Background/Purpose: Hip and knee osteoarthritis (OA) are among the leading causes of global disability. Global OA is more prevalent on the right side. This discordance in symmetry suggests an importance of biomechanical factors, including dominant side, in the pathogenesis of OA. The objective of this study is to investigate the relationship between the foot dominant side and the most symptomatic side and location in knee or hip OA, as well as its evolution over a 10-year follow-up.

Methods: The KHOALA (Knee and Hip Osteoarthritis Long-term Assessment) cohort is a representative, population-based multicenter study that included 878 patients with symptomatic knee and/or hip OA, aged between 40 and 75 years, and established between 2007 and 2009. They were asked at year 6 whether they were right-handed, left-handed, left-handed contrarian, or ambidextrous, as well as which foot they used to kick a ball. Khi² or Fisher tests were used for binary variables, while Student’s t-test was used for continuous variables.

Results: From 538 patients evaluated for laterality, 47 (8.7%) were left footers. Among the 47 left footers, only 14 were left handers (20 are right handers, 3 ambidextrous, and 10 frustrated left-handers). Proportion of right and left knee OA, among patients with unilateral OA, were 58.6% (212/364) and 41.8% (152/364), respectively. Proportion of right and left hip OA were 51.6% (78/151) vs 48,3% (73/151), respectively. Left footers were slightly younger (59.0 SD 8.1 vs 61.6 SD 8.0 years; p=0.04) and more frequently men (52.2% vs 30.2%; p=0.004) than right footers. At 0, 5 and 10 years, pain did not differ between left footers and right footers. In contrast, WOMAC was lower in left footers than in right footers at year 0 (24.3 SD 16.6 vs 32.8 SD 19.7; p=0.002), year 5 ((26.0 SD 17.1 vs 32.3 SD 17.7; p=0.02), and year 10 (26.0 SD 14.5 vs 31.6 SD 18.9; p=0.05). WOMAC function was also lower in left footers than in right footers at year 0 (23.6 SD 18.0 vs 32.3 SD 21.0; p=0.004), year 5 (25.0 SD 17.4 vs 31.8 SD 18.4; p=0.02), and year 10 (25.4 SD 15.7 vs 31.4 SD 19.9; p=0.05). There was not any difference for radiological stage (Kellgren Lawrence). After 10 years right footers did not received significantly more hip or knee replacement of the more painful joint than left footers (29.9%, 143/478, versus 18.2%, 8/44, respectively; p=0.13) (Fig 1).

Conclusion: Womac function is lower in left than in right footers suffering from symptomatic knee and/or hip OA, but we did not observe any difference between right and left footers for pain, radiograph and evolution.

Fig 1

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/foot-laterality-does-not-modify-outcome-of-knee-and-or-hip-osteoarthritis/