The Relationship between Lower Extremity Alignment Characteristics and Anterior Knee Joint Laxity

BACKGROUND: Lower extremity alignment may influence the load distribution at the knee, potentially predisposing the anterior cruciate ligament to greater stress. We examined whether lower extremity alignment predicted the magnitude of anterior knee laxity in men and women. HYPOTHESIS: Greater anterior pelvic angle, hip anteversion, tibiofemoral angle, genu recurvatum, and navicular drop will predict greater anterior knee laxity. STUDY DESIGN: Descriptive laboratory study. METHODS: Women (n = 122) and men (n = 97) were measured for anterior knee laxity and 7 lower extremity alignment variables on their dominant stance leg. Linear regression determined the extent to which the alignment variables predicted anterior knee laxity for each sex. RESULTS: Lower anterior pelvic tilt and tibiofemoral angle, and greater genu recurvatum and navicular drop were related to greater anterior knee laxity in women, explaining 28.1% of the variance (P < .001). Lower anterior pelvic tilt and greater hip anteversion, genu recurvatum and navicular drop were predictors of greater anterior knee laxity in men, explaining 26.5% of the variance (P < .001). CONCLUSION: Lower anterior pelvic tilt, greater knee hyperextension, and foot pronation predicted greater anterior knee laxity in both men and women, with genu recurvatum and navicular drop having the greatest impact on anterior knee laxity. Greater hip anteversion was also a strong predictor in men, while a lower tibiofemoral angle was a significant predictor in women. CLINICAL RELEVANCE: The associations between lower extremity alignment and anterior knee laxity suggest that alignment of the hip, knee, and ankle may be linked to or contribute to abnormal loading patterns at the knee, potentially stressing the capsuloligamentous structures and promoting greater joint laxity.