Hand Surgery Source

Polydactyly - observation

Test, Exam and Signs

Description

  • A patient with polydactyly will have an extra digit or digits. Joints, tendons and ligaments may also be affected. Polydactyly may severely decrease hand function, especially if it involves the thumb. Parents or guardians may seek operative treatment for functional and/or cosmetic reasons.1
  • Polydactyly is primarily diagnosed by observation. It is also possible to diagnose polydactyly through ultrasound, at 14 weeks of pregnancy or later.
  • Polydactyly is often syndromic; for example, it can be related to Down’s syndrome or Poland syndrome.2

Pathophysiology

  • Polydactyly can be inherited as an autosomal dominant or recessive mutation. Autosomal dominant phenotypes are usually less severe.2

Instructions

  1. Diagnose polydactyly primarily through observation. It may occur in any finger, but is not usually bilateral. 
  2. Check whether polydactyly of the central fingers is hidden within a syndactyly.3
  3. Ask the parent or guardian if the patient has any difficulties with hand function in daily activities. 
  4. Confirm the diagnosis by taking a history of the patient. 
  5. Examine the contralateral hand.

Variations

  • Polydactyly may be hidden within a syndactyly, which is called synpolydactyly.

Related Signs and Tests

  • Ultrasound, starting at 14 weeks of pregnancy
  • Radiographs

Diagnostic Performance Characteristics

  • (NA)

Differential Diagnoses

  • Clinodactyly
  • Camptodactyly
  • Synpolydactyly
  • Dermatologic manifestations of Down’s syndrome
  • Poland syndrome2
Presentation Photos and Related Diagrams
Polydactyly Clinical Photos
  • Polydactyly left hand with extra fifth finger
    Polydactyly left hand with extra fifth finger
  • Polydactyly right hand with extra fifth finger
    Polydactyly right hand with extra fifth finger
Definition of Positive Result
  • A positive result occurs when the patient presents with an extra digit or digits.
Definition of Negative Result
  • A negative result occurs when the patient does not present with an extra digit.  
Comments and Pearls
  • Operative treatment may be indicated when the patient is between 1-2 years old. This treatment may include intricate bone, ligament, and tendon realignments.3
Diagnoses Associated with Tests, Exams and Signs
References
  1. Singer G, Thein S, Kraus T, et al. Ulnar polydactyly - an analysis of appearance and postoperative outcome. J Pediatr Surg2014;49(3):474-6. PMID: 24650481
  2. Ahmed H, Akbari H, Emami A, et al. Genetic overview of syndactyly and polydactyly. Plast Reconstr Surg Glob Open 2017;5(11):e1549.PMID: 29263957
  3. Faust KC, Kimbrough T, Oakes JE, et al. Polydactyly of the hand. Am J Orthop2015;44(5):e127-34.PMID: 25950541