Strength and flexibility of the hip, knee and ankle associated with patellofemoral pain syndrome : a case-control study

Abstract

BACKGROUND: Patellofemoral pain syndrome (PFPS) has been defined as anterior knee pain in the absence of pathology, and a complex multifactorial aetiology. The identification of modifiable intrinsic factors variables which can be measured in a clinical setting would be useful for practitioners who manage people with PFPS.

OBJECTIVES: To identify intrinsic variables associated with PFPS using physical examination measures of known reliability. Design: Cross sectional, case-control. Setting: laboratory.

PARTICPANTS: Twenty participants (n=10 symptomatic, n=10 asymptomatic). Asymptomatic participants were matched to symptomatic participants by age, gender, height, weight and level of recent physical activity (RPAQ).

MAIN OUTCOME MEASURES: Participants were assessed for hip flexion, quadriceps length, iliotibial band length, isometric hip internal and external rotation strength, and the range of ankle dorsiflexion during weight bearing.

RESULTS: Isometric strength measures (hip internal and external rotation strength) were significantly different between symptomatic and asymptomatic participants and were associated with 'very large' effects (d>2.5).

CONCLUSIONS: The strong association between hip weakness and PFPS, indicates the importance of considering this factor in a clinical setting. Measures used in this research were clinically appropriate and reliable to assess strength and flexibility measures associated with PFPS.