Aseptic bone necrosis – causes, symptoms, treatment

Proven content

Aseptic bone necrosis is a disease syndrome consisting in the formation of necrotic changes in bone tissue without the participation of pathogenic microorganisms. It occurs most often in the epiphyses of growing bones in children and adolescents. It consists of many disease entities that differ in location. Their common feature is a similar course and a similar histological picture.

What is sterile bone necrosis?

Aseptic bone necrosis is a condition characterized by the death of a piece of bone tissue without the involvement of pathogenic microorganisms (therefore the term “sterile” is used). As the disease progresses, the necrotic tissue is absorbed and is replaced by new, reconstructing bone tissue, which, however, is susceptible to deformation. The childhood-adolescent form is most often located in the epiphyses. Its most common locations are the head of the femur, tuberosity of the tibia, heel tumor, and the head of the second metatarsal bone. Necrotic changes can also appear in other bones, such as the bones of the spine (Scheuermann’s disease), the upper limb or the pelvis. So far, 40 sterile necrosis in children and adolescents have been described. The causes of these changes have not been well understood so far. It is assumed that this is a blood supply disorder in a specific area of ​​bone tissue.

Aseptic bone necrosis – different stages of the disease

Four consecutive phases of sterile bone necrosis should be distinguished:

1.Initial phase – it is typical for it to die of the bone base; often asymptomatic;

2nd phase of aseptic necrosis – characterized by the formation of necrotic bone tissue;

3rd phase of fragmentation – there is a gradual replacement of necrotic bone tissue with new bone; at this stage, the bone is most vulnerable to deformation;

4. phase of reconstruction and permanent changes – in this stage, necrotic bone tissue is replaced with new bone tissue; the shape of this bone depends on the extent to which the limb was loaded in the second and third stages of the disease.

The causes of aseptic bone necrosis

In children, the cause of bone ischemia that causes bone necrosis is as yet unknown. there are, however, probable causes that affect the ischemia within the bone fragment.

1. Perthes’ disease (sterile femoral necrosis) – may occur for no apparent reason or be a complication after poorly performed treatment of hip dysplasia in children; in extreme cases, untreated dysplasia causes complications in the form of aseptic femoral necrosis;
2. Osgood-Shlatter disease (aseptic necrosis of the tibial tuberosity) – occurs most often in boys in the pubertal period, when they are in the stage of rapid growth; then the vascular system is unable to supply the right amount of nutrients to rapidly growing bones, resulting in ischemia and necrosis.

In adults, the causes of sterile bone necrosis are:

1. decompression sickness – it is a group of symptoms appearing in people who have been subjected to a sudden change in pressure in the environment (e.g. during diving). Then nitrogen bubbles form in the blood and tissues, which mechanically damage the organs and skeletal system; a late complication of caisson disease is sterile bone necrosis;
2. alcohol abuse – sterile bone necrosis is most common in men aged 40-50;
3. taking glucocorticosteroids – may lead to disturbances in the hormonal balance, which in turn lead to the development of steroid bone necrosis; usually the femoral head is affected;
4. past injuries, e.g. a fracture of a bone fragment, lead to ischemia of this fraction and its displacement, which may result in aseptic bone necrosis;
5. high levels of fat in the blood – too much cholesterol in the blood often leads to blockage of the blood vessels in bones;
6. microtrauma – may be the result of activities that cause vibrations for a long time, e.g. using a jackhammer at work may lead to sterile bone necrosis of the wrist (moon bone); in athletes, such as jumpers, there is often a load on the patellar ligament, which in turn causes aseptic necrosis of this bone.

Frequency of appearance

Aseptic osteonecrosis most often affects children and the femoral head. Symptoms in other bones are less common. Femoral head necrosis usually occurs in children between the ages of 3-14.

Although sterile bone necrosis in children can affect all bones, the most common symptoms are:

1. femoral head,
2. tibia tuberosity,
3. heel tumor or head of the XNUMXnd metatarsal bone.

Symptoms of sterile bone necrosis

They begin with pain ailments that slowly increase and disappear after rest. There may be a restriction of the range of motion in the immediate joint. If the lesion is in the lower limb, walking may be limp. In addition, no abnormalities in additional tests are found, and the general condition of the patient is good. Locally there is pressure soreness, swelling may appear, limiting the movement of the joint affected by the disease process. The development of the disease causes the necrotic tissue to deform under pressure, which may result in permanent bone deformation and disability.

Symptoms in children, based on the location of sterile bone necrosis:

1. tibial tuberosity – there is pain in the tibia, in front and a few centimeters below the knee; after a short rest, the pain subsides, while skin warming and swelling appear in the area under the knee;
2. head of the second metatarsal bone – the patient has pain and swelling in the middle part of the foot; Pain usually occurs after a long walk or dancing; along with the development of the disease, a distortion or thickening of the middle part of the foot can be observed; there is also limited mobility of the fingers;
3. heel tumor – there is pain and sometimes swelling when walking or applying pressure to the heel; the child begins to walk on the toes and limp;
4. femoral head – in the beginning, aseptic osteonecrosis may be asymptomatic; then the first symptoms appear in the form of pain in the hip joint, which is located in the front of the thigh or groin; the first stage of the disease is very often ignored by parents, especially when the pain subsides after a short rest. The development of the disease causes impairment of mobility of one lower limb, which is manifested by visible limping and problems with leg abduction in the hip joint. Another symptom is a tilting of the pelvis to one side and the patient leaning towards the healthy limb. Advanced aseptic femoral necrosis is characterized by visible contractures of the muscles of the hip joint and shortening of one lower limb.

Symptoms of aseptic osteonecrosis in adults:

necrosis of the lunar bone of the wrist of the hand – at the beginning the patient feels weakness in the hand with which it is grasping certain objects; along with the development of ailments, pain and swelling appear, as well as increased limited mobility of the wrist. In addition, the forearm muscles may atrophy as a result of excessive sparing of the upper limb in the advanced stage of the disease.

Diagnosis of sterile bone necrosis

At the beginning, the pediatrician conducts a medical interview, during which he obtains information about the duration of the symptoms and the circumstances of their appearance, e.g. injuries. It is also important to determine if the pain goes away with rest and if you notice a change in gait. In addition, the pediatrician asks in detail about the medications taken by the patient and any accompanying ailments. Then a test is carried out to determine the severity of the changes. In some cases, the patient is referred for additional tests to an orthopedist.

Changes in sterile osteonecrosis can be seen in imaging studies. Most often it is performed:

1. X-ray examination of the limb,
2. computed tomography of the limb,
3. Joint ultrasound.

Imaging changes may not be visible in the early stages of the disease.

Aseptic bone necrosis – treatment

In the case of sterile bone necrosis, treatment is usually long-lasting and is based on the protection of the dead bone against unfavorable mechanical loads, which prevent crushing of the epiphyses, and thus create conditions for the reconstruction of the dead bone with the least possible deviations from the normal state. If the lesions are located in the lower limb, e.g. the femur, the joint should be completely relieved. In other cases, such as tibial tuberosity, head of the second metatarsal bone, heel tumor, we allow weighting when the pain subsides, ie after 1-2 weeks, excluding sports activities and gymnastic exercises performed at school.

Aseptic necrosis lasts from one to four years depending on the age of the child at which it appeared. Under favorable conditions, it does not cause any complications, especially when it concerns extra-articular necrosis. If these are joint changes (especially in the lower limb), the prognosis is less favorable and depends on early initiation and consistent treatment, the extent of the changes and their location.

In patients diagnosed too late and inadequately treated, secondary degenerative-deforming changes occur in adulthood.

Can I completely cure sterile bone necrosis?

If the disease is diagnosed early enough, there is a good chance of a full recovery. On the other hand, when necrosis appeared in girls or symptoms occurred after the age of 10 – bone complications and deformities may occur. The systematic control of treatment by doctors creates a chance for complete recovery and proper development of the joint.

After completing the treatment, be sure to visit an orthopedist to check for complications, e.g. impaired mobility of joints or deformation of joints and limbs. In case of complications, the specialist will order appropriate exercises with a physiotherapist.

Aseptic bone necrosis – prevention

1. After each injury, consult an orthopedist who will perform an anastomosis resulting in proper vascularization.

2. Limit your alcohol.

3. Try to avoid taking steroid drugs, which are one of the risk factors for the disease.

4. Comply with work safety standards, especially if you perform work involving the risk of micro-injuries, eg you are a diver or operate pneumatic hammers.