View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Erasmus University Digital Repository Full Length Article Journal of Hand Surgery (European Volume) Triphalangeal thumb: clinical features 2019, Vol. 44(1) 69–79 and treatment ! The Author(s) 2018 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1753193418797922 1,2,3 1 Steven E. R. Hovius , Jacob W. P. Potuijt and journals.sagepub.com/home/jhs Christianne A. van Nieuwenhoven1 Abstract Triphalangeal thumb is a rare congenital anomaly in which the thumb has three phalanges. Clinical presen- tation of triphalangeal thumb can vary considerably and can be present in both hands or unilateral. The thumb can be long with a Enger-like appearance. The presence of clinodactyly depends on the shape of the extra phalanx varying from wedge-shaped to rectangular. Various joints, ligaments, muscles, and tendons of the Erst ray can be hypoplastic or absent, with varying degrees of stiffness or instability. The aim of surgical treatment is to reconstruct or correct the anatomic anomalies to obtain greater function and a more accept- able appearance. In our series, operations varied from removal of the delta phalanx with ligament recon- struction to multiple osteotomies and rebalancing of soft tissues. Results in these often complex cases can be rewarding if the surgeon has sufEcient knowledge of the underlying anatomic differences. This review sum- marizes our current concepts of presentation and management of the triphalangeal thumb. Keywords Congenital hand, triphalangeal thumb, reconstruction Date received: 16th June 2018; revised: 7th August 2018; accepted: 7th August 2018 Introduction Based on our results, the prevalence of TPT in the Triphalangeal thumb (TPT) is a congenital hand Netherlands is higher than stated in the literature anomaly in which the thumb has an additional phal- (1:16,000). anx, supposedly first described by Columbo in 1559 Classification of TPT may be according to the three (Columbo-Cremonensis, 1559). Although TPT is a different shapes of the extra phalanx (wedge, trapez- rare anomaly, with an estimated prevalence of 1 in oidal, or rectangular) as described by Wood or by the 25,000 newborns, variable phenotypic features are different encountered shapes from small to large as common (Hovius et al., 2004; Lapidus et al., 1943). reported by Buck-Gramcko who framed it as a The additional phalanx can be present in different ‘Teratologische reihe’ (teratologic row) (Buck- shapes and sizes. An additional preaxial polydactyly Gramcko, 2002; Wood, 1976). When radial polydactyly can be present together with syndactyly and ulnar is present it may be classified according to Wassel polydactyly of the hands. TPT can be present in an isolated form; as part of a syndrome and may be inherited in a dominant manner. In sporadic cases the deformity is unilateral and the thumb will have 1Department of Plastic, Reconstructive and Hand Surgery, a degree of opposition. When TPT is present in a syn- Erasmus University Medical Center, Rotterdam, The Netherlands drome, for example Holt–Oram Syndrome, the thumb 2Department of Plastic and Reconstructive Surgery, Radboud is usually hypoplastic. Two-thirds of patients with University Medical Centre, Nijmegen, The Netherlands 3 TPT in our series have bilateral deformities and a Xpert Clinic, Hand and Wrist surgery, Rotterdam, The family history of thumb abnormalities. Their thumbs Netherlands are mostly non-opposable. The anomaly in this spe- Corresponding Author: Steven E. R. Hovius, Department of Plastic, Reconstructive and cific group is caused by an inherited dominant trait, Hand Surgery, Erasmus University Medical Center, Wytemaweg of which the locus is mostly on chromosome 50, 3015 GE, Rotterdam, The Netherlands. 7q36 (Heutink et al., 1994; Zguricas et al., 1994). Email: [email protected] 70 Journal of Hand Surgery (Eur) 44(1) (1969) or the updated version by Zuidam et al. The functional problem that arises in many (2008b). patients is deficient opposition resulting in difficulty The aim of this article is to present an overview of with activities like writing, picking up smaller objects, the clinical presentation of TPT along with our sug- etc. When radial polydactyly is also present, the func- gested surgical treatments. tion of the best thumb of the two or three is blocked by the presence of the other(s), especially if syndac- Clinical presentation tyly between the thumbs is present. However, the findings in 12 adults (23 hands) with Thumb length varies depending on the size of the untreated TPT, or with only resection of a polydacty- extra middle phalanx of the thumb. Mostly there is lous radial hypoplastic thumb, leaving the TPT thumb a degree of radial or ulnar clinodactyly due to the intact, are interesting. Patients functioned well wedge or trapezoidal shape. although five thumbs had instability at the MP joint The thumb appearance can be thumb-like to more level. Palmar abduction strength, opposition finger-like. The more the thumb looks like a finger strength, and flexion strength at the MP joint level the more the TPT is in the same plane of the hand were, respectively, 36%, 38%, and 39% of the instead of in palmar abduction. Flexor tendons can be strength of the average of the normal population. present as flexor digitorum superficialis and profun- Patients scored lower for the domain of social func- dus or as a single flexor pollicis longus. The first web tioning in the SF-36. Patients scored their function on can be normal to aberrant and the thenar muscles average 7.7 using the visual analogue scores (VAS 0– hypoplastic, malformed or absent. The degree of 10). On appearance however, it was 2.2 (Zuidam et al., opposability of the thumb relates to the thenar 2010). muscle deEciency. Therefore, parents mostly seek correction of the Depending on the length of the thumb and hypo- deformity for their children because of the appear- plastic thenar musculature the TPT is hypermobile at ance of the TPT. In the above study, the affected child the metacarpophalangeal (MP) joint. The carpometa- had often suffered from intensive teasing at school. carpal (CMC) joint can be hypoplastic, malformed, or They and their parents wanted surgery before going even absent. In most cases the CMC joint is less to school. Requests to operate on children because of mobile and less well-developed, particularly when severe functional deficits were rare. the thumb is finger-like, when it is similar to the second CMC joint. Case series Depending on the presence of an extra ray, the tra- pezium and scaphoid are malformed or hypoplastic. If We have treated 131 patients with TPT (213 affected an extra ray is present, which is very common in bilat- hands) from 1982–2016, with 148 hands operated in eral, inherited cases, it may be as a full ray or with 225 procedures (Table 1). The non-operated patients proximally or distally developed parts. Sometimes were either not fit for operation; had a small anom- there is duplication of a malformed trapezium. With aly; an operation was declined; or were parents of proximal radial polydactyly, the ulnar thumb is mostly children who asked advice but did not proceed to better developed. Quite often we have encountered operation. In this group, a high number of domi- thumb triplication. All three are usually underdevel- nant-trait, hereditary TPTs with or without polydac- oped and often syndactylous. In radial polydactyly at tyly was present, accounting for 66% of our total the MP joint level, often so in syndromic presenta- group. tions, the thumbs are mostly hypoplastic and often the middle phalanx (the triphalangeal part) is small. Surgical considerations Co-existence of ulnar syndactyly and ulnar poly- dactyly is common in the inherited, bilaterally It is important to do a thorough examination and affected patients. In syndromes, cleft hand and lon- record the different aspects of the anomalies in gitudinal radial deficiency can occur also. Congenital detail as treatment is directed as much as possible differences of the lower extremities, such as poly- to the anatomical deficits encountered. In the treat- dactyly or syndactyly, can be encountered. Details ment scheme appearance should be included. of the endless possibilities of other malformations is beyond the scope of this article. Interestingly, we Timing have observed an increase in severity over succeed- ing generations in the patient group with a dominant For wedge-shaped phalanges with clear clinodactyly inheritance trait and bilateral affected hands (Baas and in radial polydactylies, the authors would advise et al., 2017). operation at the age of one year, to diminish the risk Hovius et al. 71 Table 1. Surgical procedures performed in our case side is enough. We described this procedure as ‘delta series (1982–2016). phalanx excision and ligament reconstruction’ (DEL) (Figure 2). 225 procedures in 148 hands In older children (>3 years old) the distal inter- Removal of delta phalanx 41 phalangeal (DIP) joint is more asymmetric. We DIP reduction and desis 65 mostly performed an excision of the DIP joint and a PIP reduction and desis 4 reduction osteotomy at the distal part of the middle Reduction-rotation osteotomy of MC 50 phalanx, followed by arthrodesis, which we called Pollicization 13 ‘distal interphalangeal reduction arthrodesis’ Opposition plasty 21 (DIPRAD). The reduction at the DIP joint is about Sesamoidesis 25 1 cm. The decision to perform DEL or DIPRAD pro- Epiphysiodesis 6 cedures was not only related to the age of the patient, but also to the size of the extra phalanx. If the size DIP: distal interphalangeal; PIP: proximal interphalangeal; was larger the decision to perform a DIPRAD was MC: metacarpal. made easier. In our series, we investigated 33 hands with a of general anesthesia. In the five-fingered hand or follow-up of an average of 7 years.