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World J Orthop. Jun 18, 2018; 9(6): 78-84
Published online Jun 18, 2018. doi: 10.5312/wjo.v9.i6.78
Understanding the medial ulnar collateral ligament of the elbow: Review of native ligament anatomy and function
Joshua R Labott, William R Aibinder, Joshua S Dines, Christopher L Camp
Joshua R Labott, Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN 55905, United States
William R Aibinder, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, United States
Joshua S Dines, Sports Medicine and Shoulder Service, Hospital of Special Surgery, New York, NY 10021, Unites States
Christopher L Camp, Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, Rochester, MN 55905, United States
Author contributions: All authors equally contributed to this paper with conception and design of the study, literature review and analysis, drafting and critical revision and editing, and final approval of the final version.
Conflict-of-interest statement: No potential conflicts of interest. No financial support.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Christopher L Camp, MD, Assistant Professor, Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St., Rochester, MN 55905, United States. camp.christopher@mayo.edu
Telephone: +1-507-2842511 Fax: +1-507-5387802
Received: March 24, 2018
Peer-review started: March 25, 2018
First decision: April 24, 2018
Revised: April 28, 2018
Accepted: May 9, 2018
Article in press: May 10, 2018
Published online: June 18, 2018
Processing time: 82 Days and 14.2 Hours
Abstract

The medial ulnar collateral ligament complex of the elbow, which is comprised of the anterior bundle [AB, more formally referred to as the medial ulnar collateral ligament (MUCL)], posterior (PB), and transverse ligament, is commonly injured in overhead throwing athletes. Attenuation or rupture of the ligament results in valgus instability with variable clinical presentations. The AB or MUCL is the strongest component of the ligamentous complex and the primary restraint to valgus stress. It is also composed of two separate bands (anterior and posterior) that provide reciprocal function with the anterior band tight in extension, and the posterior band tight in flexion. In individuals who fail comprehensive non-operative treatment, surgical repair or reconstruction of the MUCL is commonly required to restore elbow function and stability. A comprehensive understanding of the anatomy and biomechanical properties of the MUCL is imperative to optimize reconstructive efforts, and to enhance clinical and radiographic outcomes. Our understanding of the native anatomy and biomechanics of the MUCL has evolved over time. The precise locations of the origin and insertion footprint centers guide surgeons in proper graft placement with relation to bony anatomic landmarks. In recent studies, the ulnar insertion of the MUCL is described as larger than previously thought, with the center of the footprint at varying distances relative to the ulnar ridge, joint line, or sublime tubercle. The purpose of this review is to consolidate and summarize the existing literature regarding the native anatomy, biomechanical, and clinical significance of the entire medial ulnar collateral ligament complex, including the MUCL (AB), PB, and transverse ligament.

Keywords: Elbow; Anterior bundle; Medial ulnar collateral ligament; Native anatomy; Biomechanics; Valgus stability

Core tip: The anterior bundle of the medial ulnar collateral ligament complex plays a crucial role in elbow stability, specifically as a valgus and rotational constraint. Based on recent studies and our own cadaveric dissections, the ulnar footprint has a broader insertion that is more tapered and elongated than previous considered. A comprehensive understanding of the anatomy and biomechanical properties of the medial ulnar collateral ligament is imperative to optimize reconstructive efforts, and to enhance clinical and radiographic outcomes.