Pollicization: the concept, technical details, and outcome.

Pollicization substitutes a functioning finger for a deficient thumb. The most indication is thumb hypoplasia with absence or instability of the carpometacarpal joint. However, there are additional causes that may negate thumb function, such as trauma, macrodactyly, multi-fingered hand, and a mirror hand. The technique of pollicization represents a consolidation of contributions from surgeons over the last 100 years. A meticulous stepwise approach from incision to closure is necessary to optimize outcome. Following pollicization, cortical plasticity and motor relearning play a pivotal role in function following pollicization with connections and adjacent sprouting from nearby cortical and/or subcortical territories. Occupational therapy is necessary to encourage large object acquisition followed by smaller objects and ultimately fine pinch. Pollicization is more reliable in patients with isolated thumb hypoplasia and a mobile index finger with robust extrinsic and intrinsic muscle-tendon units compared to and patients with radial forearm deficiencies and diminished index mobility.