Patellar dimensions in south Indian population-An aid to implant design in total knee arthroplasty

Abstract

For a successful knee arthroplasty it is imperative to measure patellar thickness intraoperatively to guide the depth of resection. Width thickness ratio of patella is a useful indicator for assessing premorbid patellar thickness. Patellar implants for total knee arthroplasty rely mostly on data from Western population as data from Indian population is sparse. To study the dimensions of patella in South Indian population and to compare it with the previous literature. To estimate the commonest variant of patella in Indian population as per the Weibergs classification.: 101 dry patella from the Department of Anatomy of MVJ Medical College and Research Hospital were used for this study following approval from Instutional ethical committee . The dimensions of patella i.e Patellar height, width, thickness, width of medial and lateral articular facet were measured using Digital Vernier calipers. The results of various statistical parameters (Length, Width, Thickness, MAF and LAF) on the right and left side and combined were expressed in terms of mean and standard deviations along with minimum and maximum values.() The mean height, width and thickness of patella was 39.07mm, 42.56mm and 22.7mm respectively. The values of all the variables of both sides were compared. There was no statistical difference between the variables on right and left sides. Width of MAF in the present study was 19.8 ±2.82 mm while Width of LAF was 24.6±1.88mm. Ratio of width to thickness of patella was 1.8mm. There was no correlation between the two variables.Patella was classified according to Wiberg classification on the basis of dimensions of the width of medial articular and lateral articular facet as well as curvature of the facets. The most common variant observed was Type 2.The knowledge of patellar morphometry will aid the orthopedic surgeons in designing prosthesis. Morphometric data of patella on Indian population will also act as guide for forensic experts and anthropologists in sex determination.