Patellar Maltracking Persists in Adolescent Females With Patellofemoral Pain: A Longitudinal Study

BACKGROUND: Patellofemoral pain is one of the most common conditions seen in sports medicine practices, particularly among adolescent females. However, the natural history of the underlying pathology in patellofemoral pain during puberty remains poorly understood. PURPOSE: The purpose of this longitudinal study is to assess changes in patellar maltracking patterns in subjects with patellofemoral pain as they mature from mid- to late adolescence. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Three-dimensional patellofemoral kinematic data were acquired during active knee extension-flexion using dynamic magnetic resonance imaging in 6 girls (10 knees; mean age, 14.0 years) with clinically diagnosed patellofemoral pain. The subjects then returned as late adolescents (mean age, 18.5 years) for follow-up scanning. Three-dimensional patellofemoral kinematic parameters were evaluated across the range of motion, but comparison between time points was restricted to 10° of flexion. Participation in impact and nonimpact physical activities, pain score based on the visual analog scale, and the anterior knee pain score were also compared across initial and follow-up visits. RESULTS: All subjects reported improved patellofemoral pain symptoms at follow-up, and one subject reported complete resolution. However, relative to the initial visit, no differences were found in patellar maltracking. There was a decrease in hours engaged in impact physical activities for all subjects at follow-up. CONCLUSION: This study provides insight into the natural history of patellofemoral pain in adolescent females. The relatively unchanged patellofemoral maltracking across subjects suggests that potential anatomic and kinematic abnormalities contributing to patellofemoral pain during mid-adolescence persist during skeletal maturation. Symptom improvement for these subjects did not result from a change in patellofemoral tracking, but rather from other causes.