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Kirner's Deformity - observation

Exams and Signs

Historical Overview

  • Kirner’s deformity was first reported in 1927.1

Description

  • Kirner’s deformity affects the metacarpophalangeal (MP) or distal interphalangeal (DIP) joints of the small fingers. There may also be a shortening or curving of the terminal phalanx. Kirner’s deformity should not produce any pain or inflammation.
  • Patients with Kirner’s deformity may present with an L-shaped physis, similar to the C-shaped bracket observed in clinodactyly.2

Pathophysiology

  • The test for Kirner’s deformity can help diagnose camptodactyly, clinodactyly, physeal fracture, Salter-Harris fracture and frostbite. 

Instructions

  1. Observe the hand for shortening or curving of the distal phalanx of the small fingers. Determine whether the patient experiences any pain or inflammation in this area. 
  2. Check the DIP joint for extensor lag. 
  3. Confirm the diagnosis by taking a patient history, with particular attention to the functional ability of the small fingers.
  4. Examine the contralateral hand, as Kirner’s deformity is often bilateral.1

Variations

  • Also check for subluxation at the DIP joint.

Related Signs and Tests

  • Range of motion (ROM), active
  • Watch-glass nail 
  • Radiographs
  • Magnetic resonance imaging (MRI) 

Diagnostic Performance Characteristics

  • Kirner’s deformity is usually evident with a physical examination. Radiographs may improve the reliability of diagnosing mild cases.

Differential Diagnoses

  • Camptodactyly
  • Clinodactyly
  • Physeal fracture
  • Salter-Harris fracture
  • Frostbite
  • Infection

Additional Information

Presentation Photos and Related Diagrams
Kirner's Deformity
  • Kirner's Deformity left fifth finger
    Kirner's Deformity left fifth finger
Definition of Positive Result
  • A positive result occurs when the patient presents with shortening or curving of the distal phalanx of the small fingers.
Definition of Negative Result
  • A negative result occurs when the patient does not present with shortening or curving of the distal phalanx of the small fingers. 
Comments and Pearls
  • Operative treatment may be considered if Kirner’s deformity is impeding writing, typing, or playing a musical instrument. 3
Diagnoses Associated with Exams and Signs
References
  1. David TJ, Burwood RL. The nature and inheritance of Kirner’s deformity. J Med Genet1972;9:430. PMID: 4646550
  2. Fairbank SM, Rozen WM, Coombs CJ. The pathogenesis of Kirner's deformity: A clinical, radiological and histological study.J Hand Surg Eur 2015;40(6):633-7. PMID: 25274771
  3. Rayan G, Akelman E. The Hand: Anatomy, Examination and Diagnosis. Philadelphia: Lippincott Williams & Wilkins, 2012.
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