Prognostic value of dynamic MRI in assessing post-traumatic femoral head vascularity

The vascular status of femoral heads in the post-traumatic period of intracapsular femoral neck fracture (ICFNF) remains uncertain until the patient actually develops avascular necrosis (AVN). Several methods for predicting the viability of femoral head have been reported, that are not effective or widely used because of unreliability, potential complications, and technical difficulties. The present study involved the use of Dynamic MRI (DMRI) in assessing femoral head vascularity to predict AVN.

The role of DMRI was studied prospectively in 30 patients with 31 ICFNF. Fractures were divided in to three types (Type A, B, or C) based on the femoral head vascularity shown by dynamic curve patterns on MRI evaluation. Type A was preserved vascularity, Type B was some decrease in vascularity but still viable while Type C was significantly reduced vascularity. These were followed-up for 6 months to 2 years to observe the final outcome in terms of union, non-union, or AVN.

We found that Type A curves correlate well with vascular status and Type C curves correlate well with poor vascularity of the femoral heads. No AVN was seen in any of Type A (13/31) or Type B (eight out of 31). Five cases showed AVN and all of them were of Type C dynamic curves.

Dynamic MRI is a reliable tool to evaluate vascularity of femoral heads and thus reduces the uncertainty of outcome of treatment of ICFNFs. DMRI can be a useful tool to formulate a treatment algorithm in management of ICFNF.