Morphometric dimensions of distal femur and proximal tibia inference to knee joint prosthesis design in Tanzania

Abstract

ABSTRACT Introduction: The knee joint is a hinge type of synovial joint, which mainly allows for flexion and extension and a small degree of medial and lateral rotation. It is formed by articulations between the patella, femur and tibia. The knee joint is fundamentally prone to chronic disease conditions of whom knee replacement have proven to be an effective definitive management. Total knee replacement involves precisely replacing the articulating surfaces of the joint with prosthetic designs. In our settings, however, scanty data is available on knee morphometric dimensions which are essential in selecting patients specific knee joint prostheses. The currently available knee joint prosthetic models are based on western morphometries. In this study therefore we hypothesize that, the knee joint morphometries in our population is different from those from the western population. Purpose of the study: This study aimed to obtain preliminary morphometric measurements that are Tanzanian population specific. Broad objective: To determine the morphometric dimensions of the distal femur and proximal tibia of the Tanzanian subpopulation. Rationale of the study: to establish preliminary morphometric dimensions that will be useful in designing Tanzanian population specific prostheses Materials and Methods: The femur and tibia, were carefully selected and the intended morphometrics were measured. Furthermore, a skilled radiologist took and examined magnetic resonance images of a normal adult Tanzanian knee. The data were entered into Excel workbook sheets (Microsoft Office Excel; Microsoft Corporation, US; version 2020). Statistical Package for Social Sciences (version 23.0; SPSS Inc., Chicago, IL) was then used to clean and analyze the data. Measures of dispersion were among the statistical analyses performed. To ascertain whether there is a statistically significant difference in the morphological measurements between the sexes, a student's t test for equality of means was conducted. Results: The mean aspect ratio of the femur was 1.13 while Tibia was found to have mean aspect ratio of 1.38. Further there was a statistical difference between male and female morphometrics in the proximal tibia, being more significant in male p=0.003. Conclusion: The anatomical data collected in this study provides a preliminary data about the morphometry of dry adult distal femur and proximal tibiae, which will provide the basis for designing the optimal knee prosthesis in knee arthroplasty for Tanzanian population into consideration as a small sized prosthesis may show mediolateral under sizing and larger sized prosthesis may show mediolateral overhang which will lead to poor otucomes.