A prospective analytical study on the effect of posterior femoral condylar offset on range of knee flexion in patients undergoing cruciate retaining total knee arthroplasty

<p><strong>Background:</strong> Osteoarthritis (OA) of knee joint is a common problem in our society causing pain, deformity, oedema, malalignment and limitation of activity. Total knee arthroplasty (TKA) is the surgery done for treatment of this problem. The range of movement obtained after TKA is an important factor influencing success of surgery. Posterior femoral condylar offset (PCO) is one of the parameters influencing range of movement after surgery. The dearth of studies in Indian population and contradicting results in already conducted studies has been observed in assessing the effect of PCO on range of knee flexion in patients undergoing TKA. Hence this study is done to explore this correlation.</p><p><strong>Methods:</strong> A prospective analytical study on 36 patients (50 knees) who underwent cruciate retaining TKA at Department of Orthopaedics, Rajagiri Hospital, Aluva. PCO and posterior femoral condylar offset ratio (PCOR) were calculated radiologically before and after TKA. Range of flexion (ROF) and knee society scores (for functional outcome assessment) were recorded preoperatively and postoperatively (at 6 weeks and 3 months).</p><p><strong>Results:</strong> The study found a strong positive correlation between PCO difference and ROF difference (r=0.735). Strong positive correlation was also found between PCOR difference and ROF difference (r=0.777). Both these correlations were statistically significant (p&lt;0.05).</p><p><strong>Conclusions:</strong> The study enlightened us about the point that PCO is an important factor in attaining a good ROF after cruciate retaining TKA.</p>

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.

Double-high insert presents with worse mid-term outcomes in cruciate-retaining medial-pivotal total knee arthroplasty – a propensity score matched analysis with averaged 8-year follow-up

Background The aim of this study was to compare the mid-term clinical and radiographic outcomes between medial-pivotal (MP) insert and double-high (DH) insert used under cruciate-retaining condition in ADVANCE® total knee arthroplasty (TKA). Methods The follow-up was conducted for 158 consecutive patients underwent unilateral ADVANCE® TKA from January 2011 to April 2014. 84 MP inserts and 74 DH inserts were used under cruciate-retaining condition. A 1:1 propensity score matching (PSM) analysis was performed between MP insert and DH insert to compare the clinical and radiographic outcomes. Results After a 1:1 PSM, 120 patients (60 pairs) were matched between MP insert and DH insert. The baseline demographic parameters and clinical scores were comparable between the two groups. The postoperative clinical outcomes at an averaged 8-year follow-up of both groups were significantly improved. The range of motion (ROM) of DH group was better than that of MP group and equivalent Knee Society Function Score (KSFS) between the two groups was found. However, the Knee Society Score (KSS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and Forgotten Joint Score (FJS) of MP group were found to be significantly superior than those of DH group. Comparable complication rate and revision rate were observed between the two groups. The radiographic results were also equally good between MP and DH group. Conclusions Although the mid-term clinical and radiographic outcomes of DH insert are fairly good, the clinical scores of DH group were worse than those of MP group.