Ucl Injuries at the Elbow

Ulnar Collateral Ligament Injuries of the Elbow

Ulnar Collateral Ligament (UCL) injuries of the elbow have been investigated since the mid-twentieth century. They were first seen in javelin throwers in 1946. While the injury was explored during the 1940s, it wasn't until the late eighties that an in-depth examination of the injury and reconstruction were considered (Meyers, 2008, 53). The three components that form the UCL protect the elbow from valgus stress, especially during the act of overhand throwing, where the elbow is susceptible to injury. The biomechanics of throwing often place the elbow under excessive stress and cause injury to the ligament. UCL injuries are more common in certain sports like baseball, softball, football, volleyball, etc. that involve an overhand motion. These types of injuries can greatly affect the athlete's performance. Diagnosing the injury, treating, and rehabilitating the athlete are important and must be done correctly in order to return the athlete to competition.

The UCL is comprised of three parts; the anterior, posterior, and transverse bands (Hariri, 2010, 620). The anterior band is the strongest of the collateral ligaments and provides the most stability. It is divided into two portions itself (anterior and posterior). The anterior portion is taut during elbow extension verses the posterior portion which is taut during elbow flexion. The anterior bundle protects the elbow against valgus forces between 30˚ and 120˚ in the flexion-extension arc (Meyers, 2008, 53). The posterior band has a fan-shaped appearance and is the primary restraint against valgus stress during elbow flexion at 90˚. The transverse band connects two parts of the same bone and does not cross a joint; therefore, it does not play an important role in elbow stability (Hariri, 2012, 621). While the UCL is set up to provide support against valgus stress, the biomechanics of throwing place the elbow under greater amounts of stress than the ligament allows for during certain phases of throwing. The six phases of throwing start with the wind-up, progress through early cocking, late cocking, acceleration, deceleration, and end with the follow through. Large valgus loads are experienced during the acceleration phases and often produce compression and shear stress. These tensile forces often overpower the failure strength of the UCL (Langer, 2006, 500).

Several factors predispose athletes to UCL injuries. Age, sport, participation level, hand dominance, and sports participation calendar all play a role during injury. Overhand throwing sports require athletes to repeatedly perform a motion that places various amounts of stress on their upper extremities. Certain positions on the field are also important to note when suspecting a UCL injury. Quarterbacks, pitchers, and catchers are known to be at a higher risk for UCL injury because of the amount of throwing required by them. These injuries are more commonly seen in high school and collegiate athletes than in younger participants (Hariri, 2010, 623).

When a UCL injury is suspected, it is important to conduct a thorough history of the athlete. Any previous injury, bracing, surgery, etc. should be noted along with questions regarding elbow pain, throwing velocity, throwing accuracy, or any abnormal symptoms occurring during or after the overhand motion is performed (Hariri, 2012, 623). Athletes will often complain of medial elbow pain, feeling or hearing a pop, and loss of velocity or control (Meyers, 2008, 53). As these types of injuries become more common, it is important to question the athlete on the amount of work he or she is putting in. For example, asking a pitcher how many pitches he has thrown, types of pitches, the frequency of pitching, number of innings he pitches, etc. These are all vital when assessing the amount of stress being placed on the ligament (Hariri, 2010, 623).

After gathering the athlete's history, a physical examination of the suspected injured extremity should be performed. UCL injuries have been found to be more common in taller, heavier athletes because of the increased velocity of their biomechanics. As these athletes may throw harder and be more successful they are more apt to pitch more frequently, this too places them under more stress. During palpation it is important to look for any loose bodies that may be present along with any ecchymosis or tenderness. As always, a neurological exam should be performed to check the distribution of the ulnar nerve (Hariri, 2010, 624). Testing the integrity of the UCL is one of the most important parts of the exam. Special tests such as the milking maneuver, valgus stress test, and the moving valgus stress test are all reliable in diagnosing a UCL injury. When performing these tests it is vital that a bilateral comparison be conducted with the uninjured extremity. This will help prevent any false positive results from being recorded. Also, it is common for overhand throwing athletes to have abnormal amounts of laxity and ROM. Athletic trainers must keep this in mind when evaluating and performing special tests on the athlete.

During the milking maneuver, the examiner palpates the UCL for tenderness while the patient applies a valgus stress to the elbow by supporting and grasping the thumb with the contralateral arm. The valgus stress test is performed with the shoulder in a locked position; 90˚ of abduction and the humerus at max external rotation. The thumb is then pulled posteriorly, providing valgus stress to the