Management of a Thumb-In-Palm Deformity in Adult Patients With Upper Motor Neuron Syndrome

The thumb-in-palm (TIP) deformity in adults with upper motor neuron syndrome results from an imbalance of extrinsic and intrinsic muscular forces. Traditionally, the thumb is adducted against the index ray, and flexed to varying degrees at the metacarpophalangeal and interphalangeal joints. However, not all TIP deformities result from the same underlying imbalances. The severity of the deformity ranges over a spectrum dependent upon the involved muscle groups and underlying spasticity, myostatic contracture, and/or joint contractures. Surgical procedures for correcting a TIP deformity can be classified broadly as procedures used for functional, present volitional motor control, versus nonfunctional, absent motor control. Techniques include tenotomies, tenodeses, tendon lengthenings, tendon transfers, tendon reroutings, neurectomies, and joint releases. A focused physical examination is key in developing a patient-specific treatment algorithm.