Laxity in posterior cruciate sparing and posterior stabilized total knee prostheses

Two series of consecutive total knee replacements were compared retrospecti vely: 118 HLS II posterior stabilized prostheses (Group 1) versus; 138 HLS CP posterior cruciate ligament sparing prostheses (Group 2). Both implants were made by the same manufacturer, The prostheses had been inserted betwee n 1989 and 1992, Mean followup was 4 years. The authors looked for evidence of laxity in the coronal and the sagittal planes, the correlation of laxit y with other factors, and the effect of laxity on the objective and subject ive outcome as measured with the Knee Society score. Group 2 had significan tly more clinical and radiologic laxity. There was little difference betwee n the two groups regarding the overall objective, and subjective outcome; h owever, there was a significantly higher rate of excellent results in Group 1, Longer followup will be required to see whether the implants with laxit y are at heightened risk for tibial component wear.