Camptodactyly

Camptodactyly is a clinical or imaging descriptive term where there is a flexion contracture (usually congenital). Classically this occurs at the proximal interphalangeal joint of the little finger of the hand, although any finger may be affected.

Epidemiology

Prevalence ~1%; one-third unilateral, two-thirds bilateral ^ref.

Clinical presentation

The age of presentation can vary from detection in utero on an antenatal scan or as an obvious deformity after birth or in childhood.

Pathology

There is often thought to be an abnormal insertion of the lumbrical or flexor digitorum tendons.

Genetics

It can occur sporadically or with an autosomal dominant inheritance with variable penetrance and expressivity.

Associations

While it can occur in isolation, there are numerous associations with the presence of camptodactyly (especially if detected on obstetric imaging):

• aneuploidy syndromes ³
  • trisomy 18
  • trisomy 13
• non-aneuploidy syndromes
  • Freeman Sheldon syndrome
  • Pena Shokeir syndrome ⁵
  • camptodactyly-arthropathy-coxa vara-pericarditis (CACP) syndrome ²
• other conditions causing arthrogryposis

Classification

• type I
  • isolated anomaly of the little finger, presents in infancy and affects males and females equally
  • most common form
• type II
  • same clinical features as type I; presents in adolescence
  • affects girls more often than boys 
  • from abnormal lumbrical insertion, abnormal flexor digitorum superficialis (FDS) origin or insertion
• type III
  • severe contractures, multiple digits involved, presents at birth
  • usually associated with a syndrome 
• Kirner's Deformity
  • specific deformity of small finger distal phalanx with volar-radial curvature (apex dorsal-ulnar)
  • often affects preadolescent girls
  • often bilateral
  • usually no functional deficits

Radiographic features

The involved joint is flexed and often cannot be straightened. The phalangeal head may be small and if the flexion contracture is severe enough, the phalangeal head may articulate with and erode the dorsal cortex of the neck of the proximal phalanx.

Treatment and prognosis

• non-operative: stretching or splinting
• operative: lumbrical insertion excision +/- flexor digitorum superficialis release or transfer