Abstract
Introduction & Purpose
Idiopathic torsional deformities of lower limb bones can affect a patient’s gait pattern and joint health, while their cause remains unidentified (Koller et al., 2026). Abnormal joint loadings and the progression of degenerative diseases such as osteoarthritis in adults can be altered through gait modifications (Diamond et al., 2022, Uhlrich et al., 2022). Bone growth is regulated by mechanical stimuli (Carter & Wong, 1988; Frost, 2001), and normalizing joint loadings might be a non-invasive treatment option (Kainz et al., 2020; Koller et al., 2024). What constitutes normal versus abnormal joint contact forces (JCF) remains unidentified and most likely varies by individual. Koller et al. (2026) reported the effect of hip joint loads on proximal femoral growth plate stresses during different foot progression angles (FPA). This study aimed to evaluate several established gait modifications’ abilities to steer hip (HJCF) and knee JCF (KJCF) magnitude and orientation using a personalized musculoskeletal model.
Methods
One healthy child (15y, m) underwent MRI and three-dimensional gait analysis (Vicon, Oxford, UK) on an instrumented treadmill (AMTI, Watertown, USA), including electromyography of 16 lower limb muscles. After familiarization, he walked at preferred speed, and with altered FPA (in-/out-toeing), stance widths, speeds, and foot-strike patterns. A personalized musculoskeletal model was created using OpenSim Creator’s Model Warper (Kewley et al., 2026) within the MRI2MSKworkflow (Koller, 2026), adapting an OpenSim model (Rajagopal et al., 2016; Uhlrich et al., 2022, Lerner et al., 2015) to the individual’s anatomy obtained from imaging. JCFs per leg and condition were calculated using OpenSim (Delp et al., 2007) and the Muscle Redundancy Solver (De Groote et al., 2016). All trials were post-hoc classified into gait modification categories, as their implementation varied for each step.
Results
All gait modification results were compared to those of preferred walking style. Out-toeing increased the first peak of HJCF, patellofemoral (PFJCF) and KJCF, but decreased the second peak of HJCF and KJCF. A wider stance lowered, while narrow stance increased HJCF during terminal stance. KJCF had a slightly lower second peak for wide stance variations. Walking with exaggerated plantarflexion (push-off) lowered PFJCF during mid-stance and increased and slightly advanced the second peak of KJCF.
Fast walking increased PFJCF during loading response, while slow walking decreased it. Figure 1B shows that all gait deviations except forefoot and slow walking shifted HJCF orientation anteriorly, while these two shifted it posteriorly.
Discussion
Measuring subject-specific joint loading and identifying abnormal loading patterns supports movement diagnostics across all populations to detect potential risks early. This study demonstrated that coachable gait cues alter joint loads and may influence bone development. Kinematic and kinetic results agreed with Schwartz et al.(2008) for slow, preferred and fast walking. Further studies incorporating finite element simulations are needed to determine the effect of these deviations on femoral growth.
Conclusion
Recent studies emphasize the need for model personalization and individualized assessment. We showed that gait modifications induce measurable changes in hip and knee joint loading. The effect of gait alterations on longitudinal bone growth remains to be determined.
References
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