Five-year results of bipolar arthroplasty with bone grafts and reamed acetabula for osteoarthritis in young adults.

Bateman universal proximal femoral arthroplasty combined with acetabular reaming was performed in 35 cases of osteoarthritis of the hip joint. The patients were from 21 to 59 years of age (average, 41 years of age) at the time of operation. The postoperative outcome for a middle term ranging from two to eight years, with an average of five years and nine months, was studied along with postoperative migration of the outer head. The clinical outcome, assessed by the evaluation criteria for hip function proposed by the Japanese Orthopaedic Association, was favorable. A stable average score of greater than 80 occurred for eight years postoperatively; the average preoperative score was 45. Of the 35 cases, seven cases (20%) had an upward migration of the outer head, and one case (2.9%) had an inward migration of 5 mm or more, but the migration did not affect the clinical outcome in any case. There was no certain relationship between the degree of rotation of the outer head and the extent of its migration. Migration of the outer head was prevented by postoperative exercise, in which total loading was initiated after the completion of the radiolucent zone around the outer head and its circumferential zone of osteosclerosis.