The medial collateral ligament of the elbow joint: Anatomy and kinematics

Abstract

Eighteen osteoligamentous elbow joint specimens were included in a study of the medial collateral ligament complex (MCL). The morphologic characteristics of the MCL were examined, and three-dimensional kinematic measurements were taken after selective ligament dissections were performed. On morphologic evaluation the MCL is divided into the anterior bundle and the posterior bundle. The anterior bundle can be divided into anterior and posterior bands. The maximum valgus and internal rotatory instability after transection of the anterior band, 11.7 degrees and 11.2 degrees, respectively, were found at elbow flexions of 30 degrees and 40 degrees. Severance of the entire anterior bundle produced major valgus and internal rotatory laxity through the complete flexion arc of maximal 14.2 degrees and 18.5 degrees, respectively, at 70 degrees and 60 degrees of elbow flexion. Cutting both the posterior band and the posterior bundle resulted in only internal rotatory laxity of maximal 7.2 degrees at 130 degrees of elbow flexion. This study defines the anterior band as the primary constraint to valgus and internal rotatory forces, the posterior band as the secondary, and the posterior bundle as the tertiary constraint. The MCL was observed to be a complex of ligamentous fibers rather than individual bands that stabilizes the joint against valgus and internal rotatory forces.

Biomechanical differences of the anterior and posterior bands of the ulnar collateral ligament of the elbow

“…The UCL functions as the predominant stabilizer to valgus stress as elucidated by Morrey et al [10] and supported by multiple subsequent studies [3,5,11]. Overhead athletes can produce tremendous forces across the medial aspect of the elbow with throwing activities [2].…”

“…The anterior bundle has been demonstrated to be the main stabilizer to valgus force [5,6]. The anterior bundle can be further subdivided into anterior and posterior bands.…”

Is a Silastic Radial Head Still a Reasonable Option?

“…In the normally functioning elbow, the anterior band of the medial ulnar collateral ligament (MUCL) provides the primary stabilization against valgus force [6,12,16,23,32]. Transection of the anterior bundle alone is sufficient to create demonstrable instability on the application of a valgus force and abnormally high radiocapitellar pressures [28].…”

Combined posterolateral and posteromedial rotatory instability of the elbow

“…9 The anterior band of the medial collateral ligament, or the anterior oblique ligament is the primary medial stabilizer, 5 with the posterior oblique ligament as a secondary stabilizer. 2 Although this may suggest that repair of the posterior medial collateral ligament is less important, the elbow remained unstable even after the anterior band of the medial collateral ligament had been repaired, and only became stable after repair of the posterior medial collateral ligament and closure of the medial capsule. The authors' note that the anterior band is positioned to be a restraint to valgus force and the posterior band is better positioned to resist rotational forces.…”