Search

Background: Femoral head overcoverage by a deep and retroverted acetabulum has been postulated as a mechanical factor in slipped capital femoral epiphysis (SCFE). We assessed acetabular depth, coverage, and version in the hips of patients with unilateral SCFE; in the contralateral, uninvolved hips; and in healthy control hips., Methods: Thirty-six patients affected by unilateral SCFE were matched to 36 controls on the basis of sex and age. The acetabular depth-width ratio (ADR), the lateral center-edge angle (LCEA), the anterior and posterior acetabular sector angle (ASA), and version (10 mm distal to the highest point of the acetabular dome and at the level of the femoral head center) were assessed on computed tomography (CT). A repeated-measures analysis of variance was used to assess differences among the SCFE, contralateral, and matched-control hips. Pairwise comparisons were conducted using Bonferroni correction for multiple comparisons., Results: The mean coronal ADR was significantly lower in the hips affected by SCFE (311.6) compared with the contralateral hips (336.1) (p = 0.001) but did not differ from that of controls (331.9) (p = 0.08). The mean LCEA was significantly lower in the SCFE hips (29.8°) compared with the contralateral hips (33.7°) (p < 0.001) but did not differ from that of controls (32.2°) (p = 0.25). The mean anterior ASA did not differ between the SCFE hips (65.0°) and the contralateral hips (66.0°) (p = 0.68) or the control hips (64.5°) (p = 1.00). The mean posterior ASA in the SCFE hips (92.5°) was significantly lower than that in the contralateral hips (96.5°) (p = 0.002), but no difference was observed between the SCFE hips and controls (96.0°) (p = 0.83). The acetabulum was retroverted cranially in the SCFE hips compared with the contralateral hips (2.7° versus 6.6°; p = 0.01) and compared with controls (2.7° versus 9.6°; p = 0.005). A lower mean value for acetabular version at the level of the femoral head center was also observed in the SCFE hips compared with the contralateral hips (13.9° versus 15.5°; p = 0.04) and compared with controls (13.9° versus 16.0°; p = 0.045). No significant difference (p > 0.05) in acetabular measurements was observed between the contralateral and control hips., Conclusions: In SCFE, the acetabulum has reduced version but is not deeper, nor is there acetabular overcoverage. Additional longitudinal studies will clarify whether acetabular retroversion is a primary abnormality influencing the mechanics of SCFE development or an adaptive response to the slip. Our data suggest that the contralateral, uninvolved hip in patients with unilateral SCFE has normal acetabular morphology., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: The purposes of this study were to validate an innovative, percutaneous method of monitoring femoral head (epiphyseal) perfusion intraoperatively in patients with slipped capital femoral epiphysis (SCFE) and to investigate an association between intraoperative perfusion and the subsequent development of osteonecrosis., Methods: A percutaneous screw fixation technique for SCFE was utilized. A fully threaded, cannulated, stainless-steel 7.0-mm screw was inserted into the epiphysis. The guidewire was removed, and a sterile intracranial pressure (ICP) probe was placed through the screw such that the tip was in the epiphyseal bone past the end of the screw. Intraoperative epiphyseal pressure and waveform were recorded. A prospective analysis of patients undergoing percutaneous screw fixation for unstable or stable SCFE or for prophylactic treatment with the use of this technique to evaluate femoral head perfusion was performed., Results: This technique was used in 23 patients (29 hips, including 15 hips with unstable SCFE, 11 with stable SCFE, and 3 treated prophylactically). Three hips (2 with unstable SCFE and 1 treated prophylactically) in 2 patients were eliminated from the analysis because of technical problems with the ICP monitor. All hips with stable SCFE and the prophylactically treated hips had measurable pulsatile flow that was synchronous with the patient's heart rate at the initial time of probe insertion. Seven patients (7 hips) with unstable SCFE had measurable, pulsatile flow with initial insertion of the probe, and 6 patients (6 hips) with unstable SCFE had no measurable flow. We were able to demonstrate perfusion following a percutaneous capsular decompression in the patients with no initial flow. All patients left the operating room with measurable femoral head blood flow. At a mean follow-up of 1.6 years for hips with stable SCFE and 2.0 years for those with unstable SCFE, no hip subsequently developed radiographic evidence of osteonecrosis of the femoral head. No complications from the use of the ICP monitor occurred., Conclusions: Femoral head perfusion in patients with SCFE can be measured intraoperatively using this technique. Demonstrating femoral head perfusion before leaving the operating room was associated with the absence of osteonecrosis postoperatively., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.)