The shin area is subject to a great deal of stress during sports and
fitness activities and, thus, is prone to many overuse injuries. The term
""shin splints"" has been used to describe the soreness that can affect this
area, however, it is a non-specific diagnosis that can actually apply to a
number of causes of shin pain.


The shin refers to the front area of the leg between the ankle and the knee
that includes the tibia and fibula; the muscles of the leg that are divided
into compartments; and nerves and blood vessels. Shin pain can result from
injury to any of these structures, whether by direct trauma or overuse.
Overuse injuries in this area can be brought on by playing surfaces, muscle
weakness, inflexibility, and abnormal bio-mechanical function of the lower
extremities. In order to successfully treat these shin problems, an
accurate diagnosis must be made based on the history of the injury,
examination of the area, and special tests if needed.


MUSCLE AND TENDON INJURIES


The muscles in the front, or anterior part of the leg function to help bend
the ankle and foot upward to clear the ground when running and walking.
They also help balance out the strong pull of the calf muscles. The muscles
on the medial, or inside, of the leg help keep the foot from flattening out
or pronating excessively. Because of the great amount of force these
muscles and tendons are subjected to, they are prone to overuse injuries.


These injuries usually cause a dull, aching pain in the anterior or medial
side of the leg. This discomfort is present during activity, but the area
usually does not hurt when you are off your feet. It is hard to localize
one specific area of pain. Moving the foot and leg against resistance will
cause the pain to occur.


These injuries are very common when beginning a fitness program or changing
running or playing surfaces. The increased shock to this area will result
in inflammation of the muscle, causing shin discomfort. A tight calf muscle
can also cause the anterior muscles to work harder, resulting in muscle
strain.


Pain on the inside or medial side of the leg can result from excessive
pronation, making the posterior tibial muscle and tendon work harder to
stabilize the foot and possibly resulting in tendonitis.
Early treatment of muscle strains and tendonitis involves the R.I.C.E.
principle of rest, ice, compression and elevation. It is important to
reduce the amount of stress to the area in order to allow this injury to
heal. In many cases, cutting back on exercise time, changing floor
surfaces, or cross-training will allow you to maintain your fitness without
compromising your recovery.


An important consideration in both the rehabilitation and prevention of
this injury involves maintaining the correct balance between the calf
muscles and the muscles in the front part of the leg. Tight calf muscles,
combined with weak anterior muscles, will predispose people to these types
of shin injuries. A daily stretching routine that emphasizes the calf
muscle is probably the best form of preventitive medicine to decrease the
likelihood of suffering from this as well as other common overuse injuries.


In situations where pain persists, your sports medicine physician may
recommend physical therapy or the use of foot orthotics to help correct any
biomechanical abnormalities that may be contributing to this injury.


PERIOSTITIS


Periostitis is a thin membrane that surrounds bones and functions in bone
nutrition and repair. The periosteum of the tibia and fibula also serve as
a part of the lower leg muscles. When stressed, the muscular insertions may
irritate or tear off the periosteum, resulting in inflammation called
periosititis.


Periostitis of the leg bones is most painful when running, but a dull ache
may remain even after resting. The pain is usually located deep in the shin
area and along the shaft of the bone. In most instances, the pain will not
be localized to a specific spot, but rather cover an area of two to six
inches.


The causes of this injury are similar to that of muscle strains, and, in
fact, a muscle strain may progress to periostitis if left untreated. The
diagnosis is usually based on the history of the injury and a physical
examination. In some cases, there may also be subtle x-ray changes in the
affected area.


Treatment of this injury is also similar to that of muscle strains and
activities that involve impact to the leg, such as running, may need to be
restricted. A bio-mechanical evaluation of your foot and leg function may
reveal abnormalities that can predispose an individual to developing this
problem and steps can be taken to correct these, helping to speed recovery
and prevent a recurrence.


STRESS FRACTURES


Stress fractures of the tibia and fibula are another cause of shin pain in
active individuals. In contrast to muscle injury and periostitis, someone
with a stress fracture can usually point to a very specific area on the
bone that is tender. The pain from this injury is always present during
strenuous activity, but may also be noticeable when walking or standing.
Stress fractures result from small amounts or repetitive trauma to a
specific area of the bone. In the leg bones, these injuries usually occur
at the junction of the top or bottom one-third of the leg.
Our bones adapt to the increased demands of exercise by laying down more
bone and getting stronger. If not given the time to accomodate the
additional stress, small cracks will occur in the bone, resulting in a
fracture.


Most often, the bone does not move out of place, initially making the
injury difficult to diagnose by x-ray. As the bone begins to heal, new
bone, called callus, will begin to appear. This new bone can usually be
seen on x-ray four weeks after the injury occurs. A more reliable way to
confirm a stress frature is with a bone scan. This test involves injecting
a small amount of a dye into the body that is delivered to areas of healing
bone. The leg is scanned two hours later. A stress fracture will show up as
a black dot. This test can reveal a stress fracture two days after it
occurs.


Once diagnosed, treatment involves discontinuing any weight-bearing fitness
activities for a period of six to eight weeks. In most cases, a cast or
crutches will not be necessary, however, a removable brace may help provide
support. Crosstraining activities such as swimming and pool running may
help to maintain fitness during the recovery period.


In some cases, stress fractures may be the result of a structural or
bio-mechanical abnormality that places excessive pressure on a specific
area of the leg. In these instances, the use of foot orthotics may help
prevent a recurrence.


COMPARTMENT SYNDROME


The muscles of the lower leg are grouped together in four sections called
compartments. These compartments are formed by fibrous tissue called
fascia. In addition to muscles, each compartment contains nerves and blood
vessels.


During physical activity, muscles will usually expand and these
compartments will also expand slightly. If the muscles enlarge to a point
where they are placing excessive pressure on the compartment wall, soreness
and pain will occur. This might be due to a small compartment or from
overuse or over-develpment of the muscles in the compartment.


The pain resulting from an exercise-induced compartment syndrome is usually
described as a deep ache in the muscle area, rather than near the bone.
Over time, the symptoms may progress to numbness and muscle weakness in the
leg and foot caused by pressure being placed on the nerves in the leg. The
pain will usually subside after discontinuing the activity.
When a compartment syndrome is suspected, your sports medicine physician
may recomend a test that measures the pressure in the affected compartment
before and after the exercise. An elevation of pressure usually confirms
the diagnosis.


Conservative treatment for a compartment syndrome may involve minimizing
the excessive stress to which the affected leg is being subjected. This may
involve a change in activity or playing surface, rest, stretching,
anti-inflammatories, and control of any biomechanical abnormalities with
foot orthotics. These steps may help relieve the symptoms and allow the
compartment to return to normal. To prevent a recurrence, you may have to
alter your training and other factors that contributed to the injury.


When conservative treatment is ineffective, surgery may be suggested. This
involves making a small incision into the fascia of the affected
compartment or compartments to allow the muscles more room for expansion.


Although generally uncommon, compartment syndrome is another cause of
chronic shin and leg pain that, once diagnosed, can be treated, allowing
you to return to pain-free activity.


Many of the shin injuries described above are the result of not allowing
the body time to adapt to the increasing demands being placed upon it. By
establishing a reasonable training program involving a gradual increase in
exercise intensity, proper stretching and strengthening, and attention to
proper shoegear and technique, many of these overuse injuries can be
prevented.
Any pain that persists longer than seven days, gets worse, or recurs should
be evaluated by your sports medicine physician.


Perry Julien, D.P.M., is a podiatrist specializing in the medical and
surgical treatment of foot and ankle problems at the Atlanta Foot and Ankle
Center in Atlanta, GA.