Effect of a Psychologically Informed Intervention to Treat Adolescents With Patellofemoral Pain: A Randomized Controlled Trial

Objective: To determine whether the addition of a brief psychologically informed video to traditional physical therapy influenced function (primary aim), pain, and psychological beliefs (secondary aims) among adolescents with patellofemoral pain (PFP). Design: Double-blind randomized controlled trial. Setting: Outpatient physical therapy clinics of a single pediatric hospital. Participants: Sixty-six adolescents with PFP (14.8±1.7 years old, 65% female). Intervention: Adolescents were randomly assigned to view a brief psychologically informed video (n=34) or control video (n=32). The psychologically informed video targeted pain-related fear and pain catastrophizing, and the control video related basic anatomy and factors involved in PFP. Main Outcome Measures: The primary outcome was change in function (Anterior Knee Pain Scale). Secondary outcomes were change in psychological beliefs (fear-avoidance beliefs, kinesiophobia, pain catastrophizing) and pain. Outcomes were assessed at baseline, immediately post intervention, at 2 weeks, at 6 weeks, and at 3 months. Results: Using a 2-way mixed analysis of variance, change in function in the intervention group was greater than the control group, with a moderate treatment effect noted (P=.001, partial η²=0.1). Post hoc testing revealed that there was a significant interaction between the intervention and time from baseline to 2 weeks, but no interaction was noted between 2 weeks and 3 months. The psychologically informed video significantly reduced maladaptive psychological beliefs (P=.01, η²=0.32). No significant between-group differences in pain were noted. Conclusions: Incorporating a brief one-time psychologically informed video into standard physical therapy care significantly reduced pain-related fear, reduced pain catastrophizing, and improved function among adolescents with PFP. The immediate effect noted on function did not continue throughout the course of care.