Little League Shoulder

Inconsistencies and Imprecision in the Nomenclature Used to Describe Primary Periphyseal Stress Injuries: Towards a Better Understanding

Stress injuries involving the epiphyseal-physeal-metaphyseal complex affecting the extremities of child and adolescent athletes were first described in the early 1950s. Initially observed in Little League baseball players, these injuries are now known to affect skeletally immature athletes in a variety of sports that involve high-impact repetitive overuse activities. Collectively known as primary periphyseal stress injuries, they may affect the long bones around the shoulder, elbow, wrist, hand, hip, knee, ankle, and foot of young athletes. These injuries respond well to timely treatment and relative rest, while non-compliance with non-operative treatment can produce skeletal growth disruption and resultant limb deformity. A major concern raised from the existing literature on primary periphyseal stress injuries is the long history of inconsistent and imprecise terminology used to describe these injuries. A variety of terms have been used to describe primary periphyseal stress injuries, including those which potentially misinform regarding who may be affected by these injuries and the true nature and pathophysiologic mechanisms involved. These imprecisions and inconsistencies arise, at least in part, from a misunderstanding or incomplete understanding of the nature and mechanism of primary periphyseal stress injuries. In this article, we examine the inconsistent and imprecise nomenclature historically used to describe primary periphyseal stress injuries. We also offer a novel framework for understanding the pathophysiologic mechanisms behind these injuries, and provide suggestions for more standard use of terminology and further research moving forward.

Primary Periphyseal Stress Injuries in Young Athletes: A Systematic Review

BACKGROUND

Overuse injuries are common in sporting children and adolescents. These injuries are a particular concern when they involve the epiphyseal-physeal-metaphyseal (EPM) complex given their potential to disturb skeletal growth. Specifically, the limits of mechanical tolerance of the EPM complex to repetitive stress may be exceeded by the intense and continuous training characteristic of many youth sports today.

OBJECTIVE

This article describes the present status of knowledge on the occurrence and outcome of primary periphyseal stress injuries (PPSIs) affecting the EPM complex in the extremities of children and adolescents involved in youth sports.

METHODS

A comprehensive review of the sports medicine literature was conducted to determine the nature and extent of PPSIs affecting the EPM complex of the extremities among youth sports participants and the potential for consequent skeletal growth disturbance and resultant limb deformity associated with these injuries.

RESULTS

Our initial search uncovered 128 original published scientific articles reporting relevant data on PPSIs. There were 101 case reports/series, 19 cross-sectional, 1 case-control, and 7 cohort studies with relevant data. The case reports/series studies reported 448 patients with PPSIs involving the extremities. Children and adolescents representing a variety of high impact repetitive youth sports activities-including baseball, badminton, climbing, cricket, dance, gymnastics, rugby, soccer, swimming, tennis, and volleyball-may sustain PPSIs involving the shoulder, elbow, hand and wrist, knee, and ankle and foot. Although incidence data from prospective cohort studies are lacking, data arising from cross-sectional studies suggest that PPSIs may be common in select groups of youth athletes-including the shoulder in baseball players (0-36.6%), wrist in gymnasts (10-83%) and platform divers (52.6%), and fingers in rock climbers (5-58%). Notably, not all stress-related skeletal changes detected on imaging were symptomatic in these studies. When diagnosed and treated with an appropriate period of rest and rehabilitation, most patients studied were able to return to their sport activities. However, our data also show that 57/448 PPSIs (12.7%) produced growth disturbance, and that 28/448 patients (6.2%) underwent surgery for their injuries. Absence of treatment, delayed presentation and diagnosis, and non-compliance with a rest regimen were common in cases that produced growth disturbance.

CONCLUSIONS

PPSIs may affect the extremities of children and adolescents engaged in a variety of youth sports, especially at advanced levels of training and competition. Most skeletally immature patients with PPSIs respond well to timely treatment; however, in extreme cases, PPSIs can progress to produce skeletal growth disruption which may necessitate surgical intervention. Clearly, establishing the early diagnosis of PPSIs and providing timely treatment of these injuries are needed to ensure the skeletal health of youth sports participants. Rigorous prospective longitudinal epidemiological and imaging studies designed to provide incidence rates of PPSIs and to determine the effect of PPSIs on long-term skeletal health are also necessary.

Diagnosis and Management of Little League Shoulder: A Systematic Review

Background:

Little League shoulder (LLS) is an overuse injury characterized by throwing-related pain that commonly presents in adolescent male athletes. Investigations into the optimal duration of rest from throwing and protocols for graduated return to sports (RTS) are lacking.

Purpose:

To summarize the current literature with respect to the diagnosis, management, RTS, and return to throwing for LLS.

Design:

Systematic review; Level of evidence, 4.

Methods:

The databases EMBASE, MEDLINE, and PubMed were searched between inception and April 22, 2020. References of retrieved records were reviewed for potentially eligible studies. English-language studies that reported the diagnosis and/or management of LLS in children or adolescents were included. Studies of animals or cadavers, review articles, and non—peer reviewed records were excluded. Data were summarized narratively using descriptive statistics.

Results:

Overall, 23 studies (21 level 4 studies, 2 level 3 studies) met the criteria for a total of 266 participants with a weighted mean age of 12.8 years (range, 7.4-17 years). Treatment recommendations evolved from prolonged rest and complete cessation of throwing to shorter periods of rest and graduated RTS. Less than half (11/23) of studies reported specific criteria to RTS; 1 case report discussed a coaching strategy to resume throwing, and 1 case report discussed a regimented throwing program. The proportion of participants returning to any sport participation was 94.0% (n = 157/167). The proportion returning to their preinjury level of sport was 92.5% (n = 123/133). Upon RTS, 18.7% (n = 35/187) of participants experienced a recurrence of symptoms. Premature closure of the epiphysis was reported in 1 participant.

Conclusion:

Young athletes with LLS may return to play after a period of rest, and a high proportion return to their preinjury level of sport. Further prospective studies are warranted to develop evidence-based, graduated RTS protocols and to better capture any long-term sequelae of the condition.