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The most common ankle sprain occurs on the
outside or lateral aspect of the ankle. The lateral ankle is supported
by a group of three ligaments called the lateral collateral ligaments. The anterior ligament is the
ligament that is most often
injured in lateral ankle sprains. This ligament is called the anterior talo-fibular
ligament (ATF). Isolated ATF sprains make up more than 75% of all ankle
sprains. The ATF is a relatively small ligament that runs from
the anterior aspect of the fibular forward to attach to the talus. The
calcaneal fibular ligament (CF) is the second most commonly injured ligament of
the lateral ankle. The CF is rarely injured as an isolated injury. The CF
is usually injured in conjunction with the ATF. The CF runs from the
fibula to the heel bone (calcaneus). The final ligament of the three
lateral collateral ligaments is the posterior talo-fibular ligament (PTF). The PTF runs from
the fibula back to the talus. The PTF is rarely injured in a
lateral ankle sprains.
Lateral ankle sprains are graded by the location of the injury and the
amount of damage
to each of the ligaments. Typically we speak about a grade I, II or III
ankle sprains. A grade I sprain is an injury that results in a stretch
of the ATF ligament. Grade II is a partial rupture of the ATF and
stretch injury of the CF ligament. Grade III is a complete rupture
of both the ATF and CF ligaments. All ankle sprains result in an
injury of the ATF ligament. Only a grade III affects the PTF and
even in a grade III, the injury sustained by the PTF ligament is
minimal.
Medial ankle sprains do occur but are far less common than
lateral ankle sprains. The medial ankle is supported by a heavy ligament
called the deltoid ligament. The deltoid ligament actually consists of
five interwoven ligaments that create a broad fan of ligamentous tissue
supporting the medial ankle. When an injury does occur to the medial
ankle, stress applied to the deltoid ligament is often transferred to the distal
tibia resulting in a fracture of the medial ankle.
 The
term high ankle sprain describes an injury to the anterior inferior
tibial-fibular ligament (in pink in the image to the left). The anterior distal
tibial-fibular ligament is also known as the Tillaux-Chaput ligament. The
anterior inferior tibial-fibular ligament is the most distal ligament of the
lower leg and maintains the contact of the fibula and tibia. Disruption of
the anterior inferior tibial fibular ligament results in widening or what's
called diastasis of the distal tibial-fibular articulation. Diastasis of
the distal tibial-fibular articulation results in ankle instability and
progressive arthritis of the ankle if left untreated.
Treatment of ankle sprains
Lateral ankle sprains
There are two steps described in the treatment of lateral ankle
sprains. The first step is the management of the acute
injury. This step includes management of pain and swelling
along with preventive measures to control lateral ankle instability. The second
step is the
prevention of recurrent sprains.
Step 1 (acute injury treatment)
Following the ankle sprain, management of
the acute injury is best summarized by the acronym RICE;
R- rest
I- ice
C- compression
E- elevation
Rest is an
essential part of healing following an ankle sprain. Rest is represented
by many different changes in your activities. Rest can be as
simple as backing off of your normal activities all the way up to and
including a hard cast and non-weight bearing status with crutches or a
walker. What's best for your individual case? Following a sprain, give the ankle several days before getting back to
any activity. Only bear weight to tolerance. If it hurts, back off and
do less. Some weight bearing
is good from the standpoint of breaking up scar tissue and gaining an
early range of motion. Too much weight bearing leads to unnecessary
swelling.
Ice is used to control
swelling. Personally, I'm not a big fan of heat at any time during
the healing of an ankle sprain. The more ice the better.
Care should be taken not to injure the skin, particularly if a patient
has a loss of sensation such as diabetic neuropathy.
Compression is
also used to control swelling and to splint the lateral collateral ligaments in
a corrected position. Compression can be accomplished with a
number of
different aids such as ace wraps or
ankle supports.
And finally, elevation. Elevation is
one more method that can be used to control
swelling. Patients with ankle sprains usually recognize the
advantages of elevation even weeks after the injury.
Step 2 (prevention of future sprains)
There's a lot
that can be done to prevent a second or recurrent series of
sprains. The means used to prevent recurrent ankle sprains really depend upon the patient
and their activities. Issues such as work, athletic activities and
social activities are all considerations in the prevention of future
sprains.
As an example, patient A is involved in a unidirectional
sport such as running. An ankle brace would be cumbersome and
probably detract from the enjoyment of a run. For this patient we
would use a
lateral sole wedge to inhibit supination of the foot. A lateral sole
wedge is designed to realign the center of gravity and place it back over the foot.
A lateral sole wedge
would be a great tool for the chronic ankle sprainer who is a runner or
for use in street shoes. It's important to recognize that a lateral
sole wedge in this case is not a simple arch support. Increasing the
arch height would tend to move the center of gravity to a position where
the ankle would be more prone to sprain.
What about bi-directional
sports like racquetball or tennis? An
ankle brace is
indicated for these sports. The side to side forces are just too great
to be controlled by a lateral sole wedge or arch support.
Stirrup braces are helpful in the acute phase of sprains to control
edema, but aren't all that helpful in bi-directional sports in controlling torsion of
the leg or inversion of the foot.
Lace
up ankle braces, particularly those that will lace into the shoe are
very effective in preventing recurrent lateral ankle sprains. A number
of new braces are available that are
thinner
and easier
to use than a traditional lace up ankle brace.
Supination is a contributing factor to ankle sprains.
Supination is the tendency to roll to the outside of the foot. The normal
foot has a center of gravity that is aligned through the center of the ankle and
the center of the foot. The supinated foot has a center of gravity that is
lateral of the normal midfoot position. When the center of gravity is
eccentric, this will contribute to lateral ankle sprains. Supination can
be controlled by placing a lateral sole wedge on the outside of the shoe or by
using a lateral
sole wedge insert.
Heel wedges may also be used to control supination.
Several physical
therapy techniques are helpful during rehab following ankle sprains. Physical
therapists will use proprioception exercises to re-educate the ligaments
of the ankle. Proprioception is the
sense of knowing where you are in space. The lateral collateral ligaments benefit from this
re-education process. The concept is to try to make the ligaments
more responsive to the next possible injury.
Proprioception
exercises:
When able, stand in a doorway placing all your body weight on the
injured ankle. Balance by holding on to the door. As you start to
gain more balance, close your eyes. This isolates the ankle and
forces it to be 're-educated'.
 Some patients are prone to
chronic sprains even after their first sprain. If a patient tends
to have severe, recurrent sprains, surgical stabilization of the ankle is
indicated. An unstable ankle will progressively lead to ankle
arthritis. The importance of having an ankle stabilization
performed is that stabilizing the ankle can prevent early arthritis and
internal ankle injuries. Ankle stabilization is a surgical procedure that
involves repair of the lateral collateral ligaments. The status of the
lateral ligaments of the ankle can be assessed with x-rays using stress
applied to the ankle or with MRI.
The most common
procedure performed to stabilize the lateral ankle is called a Brostrom
procedure. A Brostrom procedure recreates the ATF ligament through
the use of bone anchors and adjacent soft tissue at the lateral ankle. Occasionally,
in severe cases, a tendon transfer may be indicated to assist in
stabilizing the lateral ankle. Tendon transfer procedures can be quite
extensive and all require prolonged periods of immobilization. Tendon
transfer procedure like the Christman Snook and Elmslie are used for
patients who may fail correction with a Brostrom procedure. These
patients would include athletes who will put unusual stress on the
ankle.
The following images show the steps involved with a Brostrom
lateral ankle stabilization surgery. Image 1 shows the approach to the
lateral ankle. Image 2 shows the subcutaneous space and extensor
retinaculum. Image three shows an attenuated but intact anterior
talo-fibular ligament. Images 4 and 5 show repair of the ligament with
non-absorbable suture (Ethibond) anchored to the fibula (to the right).
Image 6 shows closure of the extensor retinaculum. And image 7 shows final
skin closure prior to casting.
 
Another
commonly overlooked aspect of lateral ankle surgery is the position of the heel
bone (calcaneus). If the heel is in an inverted position, this throws the
body's center of gravity to the side of the ankle making one prone to lateral
ankle sprains. If the calcaneus is in a fixed, inverted position, then
part of a lateral ankle stabilization procedure will include a Dwyer wedge
osteotomy of the heel to bring the heel in a position back under the leg.
A Dwyer procedure helps to prevent against re-injury. The following images
show a Dwyer osteotomy of the heel. Images 2 and 3 show the open wedge
created with a saw cut on the lateral aspect of the heel. Image 4 shows
closure of the wedge and rotation of the heel into the corrected position.
Image 5 shows fixation with 2, 6.5mm bone screws through the bottom of the heel.
 An arthroscopic method of
ankle stabilization is being developed. This technique is referred
to as arthroscopic monopolar radiofrequency thermal stabilization.
AMRTS employs a radiofrequency probe to shrink the lateral wall, or
capsule, of the ankle joint. The lateral collateral ligaments are
also treated with AMRTS. This technique is currently under investigation
in shoulder surgery and
holds promise as a minimally invasive alternative to traditional methods
of lateral ankle stabilization.
Medial ankle sprains
Medial ankle sprains are diagnosed and treated in ways very similar to lateral
ankle sprains. X-ray is not a reliable tool to diagnose a medial ankle
sprain but should be used to rule out an ankle fracture. MRI can confirm
the diagnosis medial ankle sprain. Treatment of a medial ankle sprain includes rest, ice, compression and elevation.
In severe cases, casting in a non-weight bearing cast may be necessary.
It's infrequent that the medial ankle ligaments need to be surgically repaired.
In most severe medial ankle injuries, stress applied to the deltoid ligament
will be transferred to the tibia resulting in a medial ankle fracture.
High ankle sprains
High ankle sprains are often diagnosed with x-ray. The diagnosis of a
high ankle sprain is confirmed in three ways. First, widening of the ankle
results with a complete rupture of the anterior inferior tibial-fibular
ligament. Comparison views between the patient's good ankle and the
injured and con confirm widening of the ankle surrounding the talus. The
second diagnostic sign of a high ankle sprain is widening of the lower leg between the tibia and
the fibula. And lastly, in severe high ankle sprains the anterior distal
tibial-fibular ligament will avulse or pull away a small fragment of bone from
the distal margin of the tibia. This fragment is called a Tillaux-Chaput
fragment or Tillaux-Chaput fracture. High ankle sprains can also be
diagnosed by MRI.
Treatment of high ankle sprains requires surgical re-apposition of the tibia and
fibula. This can be accomplished by the use of a trans-syndesmotic screw
(between the tibia and fibula) or with the use of an
Arthrex TightRope. This
procedure is performed in a hospital or surgery center on an out-patient basis.
The procedure is performed under general anesthetic and take approximately 45
minutes to complete. Follow-up consists of 6 weeks non-weight bearing in a
hard cast.
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