Ankle Instability and Ankle Sprains
The ankle works in a systematic way.
Movement is only supposed to be in one plane, in other words, up and
down. We call this dorsiflexion and plantarflexion. The ankle joint
is held in place securely by a group of bones that house the main
anklebone (called the talus) inside a box-like effect. On the inside
is the medial malleolus and on the outside the fibula.
||Front of the ankle.
M= medial malleolus, L=lateral malleolus (fibula). The outside
of the heel is pushed inwards to stress the joint. In the normal
ankle, no tilting of the ankle should occur at all. Note the
tilting of the talus in the ankle.
The inward and outward movements of the back of the foot do not actually
occur in the ankle joint but occur in the joint underneath it called
the subtalar joint. The muscle that pulls the foot inward (inversion)
is slightly stronger than the muscles that pull the foot outward (eversion).
When the foot lands in an awkward manner there is a tendency for the
heel to roll inwards and create stress on the outside ligaments. If
this stress is severe then a sprain of the ankle occurs. A sprain
is actually a tear that occurs in the outer supportive ligaments of
the ankle. As these ligaments are stretched, a critical point is reached
beyond which ligaments do not return to their normal elastic function
and a tear of the ligament occurs. Sprains can range from the relatively
minor to those where the ligaments are completely torn and the ankle
can be quite loose.
The acute sprain of the ankle is commonly associated with marked swelling
and bruising on the outer side of the ankle. Rest of the ankle with
immobilization of some sort is critical. The classic treatment for
a sprain of the ankle is what we refer to as the Rice Program. It
involves rest, ice, compression and elevation. This treatment is designed
to decrease the inflammation and swelling of the ankle associated
with the sprain. The Rice Program by itself will not heal the ligaments.
In order for the ligaments to heal the ankle needs to be immobilized
with either a cast or a boot. For minor sprains a brace can be applied
to the ankle. Walking is permitted during this recovery process, allowing
the ankle ligaments to heal.
Following this period of initial immobilization, strengthening exercises
are essential to regain the balance of the ankle. It is critical that
the tendons and muscles on the outside of the ankle (the peroneal
tendons) are strengthened. This should be done initially in a supervised
exercise program. If the ligaments have been severely torn, the ability
to fine tune the ankle and prevent further sprains from occurring
depends on the strength of the peroneal muscles. As the ankle turns
repeatedly, the peroneal muscles weaken further. This weakens the
ability to prevent recurring sprains. Patients with a high arch or
a heel that is naturally turned in slightly are predisposed to sprains.
As a result of continued rolling, turning or instability of the ankle,
the ability to fine tune the foot on uneven surfaces becomes limited.
The ability to make rapid changes in the position of the foot on the
ground surface is called proprioception. If this ability is diminished,
the likelihood of a more severe ankle sprain occurring is increased.
In recurring ankle sprains we call this chronic recurrent instability
of the ankle. The ankle is at risk of developing other problems. These
include bruising of the cartilage of the talus and bone spurs that
develop around the front and sides of the ankle. These are all precursors
of ultimate arthritis of the ankle.
illustrate a patient with chronic ankle instability. Note
how loose the ankle is when it is turned slightly inwards.
The ligaments are completely torn in this ankle and the
likelihood of recurring sprains is very high.
The diagnosis of chronic recurrent instability is made through a careful
examination of the ankle and X-rays that are taken while stress is
applied to the ankle.
are two X-ray's of a patient with chronic recurrent instability
of the ankle. In both the right and the left ankle, an
assistant is pushing on the outside of the foot (in the
direction of the white arrow) while the XR is taken. The
XR on the left is normal, while the one on the right demonstrates
a loose (unstable) ankle.
Once the diagnosis of the extent and severity of the ankle instability
is made then a treatment plan can be initiated. A strengthening program
is helpful before proceeding with surgery. This is true even with
patients who have had recurring sprains and chronic recurrent instability.
Fortunately, surgical repair of the chronically loose ankle ligaments
can be performed. There are many different techniques used to stabilize
the ankle. Some rely upon repairing the ligaments themselves by tightening
them up. Others depend more on using a tendon behind the ankle (the
peroneal tendon) or a tendon graft to tighten up the ankle completely.
These operations are usually very successful. Individuals are able
to return to all forms of athletic activity without risk of recurrent
injury to the ankle.