Predictors of pain and function outcome after rehabilitation in patients with patellofemoral pain syndrome.

OBJECTIVE To identify changes in impairments associated with functional and pain outcome in patients with patello-femoral pain syndrome following a standardized physiotherapy treatment. DESIGN One group pre-post design. SUBJECTS Seventy-four patients (median age 27 years, 52% female) diagnosed with patellofemoral pain syndrome and referred to physiotherapy treatment. METHODS Baseline measures included self-reported function and pain, which were the dependent variables, and measures of independent variables: strength of quadriceps, hip abduction and hip external rotation; length of hamstrings, quadriceps, plantar flexors, iliotibial band/tensor fascia lata complex, and lateral retinaculum; quality of movement, and fear-avoidance beliefs. Following the baseline measurements, subjects participated in a standardized physiotherapy program. Measurements were repeated at 2-month follow-up. Data were analyzed using 2 forward regression models, the first using function outcome, and the second using pain outcome as the criterion. Age, gender, height and weight were controlled in the regression models. RESULTS Change in fear-avoidance beliefs about physical activity and change in gastrocnemius length predicted function outcome. Change in fear-avoidance beliefs about physical activity and about work predicted outcome of pain. CONCLUSION Change in fear-avoidance beliefs about physical activity was the strongest predictor of function and pain outcome. The fact that patients who decreased their fear-avoidance beliefs improved function and decreased pain indicates that perhaps fear-avoidance beliefs should be targeted during the treatment of patients with patellofemoral pain syndrome.