Abstract
Aims: The purpose of this roentgenographic study is to quantify patellar tilt after total knee arthroplasty and substantiate which factors might affect it. Methods: We reviewed the þles of 446 patients with 485 primary total knee arthroplasties, solely on the diagnosis of degenerative osteoarthritis. Mean follow-up approximated 8.5 (range, 5–20) years. Resurfacing-type prostheses were exclusively used. Patellar resurfacing was accomplished in 51 (11.4%) knees. Patellar tilt was measured pre- and postoperatively using standard Merchant views. Chi-square analysis was used in an attempt to disclose any relationship of patellar tilt with variables like button positioning, lateral release, patellar thickness, limb alignment, joint line elevation, patellar height and posterior cruciate ligament retention or sacriþce. Results: Pre-operatively, 27%, 40% and 33% of patellae demonstrated neutral, lateral and medial tilt respectively. These þgures subsequently changed to 49%, 19% and 32% immediately post-op. However, at þnal follow-up, patellar tilt pattern looked much like the pre-operative one, namely, 31%, 38% and 31% respectively. A statistically signiþcant positive correlation was only documented for patellar thickness, buttonmedialization and pre-operative tilt. The rest of the parameters tested were found not to have any statistical signiþcance with post-operative tilt values. Conclusions: After knee arthroplasty, the patella has, on the long term, a tendency to revert laterally. Lateral release does not seem to ameliorate this tendency. Finally, pre-operative tilt does not correlate to post-operative external mechanism complications.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
