Little League Shoulder: Causes and Solutions
case presentation
A healthy 12-year-old male baseball player presents to your office with left upper arm pain that has been ongoing for 2 to 3 months. He is left hand dominant. The pain has been progressive and worse whenever he pitches. His coaches have been trying to limit his pitch counts, but he continues to have pain when throwing. He has tenderness over his proximal upper arm region to palpation, but otherwise a normal examination. His x-rays show widening of the proximal humerus when compared to the opposite side. What is the most likely diagnosis?
A. Little League elbow
B. Proximal humeral epiphysiolysis
C. Labral tear
D. Kohler’s disease
introduction
Proximal humeral epiphysiolysis, or Little League shoulder, is common in adolescent players and is characterized by throwing related pain over the proximal humerus. Pain related to throwing accounts for 10 percent of all shoulder pain in pediatric patients [1].
Little league shoulder is most commonly seen in youth throwing athletes between 11 and 16 years of age with the peak age at 13. Since growth plate closure occurs between 18 and 21 years old, injuries can theoretically occur until that age [3]. While most common in male baseball pitchers, the condition can occur in females, youth catchers, other baseball positions players, and tennis players.
Repetitive loading of the humerus with the torque and distraction forces of throwing can cause microtrauma and irritation of the proximal humeral physis, which is substantially weaker than the surrounding bone. According to high speed motion analysis studies, youth pitchers can generate substantial forces at the shoulder. It is believed that the rotational force has a larger role than the distractional force in developing the condition [3].
The pathophysiology leading to Little League shoulder is believed to be the significant external rotational torque on the humeral shaft during the final part of the arm-cocking phase, just before the acceleration phase. This torque likely leads to the deformation of the proximal humeral epiphysis cartilage, which eventually leads to proximal humeral epiphysiolysis [4].
history and physical examination
As with most sports injuries, history and physical examination play an important role in proper diagnosis. There may or may not be one throw or inciting event. Altering mechanics may increase the risk of injury by distributing forces throughout the humerus differently. Forces may also be altered if a recent increase in height has occurred. The athlete usually complains of progressively worsening, non-focal shoulder pain with throwing [1].
Pain will usually improve with rest. Full effort throwing or throws from a distance can cause symptoms frequently. As symptoms advance, pain can develop with simply lifting the arm; there may even be pain at rest. Additional symptoms can include diminished throwing accuracy and/or velocity [4].
Palpation reveals tenderness over the lateral proximal humerus in the area of the patient’s proximal humerus physis [1]. There may be limitations with shoulder motion and decreased internal rotator compared to the opposite side. Weakness with rotator cuff testing or with labral testing such as O’Brien’s test may be present, though this is not well studied.
imaging
The diagnosis of proximal humeral epiphysiolysis is made by radiograph. Widening of the proximal humeral physis is seen best on plain radiograph using an anteroposterior view of the shoulder with the arm in external rotation (FIG). However, such changes may be found in asymptomatic pitchers and clinical correlation with symptoms is important [7]. Widening may be subtle and comparative radiographs of the opposite shoulder may be helpful to confirm the diagnosis, as with other pediatric injuries related to throwing in the elbow. Chronic changes such as sclerosis, demineralization, and fragmentation can also be seen.
One study looked at 2055 baseball players between the ages of 9 and 12. They found that 13.4% reported shoulder pain in their throwing arm. Of those patients with pain, 41 agreed to have x-rays taken of his or her shoulder. Of these 41, 36.6% had findings of Little League shoulder on x-ray. While this is a small sample size, this places the prevalence of Little League shoulder among all baseball players in this study, with and without pain, at 4.9% [6].
Figure 1. Radiographs of Little League Shoulder. Courtesy of Craig Young, MD.
Diagnostic musculoskeletal ultrasound (MSK US) is commonly used to help diagnose this condition in clinical settings with experienced ultrasonographers [5]. Although widening of the growth plate is difficult to quantify, MSK US demonstrates increased hypo-echoic swelling surrounding the affected shoulder that is not seen on the contralateral side. MRI is useful for confirming the diagnosis if plain radiographs are not diagnostic.
treatment
Management is non surgical and there are combinations or rest and physical therapy. If treated at the onset of pain, discontinuation of activities that cause pain can prevent an overt stress fracture of the proximal humerus’s growth plate. Prior to stress fracture occurring, pain often resolves with rest.
The treatment for Little League shoulder is 2 to 5 months of rest and discontinuation of overhead activity. Treatment can advance to core muscle and rotator cuff strengthening with a physical therapist once there is no pain at rest. Once the range of motion, strength, and scapular motion returns to normal, then a gradual return to throwing by participation in a structured throwing program and subsequent return to competition can follow [4]. There is paucity of data in regards to treatment and further randomized trials are needed.
Figure 2. Chart showing trials of treatment with past studies and case reports with Little League Shoulder. Adopted from [8].
The treatment for Little League shoulder is 2 to 5 months of rest and discontinuation of overhead activity. Treatment can advance to core muscle and rotator cuff strengthening with a physical therapist once there is no pain at rest. Once the range of motion, strength, and scapular motion returns to normal, then a gradual return to throwing by participation in a structured throwing program and subsequent return to competition can follow [4]. There is paucity of data in regards to treatment and further randomized trials are needed.
Some providers may opt to follow up with plain radiographs to reassess healing. Follow up MRIs are not common practice.
Image 3: Management of Little League shoulder part 2. Adopted from [8].
Summary
In summary, Little League shoulder (LLS), or proximal humeral epiphysiolysis, is an overuse injury com- mon in adolescent baseball players characterized by throwing-related pain over the proximal humerus. Current evidence to manage LLS supports a return to throwing after a period of rest. Almost all individuals return to pre-injury participation. Prospective longitudinal studies are warranted to identify potential long-term sequelae of the condition and to determine an optimal RTS protocol.
CASE CONCLUSION
Little league shoulder, or proximal humeral epiphysiolysis, is most commonly seen in youth throwing athletes between 11 and 16 years of age with the peak age at 13. The diagnosis of proximal humeral epiphysiolysis is made by radiograph. Widening of the proximal humeral physis is seen best on plain radiograph using an anteroposterior view of the shoulder with the arm in external rotation. It is unlikely to be Little League elbow due to the pain being in his shoulder. It is very rare for children that are 13 to have a labral tear and there is no mention of special testing to make this more likely. Kohler’s disease is a disease of the foot.
– More Little League Shoulder from Wiki Sports Medicine: https://wikism.org/Humeral_Head_Epiphysiolysis
– Sports Med Review Shoulder Pain: https://www.sportsmedreview.com/by-joint/shoulder/
References
- Osbahr DC, Kim HJ, Dugas JR. Little league shoulder. Curr Opin Pediatr. 2010 Feb;22(1):35-40.
- Ramappa AJ, Chen PH, Hawkins RJ, Noonan T, Hackett T, Sabick MB, Decker MJ, Keeley D, Torry MR. Anterior shoulder forces in professional and Little League pitchers. J Pediatr Orthop. 2010 Jan-Feb;30(1):1-7.
- Sabick MB, Kim YK, Torry MR, Keirns MA, Hawkins RJ. Biomechanics of the shoulder in youth baseball pitchers: implications for the development of proximal humeral epiphysiolysis and humeral retrotorsion. Am J Sports Med. 2005 Nov;33(11):1716-22.
- Casadei, Kyle, and John Kiel. “Proximal humeral epiphysiolysis.” (2018).
- Pai DR, Thapa M. Musculoskeletal ultrasound of the upper extremity in children. Pediatr Radiol 2013; 43 Suppl 1:S48.
- Heyworth BE, Kramer DE, Martin DJ, et al. Trends in the Presentation, Management, and Outcomes of Little League Shoulder. Am J Sports Med 2016; 44:1431.
- Murachovsky J, Ikemoto RY, Nascimento LG, et al. Does the presence of proximal humerus growth plate changes in young baseball pitchers happen only in symptomatic athletes? An x ray evaluation of 21 young baseball pitchers. Br J Sports Med 2010; 44:90.
- Bednar, E. Dimitra, et al. “Diagnosis and Management of Little League Shoulder: A Systematic Review.” Orthopaedic Journal of Sports Medicine 9.7 (2021): 23259671211017563.
