Avascular necrosis of bone
Avascular necrosis of bone, also called aseptic osteonecrosis or aseptic necrosis of bone, is a syndrome in which the cellular death and separation of the bones occur, which leads to the deformations and secondary degenerative changes. These changes often affect the cartilaginous tissue.
What cause the avascular necrosis of bone
The cause of the occurrence of such changes is usually the abnormal vascularity disorders occurring mainly in the roots of bone in children and adolescents during the growth period, caused by:
- mechanical compression of blood vessels
The avascular necrosis of bone is most likely to develop in people suffering from:
- rheumatic diseases
- especially rheumatoid arthritis and systemic lupus erythematosus
- alcohol abusers
- Caisson's disease (also call the divers disease, formed after too rapid surfacing)
- and as a result of the long-term intake of glucocorticoids
However, when the cause of the disease cannot be clearly indicated, it is referred to as idiopathic.
This disease occurs frequently in males under 50 years of age. Then the circulatory disorders also appear, which lead to a decrease in the blood supply and the hypoxia of the bone tissues , and consequently, to its necrosis and separation.
The symptoms of avascular necrosis of bone may emerge suddenly , for example, as a result of trauma or they can grow slowly . In the latter case the symptoms of the initial stage of the disease are not specific enough. There is pain:
- often radiating
- intensifying during the loading of a particular part of the body
- not ceasing at night
Along with the development of the disease , these symptoms aggravate , leading to the formation of joint contractures and the occurrence of short-lasting morning stiffness . In the course of the avascular necrosis of bone the radiological changes also occur, on the basis of which the four stages of the disease can be distinguished and the correct diagnosis can be made.
- The first phase of the disease is called the initial stage , in which no changes are visible in the radiographic images.
- The second phase, also called the condensation stage, the bone tissue affected by necrosis thickens.
- The third phase - the fragmentation stage, the tissue affected by necrosis is separated from the rest of the bone.
- The fourth phase, called the terminal stage, is characterized by the occurrence of deformations, narrowing of joint space and the irregularities of the articular surface resulting from the history of necrosis
Avascular necrosis may develop in any bone. Till now , about 40 variations have been recognized and defined according to the place of occurrence.
The most common location is:
- the head of the femur (Perthes disease)
- tibial tuberosity (the Osgood - Schlatter disease, also known as knobby knees)
- second metatarsal head (Freiberg - Köhler disease)
- the plates of vertebral bodies (Scheuermann's disease)
- the navicular (Köhler disease)
- the lunate bone (Kienböck’s disease)
- epiphysis of the calcaneus (Haglund's disease)
- the proximal medial part of tibial epiphysis (Blount's disease, also known as the tibia vara)
- the head of the humerus (Panner's disease)
- scaphoid bone (Preiser's disease)
Prevention and treatment
In most cases, avascular necrosis of the bone is not predictable, although there are some professional groups, which have a predisposition to the disease. Persons eligible to work in conditions of high pressure (hyperbaric) should be subjected to detailed radiological examination to detect possible first changes.
Avascular bone necrosis is one of the diseases, which through its specific symptoms causes great risk of joint damage or even disability. The first symptoms should not be ignored, and immediately should be reported to a specialist, who will take appropriate steps towards treatment.