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.