Kienböck’s disease

What is Kienböck’s disease?

Kienböck’s disease, also referred to as lunate avascular necrosis, lunate malacia, or lunate osteonecrosis, is named after the Austrian radiologist Robert Kienböck, and is an aseptic necrosis of the lunate bone. The term ‘necrosis’ describes the pathological death of cells leading to an inflammatory process. The term ‘aseptic’ indicates that this process is not caused by an infection.

The lunate is a carpal bone in the wrist which is shaped like a crescent moon. It forms a joint with the radius proximally (toward the forearm), and with the second row of carpal bones distally (toward the fingers). Laterally, it forms a joint with the neighboring bones of the first carpal row, including the scaphoid and triquetrum.

Kienböck’s disease predominantly affects individuals between the ages of 20 and 40.

How does Kienböck’s disease develop and what role does occupational stress play?

The exact cause of Kienböck’s disease is not fully understood. It appears to be a vascular pathology of non-traumatic origin, leading to insufficient blood supply to the proximal part of the lunate bone. Various factors may predispose patients to develop this condition. However, these factors have not been sufficiently confirmed by scientific studies. Potential causes include:

• mechanical strain, particularly from working with vibrating machinery (e.g. pneumatic hammers)
• radius plus variant: a relative lengthening of the radius compared to the ulna, for instance due to a growth disturbance of the ulna following an injury to the growth plate in childhood
• ulna plus variant: same as described above, but with a relative lengthening of the ulna compared to the radius
• certain anatomical variants of local vasculature, as well as variations in the orientation of trabecular bone within the lunate

What symptoms does Kienböck’s disease cause?

Kienböck’s disease typically presents with intermittent pain at first, particularly during physical strain or when pressure is applied to the bone. Due to the local inflammatory reaction, the wrist may also become warm and/or swollen.

As the disease progresses, there is a reduction in wrist mobility due to the development of osteoarthritis as well as loss of motor strength. The grip strength of the affected hand is often reduced by more than half compared to the healthy hand.

How is Kienböck’s disease diagnosed?

If a patient reports symptoms suggestive of Kienböck’s disease, the first medical appointment includes a thorough medical history, focusing on potential risk factors and a detailed description of the symptoms. During the physical examination, the physician will check for local signs of inflammation in the wrist area. Tenderness upon palpation over the lunate is a common finding. Range of motion and grip strength of the wrist should also be assessed.

If necrosis of the lunate is suspected, an X-ray of the wrist is performed. This image is carefully evaluated, and the stage is determined in accordance with specific radiographic changes using the Lichtman classification.  This classification not only confirms the diagnosis but also provides further clues regarding the severity of the disease.

If the X-ray does not show any signs of necrosis or other pathologies explaining the symptoms, magnetic resonance imaging (MRI) may be able to detect the condition. Especially during early stages, necrosis of the lunate is often only visible on MRI scans.

What treatment options are available for Kienböck’s disease and what are the associated risks?

Like the uncertainly regarding its causes, there is no consensus in literature about the best treatment for Kienböck’s disease. However, there is a common consensus regarding the prevention of the progression to carpal collapse and subsequent osteoarthritis. Depending on the stage of the disease, various treatments may be used.

In early stages, disease progression can be potentially prevented through immobilization of the wrist in a cast for several weeks to months. Pain may be managed with analgesics and cooling of the wrist.

Regardless of the disease stage, wrist denervation may provide additional symptom relief. During this procedure, nerve fibers responsible for the conduction of pain (nociceptive nerve fibers) that innervate the affected area are transected. This procedure targets only pain-conducting fibers, meaning motor function and general sensation are preserved.

If the condition has already progressed, or conservative management is insufficient, surgical treatment becomes necessary. Several surgical techniques are available.

In the case of a radius-plus or ulna-plus variant, the bone presenting with an overlength can be surgically shortened, or the shorter bone lengthened.

Especially in younger patients with moderately advanced stages of Kienböck’s disease, revascularization may be a reasonable treatment option. This procedure includes debridement of the necrotic tissue and transplantation of a bone graft into the lunate, commonly harvested from the radius with the supplying blood vessel. If the surgery is successful, the lunate’s blood supply is restored resulting in resolution of the disease.

Another treatment option in the moderately advanced stage is the STT arthrodesis, which involves the surgical fusion of the scaphoid, trapezium, and trapezoid carpal bones using wires. While this leads to a mild reduction in wrist mobility, it also leads to a significant pain relief, as well as improvement in grip strength.

In more advanced stages, the entire row of carpal bones may be removed. While the wrist mobility becomes significantly impaired, a degree of mobility is still intact.

If the carpal bones are already severely damaged by advanced osteoarthritis, a total wrist arthrodesis using a metal plate is usually the last treatment choice to treat the pain and improve load-bearing capacity. The mobility of the fingers and forearm remains intact.

The most significant risk of surgery, varying in severity depending on the type of procedure, and sometimes inevitable, is a reduction in wrist mobility. All procedures that do not excise or fuse the lunate carry a potential of disease progression despite surgery. Furthermore, general surgical risks apply such as bleeding, infection, and injury to adjacent structures.

Who covers the costs of treatment for Kienböck’s disease?

If a medical indication is made, conservative and surgical treatments are generally covered by statutory and private health insurance.

Which physicians and clinics specialize in the treatment of Kienböck’s disease?

Physicians who have completed additional training in hand surgery are specialized in the diagnosis and management of conditions including Kienböck’s disease. The subspecialty can be attained by board certified specialists in surgery or orthopedics who have undergone specialized training in hand surgery.

When seeking medical care, patients naturally wish for the best quality of treatment. Therefore, patients ask themselves: Where can I find the best clinic or physician for my condition? Since this question cannot be answered objectively and no reputable physician would claim to be “the best”, one must rely on the experience of the physician.

We help you find an expert for your condition. All listed physicians and clinics have been carefully reviewed for their outstanding specialization in the field of Kienböck’s disease and look forward to your enquiry.