Ethnical Differences in Knee Phenotypes Indicate the Need for a More Individualized Approach in Knee Arthroplasty: A Comparison of 80 Asian Knees with 308 Caucasian Knees.

Lukas B Moser,Jean-Baptiste De Villeneuve Bargemon,Matthieu Ollivier,Ahmad Faizan,Felix Amsler,Michael T Hirschmann,Sally Liarno,Silvan Hess

doi:10.3390/jpm12010121

Abstract

The purpose of this study was to determine the distribution of functional knee phenotypes in a non-osteoarthritic Asian population. The Stryker Orthopaedic Modeling and Analytics (SOMA) database was searched for CT scans of the lower limb meeting the following inclusion criteria: patient age at time of image >18 and <46 years, no signs of fractures and/or previous surgery and/or degenerative changes, Asian ethnicity. A total of 80 CT scans of 40 patients were included (24 males, 16 females). The hip-knee-ankle angle (HKA), femoral mechanical angle (FMA) and tibial mechanical angle (TMA) were measured. Based on these measurements, each limb was phenotyped according to the previously introduced functional knee phenotype concept. All angles and phenotypes of the present study were compared with previously published data of a non-osteoarthritic Caucasian population (308 legs of 160 patients, 102 males, 58 females). Asian knees had a significantly lower TMA (both genders p < 0.001) but a higher FMA (males p < 0.05, females p < 0.001) than Caucasian knees but showed no difference in the HKA. Asian knees differed significantly with regard to femoral and tibial phenotypes (p < 0.01), but not with regard to limb phenotypes. The high variability of all coronal alignment parameters highlights the importance of a detailed analysis prior to TKA. Ethnical differences underline the need for a more individualized approach in TKA.

Highlights

Several studies on total knee arthroplasty (TKA) suggested a connection between a more individualized coronal alignment target and improved clinical outcome [1]
The results of the present study reveal that Asian knees have a highly variable joint line orientation of the femur and tibia, and that their combination in relation to the overall alignment is unique and different compared to Caucasian knees
This might approximately be the case for the average population, severe individual deviations have been reported for Caucasian knees [14]

Summary

Introduction

Several studies on total knee arthroplasty (TKA) suggested a connection between a more individualized coronal alignment target and improved clinical outcome [1]. These individualized approaches would require a profound knowledge of the variability of coronal alignment between different patient populations, which does not yet exist [2,3]. The few existing studies were mainly focused on anthropometric parameters such as medial–lateral and/ or anterior–posterior ratios and showed significant ethnical differences [6–8]. Studies investigating ethnical differences in coronal alignment parameters are rare and their results inconclusive. Some studies reported a more valgus-aligned distal femur (FMA) in Asian knees compared to Caucasian knees [9,10], while others did not find any significant difference [11]. A similar picture evolves for alignment of the tibial joint line (TMA) and the overall limb alignment (HKA)

Objectives

Methods

Discussion

Conclusion