Topographic and Histologic Analysis of the Collateral Ligament Complex around the Elbow

Abstract

Purpose: The purpose of this study was to evaluate topographic anatomy of the footprints of key ligaments of the elbow and assess their relationships with bony parameters using micro-computed tomography (micro-CT). Additionally, the ratios of type I/III collagen at the medial collateral ligament (MCL) and lateral collateral ligament (LCL) of elbow were investigated.Methods: Eleven cadaveric elbows attached by both the MCL and LCL were scanned using micro-CT and reconstructed three-dimensionally. Additionally, the ligaments were examined under polarized light microscopy to determine the histological characteristics of collagen patterns. Results: Areas of footprints of the MCL and LCL attaching onto the humerus were 133.2±25.8 mm² and 128.3±23.2 mm², respectively. Footprint sizes of anterior and posterior bundles of the MCL in the proximal ulna and lateral ulnar collateral ligament (LUCL) attaching to the proximal ulna averaged to 109.9 mm², 89.2 mm², and 89.7 mm², respectively. There were a positive correlation between footprint size of the MCL and LUCL at the humeral side and a negative correlation between the footprint size of the MCL at humeral side and maximal diameter of the radial head. The collagen I/III ratio of the humeral attachment of the MCL was higher than distal attachment of the MCL. Conclusion: This study provides a better understanding of the pathologies of the MCL and LCL complex of the elbow and their relationships with osseous anatomy and may assist the clinician with an anatomic reconstruction of the ligaments.