SPRAINED ANKLE MANAGEMENT
by Buck Tilton
Based on an informal survey
of outdoor programs, ankle sprains account for approximately
one out of every three backcountry injuries that require an evacuation
of the patient or, at least, a shortening of the intended trip.
Sprained ankles are the reason for 53 percent of all evacuations
(due to injury) from National Outdoor Leadership School (NOLS)
courses. Interestingly, 85 percent of all ankle sprains involve
only the lateral (outside) ligaments. Many of these injuries
can be managed in the field, without an evacuation.
Basic Anatomy
The lower leg's large tibia and smaller fibula meet the ankle
at the talus, an upwardly rounded bone that allows the tib and
fib to "rock" on its top. The talus, in turn, "rocks"
on top of the calcaneous (heel bone). This ability to rock allows
for freedom of movement when the human body hikes, climbs, or
runs.
In front of the calcaneous lies two small bone, the navicular
on the medial aspect (inside) of the foot, and the cuboid on
the lateral aspect. In front of these two bones are three even-smaller
bones called the cuniforms, for a total of seven "ankle
bones." In front of the cuniforms are the five metatarsals
(foot bones) that connect to the phalanges (toe bones).
It takes a complex arrangement of ligaments to hold all those
bones together! But six of these ligaments are primary targets
for injury. Two of these, the anterior (front) and posterior
(rear) tibio-fibular ligaments, hold the tib and fib together,
preventing those bones from being wedged apart by the talus when
you take a step. Number three, the deltoid ligament, attaches
the tibia to bones on the inside of the ankle. The deltoid is
wide and tough, allows little eversion of the ankle (a roll to
the outside), and is rarely sprained. In fact, twisting of the
deltoid is more likely pull off a fragment of bone (an avulsion
fracture) than to sprain the ligament. On the outside of the
ankle, the other three primary ligaments attach the fibula to
the talus and the calcaneous: the anterior and posterior talo-fibulars,
and the calcaneo-fibular. These smaller, weaker lateral ligaments
allow much more inversion than the deltoid allows eversion and,
consequently, they are the ones most often damaged.
Assessment
Ankle assessment is relatively simple. Start with the basic historical
questions: what happened? how far did the ankle twist? which
way? was there a sound at the moment of stress on the ankle (other
than a yell from the patient)?
Look at the ankle. Is there swelling? discoloration?
Feel the ankle. Is there pain when you press on location of underlying
ligaments?
Move the ankle passively through it's range of motion. When you
stress the ligaments, gently, do they hurt? do you hear a grinding
sound?
Degree of pain and loss of range of motion are the primary indicators
of ankle injury!
Management
All ankle injuries should be managed initially with adequate
RICE-ing. REST the injury--get off it! ICE the injury--cool it
with an ice pack, snow pack, soaking in a cold mountain stream,
wrapping it in a wet T-shirt, etc. COMPRESS the injury, with
an elastic wrap from distal to proximal (from the end of the
extremity toward the heart). ELEVATE--prop the injury up higher
than the patient's heart. Maintain RICE for 20-30 minutes, then
allow the injury to rewarm naturally (12-15 minutes) before performing
the assessment tests.
Monitor the ankle post-RICE for swelling and discoloration, the
degree of which will help determine the extent of injury. In
the end, the patient will be the best determiner of usability.
Mild ankle injuries can be taped and the patient will be able
to stay in the field. Moderate injuries can be taped to allow
the patient to limp out of the field on their own, probably with
most of the weight from their pack distributed among other group
members. Ankle taping is a skill that should be mastered or,
at least, semi-mastered by all wilderness medicine providers.
A simple ankle taping method is explained in Medicine for the
Backcountry, 2nd edition, available from the WMI Bookstore. Better
yet, learn from someone who knows. Ankle taping is taught in
many wild med courses, including WFR and WEMT courses taught
by WMI. Severe ankle damage will require splinting and, most
likely, carrying of the patient out to definitive medical care.
References
1. Chisolm, "A Backcountry Guide to Lower Extremity Athletic
Injuries", NOLS, February 1986.
2. Donelan and McCaleb, "Athletic Injuries", JEMS,
January 1991.
3. Gentile, Morris, Schimelpfenig, Bass, and Auerbach, "Epidemiology
of Wilderness Injuries and Illnesses", NOLS, an unpublished
paper, 1991.
