Increased acetabular depth may influence physeal stability in slipped capital femoral epiphysis hip

Background: Multiple mechanical factors affecting the hip have been associated with the development of slipped capital femoral epiphysis (SCFE). Whether acetabular depth plays a role in the development of a SCFE has not been elucidated. Questions/purposes: (1) What is the prevalence of a deep acetabulum in SCFE? (2) Is the presence of a deep acetabulum associated with physeal instability? (3) Is the presence of a deep acetabulum associated with the occurrence of a contralateral SCFE? Methods: We retrospectively reviewed 232 patients (156 males) who presented with a unilateral SCFE. Fifty (22%) subsequently developed a contralateral SCFE. The involved and uninvolved sides were evaluated for the presence of a deep acetabulum (DA). Preoperative radiographic parameters, slip stability, development of a contralateral SCFE, and demographic factors were then compared between patients with and without DA. Results: DA was present in 120 hips (52%) with a SCFE. DA was more common in females (55 of 76 [72%]) than males (65 of 156 [42%]). Patients with DA presented with a higher lateral center-edge angle (33 versus 31), slip angle (52 versus 43), and with a lower body mass index (28.1 versus 30.0 kg/m ² ). Increased acetabular depth was more common in patients with an unstable SCFE (29 of 41 [71%]) than those with a stable SCFE (91 of 191 [48%]). The presence of DA either on the affected side or the contralateral side did not predict a contralateral SCFE. Conclusions: Despite not predicting a contralateral SCFE, DA may influence physeal stability if a SCFE does develop. Therefore, the contralateral hip with DA should be closely monitored. Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.