Clinical and radiographic outcomes of total hip arthroplasty with insertion of an anatomically designed femoral component without cement for the treatment of primary osteoarthritis - A study with a minimum of six years of follow-up

We evaluated the clinical and radiographic outcomes of 100 consecutive primary total hip arthroplasties in which a proximally coated anatomically designed femoral component was fixed without cement for the treatment of primary osteoarthritis. The minimum duration of follow-up was six years (average, 7.1 years). The eighty-eight patients who had the arthroplasties were followed prospectively with a standard clinical evaluation that involved use of the Harris hip score and a radiographic evaluation based on the criteria of the Hip Society. Bone ingrowth was evaluated with the method of Engh et al. The average age of the patients at the time of the operation was 62.6 years (range, thirty-nine to eighty-four years). Fifty-one patients were men and thirty-seven were women. The average preoperative Harris hip score was 48 points,,vith an average pain score of 15 points and an average function score of 26 points. Nonmechanical complications that necessitated a revision operation included one deep hematogenous infection, one late periprosthetic fracture, and a 0.5-inch (1.27-centimeter) limb-length discrepancy. At the time of the most recent follow-up, the average Harris hip score was 96 points, with an average pain score of 42 points and an average function score of 45 points, The prevalence of pain in the anterior part of the thigh was 5 percent (five hips). One patient had a revision of the femoral component because of aseptic loosening, and one had a revision of the acetabular component because of recurrent dislocations. Radiographic assessment revealed consistent evidence of proximal bone ingrowth. No complete radiolucent line was identified, except around the stem that had loosened. Twenty-seven femoral components were associated with slight pedestal formation. No osteolytic lesion of the femur was identified. Nonprogressive pelvic osteolysis was identified in four hips, but none of the lesions were more than two millimeters in diameter. None of the acetabular components migrated, and no radiolucent line of more than two millimeters in thickness was seen around any acetabular cup. The data from this study, in which the minimum duration of follow-up was six years, indicate that the anatomically designed prosthesis can provide good results, with low prevalences of pain in the thigh and loosening of the component, in younger, active patients.