Fracture, Lunate/Kienböck Disease
Kevin E. Burroughs
BasicsDescription
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Kienböck (pronounced “Keen-bock”) disease, or lunatomalacia, is a painful disorder of the wrist in which there are histologic and radiologic changes showing avascular necrosis of the lunate.
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1st described in 1910 by Robert Kienböck
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Synonym(s): Lunatomalacia; Lunate avascular necrosis
Epidemiology
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Most commonly seen between the ages 20 and 40 yrs
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Predilection for the right hand in manual laborers
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Bilateral changes occur less frequently than unilateral changes.
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A 2% incidence of asymptomatic cases was reported in a large study of African patients.
Risk Factors
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Previous wrist trauma including lunate fracture
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Negative ulnar variance
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Repetitive trauma (manual labor)
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Anatomic and biomechanical features, including vulnerable blood supply or fixed position of the wrist (loss of range of motion)
Etiology
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A true etiology of Kienböck disease is unknown; however, the end result of lunate fragmentation and collapse is definitively osteonecrosis.
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Essentially two theories exist: Vascular and mechanical.
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Increased intraosseous pressures have been recorded in Kienböck disease, supporting impaired venous outflow as a potential etiology. Revascularization success with vascular pedicle grafts also supports the circulatory etiology.
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Mechanical theory describes necrosis secondary to progressive trabecular collapse of the lunate owing to excessive loads and repetitive microfractures. Anatomic factors that would lead to abnormal pressure on the lunate would include negative ulnar variance, uncovering of the lunate by the distal radius, the shape of the lunate (trapezoidal), the existence of a midcarpal facet on the lunate to articulate with the hamate, and radial inclination of the distal radius.
DiagnosisLichtman classification of staging for Kienböck disease (via x-ray):
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Stage I: Normal architecture and bone density; may be either a linear or a compression fracture
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Stage II: Definite density changes, but size, shape, and anatomic relationship of the bones not altered; later in this stage, anteroposterior (AP) view shows loss of height on radial side of lunate.
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Stage IIIa: Entire lunate collapse, but the carpal height is relatively unchanged.
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Stage IIIb: There is additionally proximal migration of the capitate and disruption of the carpal architecture, including a fixed hyperflexion of the scaphoid (cortical ring sign). On lateral view, a dorsovolar ribbon-like elongation of the lunate is seen.
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Stage IV: In addition to stage III changes, generalized degenerative changes in the carpus
History
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Longer duration of pain increases probability.
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Both an inciting traumatic event and repetitive trauma have been linked with the occurrence of Kienböck disease.
Physical Exam
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Painful, stiff, and often swollen wrist joint
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Usually >1 mo of pain at presentation
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Pain most often mild to moderate in severity
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Asymptomatic presentation can occur.
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Look for swelling, erythema, and calor at the radioulnar joint. Erythema and calor are not associated with Kienböck disease.
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Evaluate range of motion; decreased in Kienböck disease, especially dorsiflexion.
Diagnostic Tests & Interpretation
Lab
Laboratory tests for the diagnosis of common arthritides can be used in those with wrist symptoms, but no radiographic findings can be used to determine other possible causes.
Imaging
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Standard AP and lateral radiographs
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Initially, the lunate may have normal architecture and density.
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Subsequently, increasing density of the lunate; then altered shape and diminished size
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Adjacent arthritic changes and carpal row collapse
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CT scan may be useful to detect early changes, including fracture lines.
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Radiographic measures such as a smaller lunate diameter and height, a more radially inclined lunate tilting angle, and a flatter radial inclination have been shown in those with Kienböck disease (see Thienpont reference for descriptors).
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MRI:
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T1-weighted images show loss of signal intensity (corresponding to osteonecrosis).
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T2-weighted images initially may show hyperintensity (early signs of osteonecrosis).
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If negative, can rule out Kienböck disease in a patient with wrist symptoms; may show alternative diagnosis better than plain films.
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Diagnostic Procedures/Surgery
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Wrist arthroscopy has been used to assess and classify Kienböck disease.
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Assessment of the surfaces of the lunate is used to stage disease and plan appropriate surgical interventions.
P.215
Differential Diagnosis
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Physical examination:
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Triangular fibrocartilage complex tear (more lateral)
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Scapholunate ligament instability
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Distal radioulnar joint complex ligament instability
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Monarticular arthritides (multiple)
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X-ray:
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Lunate fracture
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Degenerative joint disease carpals
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Treatment-
Acute treatment
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Immobilization:
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In early stages, immobilization for 7 days is a reasonable 1st step because synovitis and tenosynovitis usually resolve, and examination may become more focused.
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After classification is established, in stage I, initial treatment consists of up to 3 mos of casting or similar form of immobilization.
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Arthroscopy with synovectomy also can be used for intervention in stages I and II.
Additional Treatment
Additional Therapies
Over time, it has become evident that immobilization will not prevent long-term collapse of the lunate. Some studies showed similar pain relief in conservative versus surgical treatment.
Surgery/Other Procedures
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If the patient still has pain after conservative measures or has more advanced disease, there are a few other options.
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In stage II or IIIA with positive ulnar variance: Direct revascularization plus external fixation or temporary scaphotrapeziotrapezoid pinning (stage II only), radial wedge or dome osteotomy, capitate shortening with or without capitohamate fusion, combination of joint leveling and direct revascularization procedures.
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In stage II and IIIA with negative or neutral ulnar variance: Radius-shortening osteotomy, ulnar lengthening, capitate shortening
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In stage IIIB: Scaphotrapeziotrapezoid or scaphocapitate fusion with or without lunate excision with palmaris longus autograft, radius-shortening osteotomy, proximal row carpectomy
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In stage IV: Proximal row carpectomy, wrist arthrodesis, wrist denervation
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Silicone arthroplasty is no longer performed because of poor long-term results.
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Lunate excision can reduce symptoms but does not prevent carpal collapse.
Ongoing CareFollow-Up Recommendations
Prompt referral to an orthopedist after detection to evaluate, accurately stage, and discuss with the patient available current treatments
Complications
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A continuum from wrist stiffness to a fused and immovable wrist
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Persistent pain
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Nonunion in attempted arthrodesis
Additional Reading
Alexander AH, Lichtman DM. Kienböck's disease. Orthop Clin North Am. 1986;17:461–472.
Allan CH, Joshi A, Lichtman DM. Kienböck's disease: diagnosis and treatment. J Am Acad Orthop Surg. 2001;9:128–136.
Bain GI, Begg M. Arthroscopic assessment and classification of Kienböck's disease. Tech Hand Up Extrem Surg. 2006;10:8–13.
Beckenbaugh RD, Shives TC, Dobyns JH, et al. Kienböck's disease: the natural history of Kienböck's disease and consideration of lunate fractures. Clin Orthop Relat Res. 1980;149:98–106.
Bonzar M, Firrell JC, Hainer M, et al. Kienböck disease and negative ulnar variance. J Bone Joint Surg Am. 1998;80:1154–1157.
Gelberman RH, Szabo RM. Kienböck's disease. Orthop Clin North Am. 1984;15:355–367.
Jackson MD, Barry DT, Geiringer SR. Magnetic resonance imaging of the avascular necrosis of the lunate. Arch Phys Med Rehab. 1990;71:510–513.
Kuschner SH, Brien WW, Bindiger A, et al. Review of treatment results for Kienböck's disease. Orthop Rev. 1992;21:717–728.
Lichtman DM, Mack GR, MacDonald RI, et al. Kienböck's disease: the role of silicone replacement arthroplasty. J Bone Joint Surg 1977;59A:899–908.
Luo J, Diao E. Kienböck's disease: an approach to treatment. Hand Clin. 2006;22:465–473; abstract vi.
Mennen U, Sithebe H. The incidence of asymptomatic Kienböck's disease. J Hand Surg Eur Vol. 2009;34:348–350.
Peltier LF. The classic. Concerning traumatic malacia of the lunate and its consequences: degeneration and compression fractures. Privatdozent Dr. Robert Kienböck. Clin Orthop Relat Res. 1980;149:4–8.
Schuind F, Eslami S, Ledoux P. Kienböck's disease. J Bone Joint Surg Br. 2008;90:133–139.
Thienpont E, Mulier T, Rega F, et al. Radiographic analysis of anatomical risk factors for Kienböck's disease. Acta Orthop Belg. 2004;70(5):406–409.
CodesICD9
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732.3 Juvenile osteochondrosis of upper extremity
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814.02 Closed fracture of lunate (semilunar) bone of wrist