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Ankle injuries have long been a cornerstone of
orthopaedic and sports medicine practice.
Indeed, this column has been dedicated to the subject on
several occasions.
Being that ankle injuries are extremely common, they
are frequently evaluated in family clinics, emergency centers,
ambulatory clinics and training rooms.
It was noted several years ago that a great many ankles
were being radiographed and that only a very small percentage of
those ankles demonstrated a fracture.
A group of physicians set out to determine a set of
standardized clinical criteria to allow physicians from
different specialties, backgrounds and philosophies decide when
it is necessary to X ray an ankle following an acute injury.
Before detailing the criteria that they came up with,
lets briefly review a bit about ankle sprains and fractures.
The ankle joint is made up of several bones joined
together by ligaments. There
are two large groups of ligament that keep the ankle from
turning in or out. There
are three ligaments on the outside and one large ligament on the
inside. The three
bones that form the mortise joint of the ankle are the tibia,
the fibula and the talus.
When a force is placed on the ankle, the weakest link
in the chain is the one that gives out.
In the vast majority of ankle injuries, the weak link is
the lateral (outside) ankle ligaments.
Of ankle sprains that don’t involve a fracture, about
85% include the lateral ankle ligaments.
Occasionally, the ligaments are able to withstand
more force than the bones and a fracture occurs. There are numerous varieties of fractures involving the ankle
bones. These vary
widely in location, mechanism, prognosis, treatment and
recognizability.
Also, when a mechanism occurs that may injure the
ankle, the foot may also be hurt.
It is always necessary for the examiner to evaluate the
foot when looking at an ankle injury.
The Ottawa criteria take into account all of the
above information and serve to integrate it into a practical
algorithm that is used to determine the need for radiographs.
The criteria are as follows:
1. Is
there tenderness to palpation over the inside or outside ankle
bone or along those bones above the ankle?
2. Is
there tenderness to palpation along the 5th foot bone called the
metatarsal?
3. Is
there tenderness to palpation along any of the small bones of
the foot or ankle?
4. Is
the patient able to bear weight now?
Was he/she able to beat weight immediately after the
injury?
If the patient is unable to bear weight or has any
tenderness on any of the bones described above, then a foot
and/or ankle X ray is necessary.
In a large randomized study, when the Ottawa criteria
were put to the test, they worked more than 99% of the time.
In other words, in virtually all cases, no fractures were
missed when the Ottawa criteria were used to determine if an X
ray is necessary. Additionally,
many X rays could be avoided if the patient had zero Ottawa
criteria and, in these study patients, none of them had a
fracture.
Of course, if you injure your ankle, allow your
doctor to decide what diagnostic and therapeutic measures are
appropriate to your individual case.
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