Open extensor tendon injuries are classified according to location on the hand and wrist (Fig. 23) relative to adjacent joints. By this system, the odd numbered zones - 1,3,5,7 - are difficult management problems because they usually correspond to open mallet injury, open boutonniere injury, clenched fist bite wounds, and multiple tendon injuries, respectively. Clean open mallet or boutonniere injuries are treated by primary tendon repair (absorbable sutures are preferred because they extrude less frequently than non-absorbable) and then a splinting program appropriate for a similar but closed injury. Along the same lines, clean tendon lacerations over the dorsum of the hand or wrist may be repaired primarily and then splinted with the wrist and metacarpophalangeal joints in comfortable extension for four to six weeks. Clenched fist bite wounds are different and are discussed below.
Extensor Tendon Injuries