Type V & VI Polydactyly: Differences, Treatment & What to Expect at Huashan Hospital Shanghai

What Is Polydactyly?

Polydactyly is a congenital condition in which a child is born with one or more extra fingers or toes. It is one of the most common congenital hand anomalies worldwide, occurring in approximately 1 in 500–1,000 live births. While some cases are isolated findings, others are associated with genetic syndromes or skeletal dysplasias.

The Wassel classification system is the most widely used framework for categorizing thumb (radial) polydactyly, while ulnar (small finger) polydactyly and central polydactyly are classified separately. Types V and VI represent more complex anatomical presentations that require careful surgical planning.

Understanding Type V vs. Type VI Polydactyly

Type V Polydactyly (Wassel Type V)

In Type V polydactyly, duplication occurs at the level of the proximal phalanx — meaning both duplicated digits share a single metacarpal bone but have separate proximal phalanges. Key characteristics include:

• Both digits are typically well-formed with distinct bones, tendons, and neurovascular bundles
• The metacarpal head is often widened and bifid, requiring reshaping during surgery
• Tendon insertions are frequently abnormal and must be carefully reconstructed
• The retained digit may deviate ulnarly or radially without proper ligament balancing
• Functional outcomes are generally good with experienced surgical management

Type VI Polydactyly (Wassel Type VI)

Type VI represents duplication at the level of the metacarpal itself — both the metacarpal and all distal structures are duplicated. This is a more complex presentation:

• Two fully formed rays exist, each with its own metacarpal, phalanges, and soft tissue envelope
• The thenar musculature may be duplicated or anomalous, complicating reconstruction
• Intrinsic muscle balance is more difficult to achieve post-operatively
• Higher risk of residual deformity, stiffness, or angulation compared to lower Wassel types
• May require staged procedures rather than a single-stage correction
• Associated with a higher rate of revision surgery (reported at 10–30% in complex cases)

Key Differences at a Glance

Treatment: Surgical Approach

Surgery is the only definitive treatment for Type V and VI polydactyly. The goal is not simply to remove the extra digit, but to reconstruct a single, well-aligned, functional thumb with balanced tendons, stable joints, and normal-appearing soft tissue contour.

Optimal Timing

• Surgery is generally recommended between 6 and 18 months of age — early enough to allow normal hand development, but after sufficient tissue maturation for safe anesthesia and microsurgical work
• For complex Type VI cases, some surgeons prefer to wait until 12–18 months to allow better anatomical definition
• Delaying beyond age 2–3 years may result in adaptive grip patterns that are harder to correct

Surgical Principles

1. Preoperative imaging: X-ray (and sometimes MRI) to map bony anatomy, joint surfaces, and tendon insertions
2. Selection of the digit to retain: The better-formed, more ulnarly positioned digit is usually retained; both size and alignment are considered
3. Osteotomy and metacarpal reshaping: The bifid or duplicated metacarpal head is narrowed and reshaped to create a normal joint surface
4. Tendon centralization: Collateral ligaments and tendons from the excised digit are transferred to stabilize the retained digit
5. Skin closure: Careful flap design to avoid tight scars or web space contracture
6. Type VI staged approach: In some cases, bony correction is performed first, followed by soft tissue refinement 6–12 months later

Post-operative Care

• Cast or splint immobilization for 3–6 weeks
• Occupational therapy and hand rehabilitation to restore grip strength and fine motor skills
• Regular follow-up through skeletal maturity to monitor for growth-related deformity
• Parents should be counseled that minor residual asymmetry is common and does not necessarily indicate a poor outcome

Important Considerations for International Families

• Genetic counseling: Isolated polydactyly is usually sporadic, but Type VI with bilateral or multi-digit involvement warrants chromosomal and syndromic evaluation
• Anesthesia planning: Pediatric hand surgery requires specialized pediatric anesthesia — confirm this is available at your chosen center
• Realistic expectations: Even with excellent surgery, the reconstructed thumb may be slightly smaller or less mobile than the contralateral side
• Scar management: Silicone gel sheets and sun protection are recommended from 6–8 weeks post-op to minimize scar visibility
• Revision surgery: Families should be informed upfront that revision rates for Type V–VI are non-trivial; choosing a high-volume center significantly reduces this risk

Huashan Hospital Shanghai: A Leading Center for Congenital Hand Surgery

Huashan Hospital, affiliated with Fudan University, is widely regarded as China's premier institution for hand surgery. Its Department of Hand Surgery has treated thousands of congenital hand deformity cases, including complex polydactyly, and is home to several nationally recognized specialists in pediatric hand reconstruction.

For international families seeking treatment in Shanghai, CMCS works directly with Huashan Hospital's hand surgery team to arrange consultations, coordinate imaging, provide medical interpretation, and support families throughout the surgical journey.

Key specialists at Huashan Hospital's Hand Surgery Department include:

• Dr. Fang Yousheng (方有生) — Leading specialist in hand surgery and congenital hand deformity at Huashan Hospital, Fudan University
• Dr. Zhao Xin (赵新) — Chief Physician of Hand Surgery, with extensive experience in complex reconstructive procedures
• Dr. Dong Zhen (董震) — Chief Physician of Hand Surgery, specializing in microsurgery and pediatric hand conditions
• Hand Surgery at Huashan Hospital Shanghai — Full department overview and how to access care
• Academician Gu Yudong (顾玉东) — Pioneer of hand surgery in China and founder of Huashan's world-class hand surgery program

How CMCS Can Help

Navigating pediatric surgical care in a foreign country is challenging. CMCS — China Medical Concierge Shanghai — provides end-to-end support for international families, including:

• Pre-consultation review of imaging and medical records
• Direct appointment scheduling with Huashan Hospital hand surgery specialists
• Medical interpretation during consultations and surgery
• Coordination of pre-operative workup and anesthesia assessment
• Post-operative follow-up and rehabilitation referrals
• Accommodation and logistics support for families traveling to Shanghai

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