Examination of Kinematic Factors during Single Leg Squatting Associated with the Occurrence of Re-injury after Anterior Cruciate Ligament Reconstruction

Abstract

Objective：This study aimed to determine the difference in knee joint range of motion (ROM) and coefficient of variation (CV) during preoperative single-leg squatting in patients who developed ipsilateral lower limb anterior cruciate ligament (ACL) re-injury months after ACL reconstruction and in those who did not have the injury.

Methods：Participants included 38 patients with non-contact ACL injuries. All patients underwent single-leg squatting the day before ACL reconstruction. Knee joint ROM and CV were assessed during single-leg squatting using a three-dimensional motion analysis system. We investigated the occurrence of ACL reinjury in the ipsilateral lower limb approximately 30 months after ACL reconstruction. Knee joint ROM and CV were then compared between the postoperative and non-injury groups.

Results：The postoperative injury and non-injury groups included 9 and 29 patients, respectively. The knee internal/external rotation ROM and CV of knee varus/valgus ROM were greater in the postoperative injury group than in the postoperative non-injury group.

Conclusion：During single-leg squatting before ACL reconstruction surgery, the knee internal/external rotation ROM and CV of knee varus/valgus ROM were suggested to be points of evaluation when considering ACL re-injury prevention.