Background:
Accurate implant sizing is crucial for optimal outcomes in total knee arthroplasty (TKA). Traditional preoperative templating methods are time-intensive and dependent on imaging. This study aimed to evaluate the relationship between shoe size and femoral and tibial component dimensions to determine whether shoe size can reliably predict implant sizing and postoperative pain intensity.

Material Methods:
A prospective cross-sectional study was conducted on 100 patients (50 men, 50 women) undergoing primary unilateral TKA. Preoperative shoe size was measured using a standardized protocol, and intraoperative femoral and tibial component sizes were recorded. Linear regression analysis assessed the correlation between shoe size and implant dimensions, while postoperative pain was measured using a 10-point visual analog scale (VAS) at 24 hours.

Results:
Shoe size was a significant predictor of both femoral (R² = 0.583, p < 0.001) and tibial (R² = 0.572, p < 0.001) component sizes. Prediction accuracy within ±1 implant size was 96% for femoral and 93% for tibial components. No significant correlation was found between shoe size, implant dimensions, and postoperative pain (p > 0.1).

Conclusion:
Shoe size serves as a reliable, radiation-free anthropometric predictor for femoral and tibial component sizing in TKA, with predictive accuracy comparable to digital templating methods. This simple, cost-effective approach may improve preoperative planning efficiency and resource utilization, especially in resource-limited settings. Further multicenter studies are recommended to validate these findings across diverse populations and implant systems.

Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.