1. Six cases of malunited anterior Monteggia fracture have been treated, five of them successfully, by open reduction and reconstruction of the orbicular ligament by turning down a slip from the triceps tendon. 2. One relapse occurred after a slight injury; this was because of an unsuitable triceps tendon. 3. A slip from the triceps tendon has retained reduction of the head of the radius in a patient with congenital dislocation of the radial head.