KIENBOCK'S DISEASE

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.

The typical patient with Kienbock’s disease is a young male with a mechanical job such as carpentry.  The complaint is usually unilateral dorsal wrist pain with a history of trauma or lees specific repetitive injuries.  Also, patients frequently complain of associated wrist swelling, decreased wrist motion and loss of grip strength.

Unloading

• Joint leveling: distal radioulnar joint (DRUJ) complications, partial wrist denervation
• Radial shortening osteotomy: ulnar impaction syndrome, DRUJ dysfunction, nonunion
• Capitate shortening: increased scaphotrapezial load

Revascularization

• Infection

Salvage procedures

• STT: surgical failure, nonunion
• PRC: synovitis

Unloading

• Immobilization: conflicting findings; some studies show improvement in pain and others show disease progression
• Closing radial wedge osteotomy: ROM, grip strength and pain continue to improve after 10 years; however, 73% showed osteoarthritic changes and radiographic progression

Revascularization

• VBG: ROM, grip strength, pain scores improved; 77% of patients showed no further collapse; 71% showed evidence of revascularization
• Capitate shortening: 83% lunate healing and revascularization

Salvage procedures

• PRC: satisfactory results; grip strength increased to 65% of opposite side
• Total wrist fusion: fewer surgical failures, better post-op pain scores, higher patient satisfaction (vs carpal fusion)

• When staging Kienböck’s disease, the most reliable method of differentiating between stages IIIA and IIIB is radioscaphoid angle of greater than 60 degrees. Lichtman stage IIIB of Kienböck’s disease implies sclerosis and fragmentation of the lunate accompanied by scaphoid rotation and carpal collapse/instability. Scaphoid position can be assessed by measurement of the radioscaphoid angle.
• Negative ulnar variance is statistically associated with Kienböck’s disease.
• Based on proximity the 4 +5 extensor compartmental artery graft is the recommended choice of bone graft for the treatment of early stages of Kienbock’s disease.
• Vascularized reconstruction of the lunate in Kienbock’s disease is contraindicated for lunate fracture or collapse with extruded fragments.
• Pediatric Kienbock's disease is more likely to heal with immobilization than adult Kienbock's disease especially in patients younger than age 12 with intact lunate morphology.

New Articles

1. Stahl S, Hentschel PJ, Held M, et al. Characteristic features and natural evolution of Kienböck's disease: Five years' results of a prospective case series and retrospective case series of 106 patients. J Plast Reconstr Aesthet Surg 2014;67(10):1415-26.
2. Viljakka T, Tallroth K, Vastamäki M. Long-term outcome (20 to 33 years) of radial shortening osteotomy for Kienböck's lunatomalacia. J Hand Surg Eur 2014;39(7):761-9.
3. Lichtman DM, Pientka WF, Bain GI.  KIENBÖCK DISEASE: MOVING FORWARD. J Hand Surg (Am) 2016; 41 (May): 630-638.

Reviews

1. Stahl S, Stahl AS, Meisner C, et al. A systematic review of the etiopathogenesis of Kienböck's disease and a critical appraisal of its recognition as an occupational disease related to hand-arm vibration. BMC Musculoskelet Disord 2012;13:225.
2. Lichtman DM, Lesley NE, Simmons SP. The classification and treatment of Kienbock's disease: the state of the art and a look at the future. J Hand Surg Eur 2010;35(7):549-54.

Classics

1. Stahl, F. On lunatomalacia (Kienböck’s disease). A clinical and roentgenological study, especially on its pathogenesis and the late results of immobilization treatment. Acta Chir Scand Suppl 1947:126.
2. Lichtman DM, Mack GR, MacDonald RI, et al. Kienböck's disease: the role of silicone replacement arthroplasty. J Bone Joint Surg Am 1977;59(7):899-908.
3. Kienböck R. Über traumatische Malazie des Mondbeins und Kompression Fracturen. Fortschr Roentgenstrahlen 1910-11;16:77-103.