Arthroplasty of the hip in patients with aplastic anemia

Background: Patients with aplastic anemia are now living longer and therefo re are at increased risk for the development of osteonecrosis of the hip. H owever, studies on the results of arthroplasty for the treatment of osteoar thritis of the hip in patients with aplastic anemia are lacking. Methods: Twenty-six primary hip prostheses (one bipolar prosthesis fixed wi th cement, two bipolar prostheses fixed without cement, three hybrid total hip prostheses, and twenty total hip prostheses fixed without cement) were implanted, between March 1990 and May 1992, in nineteen patients who had be en diagnosed with aplastic anemia. A specific prospective protocol was foll owed for the perioperative transfusion of platelets and blood. Twenty-five hips were replaced because of osteonecrosis of the femoral head, and one wa s replaced because of a femoral neck fracture. The patients were followed p rospectively with preoperative and serial postoperative Harris hip ratings as well as radiographs, for a minimum of sis years or until death. Results: No patient had excessive perioperative bleeding or a postoperative infection. After a mean duration of follow-up of seventy-nine months (rang e, seventy-two to ninety-five months), two patients had died with the origi nal implant in place. No patients were lost to follow-up, The mean Harris h ip score was 55 points (range, 42 to 68 points) preoperatively and 87 point s (range, 56 to 95 points) at the time of the latest follow-up. At the time of this writing, no hip had been revised. One patient with a bipolar prost hesis had radiographic evidence of femoral loosening and will probably requ ire revision. A second patient had some medial protrusion of a bipolar pros thesis, with mild symptoms. All of the acetabular components that had been fixed without cement and all of the other femoral components appeared to be stable on radiographs after a minimum of seventy-two months of follow-up. Conclusions: Total hip arthroplasty can be performed safely in patients wit h aplastic anemia. In the present intermediate-term study, the durability o f implant fixation was maintained and the clinical results demonstrated a s ustained increase in function of the hip.