Kienbeck's disease: what is it, symptoms, treatment, prognosis

What is Kienbeck's disease?

Kienbeck's disease (necrosis of the lunate bone) - bone death due to impaired blood supply (osteonecrosis), which is accompanied by damage to the lunate bone of the hand.

The lunate bone is one of the bones in the wrist.

The bones of the wrist are the bones of the hand. The bones of the wrist are located between the bones of the forearm and the bones of the hand.

Kienbeck's disease is relatively rare. It is not known why the blood supply to the lunate bone is impaired. Usually, patients do not remember any trauma. It most often develops in the main hand in men from 20 to 45 years old, usually workers, whose functions involve heavy manual work.

Symptoms of Kienbeck's disease are usually limited to wrist pain that develops gradually in the lunate region, located in the middle of the base of the wrist. Further developing

edema at the top of the wrist, with possible impairment of freedom of movement. In 10% of patients, the disease affects both hands.

Signs and symptoms

The following list includes the most common signs and symptoms in patients with Kinbock disease. These features may differ from person to person. Some may have more symptoms than others, and symptoms can range from mild to severe. This list does not include all the symptoms or features described in this condition.

Symptoms may include:

• Wrist pain
• Restriction of movement
• Loss of grip strength
• Swelling of the joints

It is not entirely clear how Kinbock's disease changes over time. Most patients begin to show symptoms in early adulthood. Usually only one wrist is affected. Over time, the wrist joint may break, resulting in arthritis surrounding bones. Some with Kinbock disease have no symptoms and the disease is discovered by chance.

The table below lists conditions that can occur in people with this condition. The symptoms of most medical conditions can differ from person to person. Patients with the same condition may not have all of the listed symptoms.

Medical terms	Other names
80% -99% of patients have these symptoms
Wrist anomalies
Arthralgia	Joint pain
Bone pain
Limitation of joint mobility
Osteochondritis dissecans	Koenig's disease

Causes and risk factors

The exact cause of Kienbeck's disease is unknown, although a number of factors are believed to predispose a person to Kienbeck's disease. Although there is no evidence that Kienbeck's disease is hereditary, it is possible that unknown genetic factors may contribute to the development of this condition.

Lunate necrosis can often be attributed to a trauma to the wrist, such as a compound fracture, which can compromise the blood supply to the lunate bone. Blood flows to the lunar through several arteries, each of which supplies it in a percentage. When one of these pathways is ruptured, the patient is more likely to develop necrosis. Despite the overwhelming evidence, no specific cause has been conclusively confirmed.

Epidemiology

Kienbeck's disease is the second most common type of avascular necrosis of the carpal bones, preceded only by avascular necrosis of the scaphoid. Commonly affected populations are males aged 20-40.

Diagnostics

Kienbeck's disease is a clinical and visual diagnosis. Both radiography / computed tomography and magnetic resonance imaging (MRI) are very specific. However, MRI is the most sensitive and reveals hidden radiological cases.

• Magnetic resonance imaging: Diffuse decrease in the lunar type bone marrow signal on T1-weighted images is a sign of disease. Signal changes in T2-weighted or short-interval inverted images (STIR, which negates the fat signal) vary with progression and severity osteonecrosis. MRI also evaluates the integrity of the articular cartilage.
• Radiography: in the norm at an early stage of the disease. Signs, if any, depend on the morphological stage and include diffuse semilunar sclerosis, cystic changes, collapse of the articular surface, collapse of the wrist, secondary arthrosis of the middle part of the wrist and / or wrist joint.
• CT scan:useful for planning surgery. CT is also more sensitive than radiography for detecting fine subchondral fractures. coronary fractures of the lunate bone, fragmentation, wrist instability and degree of trabecular destruction.
• Scintigraphy: signs are nonspecific. It has previously been used as an aid in the early diagnosis of diseases. After the introduction of MRI, it lost popularity.

Radiographic classification

In its development, Kienbeck's disease goes through five stages, typical for aseptic bone necrosis in adult patients. It was first described by David Lichtman et al. in 1977 These stages are conditional to a certain extent, since the destruction and degenerative degeneration of the bone are continuous dynamic process, however, they help to choose the optimal treatment tactics and assess the prognosis diseases. The classification is based on radiological changes:

1. Stage I. Radiograph is normal (possible fracture of the lunate bone).
2. Stage II. Impressional fractures are formed. The bone is moderately deformed, foci of darkening appear with a violation of the structural pattern.
3. Stage IIIA. Cartilage, subchondral plate is involved. The deformity progresses, the joint space expands.
4. Stage IIIB. The lunate bone is divided into several vertical fragments.
5. Stage IV. The pictures show signs of deforming arthrosis.

Related disorders

Symptoms of the following diseases may be similar to those of Kienbeck's disease. Comparisons can be useful for differential diagnosis:

• Carpal tunnel syndrome - a condition caused by compression of the peripheral nerves of the wrist, affecting one or both hands. It is characterized by a sensation of numbness, tingling, burning, and / or pain in the arm and wrist. People with this disorder may wake up at night with a feeling of numbness in their arms. In combination with this condition, various other diseases can occur. With timely treatment, the prognosis is favorable in most cases.
• Sudeck's Syndrome (Zudeck's atrophy), also known as post-traumatic osteoporosis, characterized by acute bone atrophy. The bones of the wrist and ankle are most often affected by minor injuries, such as sprains.
• Juvenile osteoporosis characterized by a porous state or bone atrophy beginning before puberty. The exact reason has not been established. This condition can lead to pain or fractures of many bones in the body, including the wrist. Spontaneous remission may occur within a few years.

Treatment

Surgery is used to relieve pressure on the lunate bone, for example, by lengthening or shortening the bones articulated with the lunate bone. Alternative surgical treatments are used to restore the blood supply to the lunate bone (such as a bone or blood vessel graft). When the lunate bone is destroyed, removal or surgical fusion of bones (arthrodesis) is possible as a last resort for pain relief.

Attempts at nonsurgical treatment for this condition have failed, but in very mild cases, a splint on the wrist can relieve pain.

Forecast

Kienbeck's disease invariably progresses, and within 3-5 years from the onset of the disease, destruction of the joints occurs.

The forecast depends on:

Functional stage: what the more viable bone, the better the prognosis.

Negative elbow variance: than the greater the negative variance, the more severe the disease and the higher the likelihood of its progression.

Age at the time of diagnosis: patients who are diagnosed at an older age are more likely to have advanced disease and are more likely to progress.

It is important to note that the severity of symptoms does not always correlate with morphological stage.

Complications

Kienbeck's disease can lead to dissociation of the palmar bone, secondary wrist and mid-carpal degenerative arthrosis, and displacement of the triangular bone.