Pain, Sports Participation, and Physical Function in Adolescents With Patellofemoral Pain and Osgood-Schlatter Disease: A Matched Cross-sectional Study

• OBJECTIVE: To compare pain, physical activity, quality of life, strength, and knee function in adolescents with patellofemoral pain (PFP) and Osgood-Schlatter disease (OSD) to those in painfree controls. • DESIGN: Cross-sectional study. • METHODS: Self-report questionnaires were used to describe pain, physical activity, knee function, and quality of life in participants with PFP (n = 151) or OSD (n = 51) and in pain-free controls (n = 50) between 10 and 14 years of age. Hip and knee strength were measured by handheld dynamometry. Physical activity levels were measured using wearable accelerometers. • RESULTS: Adolescents were highly active (accumulating greater than 120 minutes of vigorous physical activity per day), with no differences between the OSD, PFP, and control groups. Adolescents with PFP or OSD scored 22 to 56 points lower (P<.001) on the Knee injury and Osteoarthritis Outcome Score subscales compared with controls, with the lowest scores on the "sport and recreation" and "quality of life" subscales. Adolescents with OSD had lower knee extension strength compared to controls (P<.05; effect size, 1.25). Adolescents with PFP had lower hip extension strength compared to controls (P<.05; effect size, 0.73). • CONCLUSION: Adolescents with PFP or OSD had high physical activity levels, despite reporting long-standing knee pain and impaired knee function that impacted on their sports participation and quality of life. Clinicians treating adolescents with PFP or OSD may use these findings to target treatment to the most common deficits to restore sports-related function and sports participation.