Kienböck's disease involves collapse of the lunate bone in the wrist and is caused by vascular insufficiency and avascular necrosis of the lunate. It is usually unilateral. This was first described by Robert Kienböck in 1910.
The avascular necrosis is caused by disruption of blood supply to the lunate. This may be caused by:
- Single or repetitive microfractures
- Recurrent compression of the lunate between capitate and distal radius (this disrupts interosseous blood supply)
- Extreme wrist positions or repetitive compression loading of the wrist
Gymnasts may be at risk. Use of agents such as corticosteroids or systemic disease such as osteoporosis could in theory predispose to Kienböck's disease but a study of bilateral disease did not find such risk factors.
It occurs most often in young adults between 15 and 40 years of age.
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- It is difficult to diagnose in the early stages when symptoms are similar to wrist sprain.
- It presents as wrist pain with pain and tenderness over the lunate.
- The pain may radiate up the wrist and forearm.
- There is associated stiffness at the wrist.
- There may be a history of a single injury or repetitive injury/compression loading.
- There may be associated swelling over the lunate.
- Passive dorsiflexion of the middle finger produces the characteristic pain.
- There may be limitation of wrist dorsiflexion, but wrist extension can also be limited.
- There is often a weakened grip.
Symptoms are progressive and chronic as the lunate bone progressively collapses and degenerative changes occur.
Wrist sprains and any cause of arthritis in the wrist joint may give similar symptoms.
- Wrist X-ray:
- Initially, this may be normal or show sclerosis of the lunate.
- It may show ulnar variance.
- The lunate shows progressive loss of height, and fragmentation.
- The lunate collapse causes further degenerative joint changes (because of carpal instability) with bone cysts within the lunate.
- Eventually, degenerative changes may involve the whole wrist.
- Ulnar variance has been held as important in the aetiology and treatment of Kienböck's disease but meta-analysis reveals that there is insufficient evidence to support this hypothesis.
- Measurement of ulnar variance requires a zero rotation view on a PA radiograph of the wrist in neutral pronation/supination. This measurement is mentioned a lot in relation to wrist disease. It is not simple to measure accurately.
- X-rays may show no specific abnormality in the early stages and so MRI scans are essential if early Kienbock's disease is suspected.
There are two classifications of Kienböck's disease:
- Stahl's classification (stages 1 to 5, from normal with evidence of lunate compression to 5 with osteoarthrosis of radial carpal and inner carpal joints).
- Lichtman's classification (Stages 1 to 4).
A simplified version is:
- Stage 1. Symptoms are similar to wrist sprain. Normal X-rays or a line indicating possible fracture. MRI may be useful to confirm diagnosis.
- Stage 2. Symptoms of recurrent pain and swelling. The lunate bone becomes hard/sclerotic and X-ray shows this sclerosis (indicating the bone is infarcting). CT and MRI scanning may be useful to assess the condition of the lunate bone.
- Stage 3. Increasing pain, weakened grip and limited wrist movement occur. The infarcted bone collapses and breaks up, causing a shift in position of the surrounding bones.
- Stage 4. Disruption of the surrounding bones causes arthritis of the wrist.
The aim is to reduce compressive loading of the lunate, permitting revascularisation and preventing lunate collapse. In early disease this may be aided by splinting and anti-inflammatories. Referral to an orthopaedic or hand surgeon is recommended. The aim of reducing lunate loading and allowing revascularisation may require surgery:
- Establishing a negative ulnar variance (unloading the lunate fossa and distributing load to the scaphoid fossa) by:
- Radial shortening
- Ulnar lengthening
- Fusion of the capitate and hamate
- Scaphotrapeziotrapezoid (STT) joint fusion (up to stage 3)
- Vascular bundle implantation.
- Establish neutral ulnar variance by radial wedge osteotomy.
These procedures are for more advanced disease and used less often:
- Wrist arthrodesis. This may be necessary when severe degenerative changes are present and when the hands are used for heavy labour.
- Proximal row carpectomy. This may not work with Kienböck's disease because of damage to the articular surfaces of the capitate and radius.
Stiffness and progressive loss of wrist function are well-described sequelae of the condition. Grip strength deteriorates by 40% between stages 2 and 4 of the disease.
If left untreated it is a progressive disease passing through the various stages described by Lichtman. However, it is picked up as an incidental finding on X-rays and it does not always cause pain or interfere with activities of daily living.
Awareness of this condition can prompt earlier diagnosis and corrective measures to prevent progression of the disease. However, it should be remembered that symptoms can be mild for many years with no treatment.
Further reading & references
- Lamas C, Carrera A, Proubasta I, et al; The anatomy and vascularity of the lunate: considerations applied to Kienbock's disease. Chir Main. 2007 Feb;26(1):13-20. Epub 2007 Feb 8.
- Yazaki N, Nakamura R, Nakao E, et al; Bilateral Kienbock's disease. J Hand Surg (Br). 2005 May;30(2):133-6.
- Chung KC, Spilson MS, Kim MH; Is negative ulnar variance a risk factor for Kienbock's disease? A meta-analysis. Ann Plast Surg. 2001 Nov;47(5):494-9.
- Jung JM, Baek GH, Kim JH, et al; Changes in ulnar variance in relation to forearm rotation and grip. J Bone Joint Surg Br. 2001 Sep;83(7):1029-33.
- Schuurman AH, Maas M, Dijkstra PF, et al; Assessment of ulnar variance: a radiological investigation in a Dutch population. Skeletal Radiol. 2001 Nov;30(11):633-8. Epub 2001 Sep 15.
- Laframboise MA, Gringmuth R, Greenwood C; Kienbock's disease in a varsity football player: a case report and review of the literature. J Can Chiropr Assoc. 2012 Dec;56(4):275-82.
- Kienbock's disease: Lunatomalacia; Wheeless' Textbook of Orthopaedics
- Taniguchi Y, Nakao S, Tamaki T; Incidentally diagnosed Kienbock's disease. Clin Orthop Relat Res. 2002 Feb;(395):121-7.
|Original Author: Dr Richard Draper||Current Version: Dr Colin Tidy||Peer Reviewer: Dr John Cox|
|Last Checked: 22/04/2013||Document ID: 3046 Version: 23||© EMIS|
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