لايوجد

Abstract

In many regwns of the body, there are rich anastomoses of blood

vesse Is wIII.C I1 provt.de a wt.de margm.

of saft y

.m tI1e event of ,vascIular

interruption. However there are certain regions with less liberal bllood supply. The femoral head is an example of such regions. Femoral head necrosis is caused by interruption or the blood supply especially the superior retinacular vessels. The most common causes of avascular necrosis or the femoral h ad

are major trauma like, fracture neck femur, dislocation or the hip joint Ld fracture of the acetabulum. The pathological changes of bone necrosis include medullary

necrosis and juxta-articular lesions. The extent of necrosis varies frLn small foci to large areas involving most of the width of the medulllry cavity. The pathogenesis of necrosis is related to tire cause or the

predisposing factor. Interruption of the superior retinacular vessels whibh I are the main blood supply to the femoral head is responsible for the

development of necrosis.

Clinically the condition may be suspected if patients with a predisposing factor develop pain and limitation of movements in the hip. Unfortunately, radiographs cannot help with early diagnosis. When radiographic changes do occur, it is usually late and they are due to tile reaction of living tissue to the ischaemia. Bone marrow pressure measurement is an import.t11t dmgnostic to0l especially in the preradiological and preclinical stage Intramedullary venot,'Taphy and arteriography demonstrate th

venous and arterial networks that drain and supply the femoral head.

The use of radioacttve isotopes and core biopsy can determine th viability of' the head much earlier than x-rays.