Evaluation of anatomical knee joint line restoration in revision total knee replacement patients and its functional outcome: A retrospective cohort study

Evaluation and correct reposition of joint line is ultimate challenge for arthroplasty surgeon during revision total knee replacement. Majority of landmarks had already destroyed while removing bone for either septic/aseptic loosening or for infection. This leads to poor outcome and post-operative dissatisfaction. There are various methods have been described but none is reliable. We are describing a method to evaluate joint line pre operatively and possible application intraoperatively. The medial and lateral epicondyle are easily identible landmark in radiograph as well as intraoperatively. We used Tran's epicondyle axial width (TEAW) method for the evaluation of joint line in AP view and Figgie's method for evaluation of joint line in lateral view. Patella position was diagnosed with Caton deschamps index. These measurements were tested for intra- and inter-observer differences. Then, the relationship between these two measurements was studied. All patients were called back for reevaluation and recording knee society score. The mean duration of follow up was 5.8 months. The mean Knee society score was 73.8 in preoperative period which increased up to 89 in postoperative period. The 3 patients in whom joint line was elevated more than 5 mm from native joint line shows less improvement in knee society score by 7 points compare to others. The difference of which is statistically significant with p value 0.0004 when measured by unpaired T test. Once the TEAW was determined preoperatively, the Joint line level is found during surgery by using a caliper This method leads to better pre-operative idea of joint line and can be reproduced intraoperatively and can leads to a reduced risk of re-intervention following revision total knee arthroplasty.