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Ankle Sprains
 Ankle sprain is a very
common injury in sports, work, and normal daily activities. It accounts for a
large amount of disability and time out of work and sports participation. The
foot and ankle form a complex supporting structure for the body, with the ankle
providing a large part of foot motion in the plane of forward motion. The
ligaments about the tibio-fibular joint and ankle stabilize and guide this basic
hinge joint. Ankle sprains most commonly
occur with sudden foot inversion, when the outer border of the foot rolls toward
the opposite foot. Generally, the anterior talofibular
ligament is ruptured first, followed by the calcaneofibular and
posterior talofibular ligaments as severity increases. Ankle sprain severity
grade is based on physical exam. The mildest grade has no physical laxity, and only
ligament tenderness. The second grade has anterior talofibular partial tearing
of the ligaments involved, and the third grade has complete ligament
disruption. The severity of ligament injury correlates well with calcaneofibular
disability, time to return to work or sports, and the ligament risk of recurrent
ankle sprain. Treatment is based upon the grade or severity of the injury.
Symptoms
Symptoms are generally
obvious, with severe tenderness along the anterior-lateral (outer-front) border
of the lower fibula (little outer bone at the ankle) and often also at its tip.
Commonly severe bruising and swelling occur in the first 48 hours. The outer leg
may be tender up towards the knee and especially in such a case fracture must be
excluded. Ligament injuries may be confused or associated with ankle fractures
in combination. Fractures may be caused by the same mechanisms, and may be
combined with ligament injuries or mimic them. In the child with open growth
plates, injuries of the growth plate are often mistaken for "ankle sprains,"
which are rare in children.
Diagnosis
Diagnosis is based on physical exam and simple X-Ray of the ankle. Rarely
are MRI or other imaging studies necessary. Laxity of the joint demonstrated by
physical exam, guides treatment. Sometimes, stress X-Rays may be used to
demonstrate instability.
Treatment
Treatment is aimed at reducing pain and swelling with rest, ice and compression.
In the case of significant ankle laxity, external ankle support aids ligament
healing to as near normal as possible. With low grade or single ligament
disruption support may be achieved with a functional ankle support. With high
grade, multiple ligament injuries which are as unstable as ankle fractures, cast
support or walking boots are indicated. Functional walking boots may give
the same support as a cast, while allowing for daily bathing and early motion.
These are often much more comfortable to wear, but more expensive. As swelling
and pain subside, and early healing proceeds, strengthening of the supporting
muscles of the ankle is indicated. This aids in stabilizing the joint and
restores weakened muscles arising from pain and immobilization after injury.
Exercises to aid balance on the effected leg also aids recovery. Surgery is
rarely indicated after primary ankle sprain unless fractures coexist or the
ligament sprain does not heal with significant improvement in stability, and
therapy is ineffective at improving stability to an acceptable level. It is more
important for the ankle to be stable against sliding in the front-to-back
direction than stable against rolling under into inversion. This is probably
also responsible for late arthritis in long term recurrent sprain.
Surgery
Surgery is occasionally necessary when ankle instability is recurrent and limits
normal function. It may also be helpful to slow arthritic changes in an ankle
with severe instability and resulting joint damage. This may require arthroscopy
of the ankle joint to remove loose debris, along with ligament reconstruction.
This is accomplished by advancing the ligaments originally torn free, tightening
them, and sewing them in this position. In many instances one or more ligaments
are not present because of recurrent sprain. In this case, new ligaments are
created using a strip of peroneus brevis tendon. This is woven through the fibula and heel bone (calcaneus), through small drill holes, to create new
ligaments which recreate normal stability. This allows high level function
without pain or instability in 85% of cases or greater. Late cases of
severe ankle arthritis may occur from chronic recurrent ankle injuries and
instability. In this case fusion of the ankle may be indicated. With
fusion, little
loss of motion is generally noticed, but pain is reduced or eliminated.
Ankle Fusion may be
performed arthroscopically, generally allowing rapid return to ambulation and
early fusion without the disability or healing delay resulting from open
surgical fusion.
Rehabilitation
Rehabilitation following ligament reconstruction of the ankle
requires immobilization in a cast or walking boot for approximately one month. After
Arthroscopy outlines basic surgical aftercare. During this time, early
range or motion exercises may be instituted if a removable walking boot is
utilized. Following this, a functional ankle brace should be worn within a shoe.
This is used full-time for one more month. For the next month the splint is
utilized for sports only. This results in a rapid functional return to activity
during which the ligament reconstruction is protected as it heals and gains
strength. Motion in the plane of ankle motion generally returns to essentially
normal. Inversion of the ankle is slightly limited for several months, but this
improves as the ligament reconstruction matures and remodels. A walking boot is
utilized for one month. Following this, a functional ankle brace should be worn
within a shoe. This is used full-time for one more month. For the next month the
splint is utilized for sports only. This results in a rapid functional return to
activity during which the ligament reconstruction is protected as it heals and
gains strength. Motion in the plane of ankle motion generally returns to
essentially normal. Inversion of the ankle is slightly limited for several
months, but this improves as the ligament reconstruction matures and remodels.
Time Course of
Rehabilitation
1-4 weeks cast or walking boot stabilization with weight bearing as
tolerated with crutches.
4-8 weeks Malleoloc or functional ankle brace immobilization.
8-12 weeks progressive return to high level activities with Malleoloc
brace worn.
12 weeks onward, added activities and sports without external immobilization.
Complications
Complications of ankle sprain itself is late instability, arthritis, or loose
body formation. After surgical reconstruction, infection, graft failure, or
limited range of the ankle may complicate the post-operative course. Quite
often, small sensory nerves in the incision area function poorly for a month or
two following reconstruction, but generally sensation returns to normal over the
lateral border of the foot over two or three months. This is generally a
nuisance only, and of no functional consequence. Significant complications are
rare, and in general ligament reconstruction of the ankle results in about 85% good to excellent results.
Summary
Ankle sprain is a common disabling injury generally treated with simple
conservative measures. In cases of severe recurrent instability surgical
stabilization is effective in returning patients to sports and work without
limitations.
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