Correction of Thumb Duplication: A Systematic Review of Surgical Techniques

Abstract

Surgical intervention for thumb duplication can be divided into three categories: simple excision of the accessory thumb, excision of the accessory thumb with reconstruction from available “spare parts,” and combining the two thumbs into one, as described by Bilhaut. This prospectively PROSPERO registered systematic review evaluates the overall, aesthetic and functional outcomes for the latter two options (reconstruction from spare parts vs. combining two thumbs into one), aiming to facilitate evidence-based decision making when addressing thumb duplication and direct future research. The review was performed in accordance with the Cochrane Handbook of Systematic Reviews and PRISMA statement. Embase, PubMed, Medline, and Cochrane databases were systematically searched. Studies offering comparisons of techniques were included. Risk of bias was assessed using the Risk of Bias In Non-randomized Studies—of Intervention tool. The quality of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation. Ten retrospective observational studies were included. Data did not consistently allow analysis by procedure type. Four studies reported similar overall outcomes between techniques, while two specifically reported poor overall outcomes for the Bilhaut procedure. Two studies reported comparatively worse aesthetic outcomes for the Bilhaut procedure with four studies reporting comparatively improved functional outcomes for this procedure. Overall, interpretation of outcomes was challenging with no patient-reported outcome measures used. The quality of the evidence was universally “very low” due to all studies being at risk of methodological bias. Based on the available evidence, surgical techniques for thumb duplication correction appear comparable regarding overall outcome. There is limited evidence suggesting reconstruction with spare parts offers superior aesthetic outcomes at the expense of stability. The level of evidence is III.

Epidemiological characteristics and distribution of congenital thumb duplication in south China: An analysis of 2,300 thumbs in 2,108 children

“…The choice of treatment varies depending on the anatomy of the extra thumb connected to the main thumb, which is consistent with the view of previous reports ( 10 , 11 , 24 – 27 ). Tada et al and Kim et al reported that an extra thumb connected to the main thumb by soft tissue alone should be classified as an independent subtype ( 24 , 25 ).…”

“…For example, in C type, the extra thumb can be connected to the main thumb by bifurcated phalanx at the level of the distal phalanx, proximal phalanx or bifurcated metacarpus. Flap design, muscle tendon and bone reconstruction are different depending on the duplication level ( 27 , 28 ). Therefore, it is necessary to explore a simple and comprehensive classification system useful for selecting the best treatment option ( 29 ).…”

Thumb Duplication Surgical Treatment: Outcomes and Results

“… 20 Furthermore, joint stiffness, marked broadness, and conspicuous scarring of the nail bed and pulp are noted drawbacks of the Bilhaut-Cloquet procedure, which has largely fallen out of favor because of poor outcomes and cosmesis; it often produces a wide, stiff thumb, being now used only for very distal duplications. 9 , 22 …”

“…The aim of the treatment is to achieve function nearly normal as possible, with good thumb joint stability, mobility, and strength, while providing an acceptable esthetic appearance. 8 , 9 Considerations prior to surgical intervention include analysis of patient’s bony anatomy, hand physical examination, including thumb alignment, tendons, range of motion, joint stability, and family counseling (particularly asymmetry in thumb size). 10…”

“…11 Surgical procedure selection is dictated by complexity and size and location of the anatomical abnormality. 7 , 9 …”