Effect of quadriceps strength and proprioception on risk for knee osteoarthritis

Segal NA, et al. · Medicine and Science in Sports and Exercise

High versus low knee-extensor strength lowered the odds of incident symptomatic knee OA (OR 0.43, 95% CI 0.31-0.61, p<0.0001, adjusted for age, sex, BMI, knee injury, knee surgery and physical activity) across 298 incident knees. Strength did not predict incident radiographic OA, defined as a new Kellgren-Lawrence grade of 2 or more, where BMI was the only consistent predictor. Joint position sense predicted neither outcome, and the strength-by-proprioception interaction the study was built to test was null in both sexes for both outcomes.

Population

MOST cohort, community-dwelling adults 50-79 with or at high risk of knee OA; 1,390 participants (2,276 knees) in the radiographic analysis and 1,829 participants (3,166 knees) in the symptomatic analysis

Intervention

Exposure: baseline isokinetic knee-extensor strength and knee joint position sense; 30-month follow-up

Comparator

Sex-specific tertiles of strength and of joint position sense, singly and in combination

Limitations

Observational, and a re-analysis of the MOST cohort that produced the earlier strength finding rather than an independent replication; the symptomatic endpoint requires a Kellgren-Lawrence grade of 2 or more as well as frequent symptoms, so it is not a symptom outcome on its own; symptoms were captured at two visits only, which the authors note biases toward the null; joint position sense was tested seated and non-weight-bearing in the right knee alone. NIH-funded, authors declare no conflicts.