Avascular necrosis of the head of femur (ANHF)
Avascular necrosis of the head of femur (ANHF) is associated with disturbed blood in the vascular system carrying the nutrients into this site. Such phenomena appear because of compression or convolution at arterial occlusion with a small clot or at trauma.
Long-lasting angiospasmand increased blood viscosity, venostasis and outflow disorder decreases substantially the trophism of the head of femur. In this regard, inner pressure is increased, and ischemia is developed. This provokes disorders of mechanical properties of bone tissue. As a result, cavities are formed. Subsequently, the bone starts to deform. When breaking, the articular cartilagedelaminates from it.
The etiology of this disease isstill unknown. In the opinion of many specialists, long-lastingsevere alcohol consumption contributes to the pathogenesis of the disease. Long-term treatment with high dose corticosteroid hormones may provoke a necrosis as well. Among popular factors provoking the state it should also be noted traumas such as fractures, dislocations, hurts. (Avascular) bone necrosis may also begin due to usual tiredness, stress, emotional overload. High dose radiation exposure may also be the provoking factor. Such a term as idiopathic necrosis is used in medical practice as well. It is used when determininginitiating agent of the disease is impossible.
Picture 1.Avascular necrosis of the head of femur
Picture 2. Stages of avascular necrosis of the head of femur
Avascular necrosis of the head of femur is a widespreaddisease of the hip joint. It mostly affects people of the most productive age, namely20-50 years old. Mensuffer from this disease more often than women. Due to continued existence of the articular cartilageas intact because of subchondralnature of the pathological process, the cartilage dysfunction may not be found even on late stages of the disease. It gives the appearance of clinical well-being of the injured cartilage and explains late seeking the medical advice of the patients.Besides, the clinical signs characterizing first stage of this disease are not found on X-ray images. Magnetic resonance imaging(MRI) and computed tomography (CT) allows detecting (avascular) bone necrosis on the first stages. Complex of late diagnostics of ANHF and rapid disease progression limits significantly the use of conservative treatment. When conservative treatment is ineffective the surgical treatment is required.
Radical surgical interferences, in particular total hip joint endoprosthesis replacement, provide the best results of treatment of degenerative-and-dystrophic diseases of the cartilage. But performing the surgical interferences is not recommended for young ANHF patients who get sick more often. The patient would have to change the components of the endoprosthesisseveral times during his/her life. Organ-preservative surgeries allow postponing or preventing the endoprosthesis replacement. That is whythey are more preferable in case of their implementabilityto obtain a good treatment result.