Shoulder Pain in the Pediatric Baseball Pitcher: Is Continued Throwing Realistic?
Keywords: Little leaguer's shoulder; Pitcher’s shoulder; Throwing athlete.
Figure 1. Overt and subacute fractures of the proximal humerus. (A) Overt fracture. In this patient, the Salter Harris I fracture of the right humerus is clearly apparent for the epiphyseal plate is clearly widened (arrow). Compare with the normal left side. (B) Subacute fracture. Note subtle widening of the epiphyseal plate (arrow) and that the zone of provisional calcification of the humeral head is fuzzy, expanded, and indistinct. Again compare with the normal left side. These findings are characteristic of a subacute Salter Harris I fracture.
The little leaguer's shoulder occurs in young players who undertake pitching in baseball. The bottom line is that the involved individual tends to overdo things for too long a period of time and without adequate rest. The shoulder is a complex part of the body’s anatomy with numerous muscles and ligaments attaching. Without going into anatomic detail, in the little leaguer shoulder there are traction and rotational forces exerted on these structures as the pitcher tries to throw the ball as hard as he can and often with an added twist so that a curve ball is sent on its way. The inherent rotational and shredding forces take their toll on the proximal epiphyseal plate and adjacent structures of the humerus. In essence, it results in a subacute/chronic Salter Harris I/II injury and, in terms of the pathophysiology, first there is the injury, then there is hyperemia and bone resorption, and finally healing with sclerosis. This occurs repeatedly and eventually causes the epiphyseal plate to become widened and the zone of provisional calcification in the adjacent humeral head to become less distinct. Finally, healing occurs and sclerosis of the metaphysis is seen. In the past, the literature has emphasized the more overt of these fractures where epiphyseal plate widening is relatively clear [1-3]. It is the aim of this communication to emphasize the more subtle subacute/chronic plain film imaging findings in little leaguer's shoulder.
When all of the foregoing is considered, there is very little reason to obtain studies such as CT or MR imaging. If, however, they are obtained, the findings are not very striking and on STIR/MR images, there is increased signal of the epiphyseal plate and increased diffuse signal in the adjacent metaphysis (Figure 4).
The little leaguer's shoulder is common and can be diagnosed readily on the basis of the clinical and supportive plain film imaging findings. However, it is important that one appreciate the much more common subtle acute/chronic findings involving the epiphyseal plate and adjacent bony structures. Once this is accomplished, treatment in the form of rest can be instigated. There is very little need for further imaging such as that with CT or MRI. REFERENCES
 Adams JE. Osteochondrosis of the proximal humeral epiphysis in boy baseball pitchers. Calif Med. 1966;105(1):22-5.
 Carson WG, Gasser SI. Little leaguer’s shoulder: a report of 23 Cases. Am J Sports Med. 1998;26(4):575-80.
 Osbahr DC, Kim HJ, Dugas JR. Little league shoulder. Curr Opin Pediatr. 2010;22(1):35-40.