Distribution of radiographic osteoarthritis between the right and left hands, hips, and knees

To investigate whether radiographic osteoarthritis (OA) is asymmetric and greater on the right side than on the left side in the hands, hips, and knees.

Participants were 489 individuals with posteroanterior hand radiographs from a family study of nodal OA, 1,715 community-derived individuals who had undergone intravenous urography with views of both hips, and 1,729 community-derived individuals with weight-bearing fully extended tibiofemoral (TF) joint and skyline patellofemoral (PF) joint radiographs. All radiographs were evaluated for global OA grade, osteophytes, and joint space narrowing (JSN). Minimum joint space width (JSW) was measured at the hip and knee. Odds ratios (ORs) for global OA on the right side versus the left side were calculated. Osteophytes and JSN were compared by Wilcoxon's signed rank test, and the JSW was compared by paired t-test.

Global OA was more prevalent on the right side at the distal interphalangeal joints (OR 1.57; 95% confidence interval 1.22, 2.02) and the TF joint (OR 1.24; 95% confidence interval 1.01, 1.52). Osteophyte scores for the fingers were greater on the right side, but JSN was symmetric. At the hip, there were no right-left differences in osteophytosis or JSN, but the JSW was smaller on the left. At the TF joint, the medial compartment was narrower and the lateral compartment wider on the right side, and osteophyte scores were greater on the right side. At the PF joint, there were no right-left differences in osteophytes, and for lone PF joint OA, there were no differences in JSN or the JSW.

This discordance in symmetry suggests that the relative importance of biomechanical factors in the pathogenesis of OA is site-specific and may be discordant for cartilage and bone.