Short-term effects of total hip arthroplasty using metal-on-metal prosthesis with large diameter femoral head

Abstract

Objective To evaluate mid-term clinical outcomes associated with total hip arthroplasty using metal-on-metal prosthesis with large diameter femoral head. Methods From March 2007 to December 2009, 153 patients (177 hips) with advanced hip diseases undergoing large diameter femoral head metal-on-metal total hip arthroplasty in our hospital were retrospectively analyzed in this study. Clinical physical examination and radiographic examination were used to evaluate hip function and the incidence of complications (implant loosening and inflammatory pseudotumor); ICP-MS method was used to determine serum cobalt ion and chromium ion levels and compare with normal values; revision was set as the prosthesis endpoint to evaluate the five year survival rate of implant. Results A total of 145 patients (169 hips) were followed up for average 72.4 months (67-80 months), the follow-up rate was 94.8% (145/153). For the involved patients, 85 were male (104 hips), 60 were female (65 hips); age 20-78 years old, average 49.3±12.6 years old. All patients received ASRTM-XL large femoral head metal-on-metal total hip arthroplasty operation. At the end of follow-up, the average Harris hip score improved from 44.2±12.6 points preoperatively to 91.5±5.7 points. A total of 8 patients received revision, 3 for acetabular implant spinout-out and 5 for hip inflammatory pseudotumor. The prosthetic survival rate 5 years after operation was 95.3% (161/169) for revision. Serum cobalt (2.89 μg/L) and chromium (3.31 μg/L) ion levels were significantly increased compared with normal value (<0.5 μg/L). Conclusion For the fixation and friction interface disadvantages, acetabular implant spinout-out and inflammatory pseudotumor might occur for patient receiving large femoral head metal-on-metal THA. The mid-term prosthetic survival rate was also low, with metal ion levels increased significantly. For primary THA, large femoral head metal-on-metal prosthesis cannot be the first choice. Key words: Arthroplasty, replacement, hip; Prostheses and implants; Granuloma, plasma cell; Chromium alloys