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General considerations
The injury: The mechanism of injury is important in assessing
the degree of risk of complications of a given wound. For example,
the farmer who pierces his foot with a manure-laden pitchfork is
at high risk for gas gangrene and sepsis. Management would include
extensive local wound care and possible admission to hospital for
intravenous antibiotics. Mammalian bites present another risk situation
for
infection. Is there likely to be a foreign body present in the
wound? Does the force of injury suggest there is likely to be extensive
trauma to deeper tissues?
The patient: Consider complicating medical conditions such
as diabetes, other immunosuppressed states including diabetes or
other major organ dysfunction (such as renal or hepatic failure)
and peripheral vascular disease. These all may affect both resistance
to infection and wound healing itself.
Time of injury: The age of the wound is important in deciding the
timing of closure, if at all.
Laceration |
Age / Condition |
Treatment |
| Extremity |
< 12 hours and “clean” |
suture primarily |
| Extremity |
>12 hours older or “dirty” |
Older or obviously contaminated or infected lacerations are
best left alone for healing by secondary intention or tertiary
intention (closure a few days later). Saline soaks and antibiotics
usually will be required. If cosmetic or other functional considerations
apply, then referral to a plastic surgeon is necessary. |
| Face |
< 24 hours |
suture primarily unless obviously infected (rare) |
These times are based on common medical practice in Canada. A study
of forearm and hand lacerations found that closure within 4 hours
had a lower infection rate than more than 6 hours from injury.1
Consultation: Emergency physicians may consider early referral
of certain lacerations to an appropriate surgeon. Indications for
referral
could include:
- Deep lacerations that involve nerve, tendon (often
flexor tendon injuries of the fingers) or bone,
- Complex or extensive lacerations that may be challenging to repair
or are located in difficult anatomical areas.
Assessment of function and the importance of wound exploration
Assess wounds under optimal lighting with minimal bleeding. Important
structures underlying any laceration or contusion should be assumed
divided until proven otherwise. Motor, sensory and vascular function
must always be assessed.
The physician, however, cannot rely only on tests of motor or sensory
function to rule out injuries to tendon or nerve. Only a small portion
of a tendon in the finger, for example, needs to remain intact to
maintain function. However, if the patient is sent home with such
a partial tendon injury, total rupture may occur when the tendon
is stressed.
Note that there is no reliable test for isolating a particular wrist
flexor or extensor, because more than one muscle performs the same
function.
Therefore, wounds in the vicinity of important structures should
be gently explored. If visualisation is difficult or the anatomy
complex, then an appropriate surgeon should be consulted.
Tendon, nerve or vascular injuries are all too easy to miss unless
due care is taken.
Finger Injuries
Injuries to the fingers and hands account for the majority of such
cases. Tendon and nerve injuries of the fingers will now be reviewed,
followed by a brief discussion of vascular injuries.
 Tendon,
nerve or vascular injuries are all too easy to miss unless due care
is taken. In addition for testing function, these wounds should be
gently explored. Injuries to the fingers and hands account for the
majority of such cases.
A tendon is visualized through the open wound
margin of this wound of the hand.
Finger Injuries
Tendon and nerve injuries of the fingers will
now be reviewed, followed by a brief discussion of vascular injuries.
-
Extensor Tendon Injuries of Fingers: The
anatomy of the extensor aponeurosis is depicted in the diagram
below. Extension is accomplished
through the action of the extrinsic digital extensors, and
the interosseous and lumbrical muscles.
 Transection
or avulsion of the central extensor slip from the base
of the middle phalanx may allow the lateral band to slip in a
volar direction and assume a PIP flexor action. This produces
the classical “boutonniere
deformity”. The patient may initially exhibit a full range
of motion, including extension.
- Flexor tendon injuries of fingers: A missed flexor injury of
the finger may result in long term disability. The anatomy is depicted
in the accompanying diagram. The profundus runs the entire length
of the finger and inserts into the distal phalanx. If intact, the
finger can move normally, even if the superficialis is divided.
 |
 |
Profundus tendon testing of
long
finger D3 |
Superficialis tendon testing of
long finger D3 |
The testing of these tendons – both the profundus and the
superficialis is shown
above. The test of the superfialis tendon can only be accomplished
with all of the other digits being restrained in extension. Moreover,
it is not reliable for the index finger. These tests do NOT replace
exploration and visualization of the tendons in the wound.
- Digital nerve injuries: The digital nerves exit the hand in
the region of the volar web spaces, tracking along the medial or
lateral aspects of the fingers.
The digital nerves run immediately adjacent to the flexor tendons.
Numbness or complete loss of feeling is not necessarily noted by
the patient immediately even if there is complete transection of
the nerve. A peculiar or unusual sensation in the territory of the
nerve may be the only subjective description.
If there is digital
arterial bleeding, then the digital nerve is likely to be injured.
Sensory
testing is best done using two-point discrimination.
If the history or physical findings suggest the possibility of
a digital nerve injury, then exploration to visualise the digital
nerve is necessary. A referral to a plastic surgeon is necessary.
However, digital nerve injuries beyond the level of the DIP joint
are not repaired and do not require referral.
- Vascular Injuries
Most arterial and venous injuries occur within the traumatised
limbs. Early diagnosis is important.
Consider the proximity of
the wound to arterial structures. A history of bright red blood
spurting from a wound indicates an arterial injury.
Often, by the time of evaluation within the Emergency Department,
this bleeding has stopped because of vasospasm (or uncommonly because
of hypovolemic shock).
The presence of a bruit or thrill frequently
indicates a significant vascular lesion. Look for the classic
six “P’s” in
the distal extremity:
pain
pallor
pulselessness
paresthesia
paresis
poikilothermia
Pulses may or may not be absent depending on the degree of injury.
Venous
injuries that are significant may be difficult to diagnose. These
usually co-exist with arterial or nerve injuries. Arteriovenous
fistula may occur.
Compartment syndrome: Look out for
- Passive stretch pain of the
muscles within the compartment
- Compartment swelling
The involved compartment needs to be released immediately.
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Wound
Evaluation
