Pollicisation is a complex reconstructive operation to create a thumb by repositioning the index finger (or another finger) into the thumb position. It is most commonly performed for children born without a thumb (thumb aplasia or hypoplasia).
The index finger is shortened, rotated, and repositioned to function as a thumb. The operation involves shortening the metacarpal, repositioning the tendons to provide opposition and pinch function, repositioning the neurovascular bundles, and insetting the finger into the thumb position. The operation is highly technical and takes two to three hours.
Pollicisation is recommended for congenital thumb aplasia (absent thumb) or severe hypoplasia (underdeveloped thumb) where the existing thumb cannot be reconstructed. The thumb is essential for hand function — providing 40% of total hand function.
For mild hypoplasia, opponensplasty (tendon transfer) may augment thumb function. Prosthetic thumbs are rarely functional in children. Toe-to-thumb transfer is an alternative but more complex.
Detailed hand assessment. The operation is typically performed at 12–18 months of age, before the child develops compensatory patterns. X-rays and sometimes MRI to assess the skeletal and soft tissue anatomy.
A functioning thumb that provides pinch grip and opposition. Children who undergo pollicisation develop excellent hand function — they adapt remarkably well to using the reconstructed thumb. The hand appears to have four fingers instead of five.
The pollicised thumb is shorter and thinner than a normal thumb.
Pinch strength is less than a normal thumb but usually functionally adequate.
Scars from the reconstruction.
Blood supply to the transposed finger may be compromised. Close post-operative monitoring is essential.
Joint stiffness in the reconstructed thumb.
The new thumb web may tighten over time, requiring secondary procedures.
The transposed finger may grow differently.
Wound infection.
General anaesthesia in a young child. Careful temperature management and fluid balance.
Cast for four to six weeks. Hand therapy begins after cast removal, though young children adapt largely through play. Occupational therapy to encourage pinch grip activities. Long-term follow-up throughout childhood to monitor growth and function.
Close monitoring in the first 48 hours for vascular status. Reviews at two weeks, six weeks, three months, and regularly throughout childhood.
Typically 12–18 months, before the child develops compensatory hand patterns. Earlier surgery allows the brain to adapt to the new thumb during the critical period of motor development.
Children who undergo pollicisation develop remarkably good hand function. They adapt to using their reconstructed thumb naturally and can perform most activities. Pinch strength is reduced compared to a normal thumb but is usually functionally adequate.
The pollicised thumb is shorter and thinner than a normal thumb, and the hand has four digits instead of five. However, the functional result is far more important than the cosmetic appearance, and most families are very satisfied.