Knee Confidence as it Relates to Self-Reported and Objective Correlates of Knee Osteoarthritis: A Cross-Sectional Study of 220 Patients

Study Design Cross-sectional study. Objective Little is known about correlates of lack of knee confidence in patients with knee osteoarthritis (OA). The objective was to validate, if possible, previously reported associations, and investigate other potential associations, between knee confidence and various self-reported and objective measures, in independent patient cohorts. Methods Baseline data from 220 patients with knee OA was applied in ordinal regression analyses with knee confidence, assessed using the item Q3 from the Knee Injury and Osteoarthritis Outcome Score, as the dependent variable and self-reported (pain on walking, general health, fear of movement, self-efficacy, function and previous serious injury) and objective measures (muscle strength, 20-meter walk time and radiographic severity of tibiofemoral OA) as predictor variables. Results Most (95%) of the participants reported lack of knee confidence, and 54% experienced severe or extreme lack of knee confidence. Fear of movement (Odds Ratio(OR) 2.06, 95% Confidence Intervals [95% CI] 1.15-3.68), pain on walking (OR 1.21, 95% CI 1.09-1.34) and general health (OR 0.024, 95% CI 0.002-0.259) explained 19% of the variance in knee confidence (P<0.001). Conclusion Severe lack of knee confidence is a common finding in knee OA. Pain on walking was confirmed as a correlate of knee confidence while muscle strength was not. Fear of movement and poor general health were new variables associated with lack of knee confidence. The none-existing or poor correlations with other tested variables suggest lack of knee confidence may represent an independent treatment target in knee OA of importance to improve mobility. J Orthop Sports Phys Ther, Epub 24 Aug 2015. doi:10.2519/jospt.2015.5864.