Department of Radiology, University of Texas Medical Branch; Galveston, TX, USA
Corresponding Author: Leonard E. Swischuk, MD
Department of Radiology
University of Texas Medical Branch
301 University Blvd
Galveston, TX 77555, USA
The little leaguer's shoulder is a common and growing problem. Diagnosis can be made on the basis of clinical and plain film imaging findings. In the overt case, diagnosing the condition from plain films is relatively straightforward. However, with the more common subacute/chronic fracture, plain film imaging findings are more subtle and elusive. It is the purpose of this communication to illustrate these subtle plain film imaging findings.
Level of Evidence: V; Descriptive review/Expert opinions.
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.
Figure 2. Little leaguer's shoulder: Spectrum of subacute/chronic fractures. (A) Note widening of the epiphyseal plate and that the zone of provisional calcification of the humeral head is less distinct and somewhat fuzzy (arrow). (B) Normal side for comparison. (C) In this patient, epiphyseal plate widening is very subtle (arrow). However, indistinctness of the zone of provisional calcification of the humeral head and the adjacent humeral metaphysis is present. (D) Normal side for comparison. (E) In this patient the epiphyseal plate is not really widened. However, the zone of provisional calcification of the epiphysis and the adjacent metaphysis are both fuzzy and indistinct. These are very subtle findings of a little leaguer's shoulder. (F) Normal side for comparison.
The little leaguer's shoulder represents a Salter Harris I/II fracture of the proximal humerus and when epiphyseal widening is clearly visible, the fracture is not difficult to identify (Figure 1A). However, this is not the most common scenario. The more common scenario is that associated with a subacute/chronic fracture where the epiphyseal plate widens a little and the smooth, relatively sharp zone of provisional calcification of the humeral head becomes less distinct. Overall, the findings are subtle and more difficult to identify (Figure 1B). It is this, constellation of findings of the little leaguers shoulder which is emphasized in this communication. A spectrum of the findings is presented (Figures 2 & 3).
Initially these patients present with shoulder pain, and the first thought in the case of a baseball pitcher is that one is dealing with the little leaguer's shoulder. Then, if plain film imaging supports this diagno- sis, nothing else needs to be done except to put the patient's shoulder to rest. It has been shown that a rest period of 3 months can lead to enough improvement to allow the patient to pitch again [1,2]. However, the real problem is making sure that they do rest because the athletic mentality, both the individual’s and the family’s, is not one that supports rest. This is one of the biggest problems with little leaguers shoulder and with other entities, such as little leaguer's elbow. Therefore, continued endless throwing is not acceptable. There must be periods of rest, and when pitching occurs, it must be for a few innings and not the whole game.
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.
 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.
Figure 3. Little leaguer's shoulder: Metaphyseal sclerosis. (A) In this patient notice metaphyseal sclerosis along with widening of the epiphyseal plate in the left shoulder (arrow). (B) Enlarged view more clearly demonstrates the metaphyseal sclerosis. (C) In this patient, there is epiphyseal plate widening (arrow), but, in addition, the zone of provisional calcification through the humeral head is a little indistinct, and there is sclerosis of the metaphysis adjacent to the epiphyseal plate. (D) Normal side for comparison. Slight increased sclerosis of the metaphysis all along the epiphyseal plate is a normal finding. In the patient’s affected shoulder, the area of sclerosis is more extensive, larger, and not along the epiphyseal plate.
Figure 4. Little leaguer's shoulder: MRI findings. (A) Plain films. Note that the epiphyseal plate is widened and that the zone of provisional calcification through the humeral epiphysis is a little more fuzzy and indistinct than it is on the normal side. (B) Close up view demonstrates a small metaphyseal fracture fragment (arrow). This constitutes a subacute Salter Harris II fracture. (C) MR STIR image. Note less than striking increased signal throughout the epiphyseal plate and diffusely through the adjacent proximal humeral metaphysis.