Total knee arthroplasty with a mobile-bearing prosthesis: comparison of retention and sacrifice of the posterior cruciate ligament in cementless implants.

We compared patient outcome after total knee arthroplasties with two types of low-contact-stress (LCS) cementless implants: a meniscal-bearing implant that retained the posterior cruciate ligament (n = 147), and a rotating-platform implant requiring sacrifice of this ligament (n = 44). The minimum follow-up was 5 years (mean, 68.5 months). Pain was occasional or nonexistent at follow-up in 94.6% of patients with meniscal-bearing implants and 93.2% of patients with rotating-platform implants. The mean total range of motion was 120 degrees for patients with meniscal-bearing implants and 108 degrees for those with rotating-platform implants (P < 0.001). Mean total scores on the New Jersey Orthopaedic Hospital Knee Scale were 93.2 for meniscal bearings and 87.6 for rotating platforms (P < .001). Patellar complications, including two fractures, were seen in 1.0% of cases. Five meniscal-bearing and no rotating-platform implants have been revised. The 7-year overall survival rate was 97.5% for meniscal bearings and 100% for rotating platforms.