Three hundred seventy-five consecutive total hip arthroplasty revisions done using proximally porous-coated femoral components of 6 designs were reviewed a mean of 4.7 years after surgery. Fifty-nine hips have been rerevised for aseptic femoral loosening, and 4 for osteolysis. Moderate or severe pain was present in 23% of surviving hips, and radiographic evidence of femoral loosening was present in 38% of surviving hips at the most recent followup. At 8 years, survivorship free of revision for aseptic femoral failure (for loosening or osteolysis) was 58% (95% confidence intervals, 44.3%, 69.6%); survivorship free of aseptic femoral loosening (revision for aseptic loosening or radiographic loosening) was 20% (95% confidence intervals, 12%, 27%); and survivorship free of symptomatic femoral loosening (revision for aseptic loosening or radiographic femoral loosening with moderate or severe pain) was 45% (95% confidence intervals, 32.3%, 56%). More severe preoperative bone loss correlated with poorer survivorship free of aseptic loosening and subsidence of ≥5 mm. Differences among the prosthetic-type groups with respect to patient's age, gender, and bone loss severity precluded direct comparison of performance for each prosthetic type; however, all the prostheses had a significant rate of rerevision and aseptic loosening. Stable long-term fixation with the proximally porous-coated femoral components used in this series was not achieved on a predictable and reproducible basis. The damaged, weakened bone often present in the proximal femur during revision probably does not provide an optimal environment for sturdy initial or long-term biologic fixation of these devices that rely on the proximal femoral bone for fixation.
Department of Orthopedics Mayo Clinic, Mayo Foundation Rochester, MN.
Reprint requests to Daniel J. Berry, MD, Section of Publications, Mayo Clinic and Mayo Foundation, 200 First St, SW, Rochester, MN 55905.