Radiographic pseudosubluxation of the shoulder in pediatric proximal humeral fractures.

This study was undertaken to determine the incidence, need for intervention, and time to resolution of pseudosubluxation of the shoulder in pediatric proximal humerus fractures. One hundred and ninety-nine radiographs (199 x-rays) were analyzed for pseudosubluxation of the shoulder following pediatric proximal humeral fractures. Pseudosubluxation occurs when the center of the humeral head aligns with the inferior one-fourth of the glenoid. Fourteen patients met the inclusion criteria for pseudosubluxation. The nonoperative cohort consisted of 100 females and 93 males and the operative cohort consisted of 3 males and 3 females. Total 14 children out of 199 had pseudosubluxation. Ten pseudosubluxations were seen 7 days postinjury and four were noted immediately after injury. Pseudosubluxation was seen in nine boys (64%) and five girls (36%) in the nonoperative group. Increased relative risk (RR) was associated with: fall >3 m (RR = 25.7; 95% CI, 2.7-244.0), motorized transport (RR = 11.7; 95% CI, 1.41-96.03) and sports injuries (RR = 11.0, 95% CI, 1.2-100). No statistical analysis was conducted on the operative group given the small sample. This study establishes incidence, risk factors and expected clinical course for pseudosubluxation following proximal humerus fractures. The overall incidence in the nonoperative cohort was 7.3%, radiographic evidence of pseudosubluxation resolution was available for (n = 10) patients with 100% resolution by 6 weeks. There were no readmissions or complications in the 14 patients. Pseudosubluxation occurrence was significantly increased in four mechanisms: falls >3 m, sports trauma and motor transportation. This study provides the natural history and risk factors for pseudosubluxation following proximal humerus fractures. Pseudosubluxation is more likely to occur in higher energy fracture mechanisms and will resolve without treatment. Level of Evidence: Level III, retrospective cohort.