Flexor pollicis longus rebalancing: a modified technique for Wassel IV-D thumb duplication

Area of Science:

• Orthopedic Surgery
• Hand Surgery
• Pediatric Orthopedics

Background:

• Wassel type IV-D represents a complex form of thumb duplication.
• Reconstruction requires careful management of soft tissues, including the flexor pollicis longus (FPL) tendon.

Purpose of the Study:

• To describe a modified reconstructive technique for Wassel type IV-D thumb duplication.
• To evaluate the preservation and transfer of the flexor pollicis longus (FPL) tendon.
• To assess functional and alignment outcomes post-surgery.

Main Methods:

• Analysis of 16 pediatric patients (average age 2 years) with Wassel IV-D thumb duplication.
• Surgical technique involved ablation of the radial thumb and reconstruction of the ulnar thumb.
• Key procedure included FPL rebalancing and soft tissue stabilization.
• Postoperative range of motion and joint alignment were compared to preoperative measurements.

Main Results:

• Follow-up in 14 of 16 patients for an average of 29 months.
• Significant improvement in interphalangeal joint motion and alignment of metacarpophalangeal and interphalangeal joints.
• Excellent/good results reported in 13 of 14 cases based on the Japanese Society for Surgery of the Hand scoring system.
• An average 14° extension lag at the interphalangeal joint was noted as a disadvantage.

Conclusions:

• The modified FPL rebalancing technique effectively achieves dynamic rebalance of the bifurcated FPL tendon in Wassel IV-D duplication.
• The technique demonstrates excellent outcomes in terms of alignment and joint stability.
• Long-term results of this reconstructive approach are still under evaluation.