Prosthetics for aseptic necrosis of the femoral head

Causes

The mechanism of development of aseptic necrosis of bone tissue is a local disturbance of blood circulation with deterioration or complete cessation of nutrition to a certain area of the bone. Its fragment dies, inflammation and swelling develop around it, which blocks the repair process and contributes to the spread of pathological changes. Osteoporosis develops in the surrounding areas, turning into osteonecrosis. The bone becomes loose, impression (depressed) fractures appear. Destructive changes affect cartilage, which is quickly replaced by connective tissue. The joint loses its functions.

The following reasons can lead to aseptic bone necrosis:

intoxication of the body (including alcohol);
injuries (experienced and recurring);
exposure to ionizing radiation;
blood pathologies;
pathologies of the hematopoietic organs;
vascular pathologies;
connective tissue diseases;
somatic diseases.

Factors that contribute to poor circulation or mask pathological changes in the joints can lead to necrosis. These include long-term therapy with drugs from the glucocorticoid group and NSAIDs.

Necrosis of the femoral head is considered a polyetiological disease that develops under the influence of several factors at once. One of them is alcohol consumption (this factor is found among the majority of patients with this diagnosis).

Anatomy of the knee joint

The main structures that form the knee joint are: bones, flexor muscles, extensor muscles, nerves (the largest is the popliteal nerve), menisci, vessels (popliteal artery and popliteal vein), cruciate ligaments.

The formation of the knee joint involves two long tubular bones: the tibia at the bottom and the femur at the top. In front of the joint there is a small rounded bone called the patella or in other words the kneecap.

There are two ball-shaped projections on the femur called the femoral condyles.

The femoral condyles are covered with articular cartilage. The menisci are located between the tibia and femur bones.

The outside of the knee joint is covered with a capsule, the inside layer is synovial. To facilitate movement, the joint contains synovial fluid.

The ligaments of the knee joint stabilize the bones relative to each other. Synovial bursae (bursae) are also very important structures in the joint.

Stages

The stages of development of necrosis of bones and joints are as follows:

First stage. It is characterized by loss of bone tissue, is often asymptomatic or with mild symptoms, and is not detected on x-rays.
Second stage. It is accompanied by local necrotic changes and small compression fractures, deformation of the articular surface of the bone and widening of the joint space, which is visible on x-rays. Clinically, the second stage is manifested by pain and limitations in joint function.
Third. Areas of necrosis are separated. On X-ray photographs, the contours and pathological structure of the sequestra are clearly visible. The articular surface continues to deform. At this stage, the joint almost completely loses its functions, the patient suffers from severe pain
Fourth. In the absence of a purulent process, gradual restoration of bone tissue begins.
Fifth. The bone structure is restored, but the shape remains changed. Bone tissue grows with the formation of osteophytes. Subsequently, ankylosis (fusion of the joint) is formed.

How is Koenig's disease diagnosed?

It is impossible to determine the disease by eye, therefore, if this disease is suspected, an orthopedist or rheumatologist will refer you for a comprehensive examination. This may include:

radiography - shows the condition, the degree of tissue preservation, determines the localization of necrotic processes in the third and fourth stages of the disease;
CT scan – allows you to assess the condition and area of damage to the soft tissues of the internal cavity;
Ultrasound or MRI - determine the problem at the initial stage;
arthroscopy – studies the condition of the cartilage through a micropuncture of the joint;
laboratory tests are needed to determine the degree of rheumatoid factor, as well as to obtain general information about the patient’s health.

Aseptic bone necrosis

For aseptic necrosis, it is important to start treatment in a timely manner. However, early diagnosis of the condition is difficult, since primary changes in bone tissue are not detected during routine x-ray examination. Their diagnosis requires computed tomography and magnetic resonance imaging.

The variability of the clinical picture is also a problem. In some cases, symptoms of the disease (pain, muscle weakness, lameness, stiffness) appear in the early stages. However, more often patients see a doctor with progressive necrosis, at the stage of irreversible changes.

Necrosis

Necrosis is necrosis or, in other words, death of cells and or tissues in a living organism. There are several options for the outcome of necrosis:

Organization - replacement of the necrotic area with connective tissue.
Petrification is the replacement of a necrotic area with calcium salts.
Ossification is the replacement of a necrotic area with bone tissue.
Mutilation is a very serious condition in which cells and or tissues are rejected and spontaneous amputation is possible.

Treatment

The treatment tactics for aseptic necrosis depend on the stage of the pathological process. In the early stages, conservative treatment is carried out. The patient is advised to reduce the load on the joint (by limiting activity, using a cane or crutches). Drug therapy is carried out in several areas:

correction of symptoms;
restoration of blood circulation;
strengthening bone tissue;
restoration of cartilage tissue.

With progressive necrosis, surgical treatment may be required, which involves interventions aimed at reducing compression of the problem area. If the effectiveness of therapeutic measures is unsatisfactory and in advanced cases, endoprosthetics is indicated.

Causes of aseptic necrosis of the knee joint

Aseptic necrosis of the knee joint is a very serious disease.

The main reason, as mentioned above, is injury and, as a consequence, disruption of the structure of the bone tissue of the knee joint and blood circulation and nutrition.

Other causes include endocrinological diseases, fractures, and unskilled medical procedures.

Recently, there has been an increase in the percentage of necrosis due to alcohol abuse, Kümmel's disease, hereditary predisposition, and abuse of hormonal drugs (glucocorticosteroids).

It should be noted that in males this disease develops more often. It manifests itself in different age groups, both children and adults.

Differential diagnosis of Koenig's disease

Disease	Features
Chondromatosis	With chondromatosis, it is not possible to identify a typical “niche” in the epiphysis of the femur or tibia; the chondromic bodies have a “bean” shape, their number can reach 10 or more, while with Koenig’s osteochondropathy there is a single sequester.
Deforming osteoarthritis	Fragments of osteophytes and areas of ossification of ligaments can simulate intra-articular loose bodies, but they have an irregular shape and pointed edges. The condyle defect also cannot be detected.
Hoff's disease	With Hoff's disease, the structure of the infrapatellar or suprapatellar fat body changes, it becomes dense and can lead to symptoms of strangulation, just as with Koenig's osteochondropathy. With MRI and CT, it is possible to distinguish with a high degree of reliability a compacted fat body from an articular “mouse”; on radiographs, the main distinguishing feature will be the absence of a “niche”.
Intra-articular fracture	The joint “mouse” of a traumatic nature has an irregular shape and uneven edges. It is not possible to identify a typical “niche”.
Errors in interpreting normal joint anatomy	Sometimes an inexperienced doctor may mistake the sesamoid bone in the tendon of the gastrocnemius muscle - fabella - for an intra-articular free body on radiographs. The “niche” in the lateral condyle of the femur can be confused with the subchondral “light” zone, which is well defined in some patients - a variant of the normal anatomy of the joint.

Features of therapy

The disease is very dangerous, therefore therapy is often radical in nature, in contrast to conservative treatment of osteoarthritis. Damaged tissue is dissected and removed surgically, but the surgical approach is combined with other methods to avoid complications and relapses.

Arthrotomy is the opening of the joint cavity and removal of necrotic tissue fragments. Today, a minimally invasive technique is more often practiced - three small incisions or punctures.
Drug therapy - antibiotics, analgesics, antispasmodics, non-steroidal anti-inflammatory drugs, vitamin-mineral complexes, chondroprotectors.
Physiotherapy is effective in the initial stages to improve metabolic processes, as well as during the rehabilitation stage. The most popular are electrophoresis, shock wave and magnetic therapy.

Koenig's disease cannot be treated without surgery

Types and stages of disease development

The stages of development of aseptic necrosis of the head of the hip joint do not have a clear distinction between each other. The first stage lasts about six months, when pain occurs during exercise or during bad weather, after the disappearance of the provoking factor it goes away. The second stage also lasts about six months. During this period, thinning of the muscles of the buttock and thigh appears.

The third stage takes a longer time - up to 2.5 years, during which the tissue surrounding the necrosis zone resolves. Patients are already beginning to move exclusively with a cane. In the fourth stage, which develops over about 6 months, patients cannot move on their own. However, the duration of development of the disease is individual for each person, depending on concomitant diseases, timely treatment and other factors.

Doctors distinguish four types of necrosis of the hip joint:

Segmental (observed in 48% of patients with this diagnosis). A small area of necrosis appears as a cone on the upper part of the femoral head.
Complete necrosis (diagnosed in 42% of patients). The entire head is affected.
Peripheral (occurs in 8% of patients). The pathology affects the outer part of the head, located under the articular cartilage.

Central (observed in 2% of cases). A zone of necrosis forms in the center of the head of the femur.

Causes and symptoms of avascular necrosis

There are several reasons for the development of aseptic necrosis of the head of the hip joint. These are vascular diseases when blood microcirculation changes, which leads to the development of foci of tissue necrosis. The cause of the disease can also be excessive load on the hip joint. This is due not only to a person’s profession (truck drivers, parquet workers, gas welders), but also to excess weight and a shift in the center of gravity when walking.

The reasons for the development of necrosis of the hip joint may be associated with metabolic disorders in the human body or with a genetic predisposition. But none of the above factors can independently cause this disease; it develops only as a result of a combination of several conditions.

Depending on the severity of damage to the hip joint, the course of the disease has stages, each of which is characterized by the following symptoms:

At the first stage of the development of the disease, rare pain and minor bone changes are observed. Slight pain radiates to the groin, but mobility in the hip joint remains.
At the second stage, cracks appear on the head of the hip bone, which can occupy up to 30% of its surface. The pain in the affected area intensifies.
At the third stage of the disease, the acetabulum is involved in the process, and up to 50% of the articular tissues are affected. The pain becomes constant and severe, and joint mobility decreases.
The motor function of the hip joint is completely reduced, severe pain never stops, the muscles of the buttock and thigh atrophy.

Treatment of aseptic necrosis of the head of the hip joint

After a medical examination and diagnosis, the doctor prescribes treatment for necrosis of the femur. The complex of therapeutic measures in the early stages of the disease includes: drug therapy, massage, mud baths in sanatoriums, vitamin therapy, hirudotherapy (treatment with leeches), swimming. However, conservative methods do not lead to a complete cure of the disease, but only inhibit its development, preserving the function of the joint for many years.

No modern medicine can completely destroy the necrotic process. If it is not possible to slow down the development of the disease, then doctors use surgery. This is the only radical treatment for necrosis of the femoral head, which can significantly improve the living conditions of a person with this disease. Surgeries are used at all four stages of the disease.

Medication

The tactics of drug treatment of avascular necrosis of the hip joint depends on the development of symptoms, the age of the patient and the complete picture of the disease after a thorough diagnostic examination. Medicines that doctors prescribe for this disease:

Non-steroidal anti-inflammatory drugs. They are prescribed to relax the thigh muscles, restore normal blood circulation and relieve pain. The course of treatment is one ampoule intramuscularly daily for a week. Well-known drugs are Naklofen, Diclofenac, Xefocam, Ibuprofen.

Vasodilators. They eliminate blood stagnation and improve arterial blood flow. The dosage regimen depends on the severity of necrosis of the hip joint, but is at least 8 weeks with repeated courses every six months. Popular vascular agents are “Curantil”, “Trental”, “Dipyridamole”, “Xanthinol nicotinate”.

Regulators of calcium metabolism, preventing excessive loss of calcium. They improve the process of bone restoration and reduce collagen destruction. The drugs are used for at least 8 months continuously or at intervals of several weeks. The best drugs are “Calcium D3 nycomed”, “Xidifon”, “Bonviva”, “Fosamax”, “Vitrum”, “Osteomag”, “Osteogenon”, “Alfacalcidol”. Chondroprotectors. These are the most effective drugs at stage 3 of necrosis of the hip joint, when the cartilage in the head of the femur begins to peel off and destroy. They help restore cartilage tissue by stimulating ligament regeneration. These drugs must be taken in long courses, at least 6 months, at intervals of six months. The most famous chondroprotectors are “Structum”, “Chondroitin sulfate”, “Chondrolone”.

Muscle relaxants. These drugs can relax muscles, thereby inhibiting the transmission of nerve impulses, improving blood circulation. The course of treatment is 15-20 days, one tablet 2 times daily. The best relaxing drugs are “Mydocalm”, “Sirdalud”.

Surgical methods

If drug treatment does not produce results, surgery is performed. In the first stages of aseptic necrosis of the hip joint, it is used for decompression of twisted vessels that do not provide adequate nutrition to the head of the femur, or for transplantation. Types of surgical treatment:

tunneling, when additional holes are formed in the bone to reduce pain and intraosseous pressure;
transplantation of a musculoskeletal graft to increase local blood flow and eliminate pain;
intertrochanteric osteotomy to eliminate the worn part of the femoral head and redistribute the load to other areas;
arthrodesis (artificial fusion) to immobilize the joint to eliminate pain;
arthroplasty to increase range of motion, eliminate lameness, and improve blood supply to the hip joint.

But most often in modern traumatology and orthopedics endoprosthetics is used, when a destroyed joint is replaced with an artificial one. The duration of use of the prosthesis is about 15 years, after which it requires replacement. All surgical operations are performed under general or epidural (in the lumbar region) anesthesia. The timing, level and scope of rehabilitation depend on the surgical technique and the individual characteristics of the body.

What is the danger?

If the disease is not treated, a necrotic fragment remains in the joint. The dead tissue limits the mobility of the knee and increases inflammation. The joint is blocked and remains in an unnatural state all the time. These are excellent prerequisites for the development of deforming arthrosis with all the ensuing consequences and complications.

There are no special preventive measures against this disease. However, you can reduce the risks. To do this, it is important to lead a healthy lifestyle, give up bad habits in favor of daily morning exercises. It is also important to monitor the load on the lower limbs, and seek help at the first alarming symptoms.