Multi-joint gait adaptation patterns in medial ankle osteoarthritis with and without concurrent knee osteoarthritis

Medial ankle osteoarthritis (OA) is associated with increased ankle varus loading, but multi-joint gait adaptations across the kinetic chain remain incompletely understood. This study investigated gait adaptation patterns in medial ankle OA with and without concurrent knee OA.

This retrospective comparative study included 42 patients with medial ankle OA (Takakura stage 2-3 A) who underwent three-dimensional gait analysis. Patients were categorized as isolated medial ankle OA (Group 1, n = 22) or medial ankle OA with concurrent knee OA (Group 2, n = 20), and compared with 44 age-matched controls. Spatiotemporal parameters and joint kinetics were analyzed discretely, while continuous kinematic waveforms were analyzed using statistical parametric mapping.

Both patient groups showed more than two-fold increases in ankle varus moments and reduced walking speed compared with controls. Group 1 showed greater normalized step width than Group 2 (9.0 vs 7.5, p = 0.026), while ankle plantarflexion moments were preserved in both patient groups. In waveform analysis, Group 1 showed coordinated transverse-plane adaptations, including increased foot external rotation, hip external rotation, knee internal rotation, and pelvic internal rotation. Group 2 showed a less coordinated, more distal-focused pattern relative to controls, with prolonged hindfoot external rotation and fewer proximal adaptations. Direct SPM comparison between patient groups showed limited significant waveform differences, with significance only in pelvic coronal motion.

Compared with controls, concurrent knee OA was associated with a less coordinated and more distal-focused gait adaptation pattern in medial ankle OA. These findings may reflect altered intersegmental coordination, although direct patient-group waveform differences were limited.