Idiopathic anterior knee pain in the young. A prospective controlled trial.

Idiopathic anterior knee pain is a common condition in adolescents. The aim of this study was to compare the biometric parameters such as hamstring tightness, hip and knee movements and joint laxity in patients with idiopathic anterior knee pain with a control population of similar age and gender. Patients (n = 34) and controls (n = 34) (age and sex matched) between the age of 11 and 25 were recruited for the study. The mean follow-up of the patient group was 20 months. The patients showed a statistically significant improvement in their symptoms (SF-36 physical component, p = 0.001) despite the fact that half of them did not attend physiotherapy sessions. Patients had statistically significant hamstring tightness (p = 0.04) and increased external hip rotation (p = 0.001) as compared to the control group. These findings support the theory of idiopathic anterior knee pain being a self-limiting condition that is associated with hamstring tightness.