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.