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Wednesday, March 15, 2000

Uncemented components best for RA patients

A prospective, consecutive study of 98 total hip arthroplasty (THA) performed by one surgeon in 66 patients with rheumatoid arthritis (RA), found uncemented acetabular components in this population at medium term follow-up is an improvement compared to cemented components.

The study, presented in poster exhibit 66, concludes there is a high rate of subsidence and osteolysis with first generation cementless components. Uncemented acetabular components are recommended for all patients with RA.

The mean patient age was 60 years and the mean follow-up time was six years. All 98 acetabular components were uncemented with multiple screw fixation. Fifty-seven hips had additional bulk or cancellous allograft for protrusio. Fifty-one hips (mean age 50 years) had an uncemented femoral component and 47 hips (mean age 70 years) had a cemented femoral component. All hips were rated clinically using the Harris hip score. Radiographs were evaluated for migration, subsidence, osteolysis and polyethylene wear.

Overall, 30 hips were rated excellent; 44, good; 14, fair; and 10, poor. There were no early deep infections. One hybrid hip was removed for late infection at seven years. One uncemented femoral component was revised for aseptic loosening at eight years. One acetabular component was revised for loosening at eight years.

There were two reoperations for liner exchange: one for acetabular osteolysis and one for recurrent dislocation. There were two intraoperative femur fractures. Radiographic evaluation of 98 acetabular components showed one septic loosening, two aseptic loosening (one revised) and one with severe wear and ischial osteolysis. None of 47 cemented femoral components subsided.

Osteolysis was seen in three stems (7 percent). Of 51 uncemented femoral components, subsidence occurred in seven (14 percent), and osteolysis in 15 (30%).

Co-authors of the study, both of University of North Carolina, Chapel Hills, N.C., are Henry Clayton Thomason III, MD, and Paul F. Lachiewicz, MD

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2000 Academy News March 15 Index B

Last modified 06/March/2000 by IS