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Review
. 2017 Jun;475(6):1740-1746.
doi: 10.1007/s11999-016-5068-9. Epub 2016 Sep 9.

Classifications in Brief: The Wassel Classification for Radial Polydactyly

Mary Claire Manske  1 , Colin D Kennedy  2 , Jerry I Huang  2
Affiliations
Review

Classifications in Brief: The Wassel Classification for Radial Polydactyly

Mary Claire Manske et al. Clin Orthop Relat Res. 2017 Jun.
No abstract available

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Figures

Fig. 1
Fig. 1
The Wassel classification system is a radiographic description based on the level of skeletal duplication. From distal to proximal, the phalanges and metacarpal of the thumb are identified as bifid, duplicated, or unaffected, with a Roman numeral assigned based on how proximally the bifurcation or duplication extends. (Published with permission from Wassel HD. The results of surgery for polydactyly of the thumb. Clin Orthop Relat Res. 1969;64:175–193.).
Fig. 2
Fig. 2
The Rotterdam classification of radial polydactyly as described by Zuidam et al. [29] is shown. (Published with permission from Zuidam JM, Selles RW, Ananta M, Runia J, Hovius SE. A classification system of radial polydactyly: inclusion of triphalangeal thumb and triplication. J Hand Surg Am. 2008;33:373–377.).
Fig. 3A–D
Fig. 3A–D
The photographs show the hands of (A) Patient 1 in supination and (B) pronation and (C) for Patient 2 in supination and (D) pronation. Both patients had Type VI thumb duplications. Despite having the same Wassel classification type, the duplications differ regarding the symmetry of thumb development, presence of angular deformity, joint stability, and soft tissue anomalies, which highlights this deficiency of the Wassel classification system. These characteristics are critical to recognize as they inform operative decision-making and influence surgical outcomes.
Fig. 4A–D
Fig. 4A–D
These depictions show the classification of radial polydactyly as described by Chung et al. [4]: (A) Type I is the “joint type,” with the origin of the extra digit as an independent articular surface; (B) Type II is the “epiphyseal type,” with the origin of the extra digit arising from a shared epiphysis; (C) Type III is the “enchondroma type,” with the origin of the extra digit resembling an osteochondroma; and (D) Type IV is the “hypoplastic type,” with the origin of the extra digit consisting of soft tissue only. (Published with permission from Chung MS, Baek GH, Gong HS, Lee, HJ, Kim J, Rhee SH. Radial polydactyly: proposal for a new classification system based on the 159 duplicated thumbs. J Pediatr Orthop. 2013;33:190–196.).
Fig. 5A–C
Fig. 5A–C
(A) A photograph obtained at the time of the clinical examination, (B) a radiograph, and (C) an intraoperative photograph of a patient with thumb duplication are shown. On clinical examination and on the radiograph, it is not clear whether this represents a Wassel Type V or Type VI thumb duplication. Intraoperatively, a cartilaginous bridge between the two metacarpal bases was identified (red arrow), revealing that this is a Type V thumb duplication and highlighting the limitations of classification systems based on radiographic criteria in skeletally immature patients.
See this image and copyright information in PMC

References

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    1. Cabrera Gonzalez M, Perez Lopez LM, Martinez Soto G, Gutierrez de la Iglesia D. Prognostic value of age and Wassel classification in the reconstruction of thumb duplication. J Child Orthop. 2013;7:551–557. - PMC - PubMed
    1. Chung MS, Baek GH, Gong HS, Lee HJ, Kim J, Rhee SH. Radial polydactyly: proposal for a new classification system based on the 159 duplicated thumbs. J Pediatr Orthop. 2013;33:190–196. doi: 10.1097/BPO.0b013e3182648ca8. - DOI - PubMed
    1. Dijkman RR, van Nieuwenhoven CA, Selles RW, Habenicht R, Hovius SE. A multicenter comparative study of two classification system for radial polydactyly. Plast Reconst Surg. 2014;134:991–1001. doi: 10.1097/PRS.0000000000000590. - DOI - PubMed

Supplementary concepts