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 patellofemoral 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.