Results of The Anatomic Medullary Locking Hip Arthroplasty at Minimum Fifteen Years in Korean

초록

The purpose of this study is to report the clinical and radiographic results of hip arthroplasty using anatomic medullary locking (AML®) stem at a minimum 15 years in Korean. Between June 1996 and December 2002, the senior author performed consecutively hip arthroplasties in 439 patients using the AML® stem for the patients who were diagnosed mainly avascular necrosis of femoral head, hip fracture and coxarthrosis. We excluded 152 patients who died before 15 years follow up and 78 patients who follow up lost. The mean follow-up period for the 209 patients (267 hips) is 16.9 years (range: 15.0- 21.5 years). The average age of these patients at the index operation was 50.9 years (range 15?80 years). We retrospectively evaluated 209 patients (267 hips) clinically with use of a Harris hip score(HHS), limping and radiographically including heterotopic ossification, stress shielding, osteolysis of acetabulum, wear rate of polyethylene liner, subsidence, component loosening and revision rate. All clinical and radiological evaluations were performed by three independent reviewers. In clinical outcome, HHS was improved from 67.47 to 83.64 at last follow up. Limping gait was observed slightly in 50 cases, moderate in 18 cases and severe in 6 cases. In radiographic evaluations, heterotopic ossifications were found slightly in 9 cases, moderate in 3 cases, severe in 6 cases, stress shielding occurred during follow up, Grade 1 in 10 hips, grade 2 in 32 hips, grade 3 in 30 hips, grade 4 in 10 hips. Osteolysis of acetabulum were found in small lesion in 16 cases, large in 2 cases, expansive in 19 cases. Polyethylene liner wear rate was 0.11mm/year ± 0.005. Subsidence of femoral stems were seen less than 3mm in 4 hips, more than 3mm in 6 hips. Stable bone ingrowth femoral stems were in 257 hips, fibrous stable femoral stems in 4 hips and unstable femoral stems in 6 hips. Forty-seven hips (17.6%) were required revision surgery. Causes of