http://upload.orthobullets.com/topic/6079/images/Preaxial Polydactyly - clinical image_moved.jpg
http://upload.orthobullets.com/topic/6079/images/wassel deformity.jpg
http://upload.orthobullets.com/topic/6079/images/Duplicate thumb 1 - colorado_moved.jpg
http://upload.orthobullets.com/topic/6079/images/wasseltypeii.jpg
http://upload.orthobullets.com/topic/6079/images/Duplicate thumb 2 - colorado_moved.jpg
http://upload.orthobullets.com/topic/6079/images/capture_type_3.jpg
Introduction
  • A congential malformation of the hand
  • Three forms exist
    • preaxial polydactlyly 
      • thumb duplication 
    • postaxial polydactlyly
      • small finger duplication
    • central polydactlyly
Preaxial Polydactyly (Thumb Duplication)
  • Epidemiology
    • incidence
      • 1 per 1,000 to 10,000 live births 
      • Type IV most common (43%) 
      • Type II second most common (15%)
    • demographics
      • M>F
      • caucasian > African Americans
  • Genetics
    • inheritance pattern
      • usually unilateral and sporadic 
      • except for Type VII which is associated with several syndrome including
        • Holt-Oram syndrome
        • Fanconi's anemia
        • Blackfan-Diamond anemia
        • imperforate anus
        • cleft palate
        • tibial defects
  • Associated conditions
    • pollex abductus
      • abnormal connection between EPL and FPL tendons, seen in approximately 20% of hypoplastic and duplicated thumbs
      • suggested by abduction of affected digit + absence of IP joint crease
  • Classification
 Wassel Classification of Preaxial Polydactyly 
Type I Bifid distal phalanx   
Type II Duplicated distal phalanx                            
Type III Bifid proximal phalanx                                
Type IV Duplicated proximal phalanx (most common)  
Type V Bifid metacarpal  
Type VI Duplicated metacarpal  
Type VII Triphalangia  

  • Treatment
    • operative
      • goals of treatment
        • to construct a thumb that is 80% of the size of the contralateral thumb
        • resect smaller thumb (usually radial component)
        • preserve / reconstruct medial collateral structures in order to preserve pinch function
        • reconstruction of all components typically done in one procedure
      • type 1 combination procedure (Bilhaut-Cloquet)   
        • indications
          • type I, II, or III
        • technique
          • involves removing central tissue and combining both digits into one
        • outcomes
          • approximately 20% have late deformity
          • problems include stiffness, angular and size deformity, growth arrest, and nail deformities
      • type 2 combination procedure
        • indications
          • usually favored approach for type III and IV
          • type V and VI usually require more complex transfer of intrinsics and collateral ligaments
        • technique
          • preserve skeleton and nail of one component and augment with soft tissue from other digit and ablation of lesser digit (radial digit most commonly)
      • type 3 combination procedure
        • indications
          • when one digit has superior proximal component and one digit has superior distal fragment (type V, VI, and VII)
        • technique
          • a segmental distal transfer (on-top plasty)
Postaxial Polydactyly (Small Finger Duplication)
  • Epidemiology
    • demographics
      • 10X more common in African Americans
  • Genetics
    • inherited as autosomal dominant (AD) in African Americans
    • more complex genetics in caucasians and a thorough genetic workup should be performed  
  • Classification
    • Type A - well formed digit
    • Type B - rudimentary skin tag (vestigial digits)
  • Treatment
    • operative
      • formal reconstruction with a Type 2 combination
        • indications
          • Type A
        • technique
          • preserve radial digit
          • preserve or reconstruct collateral ligaments from ulnar digit remnant
          • preserve muscles
      • tie off in nursery or amputate before 1 year of age
        • indications
          • Type B
Central Polydactyly
  • Epidemiology
    • commonly associated with syndactyly 
      • extra digit may lead to angular deformity or impaired motion
  • Treatment
    • osteotomy and ligament reconstructions
      • indications
        • perform early to prevent angular growth deformities
 

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Questions (3)

(OBQ10.151) Which of the following congenital hand deformities displayed in figures A-E is more prevalent in patients of African-American ancestry? Review Topic

QID:3239
FIGURES:
1

Figure A

2%

(28/1586)

2

Figure B

74%

(1166/1586)

3

Figure C

12%

(197/1586)

4

Figure D

6%

(94/1586)

5

Figure E

5%

(84/1586)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

Image B is consistent for postaxial polydactyly, which is more prevalent in patients of African-American ancestry.

The cohort study by Woolf found the incidence of postaxial polydactyly in African americans is 12.42 per 1,000 (1.2%) compared to the Caucasian incidence of 0.91 per 1,000 (0.09%). If postaxial polydactyly is found in a patient of Caucasian ancestry then further workup for underlying syndromes (chondroectodermal dysplasia or Ellis-van Creveld syndrome) is needed.

The article by Orioli is a case-control study that hypothesizes that a sex-linked recessive modifier gene occurs more frequently in African americans and this gene then promotes the autosomal dominant polydactyly gene.

Incorrect Answers: Constriction band syndrome or amniotic band syndrome is a type of pseudosyndactyly (Figure A) and is not the result of failure of differentiation during embryogenesis, but a result of injury by bands after the fingers are formed. Preaxial polydactyly (Figure C) is more common in caucasians and is usually sporadic except for triphalangism which is associated with Holt-Oram and Fanconi's Anemia. Syndactyly (Figure D) is defined as an abnormal interconnection between adjacent digits and syndactyly variations are associated with Apert syndrome and Poland syndrome. Macrodactyly (Figure E) represents overgrowth of all structures of the involved digit and is associated with neurofibromatosis and Klippel-Trenaunay-Weber syndrome.


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(OBQ09.54) The Bilhaut-Cloquet procedure for thumb duplication, where the central portions of bone and nail are removed and the radial half of one thumb is combined with the ulnar half of the other to create one thumb, is most appropriate in which Wassel Type shown in Figure A? Review Topic

QID:2867
FIGURES:
1

Type 2

48%

(955/1974)

2

Type 4

28%

(544/1974)

3

Type 5

14%

(279/1974)

4

Type 6

7%

(147/1974)

5

Type 7

2%

(31/1974)

Select Answer to see Preferred Response

PREFERRED RESPONSE 1

The Bilhaut-Cloquet procedure has been shown to be successful in Wassel Type 1, 2, and 3 deformities. Asymmetrical Type I or II duplications with distinct components may also be treated with ablation of the smaller thumb with transfer of the collateral ligament and centralization of the extensor tendon. Types 3 and 4 duplications (Type 4= most common duplication) are often treated with selection of a dominant thumb and ablation of the lesser counterpart after preservation and transfer of intrinics and collateral ligaments.

The article by Ogino states that the ablation of the radial thumb is most common and Miller's Review states radial thumb ablation is preferred. Treatment of Types 5 and 6 duplication utilizes similar principles as Type 4 deformities, with the added complexity of additional intrinsic reconstruction. Type 7 is a triphalangeal thumb and has variable treatment based on the presentation, and reconstruction includes excision versus fusion of the extra phalanx.

Baek el al conducted a Level 4 review of 7 patients with Type 3 and Type 4 duplication treated with an extra-articular modified Bilhaut-Cloquet and found excellent IP joint range of motion, no nail deformities, and no episodes of growth arrest.


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Question COMMENTS (2)

(OBQ09.146) Which of the following upper extremity congenital anomalies, represented in the figures below, if found in an individual of Caucasian descent requires a work-up for chondroectodermal dysplasia or Ellis-van Creveld syndrome? Review Topic

QID:2959
FIGURES:
1

Figure A

20%

(282/1381)

2

Figure B

38%

(522/1381)

3

Figure C

12%

(161/1381)

4

Figure D

5%

(68/1381)

5

Figure E

24%

(337/1381)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

Postaxial polydactyly is rare in Caucasian individuals and deserves further workup for underlying syndromes. Postaxial polydactyly is ten times more common in African Americans and does not require further workup. Constriction band syndrome or amniotic band syndrome is a type of pseudosyndactyly(Figure A) and is not the result of failure of differentiation during embryogenesis, but a result of injury by bands after the fingers are formed. Preaxial polydactyly (Figure C) is more common in Caucasians and is usually sporadic except for triphalangism which is associated with Holt-Oram and Fanconi's Anemia. Syndactyly (Figure D) is defined as an abnormal interconnection between adjacent digits and syndactyly variations are associated with Apert syndrome and Poland syndrome. Macrodactyly (Figure E) represents overgrowth of all structures of the involved digit and is associated with neurofibromatosis and Klippel-Trenaunay-Weber syndrome. The referenced article by Kozin is an excellent Current Concepts Review that summarizes upper limb embryogenesis and the most common anomalies.

Authors:

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