Results of zone II flexor tendon repair in children younger than age 6 years: botulinum toxin type A administration eased cooperation during the rehabilitation and improved outcome.

The inability of young children with a zone II flexor tendon repair to cooperate in postoperative care and rehabilitation may represent a high risk for medical and surgical complications. To forestall that risk, botulinum toxin type A (2.5 U/kg, 7 U/kg) injection was used during surgery to induce forearm flexor muscle relaxation in seven children under 6 years old with zone 2 flexor tendon repairs. Patients received a controlled passive motion regimen after surgery. Results were evaluated on the basis of the acquisition of muscle tone and active finger movements, total range of motion of affected joints, postoperative grip strength, muscle atrophy, and phalangeal length. In this prospective clinical study, the mean follow-up was 18 months. All the children had good and excellent results based on the Strickland criteria. As for postoperative complications, one patient had bowstring and another had poor finger sensibility and first web space contracture that required Z-plasty. The selective use of botulinum toxin type A to weaken the targeted muscles generated a sufficient reduction in spontaneous activity of the fingers, permitting an improved rehabilitation program. Botulinum toxin type A administration could be an effective form of therapy, serving as an alternative or adjunct to conventional rehabilitation modalities in these children.