The Ulnar Collateral Ligament (UCL) is the primary medial stabilizer of the elbow. It is most often injured, in the athletic setting, with overhand throwing and javelin throwing. Injuries to this ligament, when left untreated, can result in the premature termination of an athlete’s career.
The UCL is located on the medial side of the elbow. It is comprised of 3 parts that appear in a fan shape. The anterior bundle runs from the anterior side of the medial epicondyle of the humerus to the coronoid process of the ulna. This bundle is responsible for approximately 60% of the elbow’s resistance to valgus stress from 20° to 120° of flexion. The posterior bundle extends from the posterior aspect of the medical epicondyle and attaches to both the coronoid and olecranon processes. The oblique or transverse bundle runs between the olecranon and coronoid processes. The oblique and posterior bundles serve as a stabilizer for valgus forces, but are less important than the anterior bundle.
Injury Mechanisms & Evaluation
An injury to the UCL has two main mechanisms of injury: a slow deterioration due to repetitive stress and less commonly, an acute rupture of the ligament.
Repetitive stress, as seen in the overhand thrower or javelin thrower, can cause micro tears in the ligament that, over time, result in a loss of structural integrity of the ligament. Most often, this is due to poor throwing mechanics, lack of flexibility, lack of conditioning, and/or fatigue.
A traumatic injury may be seen in a football running back who falls on an outstretched arm while being tackled. This may result in a dislocated elbow, causing damage to the UCL, the radiocapetellar joint, and/or radioulnar syndesmosis.
An athlete with UCL laxity will present with symptoms of: pain on the medial aspect of the elbow (especially during the acceleration phase of throwing), “popping” when throwing, loss of elbow ROM, and pain with possible laxity during a valgus stress test performed at 25° of flexion.
The physician may also perform a posterolateral rotary instability (lateral pivot shift test). This test is controversial in that it is a fairly new test, it is technically very difficult to perform, and yields questionable results. This test has been shown to be potentially useful when performed by an experienced physician under anesthesia.
Pain film x-rays often show no signs of an UCL injury (the exception is seen in an avulsion fracture of the UCL which is common in pediatric patients). An MRI or CT scan may also be used to help in the diagnosis of this injury. The use of contrast media with either an MRI or CT is controversial as the dye may or may not aid in visualizing this injury due to the complicated nature of the anatomy. Also, with gradual stretching of the ligament a full thickness tear of the ligament and capsule may not be present. If a full thickness tear is not present, the contrast material may not “leak” out of the joint into the surrounding tissue, resulting in a false negative interpretation of the MRI. The MRI or CT should be used to correlate the findings of the physical exam and to look for any other associated damage.
Once it has been determined that the medial aspect of the elbow is structurally unstable there are two options for treatment of the overhead thrower: retire from competition or reconstruct the medial aspect of the elbow. Reconstruction, referred to as “Tommy John’s Surgery,” has been shown to extend the overhead thrower’s career.
Reconstruction of the UCL is performed with two types of tissue: autograft tissue, most commonly the palmaris longus tendon; or allograft tissue from a cadaver donor. Some people do not have a palmaris longus tendon; in these cases, the physician will use an allograft tendon for reconstruction. Many physicians are also opting for allograft reconstruction of the UCL to decrease the overall potential for morbidity in the athlete.
Reconstruction begins by with a 10 cm incision on the medial aspect of the elbow. The flexor-pronator muscle wad is split lengthwise to expose the ligament and joint line. Holes are drilled in the ulna and humerus so that the graft can be passed in a figure 8 fashion. Care must be taken to properly tension the graft so as to allow full range of motion.
¨ Week 0 - 3: Immobilization in a 90° splint for 10 days; progressing to 30° - 100° in protected ROM brace. Progressive shoulder, hand, wrist ROM and guarded strengthening.
¨ Week 4 - 8: Progress guarded ROM to full ROM by 8 weeks post-op. Full body conditioning exercises. Shoulder and arm strengthening progresses to allow shoulder ER.
¨ Week 9 - 13: Advanced Strengthening; eccentric elbow flexion and extension initiated; trunk and UE plyometrics, continue shoulder program.
¨ 9 Months - 1 Year: Begin throwing program and functional exercises for return to competition.Post-Op complications are rare. Ulnar nerve entrapment is the most common complication. Approximately 75 - 85% of athletes return to their previous level of competition. Some baseball pitchers have even reported increased velocity after surgery.
©2000 - 2009 David Edell
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Last Update for AthleticAdvisor.com: 10/24/2009 12:09:35 AM