summary Little Leaguer's shoulder is an overuse injury occuring in young baseball pitchers resulting in epiphysiolysis of the proximal humerus (a Salter Harris Type 1 injury). Diagnosis is made with radiographs of the shoulder showing a widened proximal humerus physis in comparison to contralateral shoulder. Treatment is cessation of throwing, followed by PT and progressive throwing program after sufficient rest. Epidemiology Demographics seen in skeletally immature overhead athletes adolescent pitchers 10% of all shoulder pain in pediatric patients is related to throwing occasionally seen in tennis players males > females age 11-16 years Etiology Pathophysiology mechanism repetitive torsional and distractive stresses at the physis (Saltar Harris 1 injury) pitching phases late cocking shoulder is maximally externally rotated, leading to extreme rotatory torque through the growth plate, approximately 400% greater than the fragile physeal cartilage can tolerate deceleration opposing forces of forward arm motion and rotator cuff results in excessive eccentric physeal stress breaking pitches are implicated number of pitches is the most important factor cell biology hypertrophic zone of the physis is affected weakest portion of the growth plate Presentation History decreased pitch velocity decreased pitch accuracy Symptoms diffuse arm and shoulder pain with throwing worse in late cocking or deceleration phases pain resolves with rest Physical exam point tenderness over lateral proximal humerus, at the shoulder physis pain reproduced with shoulder rotation glenohumeral internal rotation deficit patients with GIRD are three times more likely to experience recurrent symptoms Imaging Radiographs recommends views AP in external rotation, scapular Y and axillary views contralateral shoulder can obtained for comparison in subtle cases findings widened proximal humerus physis in comparison to contralateral shoulder metaphyseal bony changes may have normal radiographs (17%) MRI findings edema around physis may be helpful to rule out other pathology labral tear partial articular-sided rotator cuff tears (less likely) Treatment Nonoperative cessation of throwing, followed by PT and progressive throwing program after sufficient rest indications mainstay of treatment technique refrain from pitching for 3 months start progressive throwing program only after symptom resolution physical therapy rotator cuff strengthening posterior shoulder capsule stretching core strengthening progressive throwing program start with short tosses at low velocity slowly progress distance and velocity of throws Prevention proper pitching mechanics using pitching coaches discourage breaking ball pitches until skeletal maturity enforcement of pitch counts as well as days off for shoulder rest avoid year-round pitching Pitch Count Recommendations Age (years) Pitches per Game Max Games per Week 8-10 52 2 11-12 68 2 13-14 76 2 15-16 91 2 17-18 106 2 Complications Premature growth arrest of proximal humeral epiphysis can cause growth arrest angular deformity