Kienböck’s disease, or lunatomalacia, is idiovascular avascular necrosis of the lunate. Essentially, the blood supply to this carpal bone is compromised leading to lunate collapse and radioulnate degeneration. The pathogenesis of Kienböck’s disease is debated, but likely attributed to multiple inter-related factors, including individual patient differences in carpal anatomy, biomechanics and repetitive trauma. Ulnar negative variance, variations in lunate morphology, anatomic variations in lunate vascular supply, and certain wrist kinematics have all been implicated
in the pathogenesis of Kienbock's Disease.
Related Anatomy
- Lunate
- Capitate
- Hamate
- Distal radius
- Triangular fibrocartilage (TFC)
- Ulnar variance
Incidence and Related Conditions
- Kienböck’s disease usually affects those aged 20-40 years; most are male manual laborers
- Typically unilateral; both sides can be equally affected
- Frequently associated with a specific traumatic event
Differential Diagnosis
- Ulnocarpal impaction syndrome
- Fracture
- Enchondroma
- Intraosseous ganglion
- Osteoid osteoma
Staging
- Most common staging system developed by Stahl (1947)1 and modified by Lichtman et al (1977)2,3:
Stage 0
Wrist pain with normal X-rays and normal MRI
Stage I
X-rays are generally normal, but a linear fracture through the lunate may be noted. MRI will demonstrate a diffuse T1 signal decrease in lunate. Bone scan will be positive.
Stage II
Sclerosis of the lunate will be seen on X-rays. Multiple fracture lines may be seen through the lunate. Collapse of the lunate has not occurred.
Stage IIIA
Lunate collapse has occurred, but the carpal height and alignment have been maintained.
Stage IIIB
Lunate collapse has occurred, and the capitate has migrated proximally. The scaphoid assumes a flexed position.
Stage IIIC
Lunate fragmentation or coronal fracture
Stage IV
This is a continuation of stage IIIB disease with the addition of radiocarpal and/or midcarpal arthritis.
