When someone strikes another person's face with their fist, they may cut the dorsal surface of their proximal phalanx or distal metacarpal head on the victim's tooth, usually involving the middle or ring finger. This extremely contaminated bite wound equivalent may divide the extensor mechanism and contaminate the metacarpal head joint surface. Because such injuries frequently occur while the patient is intoxicated, initial medical evaluation is often delayed, and the patient may not present until they have progressive infection. Neglected injuries may require ray amputation. All suspicious injuries in this area should be taken very seriously. Because the wound is made while the hand is in a fist, inspection of the wound with the fingers straight does not usually reveal the true extent injury (Fig. 7). Standard x-ray views may be normal even if the patient has sustained an osteochondral fracture. There are two components of this injury. The first and most important is a septic open joint injury. Once suspected of this mechanism, patients immediately should be given intravenous broad-spectrum antibiotics appropriate for oral and skin organisms and be brought to the operating room at the earliest opportunity for a formal joint inspection and debridement. Documented joint surface injuries should be reinspected in the operating room 24 to 48 hours after the initial procedure. The second component is the extensor tendon injury. In the presence of infection, the extensor mechanism should not be repaired. If the injury involves the middle or ring finger, the injured metacarpophalangeal joint should be supported in a splint which maintains the joint at greater extension than that of the adjacent fingers. Because of the action on the tendinous junctures, splinting in this position results in approximation of the divided tendon ends and may provide a satisfactory result without further surgery.
Hand Bite Injuries