Subclassification and surgical algorithm for Wassel type III thumb polydactyly: a retrospective analysis of 94 cases

Area of Science:

• Hand surgery
• Pediatric orthopedics
• Congenital hand differences

Background:

• Wassel type III thumb polydactyly presents a bifid proximal phalanx, posing significant reconstructive challenges.
• Optimal aesthetic outcomes often necessitate complex combination procedures for distal duplications.

Purpose of the Study:

• To propose a novel subtype classification system for Wassel type III thumb polydactyly.
• To develop a surgical algorithm to guide the management of this complex condition.
• To correlate specific surgical techniques with outcomes based on the new classification.

Main Methods:

• Retrospective review of 94 patients with Wassel type III thumb duplication.
• Analysis of patient demographics, radiographic findings, surgical interventions, and outcomes.
• Development of a modified classification based on osseous morphology and interphalangeal joint stability (Subtypes III-A, III-B, III-C, III-D).

Main Results:

• A modified classification system was established, categorizing subtypes based on phalangeal width and joint stability.
• Specific surgical techniques were associated with optimal results for each subtype: modified Bilhaut-Cloquet for III-A/III-B, thumb resection for III-C, and type IV-D reconstruction for III-D.
• Postoperative thumb deviation was linked to surgical technique selection; nail ridging from the modified Bilhaut-Cloquet procedure showed improvement over time.

Conclusions:

• The proposed subtype classification and surgical algorithm offer a structured approach to managing Wassel type III thumb polydactyly.
• This algorithm aims to achieve superior aesthetic and functional results in reconstructive surgery.
• Further prospective multicenter studies are recommended to validate the findings and refine surgical protocols.