Clinical and radiological outcome after periacetabular osteotomy: a cross-sectional study of 127 hips operated on from 1999-2008.

PURPOSE: Few papers have described results after periacetabular osteotomy (PAO) and risk factors for conversion to total hip arthroplasty (THA). The aim of the present paper was to analyse clinical and radiographic outcome, survival of the hip joint and risk factors of early conversion to THA in patients with PAO. BASIC PROCEDURES: In the period 1999-2008, 93 patients (127 hips, median patient age 31, range 13-49 years) were operated on with PAO. Median follow-up was 7 (SD 2.1) years. Analyses of clinical and radiographic examinations, including WOMAC, were performed. Osteoarthritis was measured using Tönnis grade. Survival was assessed by the Kaplan-Meier method and predictors of conversion to THA were calculated using Cox regression analysis with THA as defined endpoint. MAIN FINDINGS: Centre-edge angle improved significantly with a mean of 8.7 (95% CI: 7.1; 10.3) preoperatively to a mean of 24.6 (95% CI: 22.6; 26.6) at follow-up. Likewise the acetabular roof obliquity angle improved significantly with a mean of 21.2 (95% CI: 19.7; 22.6) preoperatively to 8.7 (95% CI: 7.1; 10.4) at follow-up. Eleven out of 127 hips had conversion to THA. The 11.7 years cumulated hip joint survival rate was 85% (95% CI: 0.753; 0.945). Significant predictors of converting to THA were preoperative high grade of OA and postoperative high degree of acetabular roof obliquity angle. An improvement was found in Harris Hip Score pain score after receiving a PAO (p = 0.01). CONCLUSIONS: Our results, with almost 12 years survival data, are comparable with the literature. PAO is considered as an effective treatment for young adults with painful hip dysplasia, especially when preoperative criteria for conversion to THA are highlighted.

Few adverse reactions to metal on metal articulation in total hip arthroplasty in a review study on 358 consecutive cases with 1 to 5 years follow-up.

The aim of the present study was to determine the frequency of adverse reaction to metal on metal total hip arthroplasty using a M2a-38 articulation and a Magnum articulation, (Biomet Warsaw, Indiana).All patients who had received a Metal on Metal bearing prosthesis, in two centres in Copenhagen, were asked to complete a questionnaire about groin pain. Patients with self-reported groin pain, 68/314, underwent a physical examination and had Co and Cr ion levels measured in full blood samples. Fifty patients also had a CT scan performed.The present study found one patient with bilateral arthroplasty, who had an adverse reaction on one side. In addition the study showed that females had higher values of Co and Cr, and that younger patient reported groin pain more often.The conclusion of this study is that the number of adverse reactions is low, despite the time of observation being relatively short, no high frequency of adverse reactions to this prosthesis is expected.