Introduction The ulnar collateral ligament (UCL) is the primary valgus restraint in the elbow.
The ulnar collateral ligament (UCL) is the primary valgus restraint in the elbow. The UCL is comprised of the anterior oblique, posterior oblique, and transverse bundle (2,3). Image of the three bundles of the UCL The repetitive valgus stress that occurs across the elbow during throwing can lead to partial and complete tears of the anterior oblique bundle of the UCL.
Within the anterior oblique bundle, there is an anterior and posterior band and the anterior band is thought to be the valgus stabilizer between 30 and 90 degrees of elbow flexion. The anterior band of the anterior oblique bundle of the UCL originates from the medial epicondyle and inserts on the sublime tubercle of the ulna. Ultrasound image of the anterior band of the anterior oblique bundle of the UCL Ultrasound Evaluation Diagnostic tests used to evaluate the UCL include magnetic resonance imaging and ultrasound.
MRI has been found to be highly sensitive for diagnosis of complete UCL tears. Ultrasound is also used in making the diagnosis of a UCL injury. Static measurements and assessment of the UCL can provide information on ligament quality, but the moving valgus stress test (MVST) is a more accurate clinical test.
A moving valgus stress test will measure joint gapping in both elbows and assess for any difference. An increase greater than 1.5mm between an unstressed and stressed elbow typically suggests injury to the ligament. Difference in ulnohumeral joint width with a valgus stress Evaluation of the ulnar collateral ligament is typically assessed with a linear array transducer, but some studies have also used a hockey stick transducer.
Placement of ultrasound transducer to visualize anterior and posterior bands of the anterior UCL The patient is typically placed supine and the elbow is placed at thirty degrees of flexion, as this is the angle the UCL acts as the primary valgus restraint (1,4). The shoulder will be placed in external rotation with 45 degrees of abduction. Starting position for UCL evaluation In order to add valgus stress, an assistant can be used or an attached weight with 150 newtons of force can be added.
If you are experiencing symptoms that may be related to stress ultrasound of the ucl, it is important to see a sports medicine physician. Early evaluation and treatment typically lead to better outcomes. Do not ignore pain or symptoms that are limiting your activity.
*This article is for educational purposes only and does not substitute for professional medical advice. Always consult a qualified healthcare provider.*
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