The Clinical and Radiologic Results of Total Hip Arthroplasty with an AML Hip Prosthesis: Minimum 7 Years' Follow-up Study

ABSTRACT

PURPOSE: To evaluate the long-term results (minimum 7 Years'follow-up) of cementless total hip arthroplasty using an Anatomic Locking Medullary (AML) hip prosthesis. MATERIALS AND METHODS: Fifty-one patients (57 hips) underwent total hip arthroplasty between January 1995 and July 2002. They were followed up for a minimum of seven years (7.1 to 14.6) after the initial operation. The mean age of the patients was 56.8 years. The radiographs were reviewed and the clinical results were evaluated. RESULTS: The mean Harris hip score improved from 52.4 points preoperatively to 88.2 points postoperatively. Of the 40 hips showing a good press-fit, 29 hips (72.5%) exhibited bone ingrowth fixation. Of the remaining 17 hips with a poorer press-fit, 7 hips (35.3%) showed bone ingrowth fixation and 6 hips (35.3%) had unstable fixation. Of the 36 hips showing bone ingrowth fixation, 28 hips (77.8%) exhibited stress mediated bone resorption. On the last follow-up radiographic examination, osteolysis occurred around the femoral stem and acetabular cup in 21 (36.8%) and 6 (10.5%) hips, respectively. CONCLUSION: The results of cementless AML total hip arthroplasty were acceptable up to 7 years but polyethylene wear and osteolysis should be followed carefully over the long term.