Valgus extension overload syndrome

Valgus extension overload syndrome is referred to a constellation of symptoms and pathologies commonly seen in over head throwing athletes secondary to high repetitive tensile, shear and compressive forces generated by the overhead throwing motion. The hallmark of valgus extension overload syndrome is injury to ulnar collateral ligament.

Epidemiology

Mostly over head throwing young athletes such as baseball players or javelin throwers.

Clinical presentation

Typical history is an athlete with posterior elbow pain at ball release. Pain reported in posteromedial elbow at full extension or during either acceleration or deceleration phases of pitch. Restriction in full extension is common in throwing athletes in their dominant elbow, however this finding can be more pronounced in this entity.

On physical examination, focal tenderness to palpation over posteromedial elbow join and crepitus are common.  

Symptoms can be reproduced  by placing a valgus stress on the elbow at 20 to 30 degrees of flexion while forcing the elbow into terminal extension.

Pathology

Extreme tensile stress forces applies to the anterior band of the ulnar collateral ligament during forced extension due to high valgus torque. This can injure ulnar collateral tendon either in acute setting or chronically due to micro trauma.  

Other excessive forces during pitch are high shear stresses in posterior compartment causing cartilage injury of the olecranon and compressive forces radiocapitular joint with resultant osteonecrosis and AVN particularly in skeletally immature athletes.  

Radiographic features

On X-ray chronic changes can be detected such as osteophyte formation in the posteromedial olecranon fossa, loose bodies, capitellum osteochondral defects, calcium deposits or ossification of the ulnar collateral ligament.

MRI is the modality of choice for imaging assessment of these patients:

Complete UCL tear is diagnosed by ligament discontinuity and abnormal fiber laxity. Partial thickness tears of UCL are most commonly occur in mid substance and characterized by peri ligamentous edema and varying degrees of fiber discontinuity and increased signal intensity on fluid sensitive images traversing the ligament fibers. Fuid or contrast material insinuating below the ligament along the margin of the bone at the sublime tubercle known as the T sign can be observed due to partial avulsion of the UCL and periosteal stripping.