Clinical results of bone ingrowth TKA in patients with rheumatoid arthritis.

UNLABELLED: Patients with rheumatoid arthritis (RA) often are not considered for TKA with bone ingrowth fixation because of poor bone quality, but we asked whether implants with sintered metal bead surfaces could be used to durably fix implants in this group of patients. We prospectively evaluated a consecutive series of 47 patients (64 knees) between January 1, 1994, and December 30, 2001, in two separate medical centers using one TKA system. Standard primary implants were used in all knees except those with major bone defects, and in these patients we used long diaphyseal stems to stabilize the implants. Minimum followup was 61 months (mean +/- standard deviation, 83 +/- 6 months; range, 61-124 months). Survivorship was 98.4% at 10 years postoperatively. No components failed because of loosening. One femoral component was revised for fracture because of a massive intraosseous rheumatoid cyst. No knees had radiographic evidence of migration or widening radiolucent lines. Knee Society clinical, pain, and function scores improved after surgery and were maintained throughout followup. These data suggest bone ingrowth implants can provide durable fixation in patients with RA. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.