analyzed with respect to sex and direction. The metric complements anthropometrical measures and provides a unique information about the smallest bone stiffness independent from the loading configuration and can be easily computed by state-of-the-art subject specified finite element algorithms.
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Affiliation(s)
- Petr Henyš
- grid.6912.c0000000110151740Institute of New Technologies and Applied Informatics, Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 1402/2, 461 17 Liberec, Czech Republic
| | - Michal Kuchař
- grid.4491.80000 0004 1937 116XDepartment of Anatomy, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic
| | - Petr Hájek
- grid.4491.80000 0004 1937 116XDepartment of Anatomy, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic
| | - Niels Hammer
- grid.11598.340000 0000 8988 2476Department of Macroscopic and Clinical Anatomy, Medical University of Graz, Auenbruggerpl. 2, 8036 Graz, Austria ,grid.9647.c0000 0004 7669 9786Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany ,grid.461651.10000 0004 0574 2038Fraunhofer Institute for Machine Tools and Forming Technology IWU, Nöthnitzer Straße 44, 01187 Dresden, Germany
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Determinants of the primary stability of cementless acetabular cup implants: A 3D finite element study. Comput Biol Med 2021; 135:104607. [PMID: 34242871 DOI: 10.1016/j.compbiomed.2021.104607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/31/2021] [Accepted: 06/22/2021] [Indexed: 11/20/2022]
Abstract
Primary stability of cementless implants is crucial for the surgical success and long-term stability. However, primary stability is difficult to quantify in vivo and the biomechanical phenomena occurring during the press-fit insertion of an acetabular cup (AC) implant are still poorly understood. The aim of this study is to investigate the influence of the cortical and trabecular bone Young's moduli Ec and Et, the interference fit IF and the sliding friction coefficient of the bone-implant interface μ on the primary stability of an AC implant. For each parameter combination, the insertion of the AC implant into the hip cavity and consequent pull-out are simulated with a 3D finite element model of a human hemi-pelvis. The primary stability is assessed by determining the polar gap and the maximum pull-out force. The polar gap increases along with all considered parameters. The pull-out force shows a continuous increase with Ec and Et and a non-linear variation as a function of μ and IF is obtained. For μ > 0.6 and IF > 1.4 mm the primary stability decreases, and a combination of smaller μ and IF lead to a better fixation. Based on the patient's bone stiffness, optimal combinations of μ and IF can be identified. The results are in good qualitative agreement with previous studies and provide a better understanding of the determinants of the AC implant primary stability. They suggest a guideline for the optimal choice of implant surface roughness and IF based on the patient's bone quality.
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The effect of body configuration on the strain magnitude and distribution within the acetabulum during sideways falls: A finite element approach. J Biomech 2020; 114:110156. [PMID: 33302183 DOI: 10.1016/j.jbiomech.2020.110156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 01/17/2023]
Abstract
While the incidence of hip fractures has declined during the last decades, the incidence of acetabular fractures resulting from low-energy sideways falls has increased, and the mechanisms responsible for this trend remain unknown. Previous studies have suggested that body configuration during the impact plays an important role in a hip fracture. Thus, the aim of this study was to investigate the effect of body configuration angles (trunk tilt angle, trunk flexion angle, femur horizontal rotation angle, and femur diaphysis angle) on low-energy acetabular fractures via a parametric analysis. A computed tomography-based (CT) finite element model of the ground-proximal femur-pelvis complex was created, and strain magnitude, time-history response, and distribution within the acetabulum were evaluated. Results showed that while the trunk tilt angle and femur diaphysis angle have the greatest effect on strain magnitude, the direction of the fall (lateral vs. posterolateral) contributes to strain distribution within the acetabulum. The results also suggest that strain level and distribution within the proximal femur and acetabulum resulting from a sideways fall are not similar and, in some cases, even opposite. Taken together, our simulations suggest that a more horizontal trunk and femoral shaft at the impact phase can increase the risk of low-energy acetabular fractures.
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Yang J, Zhao G, Xu H, Wang F. Three-Dimensional Finite Element Analysis of the Effects of Ligaments on Human Sacroiliac Joint and Pelvis in Two Different Positions. J Biomech Eng 2020; 142:081007. [PMID: 32060536 DOI: 10.1115/1.4046361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 12/27/2022]
Abstract
To present the ligament effects on sacroiliac joint (SIJ) stability and human pelvis biomechanical characteristics in two different positions by using three-dimensional (3D) finite element (FE) models of pelvis. Based on the computed tomography (CT) data of human pelvis, three-dimensional FE models of human pelvis in sitting and standing positions were established, which include the bone (sacrum, ilium, and coccyx) and six ligaments (sacroiliac, sacrospinous, sacrotuberous, inguinal, superior pubic, and arcuate pubic ligaments). 600 N vertical load was applied at the upper surface of sacrum to analyze the stress and displacement distribution of pelvis and SIJ. The simulation results demonstrated that the maximum stresses of sacrum and ilium on SIJ contact surface were 5.63 MPa and 7.40 MPa in standing position and 7.44 MPa and 7.95 MPa in sitting position. The stresses of ligament dysfunction group were higher than that of health group, which increased by 22.6% and 35.7% in standing position and 25.2% and 43.6% in sitting position in sacrum and ilium. The maximum displacements located on the upper surface of sacrum, which were 0.13 mm and 1.04 mm in standing and sitting positions. Ligaments dysfunction group increased 30.7% and 9.6% than health group in standing and sitting positions. The integral displacement of pelvis was greater in sitting position. The location of stress concentration and displacement distribution of pelvic bone are closely resembled previous research results in two different positions. The simulation results may provide beneficial information and theoretical models for clinical research of pelvic fracture, joint movement, and ligament functional injuries, and so on.
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Affiliation(s)
- Jiajing Yang
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Gaiping Zhao
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Yangpu District, Shanghai 200093, China
| | - Haifei Xu
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Fei Wang
- Changhai Hospital of Shanghai, 168 Changhai Road, Yangpu District, Shanghai 200433, China
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Duan J, Wang K, Chang T, Wang L, Zhang S, Niu W. Tai Chi Is Safe and Effective for the Hip Joint: A Biomechanical Perspective. J Aging Phys Act 2020; 28:415-425. [PMID: 31756718 DOI: 10.1123/japa.2019-0129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/10/2019] [Accepted: 09/20/2019] [Indexed: 11/18/2022]
Abstract
There is little research related to the biomechanical effects of Tai Chi on the hip joint. This study was aimed to analyze the biomechanical characteristic of a typical Tai Chi movement, Brush Knee and Twist Step. A total of 12 experienced older men voluntarily participated in this study. Each participant was requested to perform standard Brush Knee and Twist Step and normal walking. The scaled-generic musculoskeletal model of each participant was developed. A finite element model of the hip joint and pelvis was established and validated. Data from each trail were input to the model for simulation, and the biomechanics were compared between Brush Knee and Twist Step and walking. Compared with walking, Tai Chi may have better improvement in the range of motion of the hip joint and the coordination of the neuromuscular system under safer condition. It is suitable for patients with hip osteoarthritis and the older adults with severe muscle loss, and clinical studies are required to confirm it further.
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Black RA, Houston G. 40th Anniversary Issue: Reflections on papers from the archive on "Biomechanics". Med Eng Phys 2020; 72:70-71. [PMID: 31554579 DOI: 10.1016/j.medengphy.2019.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Richard A Black
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, Scotland, UK.
| | - Gregor Houston
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, Scotland, UK
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Liu L, Fan S, Chen Y, Peng Y, Wen X, Zeng D, Song H, Jin D. Biomechanics of Anterior Ring Internal Fixation Combined with Sacroiliac Screw Fixation for Tile C3 Pelvic Fractures. Med Sci Monit 2020; 26:e915886. [PMID: 32163378 PMCID: PMC7092661 DOI: 10.12659/msm.915886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background Despite the development of minimally invasive techniques for pelvic fractures, performing minimally invasive surgery for Tile C3 pelvic fractures remains challenging. Thus, we propose use of anterior ring internal fixation combined with sacroiliac screw fixation for Tile C3 pelvic fractures. Material/Methods A normal pelvic finite element model (model 1) was established. Two-screw, three-screw, and four-screw anterior ring internal fixators and plate combined with sacroiliac screw Tile C3 pelvic fracture models (models 2, 3, 4, and 5, respectively) were also established. A vertical load of 600 N was applied on S1. The distribution of displacement and stress in the standing and sitting positions was compared. Results Models 2, 3, 4, and 5 can provide effective fixation. Compared with model 1, in the erect position, the maximum displacement of models 2, 3, 4, and 5 increased by 66.51%, 65.36%, 35.16%, and 35.47% and the maximum stress increased by 201.78%, 130.65%, 100.82%, and 99.03%, respectively. Compared with model 1, in sitting position, the maximum displacement of models 2, 3, 4, and 5 increased by 9.1%, 11.04%, 5.57%, and 8.59% and the maximum stress increased by 157.73%, 118.02%, 98.32%, and 93.16%, respectively. Conclusions Anterior ring internal fixators combined with sacroiliac screws can effectively fix Tile C3 pelvic fractures.
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Affiliation(s)
- Lin Liu
- Department of Traumatic Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhuo, Guangdong, China (mainland).,Department of Traumatic Orthopaedics, University of Chinese Academy of Sciences Shenzhen Hospital, Shenzhen, Guangdong, China (mainland)
| | - Shicai Fan
- Department of Traumatic Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhuo, Guangdong, China (mainland)
| | - Yuhui Chen
- Department of Traumatic Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhuo, Guangdong, China (mainland)
| | - Yongxing Peng
- Department of Traumatic Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhuo, Guangdong, China (mainland)
| | - Xiangyuan Wen
- Department of Traumatic Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhuo, Guangdong, China (mainland)
| | - Donggui Zeng
- Department of Traumatic Orthopaedics, University of Chinese Academy of Sciences Shenzhen Hospital, Shenzhen, Guangdong, China (mainland)
| | - Hui Song
- Department of Traumatic Orthopaedics, University of Chinese Academy of Sciences Shenzhen Hospital, Shenzhen, Guangdong, China (mainland)
| | - Dadi Jin
- Department of Traumatic Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhuo, Guangdong, China (mainland)
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Casaroli G, Bassani T, Brayda-Bruno M, Luca A, Galbusera F. What do we know about the biomechanics of the sacroiliac joint and of sacropelvic fixation? A literature review. Med Eng Phys 2019; 76:1-12. [PMID: 31866118 DOI: 10.1016/j.medengphy.2019.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 10/15/2019] [Accepted: 10/20/2019] [Indexed: 01/25/2023]
Abstract
The purpose of this review is to summarize the general knowledge about the biomechanics of the sacroiliac joint and sacropelvic fixation techniques. Additionally, this study aims to support biomechanical investigations in defining experimental protocols as well as numerical modeling of the sacropelvic structures. The sacroiliac joint is characterized by a large variability of shape and ranges of motion among individuals. Although the ligament network and the anatomical features strongly limit the joint movements, sacroiliac displacements and rotations are not negligible. Currently available treatments for sacroiliac joint dysfunction include physical therapy, steroid injections, Radio-frequency ablation of specific neural structures, and open or minimally invasive SIJ fusion. In long posterior construct, the most common solutions are the iliac screws and the S2 alar - iliac screws, whereas for the joint fixation alone, mini - invasive alternative system can be used. Several studies reported the clinical outcomes of the different techniques and investigated the biomechanical stability of the relative construct, but the effect of sacropelvic fixation techniques on the joint flexibility and on the stress generated into the bone is still unknown. In our opinion, more biomechanical analyses on the behavior of the sacroiliac joint may be performed in order to better predict the risk of failure or instability of the joint.
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Affiliation(s)
- Gloria Casaroli
- LABS, Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Tito Bassani
- LABS, Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.
| | - Marco Brayda-Bruno
- III Spine Surgery - Scoliosis Department, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.
| | - Andrea Luca
- III Spine Surgery - Scoliosis Department, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Fabio Galbusera
- LABS, Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.
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Morosato F, Traina F, Cristofolini L. Effect of different motor tasks on hip cup primary stability and on the strains in the periacetabular bone: An in vitro study. Clin Biomech (Bristol, Avon) 2019; 70:137-145. [PMID: 31491739 DOI: 10.1016/j.clinbiomech.2019.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/03/2019] [Accepted: 08/11/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Excessive prosthesis/bone motions and the bone strains around the acetabulum may prevent osteointegration and lead to cup loosening. These two factors depend on post-operative joint loading. We investigated how Walking (which is often simulated) and Standing-Up from seated (possibly more critical) influence the cup primary stability and periacetabular strains. METHODS Twelve composite hemipelvises were used in two test campaigns. Simplified loading conditions were adopted to simulate Walking and Standing-Up. For each motor task, a single-direction force was applied in load packages of increasing amplitude. Stable and unstable uncemented cups were implanted. Digital image correlation was used to measure implant/bone motions (three-dimensional translations and rotations, both permanent and inducible), and the strain distribution around the acetabulum. FINDINGS When stable implants were tested, higher permanent cranial translations were found during Walking (however the resultant migrations were comparable with Standing-Up); higher rotations were found for Standing-Up. When unstable implants were tested, motions were 1-2 order of magnitude higher. Strains increased significantly from stable to unstable implants. The peak strains were in the superior aspect of the acetabulum during Walking and in the superior-posterior aspect of the acetabulum and at the bottom of the posterior column during Standing-Up. INTERPRETATION Different cup migration trends were caused by simulated Walking and Standing-Up, both similar to those observed clinically. The cup mobilization pattern depended on the different simulated motor tasks. Pre-clinical testing of new uncemented cups could include simulation of both motor tasks. Our study could also translate to indication of what tasks should be avoided.
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Affiliation(s)
- Federico Morosato
- Department of Industrial Engineering, School of Engineering and Architecture, Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Francesco Traina
- Second Clinic of Orthopaedics and Traumatology, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Luca Cristofolini
- Department of Industrial Engineering, School of Engineering and Architecture, Alma Mater Studiorum - Università di Bologna, Bologna, Italy.
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Akrami M, Craig K, Dibaj M, Javadi AA, Benattayallah A. A three-dimensional finite element analysis of the human hip. J Med Eng Technol 2019; 42:546-552. [PMID: 30875263 DOI: 10.1080/03091902.2019.1576795] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A three-dimensional hip model was created from the MRI scans of one human subject based on constructing the entire pelvis and femur. The ball and socket joint was modelled between the hip's acetabulum and the femoral head to analyse the multiaxial loads applied in the hip joint. The three key ligaments that reinforce the external surface of the hip to help to stabilise the joint were also modelled which are the iliofemoral, the pubofemoral and ischiofemoral ligaments. Each of these ligaments wraps around the joint connection to form a seal over the synovial membrane, a line of attachment around the head of the femur. This model was tested for different loading and boundary conditions to analyse their sensitivities on the cortical and cancellous tissues of the human hip bones. The outcomes of a one-legged stance finite element analysis revealed that the maximum of 0.056 mm displacement occurred. The stress distribution varied across the model which the majority occurring in the cortical femur and dissipating through the cartilage. The maximum stress value occurring in the joint was 110.1 MPa, which appeared at the free end of the proximal femur. This developed finite element model was validated against the literature data to be used as an asset for further research in investigating new methods of total hip arthroplasty, to minimise the recurrence of dislocations and discomfort in the hip joint, as well as increasing the range of movement available to a patient after surgery.
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Affiliation(s)
- Mohammad Akrami
- a Department of Engineering, College of Engineering , Mathematics, and Physical Sciences, University of Exeter , Exeter , UK
| | - Kim Craig
- a Department of Engineering, College of Engineering , Mathematics, and Physical Sciences, University of Exeter , Exeter , UK
| | - Mahdieh Dibaj
- a Department of Engineering, College of Engineering , Mathematics, and Physical Sciences, University of Exeter , Exeter , UK
| | - Akbar A Javadi
- a Department of Engineering, College of Engineering , Mathematics, and Physical Sciences, University of Exeter , Exeter , UK
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In Silico Pelvis and Sacroiliac Joint Motion: Refining a Model of the Human Osteoligamentous Pelvis for Assessing Physiological Load Deformation Using an Inverted Validation Approach. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3973170. [PMID: 30729122 PMCID: PMC6343175 DOI: 10.1155/2019/3973170] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 12/04/2018] [Indexed: 01/01/2023]
Abstract
Introduction. Computational modeling of the human pelvis using the finite elements (FE) method has become increasingly important to understand the mechanisms of load distribution under both healthy and pathologically altered conditions and to develop and assess novel treatment strategies. The number of accurate and validated FE models is however small, and given models fail resembling the physiologic joint motion in particular of the sacroiliac joint. This study is aimed at using an inverted validation approach, using in vitro load deformation data to refine an existing FE model under the same mode of load application and to parametrically assess the influence of altered morphology and mechanical data on the kinematics of the model. Materials and Methods. An osteoligamentous FE model of the pelvis including the fifth lumbar vertebra was used, with highly accurate representations of ligament orientations. Material properties were altered parametrically for bone, cartilage, and ligaments, followed by changes in bone geometry (solid versus 3 and 2 mm shell) and material models (linear elastic, viscoelastic, and hyperelastic isotropic), and the effects of varying ligament fiber orientations were assessed. Results. Elastic modulus changes were more decisive in both linear elastic and viscoelastic bone, cartilage, and ligaments models, especially if shell geometries were used for the pelvic bones. Viscoelastic material properties gave more realistic results. Surprisingly little change was observed as a consequence of altering SIJ ligament orientations. Validation with in vitro experiments using cadavers showed close correlations for movements especially for 3 mm shell viscoelastic model. Discussion. This study has used an inverted validation approach to refine an existing FE model, to give realistic and accurate load deformation data of the osteoligamentous pelvis and showed which variation in the outcomes of the models are attributed to altered material properties and models. The given approach furthermore shows the value of accurate validation and of using the validation data to fine tune FE models.
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Hammer N, Klima S. In-silico pelvis and sacroiliac joint motion-A review on published research using numerical analyses. Clin Biomech (Bristol, Avon) 2019; 61:95-104. [PMID: 30544056 DOI: 10.1016/j.clinbiomech.2018.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 10/23/2018] [Accepted: 12/04/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Computational models of the human pelvis have become highly useful tools to assess mechanisms of injury, diagnostics and treatment options. The purpose of this systematic literature review was to summarize existing pelvic computer models, to assess their comparability and the measures taken for experimental validation. METHODS Research on virtual simulations of the posterior pelvis and sacroiliac joint available from the ISI Web of Knowledge, PubMed and Scopus databases available until January 2018 were included. FINDINGS From a total of 3938 articles, 33 studies matched the criteria. Thirteen studies reported on experimental biomechanics, of which seven were parametric. Thirteen studies focused on pelvic injury and surgery, three were clinical case reports. One study assessed the effects of lumbar surgery on the sacroiliac joint, three studies on diagnostics and the non-surgical treatment of the sacroiliac joint. The mode of load application, geometry, material laws and boundary conditions varied vastly between the studies. The majority excluded the lumbosacral transition as part of pelvic biomechanics, and used isotropic linear elastic material properties. Outcomes of the analyses were reported inconsistently with negative impact on their comparability, and validation was commonly conducted by literature with varying agreement of the loading conditions. INTERPRETATION Comparability and validation are two major issues of present computational biomechanics of the pelvis. These issues diminish the transferability of the in-silico findings into real-life scenarios. In-vitro cadaveric models remain the realistic standard to account for the present computational analyses which simplify the complex nature of musculoskeletal tissues of the pelvis.
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Affiliation(s)
- Niels Hammer
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Department of Trauma, Orthopedic and Plastic Surgery, University Hospital of Leipzig, Germany; Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany.
| | - Stefan Klima
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Department of Trauma, Orthopedic and Plastic Surgery, University Hospital of Leipzig, Germany; Orthopaedicus Clinics, Leipzig, Germany
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25
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Tanaka H, Yamako G, Kurishima H, Yamashita S, Mori Y, Chiba D, Chosa E, Itoi E. Biomechanical analysis of supra-acetabular insufficiency fracture using finite element analysis. J Orthop Sci 2018; 23:825-833. [PMID: 29866524 DOI: 10.1016/j.jos.2018.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 03/29/2018] [Accepted: 04/16/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Supra-acetabular insufficiency fractures (SAIFs) occur in the upper acetabulum and are rare compared with insufficiency sacral, femoral head, or ischial fractures. However, SAIFs are known to occur in low grade trauma, and the underlying mechanism is still remained unclear. METHODS We performed biomechanical analysis using finite element analysis to clarify the mechanisms underlying the development of SAIFs. Patient-specific models and bone mineral density (BMD) were derived from pelvic computed tomography data from two patients with SAIF (unaffected side) and two healthy young adults. The bone was assumed to be an isotropic, linearly elastic body. We assigned Young's modulus of each element to the pelvis based on the BMD, and reported the relationships for BMD-modulus. Clinically relevant loading conditions-walking and climbing stairs-were applied to the models. We compared the region of failure risk in each acetabulum using a maximum principal strain criterion. RESULTS The average supra-acetabular BMD was less than that of the hemi-pelvis and femoral head, but was higher than that of the femoral neck and greater trochanter. Greater minimum principal strain was concentrated in the supra-acetabular portion in both the SAIF and healthy models. In the SAIF models, the higher region of the failure risk matched the fracture site on the acetabulum. CONCLUSIONS Relative fragility causes compressive strain to concentrate in the upper acetabulum when walking and climbing stairs. When presented with a patient complaining of hip pain without apparent trauma or abnormal X-ray findings, physicians should consider the possibility of SAIF and perform magnetic resonance imaging for the diagnosis of SAIF.
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Affiliation(s)
- Hidetatsu Tanaka
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Go Yamako
- Department of Mechanical Design Systems, Faculty of Engineering, University of Miyazaki, Miyazaki, 889-2192, Japan.
| | - Hiroaki Kurishima
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Shutaro Yamashita
- Department of Mechanical Design Systems, Faculty of Engineering, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Yu Mori
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Daisuke Chiba
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Etsuo Chosa
- Department of Medicine of Sensory and Motor Organs, Division of Orthopedic Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Eiji Itoi
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
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Sanjay D, Mondal S, Bhutani R, Ghosh R. The effect of cement mantle thickness on strain energy density distribution and prediction of bone density changes around cemented acetabular component. Proc Inst Mech Eng H 2018; 232:912-921. [PMID: 30105942 DOI: 10.1177/0954411918793448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cement mantle thickness is known to be one of the important parameters to reduce the failure of the cemented acetabular component. The thickness of the cement mantle is also often influenced by the positioning of the acetabular cup. The aim of this study is to determine the effect of uniform and non-uniform cement mantle thickness on strain energy density distribution and prediction of the possibility of bone remodelling around the acetabular region. Furthermore, tensile stress distribution in the cement mantle due to non-uniform cement mantle thickness was also investigated. Three-dimensional finite element models of intact and 17 implanted pelvic bone were developed based on computed tomography data sets. Results indicate that implantation with non-uniform cement thickness variation in the anterior-posterior direction has a significant influence on strain energy density distribution around the acetabulum as compared to thickness variation in the superior-inferior direction. Increase in density is predicted at the anterior part of the acetabulum, whereas density decrease is predicted at the posterior, inferior and superior part of the acetabulum. The non-uniform cement mantle thickness affected the tensile stress distribution in the cement mantle, in particularly superiorly placed acetabular cup. This study concludes that uniform cement thickness is desired for the longer success of the cemented acetabular component.
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Affiliation(s)
- Devismita Sanjay
- 1 Biomechanics Laboratory, School of Engineering, Indian Institute of Technology Mandi, Mandi, India
| | - Subrata Mondal
- 1 Biomechanics Laboratory, School of Engineering, Indian Institute of Technology Mandi, Mandi, India
| | - Richa Bhutani
- 2 Department of Biomedical Engineering, Manipal Institute of Technology, Manipal, India
| | - Rajesh Ghosh
- 1 Biomechanics Laboratory, School of Engineering, Indian Institute of Technology Mandi, Mandi, India
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Fougeron N, Rohan PY, Macron A, Travert C, Pillet H, Skalli W. Subject specific finite element mesh generation of the pelvis from biplanar x-ray images: application to 120 clinical cases. Comput Methods Biomech Biomed Engin 2018; 21:408-412. [PMID: 29969279 DOI: 10.1080/10255842.2018.1469624] [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: 10/28/2022]
Abstract
Several Finite Element (FE) models of the pelvis have been developed to comprehensively assess the onset of pathologies and for clinical and industrial applications. However, because of the difficulties associated with the creation of subject-specific FE mesh from CT scan and MR images, most of the existing models rely on the data of one given individual. Moreover, although several fast and robust methods have been developed for automatically generating tetrahedral meshes of arbitrary geometries, hexahedral meshes are still preferred today because of their distinct advantages but their generation remains an open challenge. Recently, approaches have been proposed for fast 3D reconstruction of bones based on X-ray imaging. In this study, we adapted such an approach for the fast and automatic generation of all-hexahedral subject-specific FE models of the pelvis based on the elastic registration of a generic mesh to the subject-specific target in conjunction with element regularity and quality correction. The technique was successfully tested on a database of 120 3D reconstructions of pelvises from biplanar X-ray images. For each patient, a full hexahedral subject-specific FE mesh was generated with an accurate surface representation.
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Affiliation(s)
- Nolwenn Fougeron
- a Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers , Paris , France
| | - Pierre-Yves Rohan
- a Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers , Paris , France
| | - Aurélien Macron
- a Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers , Paris , France.,b CEA, LETI, CLINATEC, MINATEC Campus , Grenoble , France
| | - Christophe Travert
- a Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers , Paris , France
| | - Hélène Pillet
- a Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers , Paris , France
| | - Wafa Skalli
- a Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers , Paris , France
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