Medial instability of the elbow: findings on valgus load radiography and MRI in 16 athletes.

Medial discomfort of the elbow in athletes can be due to valgus instability after acute ligament rupture or attenuation of the medial collateral ligament caused by repetitive microtrauma during overhead throwing. We studied 16 athletes with medial instability of the elbow due to insufficiency of the medial collateral ligament. 4 patients had sensory ulnar nerve symptoms, of whom 2 had abnormalities of the ulnar nerve on electromyography. 13 showed an increase in the ulno-humeral joint space on dynamic radiography under valgus load. MRI of 10 of these 13 elbows revealed rupture of the medial collateral ligament or avulsion of the medial collateral ligament. Dynamic radiography under valgus load seems to be of value for the diagnosis of chronic medial collateral ligament insufficiency.