Altered dynamic foot kinematics in people with medial knee osteoarthritis during walking: A cross-sectional study

- Foot kinematics were compared during walking in adults with knee OA and controls.
- Adults with knee OA displayed reduced midfoot and hallux motion during walking.
- People with knee OA display altered foot function characterised by reduced mobility.
- Foot function may influence the effect of footwear and insoles to reduce knee loading.

BackgroundFootwear and insoles are used to reduce knee load in people with medial knee osteoarthritis (OA), despite a limited understanding of foot function in this group. The aim of this study was to investigate the differences in foot kinematics between adults with and without medial knee OA during barefoot walking.MethodsFoot kinematics were measured during walking in 30 adults; 15 with medial knee OA (mean age was 67.0 with a standard deviation (SD) of 8.9 years; height was 1.66 with SD of 0.13 m; body mass was 84.2 with SD of 15.8 kg; BMI was 30.7 with SD of 6.2 kg/m2; K-L grade 3: 5, grade 4: 10) and 15 aged and gender matched control participants with 12 motion analysis cameras using the IOR multi-segment foot model. Motion of the knee joint, hindfoot, midfoot, forefoot and hallux were compared between groups using clustered linear regression.ResultsThe knee OA group displayed reduced coronal plane range of motion of the midfoot (mean 3.8° vs. 5.4°, effect size = 1.1, p = 0.023), indicating reduced midfoot mobility. There was also a reduced sagittal plane range of motion at the hallux in the knee OA group compared to the control group (mean 29.6° vs. 36.3°, effect size = 1.2, p = 0.008). No statistically significant differences in hindfoot or forefoot motion were observed.ConclusionsPeople with medial knee OA display altered foot function compared to healthy controls. As foot and knee function are related, it is possible that altered foot function in people with knee OA may influence the effects of footwear and insoles.