Causes / typical injury mechanism: Avascular necrosis of the lunate bone, also known as Kienböck disease, leads to eventual collapse and loss of architecture of the carpal bones, leading to advanced wrist arthritis.

Classic history and presentation: This presents as insidious, progressive wrist pain with a history of trauma but negative x-rays in the past.

Prevalence:

• Age – This is most common in men between the ages of 20 and 40 years.
• Sex / gender – Male predominance.

Risk factors:

• Ulnar negative wrist variance, which leads to increased radial-lunate contact stress
• Decreased radial inclination
• Repetitive trauma

Grade / classification system:
Lichtman classification

• I: Changes on MRI only
• II: Sclerotic changes in the lunate
• IIIA: Collapse of lunate with NO scaphoid rotation
• IIIB: Collapse of lunate with fixed scaphoid rotation
• IV: Degenerative changes seen in the intercarpal joints

Bain and Begg classification (used in arthroscopy)

• 0-4 based on the number of articular surfaces that are involved and are "nonfunctional"