Acetabular reinforcement ring: surgical principles and technique / 中国矫形外科杂志

To investigate the surgical principle of various degrees of acetabular bone defect in acetabular arthroplasty. Indications and clinical effect of different allografts are also discussed. Acetabular reinforcement ring (ARR) is emphasized on its types, se-lection principle, surgical technique and common technical errors.

Revision hip arthroplasty with use of the acetabular reinforcement ring:8 cases follow-up study / 中国矫形外科杂志

[Objective]To evaluate the midterm clinical and radiographic results of revision hip arthroplasty by acetabular reinforcement ring (ARR) with impaction bone grafting. [Methods]Revision hip arthroplasty by ARR with impaction bone grafting of 8 hips was performed from May 2001 to December 2006. There were 5 males and 3 females with an average age of 53 years (range, 36~70 years).The mean BMI was 20 (range, 15~28). The mean interval between the primary arthroplasty and revision was 5 to 20 years (mean 6.7 years). The causes for revision were infective loosing in 2 and aseptic loosening in 6. In the 8 hips, 6 hips underwent a revision total hip arthroplasty, 2 hips received replacement of the acetabular component. Consecutive radiographs were compared to evaluate component conditions and the influence of bone deficiency to fix the prothesis was analyzed. Harris hip scores (HHSs) were determined before surgery and at the most recent follow-up examination. The Kaplan-Meier survivorship analysis was used to estimate the probability of survival of the prothesis.[Results]Seven hips were available for complete clinical and radiographic analysis. One patient died for myocardial infarction. The mean follow-up period was 4.5 years (range, 1.5~7.1 years).The mean preoperative Harris hip score of 30(range, 20~64) points improved to 88 (range, 74~94) points at the time of final follow-up, the pain and function socre improved from 13.8 and 11.5 to 40.3 and 39.9 respectively. All patients had severe limp before revision. At the time of final follow-up, 5 patients still had slight limp and 1 patients had moderate limp.Five hips had an excellent result. Infective osteolysis and migration were seen in 2 hips, which need re-revision. Heterotopic ossification developed in 2 hips . Kaplan-Meier survivorship at 4.5 years was 63% with repeat revision or radiographic loosening.[Conclusion]ARR with impaction bone grafting is an effective approach to treat massive acetabular bone defect in revision hip arthroplasty, the midterm result is acceptable, but any possible reason for infection must be monitored.

Acetabular Rebision Using Acetabular Reinforcement Ring and Allograft Impaction

Purpose: We wanted to evaluate the clinical and radiologic results of acetabular revision using the acetabular reinforcement ring and also the allograft impaction in the acetabulum having deficient bone stock. Material and Methods: Nineteen hips revision arthroplasty were performed in 18 patients (9 males and 9 females) with using an acetabular reinforcement ring and allograft between July 1993 and December 2003. The patients were followed for an average of 64 months (range: 24-153). The mean age at the time of arthroplasty was 59 years old (range: 34-76). The causes of revision were aseptic loosening of the acetabular component in 16 cases, severe progressive osteolysis around the acetabular component in 2 cases and Girdlestone state after infected total hip arthroplasty in one case. The acetabular deficiency was type II in 5 hips, type III in 13 hips, and type IV in one hip according to the AAOS classification. The clinical results were evaluated using the modified Harris hip score, and the radiologic results were evaluated by assessing the preoperative and serial follow-up radiographs. Results: The mean preoperative Harris hip score of 47 was improved to 86 points at the latest follow-up. Periacetabular osteolysis was found in 2 cases, which did not progress at follow-up. The anatomic hip center was restored after revision arthroplasty (p<0.05). Complications were dislocation in 2 cases, breakage of the hook of the Ganz ring in one case, heterotopic ossification in one case and femoral artery injury in one case. All cases showed stable fixation of the acetabular component and good remodelling of the impacted allograft. There was neither recurrence of dislocation nor progression of the acetabular component loosening on the radiographs. Conclusion: Acetabular revision with acetabular reinforcement ring and allograft impaction showed satisfactory clinical and radiologic results with restoration of the hip center and consolidation of the allograft.

Early Failure of Acetabular Component after Total Hip Arthroplasty in Irradiated Hip / 대한정형외과학회잡지

PURPOSE: The treatment of the osteonecrosis in the acetabulum and femoral head after irradiation has not been well estabilished. The early failure of acetabular component after total hip arthroplasty (THA) is the main concern in osteonecrosis after irradiation. MATERIALS AND METHODS: Our study included 18 patients with post-radiation osteonecrosis of 26 hips who had a THA, mean age 54.2 years. Average irradiation dosage was 4611 cGy and interval between irradiation and primary total hip replacement was 64.3 months. The cementless acetabular components were used in 16 hips (group one) and acetabular reinforcement rings were used in 10 hips (group two: Muller cup 6 cases, Ganz cup 4 cases). RESULTS: Acetabular loosenings were occurred at 8 of 16 hips (Group 1: 50%) during the mean follow-up 46 months. The cases of Muller cup (Group 2: 33%) was failed in 2 of 6 hips at postoperative 12 months and 22 months. CONCLUSION: Although follow up duration is short and cases are small, the use of cemented cup with acetabular reinforcement ring was better than non-cemented cup for THA in irradiated hip in terms of preventive of early failure of acetabular component.