Triphalangeal thumb with polydactyly: an alternative surgical method

Radiographic Characteristics of the Triphalangeal Thumb in Patients With Congenital Thumb Duplication: An Analysis of 383 Thumbs in 368 Children

PURPOSE

The purpose of this study was to evaluate the morphologic and radiographic characteristics of the triphalangeal thumb (TPT) in patients with congenital thumb duplication.

METHODS

We retrospectively reviewed 368 children with TPT duplication (n = 383). Data on age, sex, and laterality were obtained from medical records. The morphologic and radiographic characteristics of the TPT duplication were evaluated using plain radiographs.

RESULTS

Of the 383 fingers, 322 (84%) had a TPT duplication on the radial side, 36 (10%), on the ulnar side, and 25 (7%) were bilateral. The mean age at the time of surgery of TPT duplication on the radial side (21 ± 11 months), on the ulnar side (25 ± 15 months), and in bilateral cases (27 ± 15 months) was not significantly different. The extra thumb was connected to the main thumb by a joint (75%), bone (18%), soft tissue (6%), and epiphysis (1%). There were 26 cases (7%) of abnormal hypertrophic epiphysis of the main thumb, all of which were located in the distal phalanx of the radial side of the TPT duplications. The thumb epiphyses in patients with TPT duplication appeared in the following order: distal phalanx (mean, 24 ± 14 months; range, 7-94 months), proximal phalanx (mean, 31 ± 18 months; range, 14-94 months), and metacarpal (mean, 34 ± 20 months; range, 13-94 months).

CONCLUSIONS

Triphalangeal thumb in patients with congenital thumb duplication is more common in boys, often duplicated at the level of the proximal phalanx, with the extra thumb articulated to the main thumb by a joint, often unilateral, and frequently radial and right-sided. The epiphysis of the TPT duplication ossifies sequentially from the distal phalanx to the metacarpal, and its onset is delayed in comparison to normal children.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Surgical Reconstruction for the Triphalangeal Thumb

The triphalangeal thumb poses a complex reconstructive challenge to the congenital hand surgeon due to its rarity and variable anatomy. We discuss the available evidence, reporting clinical characteristics and outcomes of surgical reconstructive procedures of triphalangeal thumb alongside a representative case. The congenital hand surgeon must approach each patient with triphalangeal thumb individually to optimize the use of available tissues to maximize functional and aesthetic outcomes.

Clinical Characteristics and Surgical Outcomes of Congenital Ulnar-deviated Thumbs: Delta Triphalangeal Thumbs and Irregular Epiphyses

BACKGROUND

Delta triphalangeal thumbs (DTPT) and irregular epiphysis thumbs (IET) had different anatomic deformities. Our primary purpose was to evaluate the clinical and radiographic outcomes of surgical treatment in DTPT and IET.

METHODS

In total, 43 ulnar-deviated thumbs were included and categorized into 2 types according to x-ray and exploration during surgery, DTPT and IET. Surgical excision of the delta phalanx in DTPT and intraepiphysis osteotomy in IET was conducted.

RESULTS

In total, 23 ulnar-deviated thumbs were classified as DTPT and 20 as IET. Ten thumbs that could not be classified initially were followed-up until they could be categorized at the mean age of 24 months. The preoperative mean degrees of ulnar deviation at the interphalangeal joints were 40 and 33 degrees, in DTPT and IET, respectively. The mean degrees were 2 and 5 degrees in final follow-up, showing significant improvement (DTPT, P<0.05; IET, P<0.05). Complications during the study included residual ulnar deviation, overcorrection, and nonunion. The stability and range of movement at the interphalangeal joint were good overall. According to the Japanese Society for Surgery of the Hand scoring system, results were excellent in 29 cases, good in 13, and fair in 1.

CONCLUSIONS

Ulnar clinodactyly of the thumb occurs because of different anatomic features such as DTPT or IET. We recommend surgical treatment be postponed until the anatomic abnormality can be ascertained. Furthermore, almost all patients with ulnar-deviated thumbs had significant improvement in clinical and radiographic outcomes after surgery.