Kienbock Disease - Causes, Signs, Diagnosis, and Treatment

Introduction:

Keinbock's disease occurs due to the slow cellular death of the wrist bone when there is minimal to no blood supply. This condition can lead to slowly developing pain with abnormal wrist motion. Loss of blood supply to the wrist bones compromises the structural integrity of the bones, making them fragile, resulting in collapse or stiffness of the wrist, which can also lead to arthritis (a painful inflammation of the bone).

What Causes Kienbock Disease?

The exact cause of Keinbock's disease is unknown, but the loss of blood supply to the bone can be multifactorial. It may occur due to the following:

• Fall.

• Accident.

• Anemia.

• Open fractures.

• Structure of bone.

• Medical conditions like lupus and cerebral palsy.

How Does Kienbock Disease Occur?

Keinbock's disease occurs broadly due to two reasons:

1. Mechanical: The mechanical causes occur due to the shape, size, and mechanics of the wrist bone like:

• When the ulna bone is shorter than the carpal bone.

• When the inclination of the radial bone along the long axis of the hand is reduced.

• Repeated trauma to the wrist.

2. Anatomical: The anatomical causes occur due to structural deformity or any injury to the structures related to the wrist.

• The shape of the lunate bone (small bones forming the wrist).

• Interruption in the blood supply of the wrist.

How Commonly Does Kienbock Disease Occur?

It is the most common cellular death of the wrist bones due to a lack of blood supply. Keinbock's disease is mostly seen in young adults between the ages of 20 to 40 and affects males more than females.

What Are the Clinical Signs of Kienbock Disease?

Keinbock's disease is clinically seen as:

• Chronic wrist pain.

• Swelling.

• Tenderness on palpation.

• Decrease in wrist motion.

• Stiffness.

• Decreased wrist strength.

How Is Kienbock Disease Classified?

The staging of Keinbock's disease is essential to divide the disease's progression level and classify it according to its anatomy and functions.

1) Anatomic Staging: Lichtman classified the structure of Keinbock's disease into four stages depending on the radiographic (X-rays) and MRI (magnetic resonance imaging) images. They are:

1. Stage 1 - The radiographic images appear normal; there is a change in the intensity of the signal of the lunate bone.

2. Stage 2 - Abnormal hardening (sclerosis) of the lunate bone is seen with or without a fracture line. The shape of the lunate bone appears normal.

3. Stage 3 - There is a collapse in the articulating surface of the lunate bone. This stage can be subdivided into three types, with additional changes and the destruction of the lunate bone. They are :

• 3A - The height and alignment of the carpal bone are still preserved.

• 3B - There is an evident loss in the carpal bone's height and a stretched scaphoid bone.

• 3C - The lunate collapse is seen along with a coronal fracture.

4. Stage 4 - It is stage 3B (collapse of the lunate bone and evident loss of carpal bone and flexed scaphoid bone) along with degeneration of mid-carpal bone.

2) Functional Staging: This is done by injecting color dye, and contrast imaging is taken using an MRI to study the flow of blood and the level of bone necrosis (bone cell death). It is helpful to know the success of the revascularization procedure done in stages 1 and 2 as conservative treatment. The functional classifications are:

1. Stage 1 - A very intense uniform contrast of the image showing loss of blood supply to the bone marrow, fluid accumulation, and a healthy lunate bone.

2. Stage 2 - A patchy non-homogeneous color enhancement reflects partial bone necrosis. The healthy area is usually away from the bone's midline (distal part).

3. Stage 3 - No color contrast is seen, confirming total necrosis (cell death) of the bone.

How Is Kienbock Disease Diagnosed?

Firstly patients are examined for the physical skill of the wrist to rule out any defects. The physical evaluation is done by asking the patient to flex or extend their wrist, followed by a grip test which is done by asking the patient to hold a place or an object where a noticeable weakness is seen. Along with physical examination, X-rays are taken in anteroposterior, lateral, and transverse views to check for fractures. Depending on the stage of progression, the images see wear and tear of the bone, collapsed lunate bone, or rotation of the scaphoid bone.

• Computed Tomography (CT): CT imaging is a three-dimensional imaging taken to study the structure of the bone and associated structures. It is taken only after the collapse of the lacunae bone. The CT shows the extent of cell death in the bones and destruction of trabeculae (bundle of fibers making the framework of the bone) of the bone and helps in studying the structure of c-shaped lacunae bones.

• Magnetic Resonance Imaging (MRI): In the case of Kienbock's disease, an MRI scan is used to study the bony structure along with the associated soft tissues and cartilage. MRI is the best option for confirming the illness in a very early stage to rule out ulnar impaction syndrome (a painful condition seen with long ulnar bones); MRI shows decreased blood supply to the lacunae bones. MRI shows an overall decrease in bone marrow signal (T1 - an indication of MRI) of the lunate bone serving as a confirmation of the disease.

How Is Kienbock Disease Treated?

The main aim of the treatment Is to relieve pain and restore the function of the wrist. Keinbock's disease can be managed in two ways depending on disease progression. Keinbock's disease is managed by:

Non-Surgical Management: Non-surgical treatment is usually preferred in stage one and stage two levels, where the degree of progression of the disease is considerably less and can be managed with:

• Observing the disease.

• Immobilization of the wrist.

• Non-steroidal painkillers.

Though it is manageable, it is more likely to progress and require surgery.

Surgical Management: The surgical management of Keinbock's disease is divided into three methods, namely:

1. Joint Leveling: This method is advised in two stages, stages A and B, where it is done to increase or decrease the length of the bone. The radial bone is shortened mechanically by a surgical procedure called capitate shortening osteotomy to reduce the workload. The procedure is performed along with a bone graft to promote blood flow.

2. Revascularization: This is seen in stage three cases. It is the method of promoting the bone with more blood supply, and this is achieved by:

• Directly Revascularization: This method is done to increase the blood flow to the bone by placing a vascularized bone graft (bone tissue with rich blood vessels taken from one part of the body to another).

• Indirect Revascularization: This is done by core compression, applying pressure using clean and firm material like gauze and compression band-aids to promote blood flow.

3. Joint Salvage: This is indicated in stage four of disease progression. It is a procedure done to increase the blood supply in the bone by doing an intensive curettage (it is a procedure in which dead or infected tissue at a particular site is scooped out to promote healing) in the affected area, which results in fresh oozing out of the blood.

What Are the Conditions That Resemble Kienbock Disease?

• Ulnar Impaction Syndrome: It is a combination of complex diseases causing injuries to the fibrous cartilage, lunate bone, and ligaments resulting in wrist pain.

• Lunate Intraosseous: A cyst seen on the carpal bone affects wrist motion.

• Bone contusion: It is also called a bone bruise, which occurs due to trauma.

• Arthritis: It is the inflammation of the bony joints causing stiffness and compromised joint movements.

• Osteoid Osteoma: It is a non-cancerous tumor of the bone, usually measuring less than one centimeter in size.

• Enostosis: It is also called a bone island, and it is seen as a small dense, bony growth that is non-cancerous and asymptomatic.

What Are the Complications of Kienbock Disease?

Keinbock's disease can lead to other systemic complications that are:

• Scapholunate Dissociation - It is the dissociation of small bones of the wrist.

• Midcarpal Degenerative Arthrosis - It is a carpal bone's wear and tear.

• Triquetrum Malignancy - It is a giant cell tumor seen in the wrist.

What Is the Prognosis of Kienbock Disease?

Keinbock's disease shows a sustained progression of destroying the wrist joint within three to five years from the onset of the disease. Although it shows a rapid progression, the prognosis depends on the following:

• The amount of healthy bone remaining in comparison to the necrosed bone.

• Age of the patient: the younger the age, the better the healing.

• A lesser variation in the radial inclination.

Conclusion:

Kienbock's disease is a fracture of the lunate bone of the wrist occurring due to a lack of blood supply. Finding the cause and treating the bone with a viable bone graft is essential to increase blood flow. When diagnosed early and treated with a suitable method, the disease shows a good prognosis and outcome, restoring the wrist function.