96. POSTERIOR STABILISED TOTAL KNEE ARTHROPLASTY FOR RHEUMATOID ARTHRITIS: OUTCOME AT MORE THAN FIVE YEARS

Abstract

Purpose of the study: We analysed the clinical and radiographic outcomes of 113 cemented total knee arthroplasties (TKA) with resurfaced patella implanted in 83 patients with rheumatoid arthritis who were reviewed 1 to 12 years after implantation. Mean follow-up was 5.86 years. All implants were posterior stabilised (HLS) implanted by one operator using the same procedure.

Material and methods: One hundred seventy-two rheumatic arthritis patients underwent TKA from 1996 to 2007. At last follow-up, 68 could not be contacted, 11 had died, 9 declined review. The review was conducted in 2008 for 83 patients, 113 TKA. Female gender predominated (86.4%) and 29 patients (32.6%) had two TKA. Mean age at revision was 67.6 years.

Results: Seventy patients (84.4%) were satisfied or very satisfied with their prosthesis. The knee score (IKS) improved from 31.58 (0–63) preoperatively to 86.21 (59–99) postoperatively; the function score (IKS) improved from 31.7 (0–100) preoperatively to 77.12 (0–100) postoperatively. The improvement was significant for both scores. Men preoperative flexion was 97 (35–125) versus 112.1 (30–130) postoperatively. Ten knees presented anterior pain at revision (8.8%). The postoperative femorotibial mechanical angle was 180.72 (173–192). The mean femoral mechanical angle was 91.3 (78–99); the mean tibial mechanical angle was 89.4 (52–110). Men postoperative patellar height was 0.79 (0.24–2) measured with the Blackburn index. The patella was centred for 87.6% (99 knees) and subluxated laterally for 12.1% (14 knees). There were no loosening. Two arthroplasties had to be revised surgically (1.8%): one for infection (two-phase replacement with a hinged prosthesis) and one for patellar fracture treat by osteosynthesis. Two patients developed a postoperative phlebitis (2.4%).

Discussion: This study demonstrates the good mid-term outcomes achieved with a cemented posterior stabilised TKA in patients with rheumatoid arthritis. These results are nevertheless slightly less satisfactory than with TKA implanted for degenerative disease: this might be explained generally by disease-related impact on the functional result. Prosthetic surgery of the knee remains the treatment of choice for advanced arthritic degeneration.