Kienbock's disease Flashcards
What is Kienböck’s disease?
Avascular necrosis of the lunate bone in the wrist due to compromised blood supply, leading to lunate collapse and wrist dysfunction.
Is Kienböck’s disease typically unilateral or bilateral?
Typically unilateral; bilateral cases are rare, occurring in less than 5%, highlighting a primarily mechanical etiology.
What is the gold standard imaging modality for early detection of Kienböck’s disease?
MRI, which detects decreased lunate vascularity before radiographic changes become apparent.
What radiological staging system is primarily used for Kienböck’s disease?
The Lichtman classification (Stages I-IV), categorizing disease severity based on radiographic and MRI findings.
Describe Lichtman Stage II of Kienböck’s disease.
Lunate sclerosis visible on imaging without structural collapse or fragmentation.
Describe Lichtman Stage IIIB of Kienböck’s disease.
Advanced lunate collapse with proximal migration of the capitate and scaphoid rotation into a flexed position, without significant arthritis.
What differentiates Lichtman Stage IV from earlier stages?
The presence of radiocarpal or midcarpal arthritis due to advanced lunate collapse and structural deterioration.
Why is grip strength reduced in patients with Kienböck’s disease?
Grip strength decreases due to pain, mechanical dysfunction from lunate collapse, and progressive instability affecting wrist mechanics.
What clinical features raise suspicion for early-stage Kienböck’s disease?
Dorsal wrist pain, tenderness over the lunate, activity-related exacerbation, reduced grip strength, and limited wrist range of motion.
What is the primary treatment goal in early-stage Kienböck’s disease?
To reduce mechanical load on the lunate, preventing further necrosis and promoting potential revascularization.
Name a surgical procedure commonly indicated for early-stage Kienböck’s disease associated with negative ulnar variance.
Radial shortening osteotomy, performed to redistribute load away from the lunate.
What alternative surgical methods can unload the lunate in Kienböck’s disease besides radial shortening osteotomy?
Capitate shortening osteotomy or metaphyseal core decompression are alternatives aimed at reducing lunate stress.
What is the rationale behind vascularized bone grafting in Kienböck’s disease?
It aims to restore lunate blood supply and promote bone revascularization, addressing necrosis directly.
Can a positive scapholunate ballotment test reliably diagnose Kienböck’s disease?
No; it indicates scapholunate instability, not lunate avascular necrosis.
What role does conservative management play in early Kienböck’s disease?
Conservative treatment, including immobilization and activity modification, may halt or slow progression in very early or mild cases.
What distinguishes the Lichtman classification from the Bain and Begg arthroscopic system?
Lichtman relies on radiological findings (X-ray, MRI), whereas Bain and Begg classification is arthroscopic, focusing on articular surface condition.
In suspected Kienböck’s disease with normal X-rays, what imaging can confirm diagnosis?
MRI or bone scintigraphy, as they detect early vascular compromise or bone metabolic changes before X-ray abnormalities.
Why is bilateral Kienböck’s disease rare?
Because the condition typically arises from localized mechanical factors rather than systemic issues.
Summarize the natural progression of untreated Kienböck’s disease.
Progressive lunate collapse, carpal instability, and eventual wrist arthritis, severely impairing wrist function.
