DOS 2018

186 · DOS Abstracts Comparison of direct and indirect measurements of pulse in the proximal femoral epiphysis using an intracranial pressure monitoring probe Gottliebsen Martin, Mathias Bünger, Ahmed Abdul-Hussein Abood, Vilhelm Engell, Ole Rahbek Ortopædkirurgisk Afdeling E, Århus Universitetshospital; Ortopædkirurgisk Afdeling , Aalborg Universitetshospital Background: Open reduction surgery of severe cases of slipped capital femo- ral epiphysis (SCFE) guided by an intracranial pressure (ICP) monitoring probe inserted in the femoral head is a promising new technique. It has also been pro- posed to do closed reduction (CR) of acute SCFE (the condition that carries the highest risk of avascular necrosis) aided by monitoring pulse in the femoral head using ICP probes inserted through cannulated screws. However, little is known about the actual relationship between different approaches to monitor pulsatile flow in the femoral head. Purpose / Aim of Study: To compare direct and indirect techniques for moni- toring pulse in the femoral head in an experimental animal model. Materials and Methods: Animal model using anesthetized pigs with an im- mature femoral head. Perfusion of the femoral head was confirmed by a pre- operative gadolinium MRI scan. The following measurements were performed using the Codman ICP probe on 9 hip joints; direct measurement using 1.5 mm drill hole and indirect measurements through joint aspiration cannula, 4.5 mm cannulated screw and 6.5 mm cannulated screw. Direct measurements were performed through a drill hole in the adjacent metaphysis. Findings / Results: Pulsatile flow was observed on all measurements. Groups were tested using ANOVA. Pressure was significantly higher using the direct ap- proach (31.6 mmHg) to the femoral head compared to indirect techniques (6.7 - 13.7 mmHg). We were unable to find any difference between the different indirect techniques. Conclusions: Indirect monitoring through cannulated screws may have a lim- ited role for CR of acute SCFE. Because of the more reliable direct monitoring technique we advocate that CR is only undertaken in a setting where conversion to surgical dislocation and direct monitoring of pulse in the femoral head can performed. 127.