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Year : 2020  |  Volume : 12  |  Issue : 1  |  Page : 99-101

Wassel's type i modification of duplicate thumb?

1 Department of General Surgery, Consultant Plastic Surgeon, Newadkar Plastic Surgery Center, Dhule, Maharashtra, India
2 Department of Oral Medicine and Radiology, ACPM Dental College, Dhule, Maharashtra, India

Date of Submission14-Mar-2019
Date of Acceptance23-Apr-2020
Date of Web Publication26-Jun-2020

Correspondence Address:
Dr. Ujwala Rohan Newadkar
Department of Oral Medicine and Radiology, ACPM Dental College, Dhule - 424 003, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jotr.jotr_15_19

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Patients with polydactyly of the thumb demonstrate very miscellaneous manifestations, from a rudimentary floating type to a complex one. The Wassel classification system is a useful method for classifying duplicated thumbs. Bifurcation at the metacarpophalangeal joint (Type IV) is the most common type. Although Wassel classification is good, there are few shortcomings in it. Removing the nondominant part and reconstructing the dominant part are the most common procedures for thumb duplication. The aim of surgical intervention that addresses duplication thumbs is to attain a firm, mobile thumb of appropriate shape and acceptable size. Surgical concepts and techniques are still evolving. Here, we present an interesting case report of Wassel's Type I modification of duplicate thumb.

Keywords: Duplicate thumb, polydactyly, Wassel classification

How to cite this article:
Newadkar RD, Newadkar UR. Wassel's type i modification of duplicate thumb?. J Orthop Traumatol Rehabil 2020;12:99-101

How to cite this URL:
Newadkar RD, Newadkar UR. Wassel's type i modification of duplicate thumb?. J Orthop Traumatol Rehabil [serial online] 2020 [cited 2020 Oct 22];12:99-101. Available from: https://www.jotr.in/text.asp?2020/12/1/99/287708

  Introduction Top

Thumb polydactyly is the most common type of polydactyly in the hand. It is believed to arise from excessive cell proliferation and disturbed cell necrosis of preaxial ectodermal and mesodermal tissues before the 8th week of embryonic life.[1] A basic error in the Wassel classification is that it is based on an evaluation of the skeleton only. Hence, the exact nature of it cannot be radiologically evident in the case of a skeletally young patient. Type I duplication can be classified as a Type II till the ossification of a basal cartilaginous connection becomes apparent, which is not possible to define the status of physes and epiphyses. Wassel terminology affords rather a good structure for the management of a thumb duplication. The skilled and knowledgeable surgeons will definitely aware of the anomalies associated with each type, as it is important during the reconstruction. Here, we present a case report of Wassel's Type I modification of duplicate thumb with the proper management.

  Case Report Top

A 8-year-old girl reported to the hospital with the complaint of esthetically disturbed thumb of the right hand [Figure 1]. On examination, a large thumb of the left hand was noticed. Posterioanterior radiographic view of the hand revealed the duplication of thumb with a common physeal plate for distal phalanges. This was an interesting feature of our case. It was uncommon as that of the Wassel Types I and II; hence, it can be proposed as Wassel Type I modification [Figure 1]. Incision was given, as shown in [Figure 2]a. Common physeal plate and the radial phalanx were identified [Figure 2]b. The radial collateral ligament was isolated from phalanx and preserved. The radial phalanx was freed from the attachments and excised. The common physeal plate was trimmed out [Figure 2]c. Central nail and soft tissue were removed. The ulnar phalanx was centralized with 1.5 mm K-wire. Radial collateral ligament was fixed to the radial side of an ulnar phalanx with nonabsorbable suture. Radial soft tissue was sutured to the nail and nail bed. Wound was closed with absorbable sutures [Figure 2]d. Thumb spica was given for immobilization. Thumb spica was removed at 4 weeks, and K-wire was removed at 6 weeks. Postoperative follow-up [Figure 2]e showed satisfactorily functional and esthetical results.
Figure 1: Clinical assessment and radiographic features and Wassel's type

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Figure 2: Intraoperative and postoperative assessment. (a) markings, (b) exploration, (c) excised physeal plate, (d) immediate post-operative, (e) follow up

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  Discussion Top

The thumb, responsible for 40% of the hand function, must be able to oppose the other digits with a stable pinch. Congenital thumb duplication is the most frequent abnormality of the first digit. It occurs sporadically with an incidence of eight in 100,000 in both black and white populations. It occurs in a male-to-female ratio of 2.5:1 and is most often unilateral.[2] According to its anatomical location, polydactyly can be generally subdivided into pre- and post-axial forms. There is a gene responsible for preaxial polydactyly types II and III as well as for complex polysyndactyly, which is located on chromosome 7q36.[3] At present, the Wassel classification is universally accepted to categorize the pathoanatomy of the polydactyly and to guide respective surgical procedures. Wassel's original system, first published in 1969, describes seven classes of thumb deformities with the duplication in each class occurring at different levels along the bones of the thumb. Ezaki recommended surgical intervention at the age of 6–9 months, before fine motor skills have developed with abnormal anatomy. Various types of Wassel classification system, characteristic features of each and surgical modalities have been mentioned in the [Table 1]. Dijkman et al. recommended a reliable assessment system – the Japanese Society for Surgery of the Hand – to evaluate functional and esthetic outcomes after surgery for radial polydactyly by comparing several assessment systems.[5],[6]
Table 1: Wassel Classification

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Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Yasuda M. Pathogenesis of preaxial polydactyly of the hand in human embryos. J Embryol Exp Morphol 1975;33:745-56.  Back to cited text no. 1
Chew EM, Yong FC, Teoh LC. The oblique wedge osteotomy of the metacarpal condyle for reconstructing Wassel type IV thumb duplication in older children and adults. J Hand Surg Eur Vol 2010;35:669-75.  Back to cited text no. 2
Cho TJ, Baek GH, Lee HR, Moon HJ, Yoo WJ, Choi IH. Tibial hemimelia-polydactyly-five-fingered hand syndrome associated with a 404 G>A mutation in a distant sonic hedgehog cis-regulator (ZRS): A case report. J Pediatr Orthop B 2013;22:219-21.  Back to cited text no. 3
Manske MC, Kennedy CD, Huang JI. Classifications in brief: The Wassel classification for radial polydactyly. Clin Orthop Relat Res 2017;475:1740-6.  Back to cited text no. 4
Patel AU, Tonkin MA, Smith BJ, Alshehri AH, Lawson RD. Factors affecting surgical results of Wassel type IV duplications. J Hand Surg Eur Vol 2014;39:944-7.  Back to cited text no. 5
Dijkman RR, van Nieuwenhoven CA, Selles RW, Hovius SE. Comparison of functional outcome scores in radial polydactyly. J Bone Joint Surg Am 2014;96:463-70.  Back to cited text no. 6


  [Figure 1], [Figure 2]

  [Table 1]


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