LONG TERM FOLLOW-UP COMPARISON OF NEW JERSEY LCS MENISCAL-BEARING AND ROTATING-PLATFORM TOTAL KNEE REPLACEMENT

Abstract

This is a prospective study of 74 consecutive LCS total knee replacements of which 34 were meniscal-bearing and 40 rotating-platform total knee arthroplasties comparing functional and radiological outcome measures of the New Jersey total knee replacement.

The study is based on a cohort of 96 patients who were followed up over a period of 8.6 to 15.6 years (mean 11.8 years). 49 patients (64 knees) were living and 5 patients were lost to follow-up. At time of follow-up 37 patients were dead. The patients were aged 23 to 81 (mean 64.5) at the time of surgery.

The methods used include a pre- and post-operative New Jersey Orthopaedic Hospital Scoring Scale (NJOHSS). In addition the cohort were assessed postoperatively using the Knee Society Score (KSS) and the Knee Society Radiological Evaluation Form (KSREF).

The results of the study showed that there was a significant overall improvement in the NJOHSS (mean improvement = 22.4 points) with 81% of the cohort scoring ‘good to excellent’ post-operatively. When the two types of arthroplasty were compared there was no significant difference in improvement in the NJOHSS. However, both the ‘Post-op’ and ‘Function’ components of the post-operative KSS were greater in the rotating-platform total knee replacement. The comparison of the post-operative KSREF did not show any significant differences between the two types of arthroplasty.

Revision procedures were carried out in 3 patients with meniscal-bearing arthroplasty and 2 patients with rotating-platform arthroplasty. Of the Meniscal-bearing group two were for sepsis and one required liner exchange. Both of rotating-platform group were revised for aseptic loosening.

We therefore conclude that there was excellent long-term survival of the LCS knee arthroplasty in this cohort and there was no significant difference in functional outcomes for either knee replacement. We also note that there have been no revisions for aseptic loosening in the meniscal-bearing group to date.