抄録
We reviewed the clinical results of 55 bipolar endoprosthesis implantations more than five years after the surgery.
Endoprosthesis implantations was conducted for osteonecrosis of the femoral head in 27 hips of 21 patients (group N), and for fracture of the femoral neck in 28 hips of 28 patients (group F) . The average follow-up period was 6 years and 8 months for group N, and 7 years and 7 months for group F. We used a Bi-metric stem (Biomet Inc., Warsaw, IN., U.S.A) in combination with a bipolar cup for all the cases in both groups.
At the time of examination, the average postoperative JOA hip scores were 88.2 points for group N, and 79.8 points for group F. With regard to the radiographic findings, central migration of the bipolar head of more than 2 mm into the pelvis was observed in 2 hips of group N and 1 hip of group F. Only 1 stem of group F showed distal migration, but even this was not progressive. No loosening or osteolysis was observed in any patient.
Recently, failure of bipolar hemiarthroplasty has been reported, which may be due to osteolysis caused by the body's phagocytic reaction to wear debris from neck-cup impingement. In this study, bipolar hemiarthroplasty with a Bi-metric stem showed stable satisfactory results in a medium-term follow up.
