人工全髋关节置换术后脱位原因幻灯片.pptx

人工全髋关节置换术后脱位 发生率 The average incidence of dislocation after total hip arthroplasty is approximately 3%. factors a history of previous hip surgery or revision total hip replacement （7.4%） a posterior surgical approach （5.8% vs 2.3%） faulty positioning of one or both components impingement of the femur on the pelvis or residual osteophytes impingement of the neck of the femoral component on the margin of the socket inadequate soft-tissue tension insufficient or weak abductor muscles avulsion or nonunion of the greater trochanter noncompliance or extremes of positioning in the perioperative period factors Age, height, and weight do not seem to be causative factors in many series, dislocation occurred in women more often than in men. a preoperative diagnosis of osteonecrosis, proximal femoral fracture or nonunion, or inflammatory arthritis. Likely contributing factors include extensive soft-tissue release, muscular weakness, small femoral head size (22 mm), and trochanteric nonunion. 后外侧入路脱位高发的原因 a tendency to retrovert the socket nadequate anterior retraction of the femur, so the acetabular positioning device is forced posteriorly during component insertion Division of all the short external rotators 防止发生脱位的策略 fixing the cup in the proper position judge the position of the patients pelvis in the horizontal and vertical planes women with broad hips and narrow shoulders men with a narrow pelvis and broad shoulders true position of the pelvis always must be taken into account 防止发生脱位的策略 The femoral component should be fixed with the neck in 5 to 10 degrees of anteversion（ 15 degrees is acceptable ） developmental dysplasia or juvenile rheumatoid arthritis, can cause error in judging the correct position （anteversion） Retroversion of the femoral neck may be encountered with slipped capital femoral epiphysis, or if the neck is resected at an excessively low level. 防止发生脱位的策略 Bone or cement protruding beyond the flat surface of the cup can cause impingement