Early prediction of femoral head avascular necrosis following neck fracture

Abstract

Femoral neck fracture puts at risk functional prognosis in young patients and can be life-threatening in the elderly. The present study reviews methods of femoral head vascularity assessment following neck fracture, to address the following issues: what is the risk of osteonecrosis? And what, in the light of this risk, is the best-adapted treatment to avoid iterative surgery? Femoral head vascularity depends on retinacular vessels and especially the lateral epiphyseal artery, which contributes from 70 to 80% of the femoral head vascular supply. Fracture causes vascular lesions, which are in turn the prime cause of necrosis. Other factors combine with this: hematoma tamponade effect, reduced joint space and increased pressure due to lower extremity positioning in extension/internal rotation/abduction during surgery. Head deformity is not due to direct cell death but to the repair process originating from the surrounding living bone. In post-traumatic necrosis, proliferation rapidly invades the head, with significant osteogenesis. Pathologic fractures occur at the boundary between the new and dead bone. Many techniques have been reported to help assess residual hemodynamics and risk of necrosis. Some are invasive: superselective angiography, intra-osseous oxygen pressure measurement, or Doppler-laser hemodynamic measurement; others involve imaging: scintigraphy, conventionnal or dynamic MRI. The future seems to lie with dynamic MRI, which allows a new classification of femoral neck fractures, based on a non-invasive assessment of femoral head vascularity.

Assessment of Osteonecrosis in the Presence of Instrumentation for Femoral Neck Fracture Using Contrast-Enhanced MAVRIC Sequence

“…The results showed a large percentage SI enhancement at the interface of the ON and at the surrounding normal bone marrow at 3 and 12 months postoperatively. This increase in uptake may be attributable to vascular regeneration and reparative tissue in the transitional zone, as already described in previous literature [7,23,30].…”

Risk Stratification for Avascular Necrosis of the Femoral Head After Internal Fixation of Femoral Neck Fractures by Post-Operative Bone SPECT/CT

“…Given that radiotracer uptake represents blood supply, normal uptake on bone SPECT/CT indicates intact vascularity, which is essential for the viability of the ipsilateral femoral head after surgical fixation of a femoral neck fracture [1]. Therefore, prediction of fracture healing without AVN after internal fixation of the femoral head on the basis of normal uptake on bone SPECT/CT within 2 weeks of surgery is reasonable.…”

“…Femoral neck fractures are not only a life-threatening lesion in the elderly, with a mortality rate of 20-30 % [1], but also cause serious disability in the young. The increasing proportion of the older population has been accompanied by an increase in the incidence of femoral neck fractures [2].…”

Outcome analysis of neglected neck of femur treated with non vascularised fibular graft and cancellous screws

“…The intracapsular hematoma is also implicated with development of avascular necrosis of femoral head. Femoral neck fracture in young adults are associated with higher incidence of osteonecrosis, with rate as high as 12-86% [4] . As literature says, anatomical reduction and stable fixation restore the vascularity and reduce the chances of AVN.…”