ABSTRACT
Objective:To characterize the knee gait maps of ordinary people, athletes and patients with anterior cruciate ligament (ACL) injury when walking on a level ground in order to identify potential kinematic indicators for early identification of ACL injury.Methods:From December 2021 to March 2022, 39 ordinary college students (normal group) and 39 college athletes (athlete group) were recruited in Southern Medical University, and 26 patients with ACL injury (patient group) were recruited at the Department of Orthopedics, Guangdong Provincial People＇s Hospital. The normal group consisted of 20 males and 19 females with a median age of 19 (18, 21) years; the athlete group consisted of 22 males and 17 females with a median age of 19 (18, 20) years; the patient group consisted of 23 males and 3 females with a median age of 20 (19, 20) years. A portable knee joint motion capture system was used to collect the knee gait maps of the subjects walking at a speed of 3 km/h on a treadmill. The knee varus and valgus angles, internal and external rotation angles, flexion and extension angles during the movement, and anteroposterior, medial-lateral superior-inferior displacements of the tibia relative to the femur were compared between the 3 groups.Results:There was no significant difference in the general data among the 3 groups except for gender, showing they were comparable ( P>0.05). There were significant differences in the varus and valgus angles during the whole gait cycle (1% to 100%), internal and external rotation angles during the weight-bearing response period (9% to 10%), flexion and extension angles during the stance phase and swing phase (1% to 27%, 29% to 100%), anteroposterior displacements during the weight-bearing reaction phase (1% to 3%) and at the end of the swing phase (96% to 98%), superior-inferior displacements at the middle support phase (15% to 19%), the end of the support phase (29% to 33%, 36% to 43%) and the swing phase (68% to 94%), and medial-lateral displacements at the middle stance phase and the middle swing phase (12% to 82%) among the 3 groups ( P<0.05). The maximum varus and valgus angles (-10.89°±4.55°, -12.20°±4.38°) of the subjects in the normal group and the athlete group were significantly greater than those in the patient group (-5.44°±3.72°) ( P<0.05). The medial-lateral displacement at the middle support phase [3.69 (0.13, 7.25) mm] of the subjects in the normal group was significantly larger than those in the athlete group and the patient group [-0.59 (-6.65, 5.24) mm, 0.96 (-1.54, 3.89) mm] ( P<0.05). Conclusions:The gait of college athletes is significantly different from that of ordinary college students and that of patients with ACL injury. Indexes like the varus and valgus angles and the medial-lateral displacement may be used as potential indictors for early identification of ACL injury.