Knee extensor strength does not protect against incident knee symptoms at 30 months in the multicenter knee osteoarthritis (MOST) cohort

Segal NA, et al. · PM&R

Neither knee-extensor strength nor the hamstring:quadriceps ratio predicted incident frequent knee symptoms at 15 or 30 months; 307 of 2,275 eligible knees developed them. Models controlled for age, BMI, femoral neck bone mineral density, activity score and baseline Kellgren-Lawrence grade, were unchanged by adjusting for lower-limb alignment, and a sensitivity analysis using a 0.8 ratio cutoff was also null. The authors read the result as not supporting the supposition that quadriceps weakness precedes knee pain.

Population

2,275 knees (1,269 women, 1,006 men) with or at risk of knee OA, MOST cohort

Intervention

Exposure: baseline isokinetic knee-extensor strength and hamstring:quadriceps ratio

Comparator

Across strength levels

Limitations

Observational. The outcome is incident frequent knee symptoms rather than incident symptomatic OA, which is why it sits alongside the MOST analysis reporting protection against the latter rather than contradicting it. The authors note that intermittent symptoms may go unreported, that the question distinguishes no severity grades, and that the hamstring:quadriceps cutoff was borrowed from studies of younger adults; they count the 2,275 knees as a strength of the study rather than a limit on its power. NIH-funded.