Optimal Methods for Measuring Knee Aspect Ratio: A Scoping Review of Knee Morphometry Techniques and Comparison with Manual Anthropometry of Indian Knees

Abstract

Background: Current methods for measuring the knee aspect ratio vary in accuracy. The objective of the study was to conduct a scoping review of the mean values of aspect ratio using Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) among Indians, and, to compare these results with those of a descriptive study assessing the same using manual anthropometry.

Methodology: The scoping review was conducted to ascertain the mean aspect ratio among adult Indians, obtained using CT or MRI between 2004 and 2024, and published in English. Studies were eligible for inclusion if they presented mean values for anteroposterior (fAP, tAP), mediolateral diameters (fML, tML) and aspect ratios (fAR, tAR) for femur and tibia obtained by CT or MRI. PubMed, Scopus, Google Scholar, Web of Science, and Cochrane Library were screened and exported using Zotero 7.0.16 and Microsoft Excel. For comparison with manual morphometry, cadaveric dry bones of femurs and tibias available at two teaching institutions were measured with a Sliding Digital Caliper (ROBUST, Germany).

Results: Out of 144 studies from the five databases, six publications that describe 736 femurs and 680 tibias were included in the review. The aspect ratios from these studies were compared with the mean of 177 femurs and 161 tibias measured by manual morphometry. CT with three-dimensional modeling proved to be less variable than MRI and closer to manual anthropometry.

Conclusion: The study suggests that CT scans can be used as a valid measurement tool for assessing knee morphometry while choosing prostheses for Indian patients.