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Clenched Fist Injury


- See: Infections of the Hand / Human Bite Wounds

- Discussion:
    - MP joint and the adjacent tissues and spaces are most commonly involved because teeth of the opponent are struck with knuckle of the clenched fist;
          - when the hand is unclenched, the skin wound retracts proximally covering deeper part of the wound within which the bacteria have been deposited;
          - this airless, traumatized area forms an ideal site for anearobic growth;
    - up to 75% of patients will have injuries to bone, joint, tendon, or cartilage;
    - depending on the severity, a human bite may result in periarticular fibrosis sufficient to cause joint arthrodesis or even amputation of a digit;
    - in neglected cases, once the volar plate and the collateral ligaments are damaged and the flexor tendons are adherent, the chances for obtaining a functioning finger are minimal;

- Anatomy of Extensor Mechanism

           

- Offending Organisms:
    - see: bacteriology of hand infections;
    - viridans strep, grp a strep, staph aureus, eikenella corrodens, bacteriodes, fusobacterium, actinomycetes, spirochetes;
    - alpha-hemolytic streptococci are the most frequent isolates from human bite wounds;
    - anaerobic bacteria are commonly found in all types of infected bites;
    - borrelia vincentii is a spirochete that may appear in association w/ w/ bacteroides;
    - in bites inflicted by hospitalized patients, consider enterobacteriaceae;       
    - Eikenella corrodens in hand infections. 
- Treatment:
     - tetanus prophylaxis if indicated;
     - debridement:
            - cleaning, irrigation and debridement most important;
            - to adequately visualize deep structures around the wound, incise both proximally and distally;
            - excise traumatized tissue;
            - soft tissues including the capsule and extensor hood, are allowed to seek their own position over the joint;
            - partial or even complete lacerations are seldom if ever assoc w/ significant retraction at this level;
                 - see: extensor tendon lacerations:
                 - if needed lacterated tendons are repair secondarily, at one week;
            - incised skin can be closed but bite wound needs to be left open;
     - antibiotics
            - initially patients should be maintained on IV antibiotics (consider unasyn);
            - once, it is clear that the wound is clean and well debrided, oral agents may be used;
                  - amoxicillin clavulante perfered
                  - advantage is that it treats, gram positive, gram negative, as well as anaerobic organisms;
            - if patient is allergic to penicillins, then consider treating w/ combination of clindamycin and cipro;
            - alternative try cefoxitin or erythromycin



Infections following clenched-fist injury: a new perspective.

Osteomyelitis of the hand after a human bite.

Eikenella corrodens in hand infections.

Surgical findings in clenched-fist injuries.