A positive association between foot posture index and medial compartment knee osteoarthritis in Moroccan people

Objectives: To compare foot posture in people with and without medial compartment knee osteoarthritis (OA), and to assess association between its abnormalities and medial compartment knee OA. Methods: We compared the foot posture of patients with clinically and radiographically-confirmed medial compartment knee OA and asymptomatic healthy controls using the foot posture index (FPI), navicular height, and the medial arch. Results: We included 100 patients and 80 asymptomatic controls. The mean age of patients was 59 ± 7 (44-76) years and 48 ± 9 (28-60) years in the control (p=0.06). Patients group have more pronated foot for FPI (1.50 ± 2.68 vs 0.72 ± 2.63; p=0.05), more flat foot (42% vs 22%; p=0.03), and less pes cavus than the control group (58% vs 77%; p=0.004). However, there was no significant difference between the groups in the navicular height (3.90 ± 0.85 cm vs 4.00 ± 0.76 cm; p=0.41). In multivariate statistical analysis, after adjusting for age and body mass index, pronated foot in FPI (OR=1.22, 95%IC= [1.06-1.40], p=0.005), and pes cavus (OR=0.32, 95%IC= [0.11-0.93], p=0.03) had a significant correlation with the knee osteoarthritis. Conclusion: Pronated foot posture and flat foot are significantly associated with medial compartment knee osteoarthritis.