The UCL is a triangular-shaped ligament on the medial side of the elbow. The strong anterior bundle originates at the medial epicondyle, inserts into the ulna, and maintains most of the valgus stability. Overhead throwing causes valgus stress to the joint and can result in a sprain or tear of the UCL. Athletes with pathology of this ligament may complain of pain in the elbow with throwing that is relieved with rest, unexplained loss of pitch velocity, or a popping sensation during a throw. Careful physical examination should be performed to rule out other causes of pain such as medial epicondylitis, cubital tunnel syndrome, distal biceps tendinitis, joint pathology, or traction apophysitis in skeletally immature patients. Valgus stress applied with the elbow in 25° of flexion that results in joint instability (compared with the contralateral side) and symptoms that are reproducible with milking maneuver may indicate pathology of the UCL.

MRI is a useful study to diagnosis injuries of the UCL; however, because of the small size of the UCL, the sensitivity is low. MR arthrogram is more sensitive and specific than MRI alone and is generally favored when possible. Most patients with injuries of the UCL can be managed conservatively with rest, ice, and nonsteroidal anti-inflammatory drugs. Physical therapy should be initiated to maintain elbow mobility and to keep the shoulder strong. All throwing is restricted for at least 6 weeks from the date of injury or onset of symptoms. If the patient has no pain with valgus stress applied to the elbow at 6 weeks, gradual return to a throwing program can be introduced. A low-grade proximal tear of the UCL portends a favorable prognosis for conservative treatment; high-grade tears at the ulnar insertion are likely to require reconstruction of the UCL if the patient wishes to return to a throwing program.1,2

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).


  1. Bruce JR. Andrews JR. Ulnar collateral ligament injuries in the throwing athlete. J Am Acad Orthop Surg. 2014;22(5):315-325.
  2. Kadri OM, Okoroha KR, Patel RB, Berguson J, Makhni EC, Moutzouros V. Nonoperative treatment of medial ulnar collateral ligament injuries in the throwing athlete. JBJS Rev. 2019;7(1):e6.
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