Kienböck’s Disease (Osteonecrosis of the Lunate Bone)

Kienböck’s disease is also known as osteonecrosis or avascular necrosis (AVN) of the lunate. The lunate is one of the eight small bones in the wrist. It is the central bone in the wrist that is important for proper movement and support of the joint. It works closely with the two forearm bones (the radius and ulna) to help the wrist move. Kienböck’s disease was first recognized and described by Austrian radiologist Robert Kienböck, in 1910.

Kienböck’s disease is the second most common type of osteonecrosis affecting the carpal bones, with osteonecrosis of the scaphoid being more frequent. However, if the lunate bone develops this condition, its blood supply is disrupted, leading to its necrosis.

This can contribute to the appearance of symptoms such as progressive, severe pain, limited range of motion, or weakness in the wrist.

The exact cause of Kienböck’s disease remains unclear. However, several potential factors are believed to contribute to the development of the condition. More specifically, repetitive injuries to the wrist may disrupt the blood supply to the lunate bone.

Repeated impact on the wrist—especially in occupations or sports that involve repetitive hand and wrist movements—may play a significant role in the onset of the disease.

Key contributors include the presence of several anatomic variations such as a shorter ulna bone (ulnar variance) or less radial tilt, which can put increased pressure on the lunate and hinder its blood supply. Other factors such as vascular issues or medical conditions  (like lupus or sickle cell anemia)  affecting small blood vessels and bone health can also increase the risk of developing the condition.

In order to select the optimal therapeutic approach, it is important to classify the disease into different stages based on the condition of the lunate bone and the extent of the damage. The most commonly used classification system is the Lichtman system, which categorizes the disease into four stages:

• Stage I: During the first stage of the disease, the symptoms are similar to those of a wrist sprain. Although the blood supply to the lunate has been disrupted, X-rays may still appear normal or suggest a possible fracture. An MRI scan can better show bone edema and detect the effects of abnormal blood flow to the lunate bone.
• Stage II: In Stage 2, X-rays still do not contribute to diagnosis, while MRI or CT scans reveal intraosseous fractures.
• Stage III: In Stage 3, the lunate bone begins to harden due to the lack of blood supply. This hardening process is called sclerosis and is an abnormal increase in bone density. The lunate will appear brighter or whiter in areas on X-rays, which indicates that the bone is denser. To better assess the condition of the lunate, your doctor may order either an MRI scan or a computed tomography (CT) scan.
• Stage IV:  In Stage 4, the progression of the condition involves the entire wrist joint, with the lunate bone fragmented and collapsed, leading to osteoarthritis and a high risk of carpal instability.This advanced stage is characterized by severe wrist pain, stiffness, instability, and a diminished range of motion, indicating a progressive and destructive process of bone death and joint degeneration.
• Stage V: Manifestation of complete disintegration and collapse of the wrist, along with advanced arthritis affecting the entire wrist joint.

The symptoms of Kienböck’s disease may vary from person to person and often progress gradually. Some of the most common symptoms are the following:

Early Symptoms

• Wrist Pain: Often mild initially, this pain is typically located over the lunate bone (in the center of the wrist) and worsens with activity.
• Tenderness: The area over the lunate bone may feel tender to the touch.
• Swelling: The wrist may become swollen.

As the Disease Progresses

• Increased Pain: The pain becomes more persistent and intense.
• Stiffness and Reduced Motion: The range of motion in the affected wrist decreases, leading to a stiff feeling.
• Weakness: There may be a noticeable decrease in grip strength.
• Crepitus: Some individuals may experience creaking or crackling sounds when moving the wrist.

Late-Stage Symptoms 

• Deformity: In advanced stages, the lunate bone can collapse or fragment, leading to visible deformities.
• Arthritis: The collapse of the lunate and misalignment of wrist bones can result in the development of advanced arthritis.

The diagnosis of Kienböck’s disease requires a thorough evaluation by a specialist orthopedic surgeon. The diagnostic process usually begins with taking a detailed medical history, during which the doctor will ask about the patient’s symptoms, such as wrist pain (dull or sharp), swelling, stiffness, or a crackling sensation during movement.

Then, he will also ask about previous wrist injuries or repetitive activities that may have contributed to the condition. Finally, a clinical examination is performed to assess the wrist’s range of motion, stability, and signs of tenderness or swelling. Imaging tests play a crucial role in confirming the diagnosis and determining the stage of the disease.

X-rays are often the first imaging test used and can help identify any changes in the shape, alignment, or density of the bone. However, X-rays may not be able to detect Kienböck’s disease in its early stages.

In such cases, the specialist orthopedic surgeon may suggest magnetic resonance imaging (MRI) and computed tomography (CT) scans.

• Magnetic Resonance Imaging (MRI) provides detailed images of the lunate and surrounding soft tissues and is crucial for detecting early signs of the disease and changes in blood supply.
• Computed Tomography (CT) scans may be used to get more detailed images of the wrist bones if an MRI or X-ray is not sufficient.

The imaging tests are essential for confirming the diagnosis and determining the specific stage of Kienböck’s disease, which helps guide the treatment plan.

The primary goals for treating Kienböck’s disease are to manage pain, maintain the wrist’s range of motion, and restore strength, with treatment plans tailored to the disease’s stage, the patient’s age, and his/her functional needs.

Early diagnosis is crucial for effective treatment, as structural and shape changes in the lunate bone are irreversible once they occur.

Kienböck’s disease can initially be managed with conservative treatments like physiotherapy, activity modification, and immobilization with a cast or splint, especially in early stages.

However, surgical intervention is often required for advanced stages where conservative methods fail to provide symptom relief.

The chosen surgical technique depends on the disease stage, the patient’s anatomy, and the surgeon’s expertise.

Surgical options for Kienböck’s disease are chosen by disease stage and wrist characteristics, including early-stage procedures like radial shortening osteotomy to relieve pressure on the lunate, revascularization procedures such as vascularized bone grafts for blood supply, and middle-to-late stage procedures like proximal row carpectomy or limited wrist fusions.

For advanced cases with lunate collapse, such as total wrist arthrodesis (fusion) or total wrist arthroplasty (replacement), are used to manage pain and prevent further progression.

Post-Kienböck’s Disease surgery, a personalized physiotherapy program is essential for restoring muscle strength, flexibility, and range of motion in the wrist. The duration of this program, which includes gentle movements, strengthening exercises, and dexterity training, varies based on the specific surgery performed and the patient’s recovery rate.

Close monitoring with regular follow-up appointments is crucial to ensure proper healing and a successful outcome.

The accurate and timely approach to Kienböck’s Disease, that involves early diagnosis, accurate assessment of its stage, and a tailored treatment plan, is crucial for controlling symptoms, delaying disease progression, and restoring function. This strategy improves patient outcomes by allowing for earlier, more effective interventions.

Upper Limb Orthopedic Surgeon Dr. Panagiotis Pantos performs thorough and reliable diagnosis of the condition, applying a fully personalized treatment plan.