Little League Shoulder

Little League shoulder (LLS) is an overuse injury that typically affects young athletes involved in “overhead sports” especially baseball pitchers. It affects players mainly between 11 and 14 years old, which is the period of peak growth of the humeral physis and therefore of maximum susceptibility for injuries. The glenohumeral joint is the most mobile articulation of the human body. In the pediatric humerus, between the proximal epiphysis and metaphysis, is found the proximal humeral growth plate, a cartilaginous structure responsible for the longitudinal growth of the humerus. The proximal humeral physis undergoes the process of endochondral ossification; however the epiphyseal plates do not close until 16–19 years of age, exposing the physis to the risk of damage for a long period. Risk factors for the development of LLS are divided in genetic (skeletal immaturity, muscle weakness, and intrinsic properties of the cartilage and collagen) and environmental (single-sport specialization, poor throwing technique, frequency and intensity of pitching, continuous year-round activity without adequate rest periods, lack of adherence to recommendations on the number of pitches, and playing for more than one team). The major risk factor is the presence of a history of shoulder pain, therefore throwing in a setting of arm fatigue. The throwing movement in baseball is a highly repetitive action that can create great forces of distraction and twisting on the glenohumeral joint, which over time leads to high levels of mechanical stress. During the pitch, the transition from acceleration to deceleration creates rotation stress that is implicated in the pathomechanism of the LLS. LLS usually begins with tenderness and pain in the anterior or lateral proximal humeral area, at first during the throwing movement and then worsening until it becomes continuous. Radiographic imaging is useful to confirm diagnosis, showing a widening of the proximal humeral physis. In more advanced situations, it is possible to find sclerosis, fragmentation, lateral calcification, and cystic formations as well. LLS is reported as a self-limiting condition and the treatment is conservative. A rest period should be followed by an appropriate rehabilitation protocol, which involves a physical therapist, in order to maximize strength and ROM, improving shoulder function and pitching mechanics. Prevention is the key management aspect of LLS: the education of coaches, athletes, and parents is a necessary component of an effective prevention program. The fundamental recommendations include limited number of pitches (during games, weeks, seasons), avoiding participation in multiple leagues, aged-based pitch counts, appropriate number of rest days between pitching appearances, stretching before and after sport, avoiding pitching when arm fatigue or pain is present, and caution in maximum distance throwing.