How to Choose the Appropriate Posterior Slope Angle Can Lead to Good Knee Joint Function Recovery in Total Knee Arthroplasty?

Objective: In this study, we aim to examine the effects of osteotomy under varying posterior slope angles on knee joint function recovery following knee arthroplasty. Methods: We conducted a retrospective analysis from September 2015 to September 2018 on 240 patients who underwent knee arthroplasty three years previously. The study participants were categorized based on changes in the angle of the posterior slope before and after surgery: Group 1, > 5°; Group 2, 3°-5°; Group 3, 0°-3°; Group 4, -3°-0°; Group 5, < -3°. All participants were affected with knee osteoarthritis. The Knee Society Clinical Rating System (KSS) knee function score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee function score, Visual Analogue Scale (VAS) pain score, and postoperative complications were measured 3 years after surgery. Results: The level of pain experienced by the patients decreased significantly than before, with pain scores ranging from 1.0-3.0, and there was a statistical difference between groups (H = 93.400, P < 0.001). The KSS score increased, with group 5 having the lowest median score of 78.0 and group 2 having the highest median score of 97.0, and there was a statistical difference between groups (H = 164.460, P < 0.001). The WOMAC score was reduced, with the median score being 24.0, 11.0, 14.0, 20.0, and 26.0, in the five groups, respectively. Group 5 had the highest score, while Group 2 had the lowest score, and there was a statistically significant difference between groups (H = 164.223, P < 0.001). No symptoms such as periprosthetic femoral fracture, prosthetic loosening, or pad wear were detected in patients postoperatively. Conclusion: Osteotomy at various posterior slope angles in total knee arthroplasty impacts postoperative knee function rehabilitation. An excessive increase or decrease in angle can have an impact on the postoperative recovery of knee function.

An investigation into whether changes in the posterior tibial slope affect the outcome of cruciate-retaining total knee arthroplasty by affecting tibiofemoral articular contact kinematics.

Aims: The outcomes of total knee arthroplasty (TKA) are affected by many factors. This study aims to evaluate whether changes in the posterior tibial slope (PTS) affect patients' outcomes after cruciate-retaining TKA by affecting tibiofemoral articular contact kinematics. It was hypothesized that changes in PTS affect the outcomes of PCR TKA by affecting tibiofemoral articular contact kinematics. Methods: A total of 60 knees (30 patients) that underwent posterior cruciate-retaining TKA (with the same size prosthesis) for medial osteoarthritis were assessed preoperatively and one year postoperatively. Before and after TKA, changes in the PTS, as seen on lateral radiographs, were noted. The knees were placed in groups according to these PTS changes (preoperative value - postoperative value): group 1 >3° change and group 2 ≤3° change. Knee kinematics were observed under mid-flexion weight-bearing conditions and were compared between the two groups using the two-dimensional/three-dimensional registration technique. Pain was measured using the visual analog scale, and knee function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Knee Society Score (KSS). Results: Group 2 experienced paradoxical anterior motion of the medial femoral condyle postoperatively, but group 1 did not. A comparison of the results of the TKA between the two groups showed a significant difference in pain using the visual analog scale, and knee function of the KSS and the WOMAC (P < 0.05). The postoperative results were better in group 1 than in group 2. Conclusions: These results suggest that achieving a greater change in the PTS improves outcomes in patients undergoing posterior cruciate-retaining TKA because it reduces the paradoxical motion of the medial femoral condyle.

Effect of tibial slope changes on femorotibial contact kinematics after cruciate-retaining total knee arthroplasty.

PURPOSE: The present study was undertaken to evaluate the effect of tibial slope (TS) changes on the femorotibial articular contact kinematics in subjects undergoing posterior cruciate-retaining total knee arthroplasty (CRTKA). METHODS: Eighteen knees in nine patients with medial osteoarthritis who underwent CRTKA using the same size prosthesis were analysed preoperatively and 2 years after TKA. TS changes were calculated on lateral radiographs taken before and after TKA. Knees were classified into two groups according to the change in TS obtained by subtracting the post-operative value from the preoperative value: group 1 (>3°) and group 2 (<3°). The femorotibial articular contact kinematics of knees during weight-bearing flexion were compared between the two groups by two-dimensional/three-dimensional registration. RESULTS: Group 1 showed a continuous posterior translation of the medial femoral condyle during the process of knee flexion, whereas in group 2 the medial femoral condyle experienced paradoxical anterior motion from 20° to 90° of knee flexion. The lateral femoral condyle continuously moved posteriorly in both groups. CONCLUSION: A greater reduction in TS after TKA compared with preoperative TS reduces paradoxical medial femoral condylar movement. This may contribute to improved patient satisfaction after CR TKA. LEVEL OF EVIDENCE: III.