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- This is a clinical photo of thumb duplication aka Preaxial polydactyly
- 1. Level of Duplication - hazard a guess
- 2. Which duplicate dominate - radio/ ulnar
- 3. Assess web space
- 4. Rotation/ angular deformity of thumb
- 5. Stability of MCPJ/ IPJ
- Hx and PE -
- Offer to look at XR
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- It is a swanson type 3 deformity - 3. Embryology and Physis - ‼️ Classification of hand deformities?
- G - Sonic hedgehog gene mutation
- E - Affecting zone of Polarizing activity (ZPA) in limb growth; affecting radial-ulna growth
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- Family history - can be AD inheritance
- Other medical conditions - triphalangism associations systemic medical issues
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- 1. Assess Duplicate
- Decide - which is the duplicate, cosmesis by cover test, look at finger bulk
- Compared with contralateral side
- Compared with index finger
- Aim to be bigger than index finger and at least 70% of contralateral side
- Nail folds - integrity
- 2. Evaluate Joint stability, contractures
- Skin creases over joints - suggests good mobility
- 1st web contracture - may be contracted and need to be lengthened (if tight unable to grip things
- Stability - ulnar, radial deviation, hyperextension at MCPJ, IPJ
- 3. Tendons - check EPL, FPL if cooperative
- 4. Neurovascular of each digit - digital allens test, 2PD
- 5. Function - key, pen.
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- Wassel Classification
- 1/2 bifid and duplicate DP
- 3/4 bifid and duplicate PP
- 5/6 Bifid and Duplicate MC
- 7 = traiphalangia = type 4 with one of them extra phalanx (3 phalanges)
- MOST COMMON IS TYPE 4 - 43%
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- Wassel 4 involves the MCPJ, have to be mindful when reconstructing to also repair or reattach the collateral ligaments to prevent ulnar and radial deviation and instablity (actually this principle is also for the IPJ)
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- Type 7 - Triphalangia
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- Fanconi Anemia - AR condition, mean survival 16 yo
- TAR (thrombocytopenia with absent Radius) - AR condition. Rare. A/w cardiac abnormalities - Atrial Septal Defect, Tetralogy of Fallot
- Congenital heart abnormalities - Holt-Oram [heart + radius problem only]
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- Vertebral defects, Anal atresia, Cardiac defects, Tracheo-esophageal fistula, Esophageal Atresia, Renal anomalies, Limb abnormalities
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- To achieve adequate size, webspace, stable joint, good power, cosmesis, neurovascular
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- Most difficult scenario is if both thumbs are hypoplastic and CMCJ is not satisfactory. In this case, no reconstruction is ideal.
- Options are
- Simple excision of floating thumb (Ablation)
- Bilhault Cloquet procedure (this procedure is only for type 1/2)
- This is done if both duplicates are smaller than necessary and need to combine
- Need to reconstruct collateral ligaments
- Reinsertion of APB
- May need to centralize the EPL/ FPL
- Wedge osteotomy to correct alignment (e.g. in divergent convergent type 4)
- Widening of 1st web space if type
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- Early but not premature
- After 1 year of age
- Do surgery
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- bulky dressing - in a boxing glove method to prevent dressing getting loose
- Use absorbable sutures for closure (no need STO)
- If osteotomy - can remove wires 4-6 weeks
OTHER TYPES OF POLYDACTYLY
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- Small finger duplication
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- A/w polydactyly
