Review Question - QID 211127

The patient presents with advanced late-stage Kienbock disease, or avascular necrosis of the lunate. All of the above are risk factors for development of Kienbock disease except for increased carpal height. Conversely, a decrease in the carpal height is associated with avascular necrosis of the lunate.

The etiology of Kienbock disease is multifactorial and includes ulnar negative variance, decreased radial inclination, vascular congestion from high interosseous pressure, and medical conditions including scleroderma, sickle cell anemia, systemic lupus erythematosus, and corticosteroid use. The condition is more prevalent in men ages 20-40 and may also be associated with a history of trauma. Immobilization is the treatment for early Kienbock disease, prior to lunate collapse, after which surgical intervention is indicated.

Nakamura et al. compared 20 patients with Kienbocks who underwent a proximal row carpectomy (7) with those who underwent limited wrist fusion (13). They found that those who underwent a PRC had inferior range of motion, strength, and increased pain. The authors recommended consideration of scapho-trapezio-trapezoid (STT) fusion for patients with advanced Kienbock disease, as limited wrist fusion (STT or SC) or joint leveling procedures (radial shortening or capitate shortening) may help decompress the lunate. However, they concluded that late disease with lunate collapse may require proximal row carpectomy or total wrist fusion.

Lichtman et al. reviewed a series of 38 patients who underwent silicone arthroplasty for Kienbock disease. Fourteen of 20 patients had satisfactory result when the surgery was done before the lunate collapsed. The authors stressed early diagnosis and early surgical intervention.

Condit et al. reviewed 23 patients who underwent STT fusion or radial shortening osteotomy for Kienbock disease. They found that when the scaphoid was flexed (Lichtman stage IIIB), no patient had a good result regardless of surgical procedure. In general, outcomes in the radial shortening cohort were superior. The authors stressed consideration of radioscaphoid angle as preoperative predictor of surgical success.

Goldfarb et al. evaluated wrist radiographs from patients with Kienbock disease. They found that the interobserver reliability of the Lichtman classification was generally very high (k=0.63). However, that for stage IIIA (lunate collapse without scaphoid flexion) was poor (k=0.38). The authors stressed the difference in IIIA and IIIB (lunate collapse) is the presence of fixed scaphoid flexion in IIIB.

Figures:
Figure A is an AP X-Ray of a patient with Kienbock disease, Lichtman stage IIIB. The lunate is collapsed and there is a loss of carpal height secondary to proximal capitate migration.
Figure B is a lateral X-Ray of a patient with Kienbock disease, Lichtman stage IIIB, demonstrating a flexed scaphoid.

Incorrect answers:
Answer 1: Ulnar negative variance has been postulated as a cause which may put additional pressure on the lunate, leading to avascular necrosis.
Answer 2: High interosseous pressure, particularly greater than 40mmHg as compared to the capitate, may predispose to avascular necrosis.
Answer 3: A number of medical conditions may lead to avascular necrosis.
Answer 4: A decreased radial inclination has been associated with lunate avascular necrosis by possibly increasing radio-lunate contact pressure