RESUMO
BACKGROUND: Total hip arthroplasty is a commonly used treatment, but it is difficult to accurately determine the position of the pelvis, which is easy to cause pelvic displacement postoperatively. Additionally, the implant is likely to present with angle deviation, and the precise location and direction of prosthesis is difficult to identify.OBJECTIVE: To study the position and biomechanical characteristics of prosthesis in total hip arthroplasty.METHODS: (1) One male volunteer received CT examination, and a finite element model of the pelvic was established.Three acetabular placement positions (abduction angles of 0°, 20° and 25° combined with anteversion angles of 35°, 15°and 10°) were used to perform total hip arthroplasty, and the peak von Mises stress was detected under a load of 240 N.(2) Six cadaver specimens were collected and received the same interventions with the former experiment, and the stress changes at the bone cortex surrounding femoral shaft and acetabular anterior and posterior wall were measured using resistance strain technology.RESULTS AND CONCLUSION: (1) The peak von Mises stress in the acetabulum at abduction angle of 25° combined with anteversion angle of 10° increased by 25.7%. The peak von Mises stress in the acetabular cup at abduction angles of 0°, 20° and 25° combined with anteversion angles of 35°,15° and 10° was 135.21, 68.3 and 134.2 MPa, respectively.The peak von Mises stress in the lining at abduction angles of 0°, 20° and 25° combined with anteversion angles of 35°,15° and 10° was 6.8, 3.9 and 6.7 MPa, respectively. The peak von Mises stress in the femoral shaft at abduction angles of 0°, 20° and 25° combined with anteversion angles of 35°,15° and 10° was 127.1, 100.2 and 128.2 MPa,respectively. (2) The stress at the bone cortex surrounding femoral shaft and acetabular anterior and posterior wall at abduction angles of 0° and 25° combined with anteversion angles of 35° and 10° was significantly higher than that at abduction angle of 20° combined with anteversion angle of 15°. To conclude, an abduction angle of 20° combined with anteversion angle of 15° is conductive for functional recovery of the joint.