Correlation Between Tibia Nail Length and Tip of Olecranon to Fifth Metacarpal Head Measurement

Correlation between TT-MM and O-MH distance

Abstract

Introduction: Tibial shaft fractures, constituting nearly 2% of all adult fractures, are frequently managed with intramedullary (IM) nails, necessitating precise nail sizing for optimal outcomes. While various preoperative and intraoperative methods for tibial nail length measurement exist, anthropometric approaches offer promising alternatives. This study investigates whether the distance from the tip of the olecranon to the fifth metacarpal head (O-MH) can reliably estimate tibial nail length, compared to the established tibial tuberosity to medial malleolus (TT-MM) measurement.

Methods: A prospective, single-center observational cross-sectional study was conducted at Kathmandu Medical College and Teaching Hospital (KMCTH), Kathmandu, Nepal, from July 1, 2023, to June 30, 2024. Ethical clearance was obtained. Participants included individuals aged over 18 with tibial shaft fractures. Exclusion criteria encompassed severe fractures, prior injuries, congenital deformities, and hereditary bone diseases. Measurements of TT-MM and O-MH were taken, and Spearman's rank correlation was used to assess the relationship between these measurements. Regression analysis further evaluated their predictive power.

Results: The study involved 96 patients, predominantly male (72.9%). The Spearman's rank correlation coefficient between TT-MM and O-MH was 0.802 (p = 0.000), indicating a strong positive correlation. Regression analysis revealed that O-MH significantly predicts tibial nail length, with a coefficient of 0.920 and a Beta of 0.808.

Conclusion: The O-MH measurement demonstrates a strong correlation with TT-MM and effectively predicts tibial nail length. This method provides a reliable alternative for preoperative estimation, particularly in cases where direct measurements are challenging.