Spastic thumb-in-palm deformity was surgically treated in 27 adults with brain injury. Procedures included muscle lengthening, recession, or release, arthrodesis of the thumb interphalangeal joint, or Z-plasty of the thumb web space. At mean follow-up of 39 months, 23 of 27 had a satisfactory correction. Unsatisfactory results included two with inadequate correction and two with over-correction. Surgical treatment of this entity requires careful preoperative planning, addressing predominantly those spastic muscles responsible for the deformity.