The epidemiology of primary anterior shoulder dislocations in patients aged 10 to 16 years.

BACKGROUND: Clinical studies of shoulder dislocations typically include adult patients (>16 years of age). Only small case series of patients aged 10 to 16 years are available to guide management.

PURPOSE: Using a cohort of patients aged 10 to 16 years, this study sought to determine (1) the incidence density rate (IDR) of primary anterior shoulder dislocations requiring closed reduction (CR) and (2) the rate of and risk factors for repeat shoulder CR.

STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2.

METHODS: With use of administrative databases, patients aged 10 to 16 years who underwent CR of a primary anterior shoulder dislocation in Ontario, Canada, between April 2002 and September 2010 were gathered. IDRs for the entire cohort and demographic subgroups were calculated. The main outcome, repeat shoulder CR, was sought until September 2012. The cumulative incidence of repeat CR was calculated at multiple time points for the entire cohort and age subgroups. A competing risk model identified risk factors for repeat CR (reported as hazard ratios [HRs] with 95% CIs).

RESULTS: There were 1937 patients aged 10 to 16 years who underwent primary CR (median age, 15.0 years; 79.7% male). The incidence of primary CR was highest among male patients aged 16 years (164.4 per 100,000 person-years), but primary dislocations were rare in 10- to 12-year-old children (n = 115; 5.9% of all dislocations). Repeat CR was observed in 740 patients (38.2%) after a median of 0.8 years; however, the rate of repeat CR was age dependent: it was highest among 14- to 16-year-old patients (37.2%-42.3%) and considerably lower among 10- to 13-year-old patients (0%-25.0%). Male sex (HR, 1.2 [95% CI, 1.0-1.5]; P = .04) and older patient age (HR, 1.2 [95% CI, 1.1-1.3]; P < .001) significantly increased the odds of repeat CR.

CONCLUSION: Among 14- to 16-year-old patients, the rate of primary and recurrent shoulder CR mirrors that of high-risk adults (17-20 years of age) from previously published data; however, the rate of shoulder CR (primary or recurrent) is considerably lower among 10- to 13-year-olds. In addition to older patient age, male sex increased the odds of repeat shoulder CR. Going forward, clinicians should counsel male patients and those aged 14 to 16 years regarding their increased risk of recurrence after the nonoperative management of a primary anterior shoulder dislocation.