Video Analysis of Anterior Cruciate Ligament Injury: Abnormalities in Hip and Ankle Kinematics

Background Most anterior cruciate ligament research is limited to variables at the knee joint and is performed in the laboratory setting, often with subjects postinjury. There is a paucity of information on the position of the hip and ankle during noncontact anterior cruciate ligament injury. Hypothesis When landing after maneuvers, athletes with anterior cruciate ligament injury (subjects) show a more flatfooted profile and more hip flexion than uninjured athletes (controls). Study Design Case control study; Level of evidence, 3. Methods Data from 29 videos of subjects were compared with data from 27 videos of controls performing similar maneuvers. Joint angles were analyzed in 5 sequential frames in sagittal or coronal planes, starting with initial ground-foot contact. Hip, knee, and ankle joint angles were measured in each sequence in the sagittal plane and hip and knee angles in the coronal plane with computer software. The portion of the foot first touching the ground and the number of sequences required for complete foot-ground contact were assessed. Significance was set at P