Thank you for your letter outlining the limitations of current classification schemes for thumb polydactyly. In our Current Concepts article on congenital hand differences, I chose to include the Zuidam et al classification diagram for thumb polydactyly
1because I believe it is the most comprehensive yet practical system available. As depicted in the diagram and expanded on in the manuscript, the authors have included 6 subtypes (with modifiers) of the well-accepted Wassel classification.
- Zuidam J.M.
- Selles R.W.
- Ananta M.
- Runia J.
- Hovius S.E.
A classification system of radial polydactyly: inclusion of triphalangeal thumb and triplication.
J Hand Surg. 2008; 33: 373-377
- Wassel H.D.
The results of surgery for polydactyly of the thumb A review.
Clin Orthop Relat Res. 1969; 64: 175-193
However, I share your concerns relating to ossification center development; specifically, the schematic depiction of thumbs represents older children. I agree that most children are treated surgically before these growth centers are radiographically clear. Likewise, I agree that symphalangism may not be present radiographically at an age before surgical intervention.
As noted in the Introduction of their manuscript, Zuidam et al. “propose several modifications to Wassel's classification that result in a more complete taxonomy and more flexible nomenclature to facilitate communication, analysis, and treatment of all known variations.” Although they are imperfect, I believe that their modifications of the Wassel classification meet these stated goals and help both clinician and researcher better understand and treat radial polydactyly.
- A classification system of radial polydactyly: inclusion of triphalangeal thumb and triplication.J Hand Surg. 2008; 33: 373-377
- The results of surgery for polydactyly of the thumb.Clin Orthop Relat Res. 1969; 64: 175-193
© 2010 Published by Elsevier Inc.
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