Comparison of outcomes after bilateral simultaneous total knee arthroplasty using posterior-substituting versus cruciate-retaining prostheses

OBJECTIVES To compare the effectiveness and safety of posterior-substituting (PS) with cruciate-retaining (CR) total knee prostheses after the elimination of confounding variables. METHODS Between January 2008 and June 2012, a total of 32 subjects who had bilateral arthritis of the knees agreed to have one knee replaced with a PS total knee design and the other with a CR design. In addition to postoperative complications, clinical outcomes (Knee Society Score, Range of Motion, Western Ontario and McMaster Universities Arthritis Index, as well as radiographic findings) were evaluated preoperatively, and at 2-week, 3-month, 12-month, and 24-month follow-up. RESULTS At the 24-month follow-up interval, no benefit of CR design was observed over PS design regarding functional assessment, patient satisfaction, or postoperative complication. However, the PS total knee design did display statistically significant improvements in range of motion as compared with the CR design. CONCLUSION While comparable regarding supporting good clinical outcomes, the PS design does appear to support significantly improved postoperative range of motion when compared with the CR design.