Aseptic necrosis of a head of a femur

Description:

Our Kostya of a skeleton consist of a bone tissue which, as well as the majority of other body tissues consists of living cells and contains blood vessels (arteries, capillaries and veins). At disturbance of local blood supply development of necrosis (necrosis) of fabric or body is possible that can lead to serious problems. Disturbance of blood supply arises at obstruction (thrombosis or an embolism) of arteries which krovosnabzhat this area. Especially often the necrosis of fabrics arises in areas which krovosnabzhatsya from the pool of the only artery. The femur head belongs to such "problem" zones. At disturbance of blood supply of this area there is a disease which is called the aseptic necrosis (AN) of a head of a femur.

Anatomic aspects:

The hip joint is the biggest spherical joint of our body. It forms from a deep joint hollow  of a haunch bone (an atsetabulyarny hollow) and femur heads. The hip joint is surrounded with powerful muscles (buttock and muscles of front group of a hip). The Atsetabulyarny hollow and head of a femur are covered joint (hyaline) hryashchy. The joint cartilage has very smooth slippery surface, and its thickness in a hip joint reaches 0,5-0,6 cm. Function of a joint cartilage consists in decrease in friction at the movements in a joint and depreciation of shock loadings. The head of a femur krovosnabzhatsya by the only artery which passes through a femur neck. Due to the lack of collateral circulation at the termination of a blood flow on this artery blood supply of a head of a femur is broken. As a result the necrosis (necrosis) of a head of a hip develops. The necrosis leads to deterioration in mechanical properties of a bone tissue. The bone is not the "stiffened" structure. In a bone tissue constantly there is a destruction of bone beams and at the same time regenerative processes proceed. The termination of recovery processes owing to a lack of oxygen and nutrients leads to bystry deterioration in mechanical properties of a bone tissue. Under the influence of mechanical loadings the kollabirovaniye (fall) of the nekrotizirovanny site of a bone results. At development of AN a form the head of a femur changes: there is its flattening in the field of the maximum influence of gravity. Congruence (sochlenyaemost) of joint surfaces in a hip joint is as a result broken that leads to increase in internal loading during the work of a joint and to bystry wear of a joint cartilage. An outcome of AN is development of an osteoarthrosis – a degenerative disease of the joint which is followed by pain and disturbance of its function.

Reasons of an aseptic necrosis of a head of a femur:

Can lead a set of factors to development of AN of a head of a femur. Practically any reason promoting disturbance of a blood-groove in a hip head artery can be a push for development of AN. So traumatic damages of a hip joint can lead to disturbance of blood supply of a head of a hip as a result of mechanical damage or an artherothrombosis. The most frequent injuries leading to development of AN are the fracture of a neck of a hip and dislocation of a hip. AN develops in several months though the first clinical symptoms, as a rule, appear at patients much more later (frequent in 1,5-2 after the postponed injury).
Reception of some medicines can also promote development of AN. Most often AN develops against the background of long reception of high doses of glucocorticoid hormones concerning a serious rheumatic illness, bronchial asthma, etc. It is shown that treatment by short rates of hormonal drugs does not increase risk of development of AN of a head of a femur. Safely also in this respect one - either twofold intra joint or circumarticular administration of hormonal drugs at treatment of an osteoarthrosis, a bursitis, tendonit and other inflammatory diseases of a musculoskeletal system. The accurate interrelation between excess alcohol intake and frequency of development of AN is tracked. Alcohol promotes damage of blood vessels that can become the reason of development of ischemia of a head of a femur and development of its necrosis. The increased frequency of development of AN is noted at persons whose professional activity is connected with influence of high pressure (divers, miners). At the wrong mode of a decompression in blood small vials of air which can cork and damage blood vessels are formed, including lead to disturbance of a blood-groove up to a femur head artery.

Symptoms of an aseptic necrosis of a head of a femur:

The first symptom of AN is the pain in the field of a hip joint arising at transfer of body weight on a "sore" leg. Pain can extend to inguinal, buttock areas, irradiate (to give) on the front surface of a hip. When progressing a disease lameness and dysfunction (mobility) of a joint develops. At late stages pain can remains also at rest, to promote a sleep disorder.

Diagnosis:

Diagnosis of AN begins with studying of complaints of the patient, history of a disease and a physical research. The doctor will ask you on existence of chronic diseases, reception of medicines, on professional vrednost. The question of an alcohol abuse will be perhaps asked. The physical research includes survey, a palpation of a joint and studying of its function (the angle of assignment, bending of an extremity, etc.). Specification and confirmation of the diagnosis requires carrying out additional laboratory and tool methods of inspection.

X-ray analysis
On roentgenograms zone AN of a head of a femur is defined, as a rule, with the sufficient duration of a disease. At early stages of a disease at X-ray inspection of pathological changes of a bone can not be defined in spite of the fact that the expressed joint pains can already disturb the patient. At late stages of AN the osteoarthrosis joins, and it is difficult to define what of these diseases causes more the symptoms which are noted at the patient.

Radio isotope scanning  (stsintigrafiya)
In the absence of pathological changes on roentgenograms the doctor can appoint radio isotope scanning for specification of the diagnosis. At this technique the medicine containing radioelement (radiopharmaceutical) is entered into an organism of the patient. In several hours by means of the special gamma camera registration of radioactivity in a human body is carried out. Due to the lack of a blood-groove in a femur head this zone on a stsintigramma (the picture received at a stsintigrafiya) is presented in the form of a "cold" spot as in it there is no radiopharmaceutical accumulation. After emergence in clinical practice of a magnetic and resonant tomography the frequency of purpose of radio isotope scanning for diagnosis of AN considerably decreased.

Magnetic and resonant tomography
Now the magnetic and resonant tomography is the most often used research method for diagnosis of AN of a head of a hip. The principle of a magnetic and resonant tomography consists in obtaining the image of fabrics and body organs in the form of a series of cuts by means of electromagnetic waves. It is the most informative and absolutely safe method of a research. On magnetic and resonant tomograms even insignificant zones with lack of a blood-groove and in the earliest stages of development of a disease can be revealed.

Treatment of an aseptic necrosis of a head of a femur:

Tactics of treatment of AN is defined by a stage of a disease and expressiveness of clinical symptomatology. Now efficiency of the medicines allocated for recovery of blood circulation in a hip head artery is not proved. While pain can be controlled effectively purpose of analgetic and antiinflammatory drugs, operational treatment, as a rule, is not required. Though in certain cases if there was no hip head collapse, the surgeon can offer the operation directed to increase in blood supply of a head of a hip. There are several options of such operations.

Femur head decompression
The principle of this  simple operation consists in drilling of one or several channels passing through a neck in a hip head, directly in a zone where there is no blood stream. This operation pursues two aims: 1) to increase blood supply of ischemic area due to growth of new blood vessels in the drilled channel 2) to reduce intra bone pressure in a hip head and by that to promote reduction of pain at patients with AN.

This operation is carried out through very small section on the side surface of a hip under control of the electron-optical converter (EOC). EOP represents a mobile digital X-ray apparatus which allows to receive images of bones on the display screen directly during operation. After a femur head decompression the patient needs to use crutches within 6 weeks. This recommendation is caused by the fact that drilling of channels leads to temporary decrease in mechanical durability of a neck of a hip that promotes increase in risk of a change.

Change of an autograft from a fibular bone
It is more difficult operation which is directed to increase in a blood-groove in an ischemic head of a femur. Its principle consists in change of a piece of a fibular bone on a vascular leg to the area of a head and a neck of a hip. As a result the ischemic head of a femur receives additional blood supply from vessels of a bone transplant. Besides the transplant mechanically strengthens a hip head, preventing its further kollabirovaniye. This operation is carried out rather seldom in view of its high complexity. The positive effect of operation is noted not at all patients because of thrombosis of the vessels feeding a bone transplant.

Endoprosthesis replacement of a hip joint
At late stages of an aseptic necrosis at patients degenerative damage of a joint - an osteoarthrosis develops. In these cases for reduction of a pain syndrome and improvement of function of a joint performing endoprosthesis replacement of a hip joint is shown.