Association between hip and hindfoot dynamic alignment and dynamic knee valgus in high school female basketball players

Abstract

Dynamic knee valgus is considered a risk factor of noncontact ACL injuries. The aim of this study was to determine the association between hip and hindfoot dynamic alignment and dynamic knee valgus. This cross-sectional study involved 88 high school female basketball players (175 legs). Subjects performed single-leg squatting and drop landing which provided a hip-out distance (HOD) and a knee-in distance (KID) via 2D video images. Hip and hindfoot dynamic alignment was evaluated by a dynamic Trendelenburg test (DTT) and a heel-floor test (HFT), respectively , during squatting and landing. The DTT-positive group (dynamic hip mal-alignment with lower non-weightbearing pelvis) demonstrated greater HOD and KID values for both squatting (p<0.001) and landing (p<0.001) than the DTT-negative group. The HFT-positive group (5° or greater hindfoot valgus) demonstrated greater KID values for both squatting (p<0.01) and landing (p<0.001) , but smaller HOD value for squatting (p<0.01) than the HFT-negative group. In conclusion, dynamic hip mal-alignment may be associated with both greater HOD and KID, but hindfoot valgus only with greater KID.