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

Abstract

ObjectiveTo 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). DesignDouble-blind randomized controlled trial. SettingOutpatient physical therapy clinics of a single pediatric hospital. ParticipantsSixty-six adolescents with PFP (14.8±1.7 years old, 65% female). InterventionAdolescents 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 MeasuresThe 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. ResultsUsing 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. ConclusionsIncorporating 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.