32-year-old man presents with an injury to his hand

Deep structure damage is common.

Educational Objective:

Describe the clinical presentation and management of clenched-fist injuries.

Key Point:

Clenched-fist injuries often appear innocuous on cursory examination, but these types of injuries are often associated with occult yet significant damage to the joint capsule or tendon. Infection is common.

Explanation:

This patient presents with a clenched fist-injury (CFI), also called a "fight bite." These injuries occur when an individual sustains a laceration to the dorsal aspect of a metacarpophalangeal joint from the impact of an opponent’s teeth.

CFIs often appear innocuous on first glance, but, in approximately 50% of cases, careful examination in a bloodless field reveals deep structure damage, particularly to the tendons or joint capsule. Given this damage and the polymicrobial colonization of human saliva, CFIs carry a high infection rate of deep structures, with significant risk for osteomyelitis, septic arthritis, and tenosynovitis. The infection rate for this type of injury is the highest of any human bite to the hand.

Appropriate management of a CFI includes careful inspection of the wound, particularly with the hand in a flexed position, which often exposes otherwise occult, deeper injuries. The wound should be copiously irrigated and any devitalized tissue debrided. Injury to the joint, tendon, or bones requires admission for irrigation and debridement in the operating room. If examination does not reveal deep structure injury, the wound should be left open to minimize entrapment of infection, and the patient should be prescribed a course of prophylactic antibiotics. Close follow-up care is indicated within 24 to 48 hours as an outpatient.

Reference:

Eilbert WP. Mammalian bites (chapter 54). In: Wall R, et al. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th ed., 2018:690-697.