Quantifying Risk Factors for Slipped Capital Femoral Epiphysis and Postslip Osteonecrosis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is a disorder of the proximal femoral physis occurring in late childhood and adolescence. Previously postulated risk factors include obesity and endocrinopathies. The purpose of this investigation was to identify risk factors for developing SCFE, as well as postslip osteonecrosis (ON), among the United States pediatric population.

METHODS: A national database investigation was performed using PearlDiver Technologies, Inc., queried for SCFE and ON using International Classification of Disease codes (2010 to 2020). Regression analyses to determine the risk of developing a SCFE, and ON after a patient has already been diagnosed with a SCFE ("postslip"). Propensity matching between SCFE and control groups generated a pseudo-randomization model to compare the relative risk.

RESULTS: There were 11,465 patients with SCFE available in the database, matched with 134,680 controls. After matching, vitamin D deficiency, obesity, hypothyroidism, and growth hormone use were risk factors for developing SCFE [relative risk ranges from 1.42 (95% CI: 1.21-1.39, vitamin D deficiency) to 3.45 (95% CI: 3.33-3.57, obesity)]. ON risk factors were vitamin D deficiency [1.65 (1.26-2.14)] and hypothyroidism [1.49 (1.10-2.07)].

CONCLUSIONS: This United States national database study quantified risk factors of developing an SCFE and postslip ON. Obesity is the most significant risk factor for the development of a slip, but not ON. Growth hormone use, hypothyroidism, and vitamin D deficiency are also risk factors for SCFE development, whereas only the latter two were associated with ON. These findings demonstrate the public health implications of obesity and comorbid conditions in pediatric hip pathology.

LEVEL OF EVIDENCE: Level III.