Medial Open Wedge High tibial Osteotomy (MOWHTO) does not relevantly alter patellar kinematics: a cadaveric study.

PURPOSE: The purpose of this study was to quantify the influence of medial open wedge high tibial osteotomy on patellar kinematics using optical computer navigation, as anterior knee pain infrequently occurs postoperatively and the reason is still being unknown. METHODS: Ten medial open wedge high tibial osteotomies at supratuberosity level in 5 full body specimens were performed. The effect of the surgical procedure on patellar kinematics, measured at 5 and 10 degrees of leg alignment correction angle, was analyzed and compared to native patellar kinematics during passive motion-regarding patella shift, tilt, epicondylar distance and rotation. Linear mixed models were used for statistical analysis, a two-sided p value of ≤ 0.05 was considered statistically significant. RESULTS: Tilt behavior, medial shift and epicondylar distance did not show a significant difference regarding natural patellar kinematics at both osteotomy levels. Both osteotomy correction angles showed a significant less external rotation of the patella (p < 0.001, respectively) compared to natural kinematics. CONCLUSIONS: Except less external rotation of the patella, medial open wedge high tibial osteotomy does not seem to relevantly alter patellar alignment during passive motion. Future clinical studies have to prove the effect of MOWHTO on patellar kinematics measured in this experimental setup, especially regarding its influence on anterior knee pain.

Kinematic component alignment in total knee arthroplasty leads to better restoration of natural tibiofemoral kinematics compared to mechanic alignment.

PURPOSE: Kinematically aligned total knee arthroplasty is associated with superior pain relief, increased flexion and a more normal feeling knee. It was hypothesized that due to restoring the knee's natural anatomy, kinematically aligned knees show more physiological tibiofemoral kinematics than mechanically aligned knees. METHODS: Investigations were performed in nine healthy cadaveric knees of whole bodies fixed by the Thiel method. Tibiofemoral kinematics of healthy knees and after kinematically and mechanically aligned total knee arthroplasty were assessed between 0° and 90° of flexion by a navigational device. RESULTS: Regarding tibial internal rotation or femoral roll back, respectively, kinematically aligned total knee arthroplasties showed no significant differences between 0° and 70° of flexion in comparison to knees before total knee arthroplasty. In contrast, mechanically aligned total knee arthroplasties showed significant changes between 10° and 90° of flexion. Kinematically aligned knees showed a significant changed abduction/adduction between 20° and 70° of flexion, mechanically aligned knees within 20° and 90° of flexion. CONCLUSION: In the present study setting kinematically aligned total knee arthroplasties showed more natural and physiological tibiofemoral kinematic pattern with regard to tibial internal rotation or femoral rollback, respectively, and tibial adduction than mechanically aligned total knee arthroplasties. While these results may support promising early clinical results of kinematical alignment proposing a better function, long-term results especially implant survival need to be awaited.

Course of pain after total hip arthroplasty within a standardized pain management concept: a prospective study examining influence, correlation, and outcome of postoperative pain on 103 consecutive patients.

INTRODUCTION: Postoperative pain management options are of great importance for patients undergoing total hip arthroplasty, as joint replacement surgery is reported to be one of the most painful surgical procedures. This study demonstrates pain outcome until 4 weeks postoperatively and evaluates factors influencing pain in the postoperative course after total hip arthroplasty. MATERIALS AND METHODS: A total of 103 patients were included in this prospective cohort trial and underwent total hip arthroplasty. Postoperative pain was described using a numerical rating scale (NRS); demographic data and perioperative parameters were correlated with postoperative pain. RESULTS: Evaluation of pain scores in the postoperative course showed a constant decrease in the first postoperative week (mean NRS 3.1 on day 1 to mean NRS 2.3 on day 8) and, then, a perpetual increase for 3 days (mean NRS 2.6 on day 9 to mean NRS 2.3 on day 12). Afterwards, a continuous pain-level decrease was stated (continuous to a mean NRS 0.9 on day 29). No correlation was found between the potential influencing factors sex, age, body mass index, duration of surgery, ASA score, and postoperative pain levels, but a high significant correlation could be stated for preoperative pain levels and postoperative pain intensity (pain while moving p < 0.02 to p < 0.05 depending on the time period "week 1 postoperatively", "week 2-4", or "week 1-4"; pain while resting p < 0.001, in all the measured time intervals, respectively). CONCLUSION: Increasing pain levels after the first week postoperatively, for 3 days, are most likely to be caused by the change to more extensive mobilization and physiotherapy in the rehabilitation unit. No significant influence or correlation on the intensity of postoperative pain could be found while evaluating potential predictors except preoperative pain levels. Pain management has to take these findings into account in the future to further increase patients' satisfaction in the postoperative course after total hip arthroplasty and to adapt pain management programs.