A Simple Modified Technique for In-Situ Screw Fixation in Slipped Capital Femoral Epiphysis.

Abstract

In-situ pinning has a definite role in the management of slipped capital femoral epiphysis (SCFE). We describe a modified technique for in-situ screw fixation on a regular radiolucent operating table which avoids certain complications innate with the existing techniques. Sixty consecutive hips which underwent either in-situ fixation for SCFE (28 hips) or prophylactic fixation of the contralateral hip (32 hips) by the modified technique were analysed. The femoral head was divided into three zones (A-central, B-middle, C-peripheral) of equal circles. The zone of the screw was noted in both AP and lateral views. The angle between the physeal line and the screw in AP(SAP) and lateral (Slat) view, and the distance from screw tip to articular surface in both views were measured. In AP view, 55/60 (91.6%) screws were in zone-A, and five were in zone-B. In the lateral view, 56/60 (93.3%) screws were in zone-A, and four were in zone-B. There was no screw placed in zone-C in either of the views. The average deviation was < 15° in AP view and < 7° in lateral view from the ideal placement. The mean distance from the screw tip to the articular margin in AP was 5.15mm and that in lateral was 6.15mm. The interobserver agreement rate was found to be 0.8. No patient had intraoperative breakage of a drill bit or joint penetration, avascular necrosis, chondrolysis or screw-related complications at a minimum follow-up of one year. In-situ pinning on the radiolucent table is safe and has distinct advantages. The modified technique of in-situ screw fixation adds to the safety and accuracy of the procedure. Level IV.