Does commonly used femoral components of total knee arthroplasty fit well in the Indian population?

ABSTRACT

Background: 20 % of patients remain dissatisfied post-Total Knee Arthroplasty. We intend to find the correlation between sizes of commonly used femoral components and morphometric data of distal femur in Indian population. Materials and methods: Prospective observational study in 178 knees (178 individuals) was conducted on Magnetic Resonance Imaging scans (Axial section). The anteroposterior dimension at intercondylar notch (AP), anteroposterior dimension on the medial (MAP) and lateral (LAP) femoral condyle, total mediolateral width (ML), width of medial condyle (MLM), lateral condyle (MLL) and intercondylar distance (ICD) and aspect ratio (AR) were measured on males and females separately. These measurements were then analyzed keeping in view the available sizes of three latest knee arthroplasty systems (Attune CR, Next Gen II, Genesis II) to look for correlation and best fitting system. Results: On observation between values of male and female femur, a significant difference was seen in all the parameters (p-value<0.0001) except ICD (p-value 0.6591). On scatter plots, Attune was found to be nearer to the line of best fit compared to other two implant companies in both males and females. Outliers were highest in cases of NextGen II (45 % in males and 46 % in females) whereas it was lowest in the case of Attune (12.5 %in males and 41 % in females). Conclusion: Attune CR was seen to fit best in the Indian population followed by Genesis II and NextGen II. These femoral implants are designed as per the sizes of the Western population and the Caucasians are oversized for the Indian subcontinent, especially female patients, thus needing improvement in design/sizes. Level of evidence III.