Osteonecrosis of the femoral head is a dreaded complication for patients with a slipped capital femoral epiphysis (SCFE). This complication is far more common with acutely displaced and unstable slips. Safely reducing the femoral head back on the neck while preserving blood supply can often be accomplished with closed reduction maintained by in situ cannulated screw fixation, although some recent efforts to treat SCFE have focused on open approaches.
In the June 15, 2016 edition of The Journal, Schrader et al. demonstrate the benefits of using a simple intracranial pressure (ICP) monitoring probe (see photo) inserted through the cannulated screw to measure femoral head perfusion. While using this technique intraoperatively on 26 hips with SCFE, the authors encountered six hips in which there was no blood flow to the femoral head after closed reduction and screw stabilization. In these situations, they performed percutaneous capsular decompression.
The fact that all patients—even those with no initial femoral head perfusion—left the operating room with measurable blood flow confirms the long-held principle that lack of perfusion can be treated with capsulotomy. The ICP device uses waveforms to measure blood flow and is an accurate gauge of perfusion. Moreover, the technology is available in most hospitals with trauma centers or neurosurgery services.
Having researched femoral head perfusion myself as a young orthopaedist and having kept abreast of more recent findings in this area, I think the monitoring protocol described by Schrader et al. is the best yet published to limit the devastating complication of hip osteonecrosis. I feel that if ICP monitors are available, this protocol should be adopted by all centers treating patients with acute SCFE.
Marc Swiontkowski, MD