What is Kienböck's disease?

What is Kienböck's Disease?

Kienböck's disease is avascular osteonecrosis (death of bone tissue due to loss of blood supply) of the lunate bone in the wrist, presenting as progressive wrist pain, swelling, and reduced range of motion, typically affecting one wrist. 1, 2

Pathophysiology and Risk Factors

• The disease results from vascular compromise to the lunate bone, leading to progressive bone necrosis and eventual collapse if untreated 1, 2
• Common risk factors include:
  • Negative ulnar variance (anatomical variation where the ulna is shorter than the radius) 1
  • Variations in blood supply to the lunate, particularly when supplied by only one volar vessel 3
  • Direct trauma or repetitive stress fractures 1, 3
  • Increased intraosseous pressure within the bone 1

Clinical Presentation

• Patients present with unilateral wrist pain, limited range of motion, decreased grip strength, and wrist swelling 1, 2
• The disease is rare, making it easily missed in initial evaluations, particularly in regions where it is uncommon 4, 5
• Symptoms may be nonspecific early in the disease course, leading to diagnostic delays that worsen prognosis 5

Diagnostic Approach

Start with standard wrist radiographs (anteroposterior, lateral, and oblique views) as the initial imaging study for any patient with chronic wrist pain. 6, 7

• Radiographic findings vary by disease stage and include:

  • Early stages: Small fracture lines and rarefaction 3
  • Progressive stages: Sclerosis of bone, lunate collapse, joint space narrowing, and subchondral cysts 3, 4
  • Advanced stages: Secondary arthritic changes in the radius and surrounding carpal bones 3, 4

• When Kienböck's disease is suspected but radiographs are normal or nonspecific, MRI without contrast is the gold standard and preferred next step 6, 7

• MRI can detect early osteonecrosis before radiographic changes appear, making it critical for early diagnosis 7

• CT without contrast may be used for surgical planning when evaluating the degree of bone collapse or fragment size 6, 7

Disease Staging

• Staging is based on radiographic characteristics using the modified Lichtman classification system, which guides treatment decisions 1, 4
• The staging system ranges from early disease (Stage I with minimal changes) to advanced disease (Stage IV with secondary arthritis) 1, 3

Common Pitfalls

• The disease is frequently missed initially because wrist pain is nonspecific and the condition is rare 5
• Radiographic features may not correspond directly to clinical symptom severity, particularly in early stages 1
• Delayed diagnosis reduces surgical options and leads to worse outcomes, as the disease is progressive 5
• Regular radiographic follow-up is essential once diagnosed to monitor for disease progression 6, 7