A Serial Study Of Surface Replacement Of Formal Head

1. Objective: To observe the histological degeneration of acetabular cartilage in ARCO stage II, III hips, put forward the recommendation of the best stage of the surface replacement in osteonecrosis of femoral head. Method: Biopsy specimens of cartilage and adjacent subchondral bone were obtained from the weight-bearing dome of the acetabulum of 15 hips in 13 patients who were having a total hip replacement. The cartilage was evaluated grossly and histologically. The degree of collapse of the femoral head was measured on radiographs. Result: On gross examination, the cartilaginous surface of the acetabulum was graded as 0-I in two hips, I in one hip, II in 9 hips, III in 3 hips. The degree of collapse of femoral head range from 0 to 4. 3mm. The score range from 4 to 14 on histological evaluation. Conclusion: The amount of deterioration of acetabular cartilage was directly proportional, to a highly significant degree, to the degree of collapse of femoral head and to the duration of pain of the hip. The best stage of the surface replacement in osteonecrosis of femoral head is ARCO- II c. The duration of pain of hip, as well as the stage, should be considered when we choose the surface replacement in osteonecrosis of femoral head.2. Objective: To investigate the degeneration of cartilage after hemiathroplasty and to find factors related to the degeneneration. Mathod: The ace tabular cartilage was evaluated grossly and the biopsy specimens of cartilage and adjacent subchondral bone were obtained from the weight-bearing dome of the acetabulum of 14hips in 14 patients who were having a revision of unipolar hemiarthroplasty of the hip. Biopsy specimens were examinated histologically. The radiograph of 14 hips with unipolarhemiarthroplasty and 13 hips with surface replacement hemiarthroplasty was evaluated. Result: The score range from 6 to 14 on histological evaluation in 14 hips with unipolar hemiarthroplasty. On radiographic evaluation: All surface replacement hemiarthroplasty components fit the acetabulum, and 7 unipolar hemiarthroplasty components fit the acetabulum and the others didn't. Conclusion: The fit between the component and acetabulum correlate to duration of erosion of the acetabular cartilage but not to degree of degeneration of it. The femoral shell in 1mm increment could precisely fit the acetabulum, and it will improve the result.3. Objective: To evaluate the clinical result of hemiresurfacing for osteonecrosis in young adults and review the factors which effect the hemiresurfacing result. Method: 13 hips with Ficat stage III, or early IV osteonecrosis were treated with hemiresurfacing and followuped after operation. Result: At a followup of 9-38 months, the average Harris hip scores improved significantly from 39 (28-62) to 91 (85-96), and without the operation complications of infection, dislocation, nerve and vascular injuries. Conclusion: we conclude that surface hemiarthroplasty can gain time against the progressive disease and delay the time when the THA is needed. It is an effective solution to the problem of the young patient with Ficat stage III, or early IV osteonecrosis of the femoral head.