Fact-sheet: Avascular necrosis of lunatum - Kienböck disease
Updated on 03/25/2020 at 10:56 AM
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Definition
Avascular necrosis of the lunate.
Etiopathogenesis not clearly established.
Predictive factors:
- Trauma: repeated microtrauma in hyperextension
- Biomechanical predisposition: shorter ulna, increased radial inclination
- Vascular predisposition: insufficient arterial supply, venous hyperpressure.
Sex ratio: 7 men/1 woman
20-40 years old
Manual laborer
Clinical features
- Insidious onset
- Pain on the dorsal aspect of the wrist
- Decreased range of motion, predominantly in extension
- Loss of grip strength
Radiography
First-line:
- Sclerosis then fragmentation of the lunate
- Radiocarpal osteoarthritis
- Scaphoid tilt
- Negative ulnar variance
CT
Not essential.
Bone sclerosis.
At a later stage, fragmentation of the lunate.
MRI
Early diagnosis:
Lunate signal:
- Hypointense on T1
- hyperintense on T2 (edema)
- No enhancement on post-gadolinium T1
Management
Conservative management with analgesics and immobilization.
Surgical treatment if failure.
Classification
Lichtman classification:
• Stage I: normal radiograph
• Stage II: sclerosis of the lunate
• Stage III:
– IIIA: lunate collapse without carpal collapse
– IIIB: lunate collapse with carpal collapse, decreased lunate height, scaphoid flexion
• Stage IV: stage III with carpal osteoarthritis
Differential diagnosis
- Lunate fracture
- Ulnocarpal impaction syndrome
