[Gait analysis at the early stage after direct anterior approach in total hip arthroplasty]

To evaluate the result of operation and gait analysis at the early stage after direct anterior approach (DAA) in total hip arthroplasty (THA).

In this study, 20 patients who suffered from necrosis of femoral head or developmental dysplasia of the hip were scheduled to undergo THA. The basic information and visual analogue scale (VAS) score, Harris score before and after surgery were recorded. All of the patients finished the gait analysis before the surgery and 6 weeks and 12 weeks after the surgery, the data were compared with those of normal adult people.

Their hospital stay after the operation was 3.3 d, the VAS score after the operation was no more than 4 points, the positions of prosthesis were satisfactory, and there was no dislocation. The gait analysis results contained step speed, stride, the range of motion (ROM) of hip and knee. The step speed before the surgery (preoperation, Pre) was 0.64 m/s, 6 weeks after the surgery (6W) was 0.77 m/s, 12 weeks after the surgery (12W) was 1.07 m/s, and the control group was 1.19 m/s. The stride at Pre, 6W, 12W, and control group were 43.15 steps/min, 51.42 steps/min, 55.52 steps/min, and 57.15 steps/min, respectively. The ROM of hip joint at Pre, 6W, 12W, and control group were 31.00°, 39.62°, 40.40°, and 45.67°, respectively. The ROM of knee joint at Pre, 6W, 12W, and control group were 50.52°, 59.28°, 67.29°, and 70.42°, respectively. The results of the gait analysis showed that the gait recovery after the direct anterior total hip arthroplasty was very fast and at the 12th week after surgery the gait of the patients was close to the normal adult people.

The direct anterior approach is one of the choosable approach of the THA, and this kind of surgery has a better recovery of gait after the operation, and at the end of 12 weeks after the surgery the gait is very close to the normal adult people. But we also need more studies to prove this conclusion.