Unicompartmental Knee Arthroplasty for the Indian Patient: An Unmet Clinical Need for Redesigning Implants Based on Caucasian Morphometry.

Abstract

Accurate prosthesis sizing is crucial for successful unicompartmental knee arthroplasty (UKA). Indian patients have distinct knee morphometry due to cultural practices requiring deep flexion. Understanding these anatomical nuances is essential to optimize implant fit and functional outcomes. A comprehensive review analyzed knee morphology among Indian, Caucasian, and other ethnic populations. Data were sourced from PubMed, Scopus, and Google Scholar using keywords such as "knee morphology," "unicompartmental knee arthroplasty," "Indian population," and "prosthesis design." Key parameters, including anteroposterior (AP) and mediolateral (ML) dimensions, tibial plateau morphology, and aspect ratios, were statistically compared (<i>p</i> < 0.05). Significant ethnic and gender-based differences in knee morphology were observed. Indian males had a smaller femoral AP dimension (57.5 ± 3.1 mm) than Caucasian males (59.6 ± 3.2 mm), <i>p</i> < 0.001, while Indian females had 52.8 ± 3.1 mm compared to 55.4 ± 2.8 mm in Caucasian females (<i>p</i> < 0.001). Tibial ML dimensions were also smaller in Indian knees (males: 69.1 ± 5.5 mm vs. Caucasian males 79.4 ± 4.3 mm, <i>p</i> < 0.001; females: 65.4 ± 4.7 mm vs. Caucasian females 70.2 ± 2.7 mm, <i>p</i> < 0.001). Approximately 25% of Indian patients did not achieve optimal tibial fit. Western-designed UKA implants do not fully accommodate Indian knee anatomy, leading to ML overhang, AP undersizing, and compromised stability. Although statistically significant variations exist, their clinical impact warrants further investigation. Developing population- and gender-specific prosthetic designs is essential to improve implant fit, stability, and long-term surgical outcomes for Indian patients.