Results of Treatment of Delta Triphalangeal Thumbs by Excision of the Extra Phalanx

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.

Analysis of Causes for Congenital Ulnar Deviated Thumbs at the Distal Phalanx Level in 157 Thumbs

PURPOSE

To investigate anatomic abnormalities causing a congenital ulnarly deviated thumb at the distal phalanx.

METHODS

A total of 122 children with 157 congenital ulnarly deviated thumbs at the distal phalanges were reviewed, including those with isolated deformity or polydactyly. We analyzed the incidence and characteristics of the underlying anatomic abnormalities as well as the differential diagnoses.

RESULTS

Three main causes of an ulnarly deviated thumb were observed. Abnormal hypertrophic epiphyses were found in 96 thumbs. An extra phalanx lying between the normal proximal and distal phalanges was found in 59 thumbs. A previously undescribed cause was found in 2 thumbs with Wassell IV polydactyly, in which an obliquely angled articular surface of the proximal phalanx manifested with ulnar deviation at the interphalangeal joint. Radiographic analysis showed that in cases with abnormal epiphyses, the epiphysis was in good apposition and good alignment with its relevant distal phalanx; the distance from the abnormal epiphysis to the phalanx was usually less than 1 mm. In contrast, in cases of extra phalanges, the distance from the epiphysis to the phalanx averaged more than 2 mm and there was poor apposition between the distal phalanx and the extra bone.

CONCLUSIONS

Abnormal hypertrophic epiphysis and triphalangeal thumb are the 2 main causes of a congenital ulnarly deviated thumb. A distance of more than 2 mm between the abnormal bone and the distal phalanx suggests a triphalangeal thumb.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Triphalangeal Thumb Reduction Osteotomy Through a Versatile Spiral Approach

Triphalangeal thumb (TPT) is a congenital condition characterized by the presence of an additional phalanx. Variable degrees of thumb deformity, malalignment, and excessive length are common features. Impairment of hand function has been reported with TPT probably secondary to anomalistic long thumb incompatible with fine hand skills. Abnormal thumb appearance moreover represents a major psychological concern from patient's perspective. Both removal of the extra phalanx and phalangeal reduction osteotomy with resection of the unhealthy extra interphalangeal joint are established methods for correction of the associated excessive thumb length. In our experience, however, previous surgical approaches have not been able to sufficiently reduce the skin and soft tissue surplus, which exists after reduction osteotomy through classic circular incisions. We thus feel that conduction of TPT reconstruction through a spiral incision provides a safe and generous anatomic exposure required for simultaneous reduction of skeletal and soft tissue components.