Keinbock’s Disease

What is Keinbock’s disease?

Keinbock’s disease⁷ is a condition which restricts blood supply to smaller bones such as the wrist joints. This means that patients will have no circulation in certain parts of the body, resulting in osteonecrosis, where the bones ultimately die. There are many causes of Keinbock’s disease, including previous conditions such as osteoarthritis and carpal tunnel syndrome. The symptoms can be reduced with effective treatment. 

Keinbock’s disease can also be referred to as avascular necrosis of the lunate bone⁵. Necrosis refers to the death of tissue or a bone, mostly due to a lack of blood circulation. The lunate bone is found in the wrists and allows wrist motion and movement. The lunate bone is vital for everyday functions such as writing, cooking, and lifting; therefore, damage to the lunate bone can result in severe alterations to lifestyles. 

How many people have Keinbock’s disease?

On average, lunate carpal bone disease affects males between the ages of 20 and 40. Discovered by the radiologist Robert Keinbock’s in 1910¹, the disease affects around 7 in 100,000 people worldwide, meaning that almost half a million people live with Keinbock’s disease. 

What are the signs of Keinbock’s disease?

There are many causes of Keinbock’s disease^1,2,3. These include injuries to the wrist joints and carpal bone as a result of repeated stress. For example, people with high-intensity labour occupations where heavy lifting is required may be more prone to developing the disease due to the stresses placed upon the lunate bone. Additionally, people already diagnosed with arthritis or carpal tunnel syndrome are more susceptible to getting the disease. This is because arthritis involves swollen wrists and joints, and movements of these joints are restricted.

There are many different types of arthritis, such as osteoarthritis. It is mostly caused by degenerative bone changes, resulting in swollen wrist joints. The main symptoms of arthritis are stiffness of the joints, and inflammation including swelling, redness, and pain, with even a loss of function in chronic inflammation. 

Another sign of Keinbock’s disease is carpal tunnel syndrome, where the carpal joints are severely affected. This occurs in people where the median nerve in hand undergoes extreme stress and causes numbing of the hand. Injury to the median nerve and increased symptoms of carpal tunnel syndrome can result in Keinbock’s disease. 

What are the different types of Keinbock’s disease?

There are many different types of Keinbock’s disease^3,6. These include:

• Ulnar negative variance – This occurs in around 78% of cases and is caused by increased mechanical stress and lots of use of the lunate bone. 
• Vascular supply to the lunate bone – This occurs when the blood supply between the body and the bones is restricted, and there is a fluctuation between the blood supply to the wrist joints. 
• Lunate morphology – This means that the lunate bone decreases in size, resulting in smaller blood vessels and ultimately less blood reaching the wrist joints. 
• Radial inclination angle – The angle of the bones and joints change, resulting in decreased blood supply to the bone, leading to necrosis.

What are the stages of Keinbock’s disease? 

There are various stages to Keinbock’s disease⁴. In stage 1, symptoms such as numbness and tingling may occur, but there will be no visible changes to the wrist joints when X-rays are performed. During stage 2, injury to the lunate bone will be seen. This means that there may be scarring. Stage 3 is split into 2 parts: (1) stage 3A - the lunate bone collapses, leaving the carpal bone unable to move; (2) stage 3B - the carpal bone moves around, and blood supply may be drastically reduced. Finally, at stage 4, complete degeneration and immobilisation occur, as well as arthritis. 

What are the risk factors of Keinbock’s disease?

The main risk factors of Keinbock’s disease are differences in the lengths of the forearms^3,6. This means that there is increased pressure on the lunate and carpal bones which can result in a high risk of suppressing blood vessels and restricting the blood flow to the joints.

Another major risk factor includes people with the diagnosis of lupus or sickle cell anaemia and cerebral palsy, where they already have restricted blood supply. 

How can Keinbock’s disease be diagnosed? 

The disease can be diagnosed through both clinical and imaging presentation⁶. This means that X-ray radiography and MRI scans can be used. In addition to these conventional methods, computerised tomography (CT) can be used as it allows doctors to plan for surgeries in the later stages of Keinbock’s disease. Additionally, nuclear scintigraphy can also be used to diagnose the early stages of the disease. 

How can Keinbock’s disease be treated?

There are different treatments for various stages of Keinbock’s disease³. For stage 1, where there are symptoms but no visible changes, non-steroidal anti-inflammatory drugs (NSAIDs) are used. NSAIDs are also painkillers such as aspirin and ibuprofen, which can reduce the pain and the swelling caused by arthritis. For stage 2, patients undergo scaphotrapeziotrapezoid (STT) fusion where bones are joined together to prevent movement. This is done using a bone graft from the hip bone and surgically joining them together. During stage 3A, more STT fusion is done to keep the bones intact. When the disease worsens at stage 3B, scaphocapitate (SC) fusion occurs where another bone graft is taken to make 4 different joints together. Immobilisation can also be a potential treatment. This is where the patient stops putting pressure on the bone by reducing movement. 

Conclusion

Overall, Keinbock’s disease can be painful and discomforting for patients. People with arthritis and carpal tunnel syndrome need to be wary of the symptoms that could lead to the disease, otherwise surgical interventions must be taken to relieve symptoms.