ARRS Case of the Week- Apr 16, 2018

PEDIATRIC RADIOLOGY: Musculoskeletal Radiology

Case Author: Krista L. Birkemeier, MD, Cincinnati Children’s Hospital Medical Center

History

13-year-old male baseball player with right shoulder pain for 3 months who reports no trauma when asked about it.

Imaging Findings

Frontal radiograph of the right shoulder (A) shows mild widening and irregularity (arrow) of the lateral aspect of the proximal humeral physis. The medial aspect of the physis is preserved. Coronal STIR MR image (B) shows localized widening and hyperintensity (arrow) of the lateral aspect of the proximal humeral physis. Coronal T1-weighted MR image (C) shows widening (arrow) of the lateral aspect of the humeral physial plate.

Diagnosis

Little League shoulder.

Teaching Points

Hill-Sachs deformity occurs after anterior shoulder dislocation. A posterolateral humeral head compression fracture occurs as the humeral head hits the anteroinferior lip of the glenoid fossa.

Little League shoulder refers to proximal humeral epiphysiolysis due to repetitive microtrauma in overhead activities. The mechanism is torque or rotational force and distraction on the physial plate, which is the weakest structure in a skeletally immature joint. Clinically, Little League shoulder presents with lateral shoulder pain. The diagnosis is usually made with shoulder radiographs, but in early stages, MRI can be helpful.

Rotator cuff tears in children are rare because the cuff is more elastic, has more tensile strength, and lacks the degenerative changes that occur in adults. Rotator cuff tears occur in adolescent athletes and are most commonly rim-rent tears (partial articulation-side tears).

Salter-Harris type 1 fractures of the proximal humerus are rare and tend to occur in children younger than 5 years. Differentiating a fracture from Little League shoulder is important to treatment. The former requires immobilization for 4–6 weeks, but the latter may require rest for several months.

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