Medial knee osteophytes have little influence on the medial collateral laxity during total knee replacement

Introduction  To get balanced ligaments is generally accepted as a relevant prognostic factor after total knee replacement (TKR). The exact influence of the medial osteophytes on the medial collateral laxity has never been investigated. We hypothesized that the resection of the medial femoral and tibial osteophytes would increase the medial laxity during TKR. Materials and methods  We studied 20 cases of varus gonarthrosis operated on for TKR under navigation control. Medial laxity before and after osteophyte resection were measured with the navigation system. The thickness of the resected osteophytes from the femur and the tibia was measured by comparing the pre-operative and post-operative coronal plain X-rays. Medial laxity before and after osteophyte resection were compared with a Spearman test at a 0.05 level of significance. Correlation between the difference in medial laxity and the thickness of the resected osteophytes was studied with the calculation of the Spearman correlation test at a 0.05 level of significance. Results  The mean paired difference between pre-resection and post-resection laxity was 0.5° ± 1.0°; this difference was statistically significant but of little clinical relevance. There was no difference between pre- and post-resection medial laxity by 10 patients, a 1° difference in 9 patients, and a 2° difference in one patient. There was no correlation between the thickness of the resected osteophytes (femur, tibia and total) and the difference between pre- and post-resection medial laxity. Conclusion  We demonstrated that the medial osteophytes had no clinically significant influence on the medial laxity during TKR. There is no need for routine medial osteophytes resection only for the purpose of ligamentous balancing during TKR.