Syndactyly

Introduction

Most common congenital malformation of the limbs
Epidemiology
- incidence
  - 1 in 2,000 - 2,500 live births
- demographics
  - M > F
  - Caucasians > African Americans
- ray involvement
  - 50% long-ring finger
  - 30% ring-small finger
  - 15% index-long finger
  - 5% thumb-index finger
Pathophysiology
- failure of apoptosis to separate digits
Genetics
- autosomal dominant in cases of pure syndactyly
  - reduced penetrance and variable expression
    - positive family history in 10-40% of cases
Associated conditions
- acrosyndactyly
  - digits fuse distally and proximal digit has fenestrations (e.g., constriction ring syndrome)
- Poland Syndrome
- Apert Syndrome
- Carpenter syndrome
  - acrocephalopolysyndactyly

Classification

Syndactyly Classification
Simple	Only soft tissue involvement, no bony connections
Complex	Side to side fusion of adjacent phalanges
Complicated	Accessory phalanges or abnormal bones involved in fusion
Complete vs. Incomplete	Complete syndactyly the skin extends to finger tips; with incomplete, skin does not extend to fingertips

Treatment

Operative
- release of involved digits
  - indications
    - syndactyly
      - perform at ~ 1 year of age
    - acrosyndactyly
      - perform in neonatal period

Technique

Digit Release
- if multiple digits are involved perform procedure in two stages to avoid compromising vasculature
- release digits with significant length differences first to avoid growth disturbances
- zigzag flaps are created during release to avoid longitudinal scarring
- most common complication is web creep

Complications

Web creep
- reconstruct web space with local skin flaps
Nail deformities

TAG

(OBQ11.125) Figure A depicts a child with syndactyly. Following surgical treatment, the most common complication involves which of the following? Topic

Review Topic

FIGURES: A

1. Nail plate
2. Nail bed
3. Web commissure
4. Radial digital nerve
5. Radial digital artery

PREFERRED RESPONSE ▶

DISCUSSION: Web creep, the most common complication of this procedure, is the distal migration of the web commissure seen in surgically corrected syndactyly patients. It is caused by abnormal scar tissue formation and increasing growth of underlying osseous structures. Informing parents of this complication preoperatively is advised.

Deunk et al reviewed the long-term results of 27 patients treated with either STSG or FTSG at 21 years. The STSG group had increased flexion and extension lags but decreased finger abduction and increased graft breakdown. The FTSG had higher rates of web creep, hyperpigmentation and hair presence. The authors did not favor one technique over the other.

Ricterman et al performed a radiographic analysis of web height in children. They were able to radiographically determine a standard web height quantification system using anatomic landmarks. This technique serves as the foundation for measuring web creep in syndactlyly.

Illustration A is a clinical photo demonstrating web creep as a late complication.

Illustrations: A

REFERENCES:

1. Deunk J, Nicolai JP, Hamburg SM. Long-term results of syndactyly correction: full-thickness versus split-thickness skin grafts. J Hand Surg Br. 2003 Apr;28(2):125-30. PMID:12631483 (Link to Abstract)

2. Richterman IE, DuPree J, Thoder J, Kozin SH. The radiographic analysis of web height. J Hand Surg Am. 1998 Nov;23(6):1071-6. PMID:9848561 (Link to Abstract)

Question Authors:

Terrill Julien MD, John Badylak MD,

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Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012

Undefined

Deunk J, Nicolai JP, Hamburg SM. Long-term results of syndactyly correction: full-thickness versus split-thickness skin grafts. J Hand Surg Br. 2003 Apr;28(2):125-30. PMID:12631483 (Link to Abstract)
Richterman IE, DuPree J, Thoder J, Kozin SH. The radiographic analysis of web height. J Hand Surg Am. 1998 Nov;23(6):1071-6. PMID:9848561 (Link to Abstract)

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