Effect of Changes in the Posterior Tibial Slope on Femorotibial Articular Contact Kinematics after Cruciate-Retaining Total Knee Arthroplasty: Do the Changes Affect Outcomes?

Background Total knee arthroplasty (TKA) outcomes are affected by many factors.This study aimed to evaluate whether changes in the posterior tibial slope (PTS) affects patients’ outcomes after cruciate-retaining TKA by affecting femorotibial articular contact kinematics. Methods Altogether, 20 knees in 10 patients who underwent posterior cruciate ligament-retaining TKA using the same size prosthesis for medial osteoarthritis were assessed preoperatively and 1 year postoperatively. PTS changes seen on lateral radiographs before and after TKA were calculated. Knees were placed in groups according to the PTS change at 1 year postoperatively (preoperative value − postoperative value). Group 1 had a >3° change and group 2 a ≤3° change. Knee kinematics under the weight-bearing mid-flexion condition were compared between the two groups via two-dimensional/three-dimensional registration. Pain was measured using the visual analog scale, and knee function was based on the Western Ontario and McMaster universities (WOMAC) osteoarthritis index and Knee Society Score (KSS) questionnaire results. Results Group 2 experienced paradoxical anterior motion of the mediofemoral condyle postoperatively, whereas group 1 did not. Comparison of TKA results between the two groups showed a significant between-group difference in pain and knee function of the KSS and in the WOMAC osteoarthritis index score (P ≤ 0.05). Postoperative results were better in group 1 than in group 2. Conclusions Achieving a greater change in the posterior tibial slope apparently improves outcomes in patients undergoing posterior cruciate ligament-retaining TKA because it reduces the paradoxical medial femoral condylar movement.

Comparsion of Mobile-bearing UKA and Posterior Cruciate Ligament Retaining TKA for Patients with Unicompartmental Knee Osteoarthritis:a Retrospective Cohort Study

Introduction: Many studies have compared unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) for knee osteoarthritis suggesting that both procedures had good clinical outcomes. However, there have been fewer studies comparing the mobile-bearing UKA (MB-UKA) and posterior cruciate ligament retaining TKA (CR-TKA) for patients with unicompartmental knee osteoarthritis. Thus, we explored the differences in outcomes and complications between the two cohorts.Methods: In this retrospective study, 41 patients who underwent MB-UKA and 40 who underwent CR-TKA in our institution were included. All patients were suffered from unicompartmental knee osteoarthritis. Patient demographics, preoperative and latest postoperative range of movement (ROM), Knee Society (KS) scores, and Forgotten Joint Score (FJS) were compared between the two cohorts. Additionally, complications, revisions, and 5-years survivorship were also analyzed.Results: The results showed MB-UKA patients had similar preoperative ROM and Knee Society pain (KSP), functional (KSF), and clinical (KSC) scores with CR-TKA patients (p = 0.104, p = 0.755, p = 0.32, p = 0.928, respectively). The mean follow-up for MB-UKA and CR-TKA groups was 3.4 and 3.7 years, respectively. Two MB-UKA and one CR-TKA patient required revision surgery. The latest postoperative KSF scores, ROM, FJS, and change in KSC scores and ROM were higher (p < 0.05) after MB-UKA, but the latest postoperative KSP, KSC, and change in KSF scores were equivalent between the two cohorts. There were no differences in complication, revision rates, and 5-year survivorship estimates.Conclusions: MB-UKA patients showed better functional outcomes and FJS, and higher ROM with similar survivorship compared with CR-TKA patients. MB-UKA should be considered as a primary treatment option for patients with unicompartmental knee osteoarthritis.Trial registration: researchregistry5032. Registered 23 July 2019, retrospectively registered

Comparative gait analysis of patients with different design of total knee arthroplasty

Introduction/Objective. The essence of the treatment of degenerative knee joint diseases is pain relief, restoring motion range and stability of knee joints. Methods. In this study, 35 patients participated after having surgery of the knee joint. The patients had a posterior - stabilized (PS) endoprosthesis in one joint, and a posterior cruciate ligament retaining (CR) endoprosthesis in the other. Kinematic data was collected using a 3D optical system for tracking fluorescent markers in time. Based on these data, the following parameters were determined: degree of flexion, medio - lateral (ML) translation, lateral gap, medial gap and the angle of change between the transtibial and transfemoral axes. Results. The results show a more pronounced flexion degree with the PS prosthesis compared to the CR prosthesis. Also, the results show negligible values of the ML translation, lateral gap and medial gap in both types of prostheses. Using the non-parameter Wilcoxon test, a substantial difference in the angle change between the transtibial and transfemoral axes was confirmed, that is, in the flexion angles on the CR and PS prostheses. Conclusion. This study shows that there is no great difference in the use of the PS or CR designs of endoprostheses. Better behavior and range of motion in the knee joint were established with the implantation of the PS endoprosthesis. This conclusion is confirmed by the substantial difference in the degree of flexion of the knee joint and in the position of the transversal axes of the tibia and femur