Females with patellofemoral pain syndrome have weak hip muscles: a systematic review

Question: Do females with patellofemoral pain syndrome have decreased hip muscle strength compared with the unaffected side and with healthy controls? Design: A systematic review of observational studies published up to January 2008. Participants: Females with patellofemoral pain syndrome and healthy controls. Outcome measures: Strength for at least one hip muscle group had to be included in the study. Hip muscle strength was recorded as force or torque. Results: Five cross-sectional studies with a mean Newcastle-Ottawa Assessment Scale score of 6 out of 9 met the inclusion criteria. Strong evidence was found for a deficit in hip external rotation, abduction and extension strength, moderate evidence for a deficit in hip flexion and internal rotation strength, and no evidence for a deficit in hip adduction strength compared with healthy controls. Moderate evidence was found for a decrease in hip external rotation and abduction strength but no evidence for a decrease in hip extension, flexion, adduction and internal rotation strength compared with the unaffected side. Conclusion: Females with patellofemoral pain syndrome demonstrate a decrease in abduction, external rotation and extension strength of the affected side compared with healthy controls. [Prins MR, Wurff van der P (2009) Females with patellofemoral pain syndrome have weak hip muscles: a systematic review. Australian Journal of Physiotherapy 55: 9-15]