No difference in patient preference for medial pivot versus posterior-stabilized design in staged bilateral total knee arthroplasty: a prospective study.

PURPOSE: Medial pivot (MP) TKA has been shown to mimic normal knee kinematics with long-term survivorship comparable to most contemporary TKA. However, there are inadequate evidences to suggest its superiority in terms of patient preference and satisfaction. The aim of this study is to compare the MP with posterior-stabilized (PS) TKA in terms of patient preference and satisfaction. METHODS: 46 patients with staged bilateral TKA were recruited. TKA with MP or PS design was performed at interval of 6-12 months. Patient preference, patient satisfaction score (0-100), Forgotten Joint Score (FJS), range of motion (ROM), Pain Score, Knee Society Score (KSS), Knee Function Score (KFS) and WOMAC Score were compared at up to 12 months. RESULTS: The mean age was 70 and 69.6% were female. There was no difference in all preoperative parameters, operative time and length of stay between two knees. No difference was found in in range of motion and all outcome scores at 6 months and 12 months. Satisfaction score was similar for the two designs (82 vs 85, p = n.s.) at 1 year after the second TKA. Proportion of patients with preference on one design over another was not significantly different (28.9 vs 35.6%, p = n.s.). CONCLUSIONS: There is no evidence to support the superiority of MP TKA over PS TKA in terms of preference and satisfaction. The choice between MP TKA versus PS TKA maybe more a surgeon's preference than a patient's preference based on current evidence.

Forgotten Joint Score for early outcome assessment after total knee arthroplasty: Is it really useful?

Background@#Forgotten Joint Score (FJS) has become a popular tool for total knee arthroplasty (TKA), but almost all studies had assessment performed 1 year after surgery. There is a need for a sensitive tool for earlier outcome assessment. The aim of this study was to investigate the usefulness of FJS within the first year after TKA. @*Methods@#This was a cross-sectional study. Patients within the first year after primary TKA were recruited. FJS was translated into the local language with a cross-cultural adaptation and was validated by assessing the correlation with the Western Ontario and McMaster Universities Arthritis Index score (WOMAC). Ceiling and floor effects (highest or lowest 10% or 15%) of both scores were compared. Skewness of scores was assessed with a histogram. @*Results@#One hundred sixty-three subjects were recruited: 84 (51.5%) had evaluation at 3 months after the operation, 56 (34.4%) at 6 months, and 23 (14.1%) at 12 months. FJS had fewer patients at the highest 10% (10.7% vs. 16.1%, P = 0.046) or 15% (19.6% vs. 32.1%, P = 0.027) at 6 months and within the first year overall (6.7% vs. 13.5%, P <0.001; 14.1% vs. 22.7%, P <0.001). Also, it had more patients at the lowest 10% (16.7% vs. 0%, P <0.001) or 15% (21.4% vs. 0%, P < 0.001) at 3 months, 6 months (10.7% vs. 0%,P <0.001), and overall (12.9% vs. 0%, P <0.001; 16.6% vs. 0%, P <0.001). The skewness was much less than WOMAC (0.09 vs. −0.56). @*Conclusions@#FJS has a low ceiling effect but a high floor effect in the first year after TKA. Such characteristics make it less useful for the general assessment of early patient report outcome after operation.

Intraoperative femoral condyle fracture in primary total knee arthroplasty - a case-control study in Asian population

Purpose@#Intraoperative femoral condyle fracture is a significant but rarely reported complication during primary total knee arthroplasty (TKA). This is the first study to identify the incidence, risk factors, location and outcome of these fractures in an Asian population with modern posterior-stabilized (PS) TKA. @*Materials and methods@#We reviewed 2682 consecutive primary TKAs performed between 2011 and 2017 in a single centre; 23 femoral condyle fractures were identified and analysed. @*Results@#Fractures were managed conservatively with screw fixation or revision arthroplasty. Mean follow up was 3.0 years (range 3 months to 5.9 years). All patients achieved bone union and good functional outcome. The mean Knee Society Knee score was 89.4 (range 71–100) and the function score was 80.2 (range 60–95) at a mean of 3.0 years post-operation. Bilateral surgery was found to be a significant risk factor for femoral condyle fracture, while there was a higher trend of fracture in female patients and Stryker articular surface mounted (ASM) navigation. @*Conclusions@#Intraoperative fracture is not uncommon with modern PS TKA. Postulated risk factors for fracture were discussed. Early identification of risk factors and a rigorous surgical technique may reduce risk of fracture. A good functional result was expected after proper treatment.