Kienbock's disease

Kienböck disease is condition where the lunate (one of the carpal bones) develops osteonecrosis (the bone loses its blood supply, dies and crumbles). It is most common in males aged 20-40 and can cause wrist pain, limited wrist motion and arthritis. Kienbock disease was first described by the Austrian radiologist Robert Kienböck in 1910. Over the last century there has been progress in understanding the disease, but its exact cause, natural history and best treatment is not known.

The image on the right shows the names of the wrist and hand bones. The lunate bone is one of the small bones of the wrist. It is in contact with the radius, scaphoid, triquetral and capitate bones. (Image credit: HandDecide)

Causes

Suggested causes of Kienböck disease mostly relate to the anatomy of the blood vessels or surrounding bones.

• The pattern of arterial blood supply to the lunate (which is mostly from the palmar side, but also comes through 1-3 holes in the dorsal side). People with a single blood vessel supplying the lunate or with limited branching of the blood vessels may be at greater risk of Kienböck disease.

• A problem with blood flow away from the lunate (obstruction of veins).

• The length of the ulna; a Swedish study in 1928 suggested that patients who had a short ulna (or a long radius) were more likely to develop Kienböck disease.

• Lunate size (smaller lunates may be more likely to develop Kienbock disease).

Symptoms

• Pain and weakness of the affected wrist

• Rarely affects both hands

• Variable severity: may be mild and intermittent, or severe and debilitating

• Pain is exacerbated by activities, especially extension and loading of the wrist

• Tenderness +/- swelling over the lunate

• Reduced flexion/extension of the wrist

• Loss of grip strength

The degree of changes on an x-ray do not always match with the severity of symptoms - it is possible to have severe symptoms and no changes on an x-ray, or to have mild symptoms and severe changes on an x-ray.

X-rays and scans

X-rays are normal early in the disease.  As Kienböck disease progresses the lunate becomes sclerotic (denser and whiter on the x-ray) and smaller, with signs of arthritis (reduced gap between bones with fuzziness of the bone edges on the x-ray). Bone scans show abnormalities, but these are not diagnostic of Kienböck disease.

MRI is a very useful test to diagnose Kienböck disease, especially in the early stages of the disease when x-rays are normal. The MRI image on the right shows early disease where the lunate is a different colour (darker) than the normal bones, but the bone is of normal size and shape with no signs of arthritis.

Stages

Treatment is determined by the stage of the disease. Kienböck disease is described as having 4 stages (according to the “Lichtman’s” Classification, which is the most common classification used). Stage 1 is the earliest and Stage 4 is advanced disease.

Lichtman’s Classification of Kienböck Disease

Stage	Appearance on X-rays and MRI
Stage 1	Normal x-ray, signal intensity changes on MRI
Stage 2	Lunate sclerosis on plain x-ray, fracture lines may be present
Stage 3A	Normal carpal alignment and height
Stage 3B	Fixed scaphoid rotation, proximal capitate migration, loss of carpal height
Stage 4	Lunate collapse along with radiocarpal or midcarpal arthritis

Treatment

Because the precise natural history of Kienböck disease is unknown treatment is not necessarily required in people who have no symptoms. There are a variety of treatment options and no treatment has been clearly proven to be superior to another. Many patients improve with non-surgical treatment and a trial of non-surgical treatment is warranted in most patients. Non-surgical treatment involves immobilisation with a splint or cast, combined with anti-inflammatories and pain medications.

Surgical treatment is appropriate for patients who remain symptomatic despite a trial of non-surgical treatment. Anatomical features (such as the relative length of your ulna and radius) are taken into account in determining which procedure is appropriate for you.

In early disease (stages 1-3A) the aim of surgery is to restore the blood supply to the lunate or take pressure off the lunate (or both). This can include pedicled bone grafts (including ones based on the 4 + 5 extracompartmental artery and vascularised pisiform bone transfer), free vascularised bone graft from the hip bone, radial closing wedge osteotomy, radial dome osteotomy and capitate shortening. The MRI image on the right shows early disease, with a lunate of normal size and shape with no arthritis.

In advanced disease (stages 3B and 4) the aim of surgery is to fuse the arthritic joints or to remove the arthritic bones. This can include fusion of carpal bones, lunate removal, shortening of the radius, proximal row carpectomy (removal of the scaphoid, lunate, triquetrum and pisiform), wrist arthrodesis (wrist fusion) and wrist denervation (cutting of the nerves that transmit pain from the wrist). The x-ray on the right shows the collapse and arthritis seen in advanced disease.

Treatment

Stage	Treatment
Stage 1	Cast immobilisation for 3 months
Stage 2 or 3A	Radial shortening, ulnar lengthening or capitate shortening for patients with ulnar-negative variance
Stage 2 or 3A	Vascularised bone graft and external fixation; radial wedge or dome osteotomy, capitate shortening for patients with ulnar positive variance
Stage 3B	Intercarpal fusion (STT, scaphocapitate), lunate removal, radial shortening, proximal row carpectomy
Stage 4	Proximal row carpectomy, wrist arthrodesis, wrist denervation

 

Image Credits

The X-ray and MRI images on this page are from Radiopaedia.org

Reference

Lutsky K, Beredjiklian PK. Kienböck Disease. J Hand Surg 2012;37A:1942–1952