RESUMO
BACKGROUND: The impact of obesity on total hip arthroplasty has been discussed. However, there is a lack of follow-up study on the patients with different body mass indexes using three-dimensional gait analysis. OBJECTIVE: To investigate the effect of body mass index on the early-term functional recovery after total hip arthroplasty by three-dimensional gait analysis. METHODS: Sixty patients who underwent total hip arthroplasty at Department of Joint Surgery of Affiliated Zhongshan Hospital of Dalian University from January 2017 to June 2018 were enrolled. According to the body mass index at admission, they were divided into overweight group (body mass index ≥ 25 kg/m2) and normal group (body mass index 0.05). The operation time in the overweight group was significantly longer than that in the normal group (P=0.000). (2) In terms of time-distance parameters, there was no significant difference in the stride length, stride frequency and mean velocity between two groups. The stride length in the overweight group was smaller than that in the normal group (1.08±0.18 vs. 1.35±1.45 m). (3) The range of motion of each planes of hip joint in the overweight group was significantly less than that in the normal group (P < 0.05). (4) In terms of kinetic parameters, the peak torque of hip flexion in the overweight group was significantly less than in the normal group (P=0.011). There was no significant difference in the peak torque of hip extension between two groups (P=1.000). (5) To conclude, obesity has certain effect on the early functional recovery after total hip arthroplasty.