Jacob J Capin, Joseph A Zeni, Jeri E Forster, Victor A Cheuy, Amy Peters, Craig Hogan, Charlie Yang, Cory L Christiansen, Jennifer E Stevens-Lapsley, Michael J Bade
{"title":"Preoperative and Post-Rehabilitation Predictors of Gait Biomechanics Six Months After Total Knee Arthroplasty.","authors":"Jacob J Capin, Joseph A Zeni, Jeri E Forster, Victor A Cheuy, Amy Peters, Craig Hogan, Charlie Yang, Cory L Christiansen, Jennifer E Stevens-Lapsley, Michael J Bade","doi":"10.1002/jor.70052","DOIUrl":"https://doi.org/10.1002/jor.70052","url":null,"abstract":"<p><p>The primary purpose of this study was to determine the preoperative predictors of gait biomechanics 6 months after unilateral total knee arthroplasty (TKA). There were 126 participants (age 64.4 ± 7.1 years, 75 females) who underwent instrumented biomechanical assessments while walking at a self-selected pace preoperatively, 10 weeks after (post-rehabilitation), and 6 months after unilateral TKA. Outcomes were peak knee extension moment (pKEM), knee angle excursion, and vertical ground reaction force (vGRF) ratio (surgical/contralateral). Potential clinical, demographic, and biomechanical predictors were tested univariately and considered a candidate for the final model if p < 0.15. Each multivariate model initially contained all candidates, and backward selection was used to determine the final model. Greater 6-month surgical limb pKEM was predicted (r<sup>2</sup> = 0.31) by greater preoperative pKEM (β = 0.44, p < 0.0001), better quadriceps activation (β = 0.23, p = 0.004), and male sex (β = -0.21, p = 0.009). Greater 6-month surgical knee excursion was predicted (r<sup>2</sup> = 0.34) by greater preoperative excursion (β = 0.39, p < 0.0001), male sex (β = -0.28, p = 0.0007), and preoperative quadriceps strength (β = 0.16, p = 0.047). Six-month vGRF ratio was predicted (r<sup>2</sup> = 0.16) by preoperative vGRF ratio (β = 0.37, p < 0.0001) and study treatment group (β = 0.18, p = 0.03). Preoperative biomechanical variables at post-rehabilitation were also the strongest predictors of 6-month biomechanics. Statement of Clinical Significance: The strongest and most consistent predictor of gait biomechanics 6 months after TKA was the respective preoperative gait biomechanics variable, which may have important clinical implications for surgical decision making and prehabilitation/rehabilitation strategies. Biofeedback targeting vGRF predicted vGRF symmetry, but no other gait parameters, suggesting targeted interventions are needed. Improving quadriceps strength and activation may also facilitate knee biomechanics.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145023521","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}
{"title":"Tibia-Fibula Relative Motion During Gait Cycle by 2D-3D Registration.","authors":"Lichao Zhang, Peng Su, Junlin Zhou","doi":"10.1002/jor.70053","DOIUrl":"https://doi.org/10.1002/jor.70053","url":null,"abstract":"<p><p>Injuries to the distal tibiofibular joint are often associated with ankle fractures, sports-related injuries, or instability, whereas proximal tibiofibular joint injuries are more commonly present with lateral- or posterolateral-compartment lesions of the knee. These conditions may be related to the relative motion between the tibia and fibula; however, precise movement patterns have yet to be fully elucidated. This study analyzes the relative motion of the tibia and fibula in 16 healthy adults (32 bones; 8 males and 8 females) throughout a normal gait cycle. CT scan data were initially acquired to construct 3D models of the tibia and fibula. X-ray images were taken at seven points during the gait cycle for 3D-2D and 3D-3D model registration, facilitating the calculation of relative degrees of freedom (DOF) movements between these bones. Our results demonstrate that from the heel strike to the single-legged stance phase, the fibula transitions from plantarflexion to dorsiflexion, reaching up to 0.41°. It shifts from inversion to eversion, increasing to 0.06°, while internal rotation decreases to 0.5°. From the single-legged stance to the toe-off phase, changes in plantarflexion/dorsiflexion are minimal, eversion decreases to 0.02°, and internal rotation increases to 0.63°. The proximal fibula exhibits anterior-posterior, medial-lateral, and inferior-superior movements, with similar patterns observed in the distal fibula. During a standard gait cycle, internal/external rotational movements, along with anterior-posterior and medial-lateral shifts, are predominant. Orthopaedic Research Society.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145023560","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}
R Peter Suderman, Mark B Hurtig, Marc D Grynpas, Paul R T Kuzyk, Adele Changoor
{"title":"Patient-Specific 3D-Printed Drill Guides for an Ovine Osteochondral Allograft Transplantation Model.","authors":"R Peter Suderman, Mark B Hurtig, Marc D Grynpas, Paul R T Kuzyk, Adele Changoor","doi":"10.1002/jor.70057","DOIUrl":"https://doi.org/10.1002/jor.70057","url":null,"abstract":"<p><p>Proper alignment between donor and recipient cartilage in osteochondral allograft transplantation supports tissue integration and the formation of a stable articulating surface. This study evaluated the use of patient-specific 3D-printed drill guides to improve alignment in an ovine model of osteochondral allograft transplantation when used in place of a free-hand drilling technique. Fourteen female Arcott sheep underwent bilateral osteochondral allograft transplantation. Drill guides were used to transplant 51 grafts (6.5 mm diameter), while the freehand drilling technique was used to transplant 32 grafts. After a 9-month survival time, tissues were harvested. Cross-sectional confocal microscopy images and histological sections were used to quantify height differences between donor and recipient tissues. Grafts transplanted with the drill guides showed significantly reduced (p = 0.0005) height differences between donor and recipient tissues compared to the freehand drilling technique. However, the guide technique was associated with increased osteophyte development (p = 0.0180) and synovial inflammation (p = 0.0451). These findings demonstrate that patient-specific 3D-printed drill guides improve graft alignment in an ovine model of osteochondral allograft transplantation. Methodological improvements are proposed to minimize osteophyte formation and inflammation in future studies.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145008338","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}
Anna E Duncan, Arthur L Malkani, Michael J Stoltz, Nabid Ahmed, Maunil Mullick, John E Whitaker, Andrew Swiergosz, Langan S Smith, Arinan Dourado
{"title":"Machine Learning Model for Selection of Cementless Total Knee Arthroplasty Candidates Utilizing Patient and Radiographic Parameters.","authors":"Anna E Duncan, Arthur L Malkani, Michael J Stoltz, Nabid Ahmed, Maunil Mullick, John E Whitaker, Andrew Swiergosz, Langan S Smith, Arinan Dourado","doi":"10.1002/jor.70059","DOIUrl":"https://doi.org/10.1002/jor.70059","url":null,"abstract":"<p><p>The use of cementless total knee arthroplasty (TKA) has significantly increased over the past decade. However, there is no objective criteria or consensus on parameters for patient selection for cementless TKA. The purpose of this study was to develop a machine learning model based on patient and radiographic parameters that could identify patients indicated for cementless TKA. We developed an explainable recommendation model using multiple patient and radiographic parameters (BMI, Age, Gender, Hounsfield Units [HU] from CT for density of tibia). The predictive model was trained on medical, operative, and radiographic data of 217 patients who underwent primary TKA. HU density measurements of four quadrants of the proximal tibia were obtained at region of interest on preoperative CT scans. which were then incorporated into the model as a surrogate for bone mineral density. The model employs Local Interpretable Model-agnostic Explanations in combination with bagging ensemble techniques for artificial neural networks. Model testing on the 217-patient cohort included 22 cemented and 38 cementless TKA cases. The model successfully identified 19 cemented patients (sensitivity: 86.4%) and 37 cementless patients (specificity: 97.4%) with an AUC = 0.94. Use of cementless TKA has grown significantly. There are currently no standard radiographic criteria for patient selection. Our machine learning model demonstrated 97.4% specificity and should improve with more training data. Future improvements will include incorporating additional cases and developing automated HU extraction techniques.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145008306","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}
{"title":"Dynamic Analysis of Ultrasound Images of the Median Nerve Using Particle Image Velocimetry.","authors":"Issei Shinohara, Takahiro Furukawa, Atsuyuki Inui, Yutaka Mifune, Kohei Yamaura, Tomoyuki Matsumoto, Ryosuke Kuroda","doi":"10.1002/jor.70009","DOIUrl":"10.1002/jor.70009","url":null,"abstract":"<p><p>Carpal tunnel syndrome (CTS) diagnosis is typically confirmed through electrophysiologic studies and ultrasound (US) imaging. Recent studies have suggested that median nerve gliding is reduced in patients with CTS. This study employed particle image velocimetry (PIV) to analyze median nerve dynamics. Ultrasound movies were captured during finger flexion and extension for 20 healthy volunteers (control group) and 20 CTS patients (CTS group). These movies were then analyzed using the PIV method. Within a 10 x 10 mm² region of interest (ROI) that included the median nerve and flexor tendon, the velocity magnitude and vector direction of movement were examined using PIV software. The maximum and mean velocity magnitudes were compared between the two groups using the Mann-Whitney U test. The maximum velocity in the ROI was significantly lower in the CTS group (9.3 ± 3.0 mm/s) than in the control group (11.5 ± 3.4 mm/s). The mean velocity was also significantly lower in the CTS group (1.7 ± 0.3 mm/s) than in the control group (2.5 ± 0.7 mm/s). Regarding motor properties, transverse motor velocity was significantly lower in CTS patients than in controls, while vertical movement showed no significant difference between the two groups. This study applied the PIV method to US images for dynamic analysis of the median nerve, revealing reduced gliding of the median nerve and flexor tendon in CTS patients, particularly in transverse movements. The application of dynamic analysis using the PIV method has potential for use in diagnosis and rehabilitation of CTS.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":"1673-1678"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528404","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}
Zachary A Koroneos, Hwabok Wee, J Spence Reid, Gregory S Lewis
{"title":"Effects of Plate-Bone Contact on Bridge Plate Fracture Fixation Biomechanics: Computational, Experimental, and Analytical Modeling.","authors":"Zachary A Koroneos, Hwabok Wee, J Spence Reid, Gregory S Lewis","doi":"10.1002/jor.26114","DOIUrl":"10.1002/jor.26114","url":null,"abstract":"<p><p>Bridge plating is commonly used for internal fixation of comminuted fractures. The inner working length between screws has been established as a key parameter controlling postoperative biomechanical stability. However, plate-bone contact may affect these biomechanics in complex ways, and the offset between the plate and bone is variable across surgeries. The objective of this study was to examine the effects of construct and loading parameters on interfragmentary motion and maximum plate stress of bridge plating constructs. Finite element models were developed with variations in inner working length, plate-bone offset, fracture gap size, and loading type and magnitudes. Experiments with synthetic bones were conducted in parallel to support model credibility. Analytical models were also developed based on beam bending and torsion of the plate, assuming rigidity outside the inner working length. Finite element and experimental results of axial and torsional loading scenarios without plate-bone contact confirmed linear relationships between inner working length and interfragmentary motion. Analytical predictions of interfragmentary motion showed very good agreement with the finite element simulations in these scenarios. Conversely, in cases with plate-bone contact, a shorter effective working length was formed, and results were dependent on additional variables such as fracture gap. The study shows how the mechanics of bridge plating can be understood and predicted based on beam theory up to the point of plate-bone contact, and how interfragmentary motions and maximum plate stresses are influenced by the interaction of surgical variables in the presence of plate-bone contact.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":"1606-1618"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12329631/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144248303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyung Wook Kim, Andrew Reyes Padalhin, Hyun Seok Ryu, Celine Abueva, So Young Park, Jun Sang Bae, Seung Hyeon Yoo, Hwee Hyon Seo, Phil-Sang Chung, Hyun Sik Gong, Seung Hoon Woo
{"title":"The Interplay of Angiogenesis and Osteogenesis in Non-Stabilized Incomplete Tibial Fractures: A Temporal Study in Rats.","authors":"Kyung Wook Kim, Andrew Reyes Padalhin, Hyun Seok Ryu, Celine Abueva, So Young Park, Jun Sang Bae, Seung Hyeon Yoo, Hwee Hyon Seo, Phil-Sang Chung, Hyun Sik Gong, Seung Hoon Woo","doi":"10.1002/jor.70006","DOIUrl":"10.1002/jor.70006","url":null,"abstract":"<p><p>Prior research on angiogenesis and osteogenesis during bone fracture healing has primarily focused on stabilized models, often within controlled environments. However, the dynamic interplay of these processes in the context of long bone fractures without scaffolds or external factors remains poorly understood. This study investigated the temporal dynamics of angiogenesis and osteogenesis in a non-stabilized incomplete transverse tibia bone fracture model. Multi-modal observation approach was carried out using micro-CT analysis of bone mineral density, histological assessment of fracture healing, and confocal microscopy for visualization and co-localization of key angiogenic (CD31, endomucin) and osteogenic (collagen 1, osteocalcin, PDGFRB) markers. Our findings revealed a dynamic and interdependent relationship between these processes. H type blood vessels persisted throughout the healing process, and significant correlations were observed between the expression of angiogenic and osteogenic markers. The role of hypoxia, a critical regulator of both processes, was investigated by analyzing HIF1-α expression. Increased expression of SLIT3, a guidance molecule, was also observed at later stages of healing, suggesting its potential involvement in vascular remodeling. These findings provide crucial insights into the molecular mechanisms underlying bone fracture repair in the absence of additional supporting external elements such as scaffolds or stabilizers. By elucidating the temporal dynamics of these key processes, we identify potential targets for therapeutic interventions aimed at accelerating and optimizing bone regeneration. Consideration of these interactions can lead to the development of effective clinical strategies for enhancing bone healing in non-stabilized incomplete fractures.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":"1632-1646"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12329645/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144333342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joose P J Peitola, Amir Esrafilian, Morten B Simonsen, Michael S Andersen, Rami K Korhonen
{"title":"Reduced Muscle Strength Can Alter the Impact of Gait Modifications on Knee Cartilage Mechanics.","authors":"Joose P J Peitola, Amir Esrafilian, Morten B Simonsen, Michael S Andersen, Rami K Korhonen","doi":"10.1002/jor.70007","DOIUrl":"10.1002/jor.70007","url":null,"abstract":"<p><p>Muscle strength can substantially influence knee joint loading, stability, and cartilage biomechanics, all of which are important factors in the onset and progression of knee osteoarthritis (KOA). Noninvasive rehabilitation methods, such as gait modifications, are suggested to effectively alter knee joint loading, potentially helping to prevent or slow KOA progression. However, no studies to date have assessed if reduced lower limb muscle strength can influence the effects of rehabilitation exercises such as gait modifications. This study aimed to reveal how reducing the strength of three lower limb muscle groups (knee extensors, hip abductors, and ankle extensors) impacts the effects of gait modifications (Toe-out, Toe-in, and Wide gait) on knee cartilage stresses. We analyzed motion and ground reaction force data from seven healthy male participants using a musculoskeletal-finite element workflow, where we systematically reduced the isometric strength of the selected muscle groups in the musculoskeletal models. Our findings indicate that reductions in hip abductor and ankle extensor strength had the most pronounced impact on the effects of gait modifications on cartilage mechanics (maximum decrease of 6 percentage points (PP) in the changes of maximum principal stress). Overall, Toe-out gait was least affected by reduced muscle strength compared to other gait styles, although responses varied greatly between participants (0-14 percentage point differences). This study emphasizes the importance of considering participant-specific muscle strengths when designing personalized rehabilitation strategies such as gait modifications and provides theoretical insights into optimizing rehabilitation exercises for managing KOA based on a given motion and joint kinetics.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":"1566-1580"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12329646/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rebecca F Reals, Alex J Reiter, Ryan M Castile, Sophia D Miller, Paul C Cannon, Benjamin M Zmistowski, Aaron M Chamberlain, Spencer P Lake
{"title":"Soft Tissue Injury and Immobilization Are Both Required for Persistent Elbow Contracture in a Rat Model.","authors":"Rebecca F Reals, Alex J Reiter, Ryan M Castile, Sophia D Miller, Paul C Cannon, Benjamin M Zmistowski, Aaron M Chamberlain, Spencer P Lake","doi":"10.1002/jor.70010","DOIUrl":"10.1002/jor.70010","url":null,"abstract":"<p><p>Post-traumatic joint contracture commonly occurs after elbow injury. Although known as a risk factor for poor outcomes, immobilization is necessary to prevent reinjury. The objective of this study was to isolate the contribution of immobilization to mechanical and functional disability using an animal model. Left elbows of Long-Evans rats were immobilized in the absence (IM) or presence of an elbow injury (INJ+IM). Animals were immobilized for 21 or 42 days or immobilized for 21 days followed by free mobilization (FM) for 21 days. Uninjured animals without immobilization (CTRL) were also evaluated. Forelimb strength and gait were measured during FM, and joints underwent post-mortem mechanical testing. Contracture in 21IM elbows was moderate compared to CTRL but not as severe as 21INJ+IM. 42IM elbows were severely contracted compared to CTRL and not different from 42INJ+IM. 21IM/21FM mechanics were no longer different from CTRL while 21INJ+IM/21FM were still contracted. Gait was less altered for IM compared to INJ+IM and nearly returned to CTRL levels over time. Forelimb strength was not different between IM and INJ+IM but both were decreased compared to CTRL. For immobilization without injury, contracture took longer to develop but eventually reached levels of INJ+IM. Following remobilization, IM groups recovered faster and to a greater extent than INJ+IM groups. Thus, immobilization alone is not sufficient to recapitulate characteristics of human elbow PTJC (e.g., long-term loss of motion) in an animal model. Clinically, immobilization may not contribute to irreversible contracture development if duration is limited and strategic, active mobilization is provided.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":"1679-1688"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144506021","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}
Edward Godbold, Connor Luck, Camille Johnson, Ashley Disantis, Craig Mauro, Michael McClincy, William Anderst
{"title":"Using Dynamic Joint Space During Physiological Loading to Objectively Measure Hip Stability.","authors":"Edward Godbold, Connor Luck, Camille Johnson, Ashley Disantis, Craig Mauro, Michael McClincy, William Anderst","doi":"10.1002/jor.70011","DOIUrl":"10.1002/jor.70011","url":null,"abstract":"<p><p>An objective measurement of hip stability during functional loading is needed to improve diagnosis, guide treatment decisions, and evaluate intervention success. This study aimed to develop a reference measurement for stable hips based upon dynamic minimum hip joint space (HJS) in healthy young adults. Synchronized biplane radiographs of the hips of 24 healthy young adults were collected (50 images/s) during treadmill walking and squatting. Subject-specific femur and pelvis models were created from CT scans, and bone motion was determined by a validated volumetric model-based tracking technique. The distance between femur and acetabulum subchondral bone surfaces was calculated during each movement. Range in minimum subchondral bone distance was measured in radial and sagittal regions of the acetabula. Regression analysis identified kinematics and morphologic predictors of range in minimum HJS. Range in minimum HJS during gait in the anterior-inferior (1.8 mm) and posterior-superior regions (1.7 mm) was 31%-38% larger than in the anterior-superior and superior regions (1.3 mm; p ≤ 0.001), and 13%-20% larger than in the posterior-inferior region (1.5 mm; p ≤ 0.001). No differences in minimum HJS were identified in radial regions during squat (range: 0.7-0.9 mm). No sex differences were identified. Femur head translation during gait was a stronger predictor of the range in minimum HJS than changes in femur head morphology. This suggests anterior-inferior to posterior-superior pistoning of the femur may be a mechanical mechanism for commonly observed pathology. These results suggest that gait is a better activity than squatting to assess dynamic hip stability when using this metric.</p>","PeriodicalId":16650,"journal":{"name":"Journal of Orthopaedic Research®","volume":" ","pages":"1666-1672"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12329620/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}