title: Factors affecting anteroposterior instability following cruciate-retaining total knee arthroplasty in patients with rheumatoid arthritis.
abstract: Controversy persists concerning around posterior cruciate ligament (PCL) retention in total knee arthroplasty (TKA) for patients with rheumatoid arthritis (RA). This study investigated factors affecting anteroposterior (AP) instability following cruciate-retaining (CR)-TKA. In a consecutive series of 70 knees from 52 RA patients, total displacement (TD) was measured using a KT-2000 arthrometer before and after CR-TKA under anesthesia, and changes in TD were defined as DeltaTD. TD was also measured under anesthesia in 65 knees from 48 RA patients at a mean of 7.5 years after CR-TKA. Mean postoperative TD was 9.4+/-0.95 mm, representing an increase of about 1.5-1.8 mm compared to preoperative TD, and possibly reflecting resection of the anterior cruciate ligament. Correlation analysis revealed significant negative correlations between DeltaTD and both preoperative flexion angle (r=-0.67, p<0.001) and preoperative extension angle (r=-0.63, p<0.001), suggesting that TD in knees with flexion contracture increased postoperatively. At medium-term follow-up, no patients displayed AP instability, and mean TD was 8.3+/-0.48 mm. A significant correlation was found between TD and permissible flexion angle (r=0.61, p<0.001). These results indicate that TD is basically maintained during the course of CR-TKA in RA, but may be slightly affected by factors other than the PCL itself.
authors: Department of Orthopaedic Surgery, Keio University, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. y.niki@lib.bekkoame.ne.jp
authors: Yasuo
authors: Y
authors: Niki
authors: Takeshi
authors: T
authors: Mochizuki
authors: Shigeki
authors: S
authors: Momohara
authors: Seiji
authors: S
authors: Saito
authors: Hideo
authors: H
authors: Matsumoto
authors: Taisuke
authors: T
authors: Tomatsu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged