Pub Date : 2025-09-22DOI: 10.1016/j.clinbiomech.2025.106672
V. Vanaclocha , C. Atienza , A. Vanaclocha , P. Jorda-Gomez , A. Peñuelas , E. Medina-Ripoll , A. Gómez-Pérez , N. Saiz-Sapena , L. Vanaclocha
Background
Facet joint overload often causes persistent low back pain after lumbar total disc replacement (TDR). This study is the first to test whether adding an anterior Kevlar band (K) can restore normal facet joint loading after lumbar TDR.
Methods
We tested six human lumbosacral spines under four conditions: intact, after discectomy, with the ADDISC prosthesis, and with ADDISC plus Kevlar reinforcement. Facet joint pressures were measured at L3–L4, L4–L5, and L5–S1 during flexion, extension, lateral bending, and axial rotation.
Findings
Discectomy caused a significant rise in facet pressures, especially during extension and axial rotation (p < 0.01). The ADDISC prosthesis lowered facet pressures but did not fully return them to baseline. Kevlar reinforcement lowered pressures by up to 35 % compared to the prosthesis alone, nearing intact spine levels, especially in flexion and extension.
Interpretation
Kevlar reinforcement improves load distribution more than the prosthesis alone. It may help prevent facet degeneration and adjacent segment disease, offering a better biomechanical option for motion-preserving spine surgery.
Clinical relevance
The combination of the ADDISC prosthesis and Kevlar reinforcement may help prevent facet joint degeneration and adjacent segment disease, potentially enhancing long-term outcomes in lumbar disc arthroplasty.
{"title":"Reducing facet joint overload with a Kevlar-augmented lumbar disc replacement: An ex vivo investigation","authors":"V. Vanaclocha , C. Atienza , A. Vanaclocha , P. Jorda-Gomez , A. Peñuelas , E. Medina-Ripoll , A. Gómez-Pérez , N. Saiz-Sapena , L. Vanaclocha","doi":"10.1016/j.clinbiomech.2025.106672","DOIUrl":"10.1016/j.clinbiomech.2025.106672","url":null,"abstract":"<div><h3>Background</h3><div>Facet joint overload often causes persistent low back pain after lumbar total disc replacement (TDR). This study is the first to test whether adding an anterior Kevlar band (K) can restore normal facet joint loading after lumbar TDR.</div></div><div><h3>Methods</h3><div>We tested six human lumbosacral spines under four conditions: intact, after discectomy, with the ADDISC prosthesis, and with ADDISC plus Kevlar reinforcement. Facet joint pressures were measured at L3–L4, L4–L5, and L5–S1 during flexion, extension, lateral bending, and axial rotation.</div></div><div><h3>Findings</h3><div>Discectomy caused a significant rise in facet pressures, especially during extension and axial rotation (<em>p</em> < 0.01). The ADDISC prosthesis lowered facet pressures but did not fully return them to baseline. Kevlar reinforcement lowered pressures by up to 35 % compared to the prosthesis alone, nearing intact spine levels, especially in flexion and extension.</div></div><div><h3>Interpretation</h3><div>Kevlar reinforcement improves load distribution more than the prosthesis alone. It may help prevent facet degeneration and adjacent segment disease, offering a better biomechanical option for motion-preserving spine surgery.</div></div><div><h3>Clinical relevance</h3><div>The combination of the ADDISC prosthesis and Kevlar reinforcement may help prevent facet joint degeneration and adjacent segment disease, potentially enhancing long-term outcomes in lumbar disc arthroplasty.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106672"},"PeriodicalIF":1.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145151649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pressure ulcers are a common occurrence in the sacrum and are frequently associated with deep tissue injury. Research has demonstrated that compression and mechanical strain contribute to tissue damage and can be employed to assess the risk of injury. Despite the existence of several finite element models based on this evidence, the experimental evaluation of localized tissue strain is rarely addressed.
Methods
The objective of this study is to present a proof-of-concept protocol for creating subject-specific finite element models of sacral soft tissues under compressive loading and to compare the model predictions with experimental data based on Digital Volume Correlation of MRI data. The data was collected from one asymptomatic volunteer in four loading conditions (vertical loading of 4.3 N, 6.1 N, 8 N and 11.9 N).
Findings
A comparison of DVC-derived tissue displacements with the Finite Element simulations demonstrated accurate estimations for maximum values and displacement distribution fields for all load cases, with less than 5 % discrepancy for load configurations L1-L3 and 7 % for load configuration L4. Concerning shear strains, it was observed that there were significant differences between the DVC-derived experimental tissue shear strains and the simulation predictions when generic constitutive parameters were used. The highest difference was 43 % for the highest load configuration (11.9 N).
Interpretation
These results demonstrate that incorporating personalized tissue properties substantially improves model fidelity, highlighting the potential of combined imaging, mechanical testing, and FE modelling for individualized risk assessment of deep tissue injury.
{"title":"Finite element modelling of the sacral soft tissues under compressive loading in the context of pressure ulcer prevention: importance of the personalization of the material parameters","authors":"Ekaterina Mukhina , Pierre-Yves Rohan , Nathanael Connesson , Yohan Payan","doi":"10.1016/j.clinbiomech.2025.106668","DOIUrl":"10.1016/j.clinbiomech.2025.106668","url":null,"abstract":"<div><h3>Background</h3><div>Pressure ulcers are a common occurrence in the sacrum and are frequently associated with deep tissue injury. Research has demonstrated that compression and mechanical strain contribute to tissue damage and can be employed to assess the risk of injury. Despite the existence of several finite element models based on this evidence, the experimental evaluation of localized tissue strain is rarely addressed.</div></div><div><h3>Methods</h3><div>The objective of this study is to present a proof-of-concept protocol for creating subject-specific finite element models of sacral soft tissues under compressive loading and to compare the model predictions with experimental data based on Digital Volume Correlation of MRI data. The data was collected from one asymptomatic volunteer in four loading conditions (vertical loading of 4.3 N, 6.1 N, 8 N and 11.9 N).</div></div><div><h3>Findings</h3><div>A comparison of DVC-derived tissue displacements with the Finite Element simulations demonstrated accurate estimations for maximum values and displacement distribution fields for all load cases, with less than 5 % discrepancy for load configurations L1-L3 and 7 % for load configuration L4. Concerning shear strains, it was observed that there were significant differences between the DVC-derived experimental tissue shear strains and the simulation predictions when generic constitutive parameters were used. The highest difference was 43 % for the highest load configuration (11.9 N).</div></div><div><h3>Interpretation</h3><div>These results demonstrate that incorporating personalized tissue properties substantially improves model fidelity, highlighting the potential of combined imaging, mechanical testing, and FE modelling for individualized risk assessment of deep tissue injury.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106668"},"PeriodicalIF":1.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145349907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-15DOI: 10.1016/j.clinbiomech.2025.106671
Katja Brand , Golzar Dakhili , Frank Lampe , Benjamin Ondruschka , Michael M. Morlock , Gerd Huber
Background
Collared cementless hip stems have demonstrated a reduced incidence of periprosthetic femoral fractures compared to collarless counterparts. Many fractures occur during implantation, when collarless stems are seated to achieve press-fit, causing critical tensile strains in the femur. Collared stems can limit excessive seating and subsidence through calcar-collar contact.
This study aimed to explain the clinically observed smaller fracture rates with collared stems by comparing strain distributions during implantation and loading between collared and collarless stems. It was hypothesized that collared stems distribute applied forces through both the collar and stem, increasing compressive axial and shear strains, allowing higher load tolerance.
Methods
Seven collared and seven collarless stems were implanted with constant velocity (0.1 mm/s) in porcine femurs until failure. Two human cadaveric femurs were tested as proof of concept. Shear, axial compressive and tangential tensile strains were compared alongside fracture patterns, subsidence and forces.
Findings
Collared stems in porcine femurs resisted approximately twice as much force until failure occurred (collared: 4187 N, collarless: 1980 N; p < 0.001), with similar tangential tensile strains (1 % to 1.4 % p = 0.805) and subsidence of 1.6 mm for collarless and 1.1 mm for collared stems at different failure forces (p = 0.288). Axial compressive strain was heavily increased by 1147 % with collared stems (collared: 1.2 %, collarless: 0.1 %; p = 0.026). Human femurs exhibited similar trends.
Interpretation
During loading, the collar prevents periprosthetic femoral fractures by increasing axial compressive strains instead of causing critical excessive tangential tensile strains (hoop strains) that can result in fractures.
{"title":"How does the collar in cementless hip stems work? Comparison of the strain distribution in the cortex of the proximal femur","authors":"Katja Brand , Golzar Dakhili , Frank Lampe , Benjamin Ondruschka , Michael M. Morlock , Gerd Huber","doi":"10.1016/j.clinbiomech.2025.106671","DOIUrl":"10.1016/j.clinbiomech.2025.106671","url":null,"abstract":"<div><h3>Background</h3><div>Collared cementless hip stems have demonstrated a reduced incidence of periprosthetic femoral fractures compared to collarless counterparts. Many fractures occur during implantation, when collarless stems are seated to achieve press-fit, causing critical tensile strains in the femur. Collared stems can limit excessive seating and subsidence through calcar-collar contact.</div><div>This study aimed to explain the clinically observed smaller fracture rates with collared stems by comparing strain distributions during implantation and loading between collared and collarless stems. It was hypothesized that collared stems distribute applied forces through both the collar and stem, increasing compressive axial and shear strains, allowing higher load tolerance.</div></div><div><h3>Methods</h3><div>Seven collared and seven collarless stems were implanted with constant velocity (0.1 mm/s) in porcine femurs until failure. Two human cadaveric femurs were tested as proof of concept. Shear, axial compressive and tangential tensile strains were compared alongside fracture patterns, subsidence and forces.</div></div><div><h3>Findings</h3><div>Collared stems in porcine femurs resisted approximately twice as much force until failure occurred (collared: 4187 N, collarless: 1980 N; <em>p</em> < 0.001), with similar tangential tensile strains (1 % to 1.4 % <em>p</em> = 0.805) and subsidence of 1.6 mm for collarless and 1.1 mm for collared stems at different failure forces (<em>p</em> = 0.288). Axial compressive strain was heavily increased by 1147 % with collared stems (collared: 1.2 %, collarless: 0.1 %; <em>p</em> = 0.026). Human femurs exhibited similar trends.</div></div><div><h3>Interpretation</h3><div>During loading, the collar prevents periprosthetic femoral fractures by increasing axial compressive strains instead of causing critical excessive tangential tensile strains (hoop strains) that can result in fractures.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106671"},"PeriodicalIF":1.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145092713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-11DOI: 10.1016/j.clinbiomech.2025.106670
Young-Hwan Kwag
Background
This study aimed to investigate the correlations between the arch height index (AHI), spatiotemporal gait parameters, and plantar pressure in children with spastic hemiplegic cerebral palsy.
Methods
A cross-sectional study was conducted with 15 children diagnosed with spastic hemiplegic cerebral palsy. The AHI was measured using the method developed by Williams and McClay. Spatiotemporal gait parameters were assessed using the GAITRite system, and plantar pressure was evaluated with the Dynafoot platform.
Findings
On the affected side, the AHI showed moderate positive correlations with step length (0.522) and stride length (0.529). On the non-affected side, the AHI demonstrated a moderate negative correlation with plantar pressure in the medial heel region (−0.629).
Interpretation
The findings suggest that the AHI is associated with shorter step and stride lengths and plantar pressure distribution in children with spastic hemiplegic cerebral palsy. These results support the clinical utility of AHI as an assessment tool and its potential role in guiding interventions to improve gait and foot posture in this population.
{"title":"Correlation between arch height index, spatiotemporal gait parameters and plantar pressure in children with spastic hemiplegia cerebral palsy","authors":"Young-Hwan Kwag","doi":"10.1016/j.clinbiomech.2025.106670","DOIUrl":"10.1016/j.clinbiomech.2025.106670","url":null,"abstract":"<div><h3>Background</h3><div>This study aimed to investigate the correlations between the arch height index (AHI), spatiotemporal gait parameters, and plantar pressure in children with spastic hemiplegic cerebral palsy.</div></div><div><h3>Methods</h3><div>A cross-sectional study was conducted with 15 children diagnosed with spastic hemiplegic cerebral palsy. The AHI was measured using the method developed by Williams and McClay. Spatiotemporal gait parameters were assessed using the GAITRite system, and plantar pressure was evaluated with the Dynafoot platform.</div></div><div><h3>Findings</h3><div>On the affected side, the AHI showed moderate positive correlations with step length (0.522) and stride length (0.529). On the non-affected side, the AHI demonstrated a moderate negative correlation with plantar pressure in the medial heel region (−0.629).</div></div><div><h3>Interpretation</h3><div>The findings suggest that the AHI is associated with shorter step and stride lengths and plantar pressure distribution in children with spastic hemiplegic cerebral palsy. These results support the clinical utility of AHI as an assessment tool and its potential role in guiding interventions to improve gait and foot posture in this population.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106670"},"PeriodicalIF":1.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reduced knee extensor moment after anterior cruciate ligament reconstruction is associated with quadriceps weakness, increased risk of second anterior cruciate ligament injuries, and early onset of knee osteoarthritis. This study investigated the association between the knee extensor moment, anterior-posterior center of pressure, and trunk and lower limb joint angles during single-leg squatting following anterior cruciate ligament reconstruction.
Methods
Twenty-one patients who underwent anterior cruciate ligament reconstruction performed a single-leg squatting with both legs. Regression analyses were performed to examine the association between the knee extensor moment, anterior-posterior center of pressure, and trunk and lower limb joint angles, all of which were measured using a 3-dimensional motion analysis system.
Findings
The knee extensor moment was predicted by the anterior-posterior center of pressure in the involved limb (P = 0.038, R2 = 0.208). The knee extensor moment was significantly predicted by the knee flexion angle (involved: P = 0.003, R2 = 0.373; uninvolved: P < 0.001, R2 = 0.557) and ankle dorsiflexion angle (involved: P = 0.035, R2 = 0.214; uninvolved: P < 0.001, R2 = 0.554). The anterior-posterior center of pressure and ankle dorsiflexion angle significantly predicted the knee extensor moment in the involved limb in multivariate regression analysis (P = 0.006, model R2 = 0.429).
Interpretation
The knee extensor moment was associated with the anterior-posterior center of pressure, knee flexion angle, and ankle dorsiflexion angle. Evaluating these parameters may enhance our understanding of the knee extensor moment during single-leg squatting after anterior cruciate ligament reconstruction in a clinical setting.
{"title":"Association of the center of pressure position, trunk and lower limb joint kinematics with knee extensor moment during single-leg squatting after anterior cruciate ligament reconstruction","authors":"Masato Chijimatsu , Rui Henmi , Hiroko Yokoyama , Takeshi Hoshi , Gai Maeda , Yuka Kimura , Yasuyuki Ishibashi , Eiichi Tsuda","doi":"10.1016/j.clinbiomech.2025.106669","DOIUrl":"10.1016/j.clinbiomech.2025.106669","url":null,"abstract":"<div><h3>Background</h3><div>Reduced knee extensor moment after anterior cruciate ligament reconstruction is associated with quadriceps weakness, increased risk of second anterior cruciate ligament injuries, and early onset of knee osteoarthritis. This study investigated the association between the knee extensor moment, anterior-posterior center of pressure, and trunk and lower limb joint angles during single-leg squatting following anterior cruciate ligament reconstruction.</div></div><div><h3>Methods</h3><div>Twenty-one patients who underwent anterior cruciate ligament reconstruction performed a single-leg squatting with both legs. Regression analyses were performed to examine the association between the knee extensor moment, anterior-posterior center of pressure, and trunk and lower limb joint angles, all of which were measured using a 3-dimensional motion analysis system.</div></div><div><h3>Findings</h3><div>The knee extensor moment was predicted by the anterior-posterior center of pressure in the involved limb (<em>P</em> = 0.038, <em>R</em><sup>2</sup> = 0.208). The knee extensor moment was significantly predicted by the knee flexion angle (involved: <em>P</em> = 0.003, <em>R</em><sup>2</sup> = 0.373; uninvolved: <em>P</em> < 0.001, <em>R</em><sup>2</sup> = 0.557) and ankle dorsiflexion angle (involved: <em>P</em> = 0.035, <em>R</em><sup>2</sup> = 0.214; uninvolved: <em>P</em> < 0.001, <em>R</em><sup>2</sup> = 0.554). The anterior-posterior center of pressure and ankle dorsiflexion angle significantly predicted the knee extensor moment in the involved limb in multivariate regression analysis (<em>P</em> = 0.006, model <em>R</em><sup>2</sup> = 0.429).</div></div><div><h3>Interpretation</h3><div>The knee extensor moment was associated with the anterior-posterior center of pressure, knee flexion angle, and ankle dorsiflexion angle. Evaluating these parameters may enhance our understanding of the knee extensor moment during single-leg squatting after anterior cruciate ligament reconstruction in a clinical setting.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106669"},"PeriodicalIF":1.4,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145151665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-08DOI: 10.1016/j.clinbiomech.2025.106664
S. Minkes-Weiland , H. Houdijk , S. Floor , P.P. Hartman , H.A. Reinders-Messelink , L.H.V. van der Woude , A.R. den Otter
Background
A decreased propulsive capacity post stroke is associated with a diminished walking ability. When walking with a restraining force applied to the pelvis, more propulsion is required to enable forward progression. This may stimulate propulsion capacity in people post-stroke. Before incorporating restraining forces into training, their effects on propulsion mechanics and other gait characteristics must be evaluated. This study investigated: (1) the immediate bilateral effects of restraining forces during treadmill walking on propulsive force, braking force, and mechanical work in people post-stroke, and (2) the impact of this manipulation on step length symmetry, single support time symmetry and muscle activity. Additionally, we explored whether these effects vary with gait speed and force magnitude.
Methods
13 individuals post-stroke walked on a treadmill at 0.28 m/s and 0.56 m/s while a horizontal restraining force (0 %, 5 % or 10 % of their body weight) was applied to the pelvis. During walking, ground reaction forces and muscle activity of gluteus Medius, rectus Femoris, vastus Medialis, biceps Femoris, tibialis anterior, medial gastrocnemius and soleus were bilaterally recorded
Findings
Applying restraining forces up to 10 % of body weight increased propulsive impulse and mechanical work while reducing braking impulse. Although no significant effects were found on step length symmetry or swing phase symmetry, subtle changes in muscle activity were observed when walking with restraining forces
Interpretation
Restraining forces up to 10 % of body weight can activate propulsive capacity. Future research should explore how this direct effect translates into long-term training effects.
{"title":"Effects of restraining forces on propulsion and other gait characteristics during treadmill walking post-stroke","authors":"S. Minkes-Weiland , H. Houdijk , S. Floor , P.P. Hartman , H.A. Reinders-Messelink , L.H.V. van der Woude , A.R. den Otter","doi":"10.1016/j.clinbiomech.2025.106664","DOIUrl":"10.1016/j.clinbiomech.2025.106664","url":null,"abstract":"<div><h3>Background</h3><div>A decreased propulsive capacity post stroke is associated with a diminished walking ability. When walking with a restraining force applied to the pelvis, more propulsion is required to enable forward progression. This may stimulate propulsion capacity in people post-stroke. Before incorporating restraining forces into training, their effects on propulsion mechanics and other gait characteristics must be evaluated. This study investigated: (1) the immediate bilateral effects of restraining forces during treadmill walking on propulsive force, braking force, and mechanical work in people post-stroke, and (2) the impact of this manipulation on step length symmetry, single support time symmetry and muscle activity. Additionally, we explored whether these effects vary with gait speed and force magnitude.</div></div><div><h3>Methods</h3><div>13 individuals post-stroke walked on a treadmill at 0.28 m/s and 0.56 m/s while a horizontal restraining force (0 %, 5 % or 10 % of their body weight) was applied to the pelvis. During walking, ground reaction forces and muscle activity of gluteus Medius, rectus Femoris, vastus Medialis, biceps Femoris, tibialis anterior, medial gastrocnemius and soleus were bilaterally recorded</div></div><div><h3>Findings</h3><div>Applying restraining forces up to 10 % of body weight increased propulsive impulse and mechanical work while reducing braking impulse. Although no significant effects were found on step length symmetry or swing phase symmetry, subtle changes in muscle activity were observed when walking with restraining forces</div></div><div><h3>Interpretation</h3><div>Restraining forces up to 10 % of body weight can activate propulsive capacity. Future research should explore how this direct effect translates into long-term training effects.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106664"},"PeriodicalIF":1.4,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-07DOI: 10.1016/j.clinbiomech.2025.106666
Jacob H. Chen , Ian Al’Khafaji , Lukas Ernstbrunner , John O’Donnell , David Ackland
Background
The ligamentum teres is known to contribute to hip joint stability; however, the effect of surgical reconstruction of ligamentum teres tears on hip joint function is poorly understood. This study aimed to employ a cadaver model to quantify peak pressure, average pressure, contact force, and contact area between the femoral head and acetabulum in native, ligamentum teres deficient and reconstructed hips.
Methods
Nine fresh-frozen human cadaveric hips were dissected and mounted to a multi-axis Materials Test System. Digital pressure sensors were placed on anterior, posterior, and superior regions of the acetabulum. Joint loading was simulated in 20deg flexion, neutral position, and 10deg extension. Peak pressure, average pressure, contact force, and contact area were measured.
Findings
Ligamentum teres deficiency caused a significant increase in average pressure (mean difference: 161.6 kPa, p = 0.002) in the superior acetabulum of the neutral hip relative to the ligament intact hip and in peak pressure (mean difference: 1462.5 kPa, p = 0.023) in the anterior acetabulum of the extended hip compared to the intact hip. Ligamentum teres reconstruction subsequently restored average and peak pressure to levels not significantly different from those in the intact state (p > 0.05). Reconstruction also led to a significant decrease in average pressure (mean difference 241.0 kPa, p = 0.047) and contact force (mean difference: 124.5 N, p = 0.039) in the posterior acetabulum of the flexed hip relative to the intact hip.
Interpretation
Ligamentum teres reconstruction may help to prevent excessive contact that occurs in the ligamentum teres deficient hip and may mitigate or slow the onset of degenerative changes associated with ligamentum teres deficiency.
背景：众所周知，圆韧带有助于髋关节的稳定性；然而，手术重建圆韧带撕裂对髋关节功能的影响尚不清楚。本研究旨在采用尸体模型量化天然髋关节、圆韧带缺损髋关节和重建髋关节股骨头与髋臼之间的峰值压力、平均压力、接触力和接触面积。方法采用多轴材料测试系统对9例新鲜冷冻人体髋关节进行解剖。数字式压力传感器放置在髋臼的前、后、上区域。模拟关节在20度屈曲、中立位和10度伸展时的载荷。测量了峰值压力、平均压力、接触力和接触面积。结果：圆韧带缺失导致中性髋上髋臼相对于韧带完整髋的平均压力（平均差值：161.6 kPa, p = 0.002）显著升高，伸展髋前髋臼相对于完整髋的峰值压力（平均差值：1462.5 kPa, p = 0.023）显著升高。圆韧带重建后，平均和峰值压力恢复到与完整状态无显著差异的水平（p > 0.05）。重建后髋臼相对于完整髋的平均压力（平均差值241.0 kPa, p = 0.047）和接触力（平均差值124.5 N, p = 0.039）也显著降低。结论：圆韧带重建有助于防止在圆韧带缺乏的髋关节发生过度接触，并可能减轻或减缓与圆韧带缺乏相关的退行性变化的发生。
{"title":"Joint contact behavior in the native, ligamentum teres deficient and surgically reconstructed hip: A biomechanics study","authors":"Jacob H. Chen , Ian Al’Khafaji , Lukas Ernstbrunner , John O’Donnell , David Ackland","doi":"10.1016/j.clinbiomech.2025.106666","DOIUrl":"10.1016/j.clinbiomech.2025.106666","url":null,"abstract":"<div><h3>Background</h3><div>The ligamentum teres is known to contribute to hip joint stability; however, the effect of surgical reconstruction of ligamentum teres tears on hip joint function is poorly understood. This study aimed to employ a cadaver model to quantify peak pressure, average pressure, contact force, and contact area between the femoral head and acetabulum in native, ligamentum teres deficient and reconstructed hips.</div></div><div><h3>Methods</h3><div>Nine fresh-frozen human cadaveric hips were dissected and mounted to a multi-axis Materials Test System. Digital pressure sensors were placed on anterior, posterior, and superior regions of the acetabulum. Joint loading was simulated in 20deg flexion, neutral position, and 10deg extension. Peak pressure, average pressure, contact force, and contact area were measured.</div></div><div><h3>Findings</h3><div>Ligamentum teres deficiency caused a significant increase in average pressure (mean difference: 161.6 kPa, <em>p</em> = 0.002) in the superior acetabulum of the neutral hip relative to the ligament intact hip and in peak pressure (mean difference: 1462.5 kPa, <em>p</em> = 0.023) in the anterior acetabulum of the extended hip compared to the intact hip. Ligamentum teres reconstruction subsequently restored average and peak pressure to levels not significantly different from those in the intact state (<em>p</em> > 0.05). Reconstruction also led to a significant decrease in average pressure (mean difference 241.0 kPa, <em>p</em> = 0.047) and contact force (mean difference: 124.5 N, <em>p</em> = 0.039) in the posterior acetabulum of the flexed hip relative to the intact hip.</div></div><div><h3>Interpretation</h3><div>Ligamentum teres reconstruction may help to prevent excessive contact that occurs in the ligamentum teres deficient hip and may mitigate or slow the onset of degenerative changes associated with ligamentum teres deficiency.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106666"},"PeriodicalIF":1.4,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-06DOI: 10.1016/j.clinbiomech.2025.106665
Maxwell Thurston , Harri Piitulainen , Ivan Vujaklija , Janne Avela , Juha-Pekka Kulmala
Background
This study aimed to investigate the potential of an assistive ankle exosuit to acutely augment clinically relevant walking parameters in adolescents with Cerebral Palsy (CP).
Methods
Ten exosuit-naïve adolescents with unilateral CP (11–16 years old) walked on a treadmill without the exosuit (baseline), and with the exosuit (ReWalk ReStore®) providing unilateral dorsiflexion and plantarflexion assistance to their more-affected ankle. Five participants also walked with their regular orthosis. Energy cost of transport, kinematics and kinetics, and electromyography of Tibialis Anterior and Gastrocnemius Medialis muscles were assessed.
Findings
The exosuit increased ankle dorsiflexion during swing-phase, alleviating drop-foot on the more-affected side observed during baseline walking. Peak ankle moment was increased with the exosuit. While participants' orthoses restricted plantarflexion during push-off, the exosuit enabled more-typical push-off plantarflexion motion. There were no significant changes in energy cost or muscle activity with the exosuit.
Interpretation
The exosuit facilitated heel-toe ankle kinematics of the more-affected leg during gait, preventing drop-foot, while preserving plantarflexion during push-off. The exosuit slightly increased plantarflexor torque, however this did not translate to increased positive power from the more-affected ankle during gait. Lack of changes in muscle activity or energy cost indicate an inability of exosuit assistance to acutely alter these parameters on initial use of the device. These results display potential of an assistive exosuit to immediately augment ankle kinematics, but also underline limitations of the exosuit to acutely alter other clinical outcomes important for lasting gait changes, namely muscle activity and energy consumption.
{"title":"Acute effects of ankle exosuit on biomechanics, muscle activity, and energy cost of walking in adolescents with unilateral cerebral palsy","authors":"Maxwell Thurston , Harri Piitulainen , Ivan Vujaklija , Janne Avela , Juha-Pekka Kulmala","doi":"10.1016/j.clinbiomech.2025.106665","DOIUrl":"10.1016/j.clinbiomech.2025.106665","url":null,"abstract":"<div><h3>Background</h3><div>This study aimed to investigate the potential of an assistive ankle exosuit to acutely augment clinically relevant walking parameters in adolescents with Cerebral Palsy (CP).</div></div><div><h3>Methods</h3><div>Ten exosuit-naïve adolescents with unilateral CP (11–16 years old) walked on a treadmill without the exosuit (baseline), and with the exosuit (ReWalk ReStore®) providing unilateral dorsiflexion and plantarflexion assistance to their more-affected ankle. Five participants also walked with their regular orthosis. Energy cost of transport, kinematics and kinetics, and electromyography of Tibialis Anterior and Gastrocnemius Medialis muscles were assessed.</div></div><div><h3>Findings</h3><div>The exosuit increased ankle dorsiflexion during swing-phase, alleviating drop-foot on the more-affected side observed during baseline walking. Peak ankle moment was increased with the exosuit. While participants' orthoses restricted plantarflexion during push-off, the exosuit enabled more-typical push-off plantarflexion motion. There were no significant changes in energy cost or muscle activity with the exosuit.</div></div><div><h3>Interpretation</h3><div>The exosuit facilitated heel-toe ankle kinematics of the more-affected leg during gait, preventing drop-foot, while preserving plantarflexion during push-off. The exosuit slightly increased plantarflexor torque, however this did not translate to increased positive power from the more-affected ankle during gait. Lack of changes in muscle activity or energy cost indicate an inability of exosuit assistance to acutely alter these parameters on initial use of the device. These results display potential of an assistive exosuit to immediately augment ankle kinematics, but also underline limitations of the exosuit to acutely alter other clinical outcomes important for lasting gait changes, namely muscle activity and energy consumption.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106665"},"PeriodicalIF":1.4,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145042131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-05DOI: 10.1016/j.clinbiomech.2025.106662
Axel Degrande , Louise Wittouck , Pieter D'Hooghe , Matthias Peiffer , Thomas Tampere , Sam Van der Jeught , Arne Burssens , Amélie Chevalier
Background
Syndesmotic ankle injuries, particularly those involving the distal tibiofibular joint, are challenging to diagnose due to subtle clinical presentation and complex ankle biomechanics. Both clinical and biomechanical studies struggle with accurately assessing the severity and extent of these injuries. External torque has recently shown promise in enhancing the detection and assessment of syndesmotic injuries, especially in weight-bearing computed tomography (WBCT). This study explores the impact of external torque on the assessment of syndesmotic ankle lesions in clinical versus biomechanical studies.
Methods
A systematic search was conducted using PubMed, Scopus, EMBASE, The Cochrane Library, and Web of Science. The review protocol was registered on PROSPERO (CRD42024535265). Inclusion criteria were biomechanical studies on lower limbs with intact and sectioned syndesmosis; clinical studies comparing injured ankles to healthy contralateral ones; and studies applying torque or weight-bearing to injured ankles. Exclusion criteria consisted of reviews, meta-analyses, studies on syndesmosis repair, acute injuries involving fractures, and studies lacking measurements.
Findings
Eleven studies met the inclusion criteria, including eight biomechanical and three clinical studies.
Interpretation
While biomechanical evidence provides a solid foundation, its translation into clinical practice requires further validation. The importance of assessment of the ankle syndesmosis under torque has been demonstrated, and the application of external torque shows promising results. Multiple studies indicate that applying an external torque between 4.5 and 7.5 [Nm] is sufficient to distinguish between intact and sectioned syndesmotic injuries. However, the need for a standardized diagnostic tool has yet to be established.
踝关节联合损伤，特别是涉及胫腓骨远端关节的损伤，由于其微妙的临床表现和复杂的踝关节生物力学，诊断具有挑战性。临床和生物力学研究都在努力准确评估这些损伤的严重程度和范围。外扭矩最近在增强韧带联合损伤的检测和评估方面显示出前景，特别是在负重计算机断层扫描（WBCT）中。本研究在临床与生物力学研究中探讨了外部扭矩对踝关节联合病变评估的影响。方法系统检索PubMed、Scopus、EMBASE、The Cochrane Library、Web of Science。审查方案已在PROSPERO注册（CRD42024535265）。纳入标准为完整和切片的下肢联合的生物力学研究；损伤踝关节与对侧健康踝关节的临床比较研究研究对受伤的脚踝施加扭矩或负重。排除标准包括综述、荟萃分析、关于韧带联合修复的研究、涉及骨折的急性损伤和缺乏测量的研究。11项研究符合纳入标准，包括8项生物力学研究和3项临床研究。虽然生物力学证据提供了坚实的基础，但其转化为临床实践需要进一步验证。评估踝关节联合在扭矩作用下的重要性已被证明，外扭矩的应用显示出良好的结果。多项研究表明，施加4.5 - 7.5 [Nm]的外扭矩足以区分完整型和节裂型联合损伤。然而，对标准化诊断工具的需求尚未确定。
{"title":"External torque application during assessment of syndesmotic ankle lesions: A systematic review","authors":"Axel Degrande , Louise Wittouck , Pieter D'Hooghe , Matthias Peiffer , Thomas Tampere , Sam Van der Jeught , Arne Burssens , Amélie Chevalier","doi":"10.1016/j.clinbiomech.2025.106662","DOIUrl":"10.1016/j.clinbiomech.2025.106662","url":null,"abstract":"<div><h3>Background</h3><div>Syndesmotic ankle injuries, particularly those involving the distal tibiofibular joint, are challenging to diagnose due to subtle clinical presentation and complex ankle biomechanics. Both clinical and biomechanical studies struggle with accurately assessing the severity and extent of these injuries. External torque has recently shown promise in enhancing the detection and assessment of syndesmotic injuries, especially in weight-bearing computed tomography (WBCT). This study explores the impact of external torque on the assessment of syndesmotic ankle lesions in clinical versus biomechanical studies.</div></div><div><h3>Methods</h3><div>A systematic search was conducted using PubMed, Scopus, EMBASE, The Cochrane Library, and Web of Science. The review protocol was registered on PROSPERO (CRD42024535265). Inclusion criteria were biomechanical studies on lower limbs with intact and sectioned syndesmosis; clinical studies comparing injured ankles to healthy contralateral ones; and studies applying torque or weight-bearing to injured ankles. Exclusion criteria consisted of reviews, meta-analyses, studies on syndesmosis repair, acute injuries involving fractures, and studies lacking measurements.</div></div><div><h3>Findings</h3><div>Eleven studies met the inclusion criteria, including eight biomechanical and three clinical studies.</div></div><div><h3>Interpretation</h3><div>While biomechanical evidence provides a solid foundation, its translation into clinical practice requires further validation. The importance of assessment of the ankle syndesmosis under torque has been demonstrated, and the application of external torque shows promising results. Multiple studies indicate that applying an external torque between 4.5 and 7.5 [Nm] is sufficient to distinguish between intact and sectioned syndesmotic injuries. However, the need for a standardized diagnostic tool has yet to be established.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106662"},"PeriodicalIF":1.4,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-04DOI: 10.1016/j.clinbiomech.2025.106663
Tianxiao Chen , Datao Xu , Meizi Wang , Zhifeng Zhou , Tianle Jie , Huiyu Zhou , Yi Yuan , Julien S. Baker , Zixiang Gao , Yaodong Gu
Background
Anterior cruciate ligament reconstruction (ACLR) can restore knee stability, yet many patients fail to regain pre-injury function or develop secondary injuries. Vertical ground reaction force (vGRF) reflects joint loading and recovery but is typically measured via lab-based force plates, limiting real-world use. Wearable sensors and deep learning could enable portable monitoring, but current studies lack accuracy in complex movements and patient-specific adaptations.
Methods
Lower-limb kinematics and vGRF data from 25 ACLR patients during three daily activities (walking, running, descending stairs) was collected by wearable sensors and Vicon system. Three deep learning models were developed and optimized for the prediction tasks. The collected data was used to train the three developed models and the performance of each model was evaluated.
Findings
Among the three deep learning models, CNN-BiGRU-Attention model demonstrated the best predictive performance across all three movement tasks (R2walking = 0.953 ± 0.006, R2running = 0.971 ± 0.005, R2descending stairs = 0.979 ± 0.003). Additionally, for the three selected daily activities, all models showed superior vGRF prediction performance in running and stair descending tasks compared to walking.
Interpretation
By integrating data from wearable sensors with a hybrid deep learning framework, the proposed CNN-BiGRU-Attention model successfully achieved accurate estimation of vGRFs of ACLR patients in various movements. This provides a key technical reference for optimizing personalized rehabilitation strategies and improving patient outcomes, demonstrating significant clinical application value and social benefits.
{"title":"Wearable monitoring for rehabilitation: Deep learning-driven vertical ground reaction force estimation for anterior cruciate ligament reconstruction","authors":"Tianxiao Chen , Datao Xu , Meizi Wang , Zhifeng Zhou , Tianle Jie , Huiyu Zhou , Yi Yuan , Julien S. Baker , Zixiang Gao , Yaodong Gu","doi":"10.1016/j.clinbiomech.2025.106663","DOIUrl":"10.1016/j.clinbiomech.2025.106663","url":null,"abstract":"<div><h3>Background</h3><div>Anterior cruciate ligament reconstruction (ACLR) can restore knee stability, yet many patients fail to regain pre-injury function or develop secondary injuries. Vertical ground reaction force (vGRF) reflects joint loading and recovery but is typically measured via lab-based force plates, limiting real-world use. Wearable sensors and deep learning could enable portable monitoring, but current studies lack accuracy in complex movements and patient-specific adaptations.</div></div><div><h3>Methods</h3><div>Lower-limb kinematics and vGRF data from 25 ACLR patients during three daily activities (walking, running, descending stairs) was collected by wearable sensors and Vicon system. Three deep learning models were developed and optimized for the prediction tasks. The collected data was used to train the three developed models and the performance of each model was evaluated.</div></div><div><h3>Findings</h3><div>Among the three deep learning models, CNN-BiGRU-Attention model demonstrated the best predictive performance across all three movement tasks (R<sup>2</sup><sub><em>walking</em></sub> = 0.953 ± 0.006, R<sup>2</sup><sub><em>running</em></sub> = 0.971 ± 0.005, R<sup>2</sup><sub><em>descending stairs</em></sub> = 0.979 ± 0.003). Additionally, for the three selected daily activities, all models showed superior vGRF prediction performance in running and stair descending tasks compared to walking.</div></div><div><h3>Interpretation</h3><div>By integrating data from wearable sensors with a hybrid deep learning framework, the proposed CNN-BiGRU-Attention model successfully achieved accurate estimation of vGRFs of ACLR patients in various movements. This provides a key technical reference for optimizing personalized rehabilitation strategies and improving patient outcomes, demonstrating significant clinical application value and social benefits.</div></div>","PeriodicalId":50992,"journal":{"name":"Clinical Biomechanics","volume":"130 ","pages":"Article 106663"},"PeriodicalIF":1.4,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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