The
Achilles tendon connects the calf muscle to the heel bone. It lets you rise up on
your toes and push off when you walk or run.
What are common Achilles tendon problems?
The
two main problems found in the Achilles tendon are:
Achilles tendinopathy. Achilles tendinopathy includes one of two conditions:
Tendinitis. This actually means "Inflammation of the tendon," but inflammation is
rarely the cause of tendon pain.
Tendinosis. This refers to tiny
tears (microtears) in the tissue in and around the tendon caused by overuse. In
most cases Achilles tendon pain is the result of tendinosis, not tendinitis.
Some experts now use the term tendinopathy to include both inflammation and
microtears. But many doctors may still use the term tendinitis to describe a
tendon injury.
Achilles tendon tear or rupture. An Achilles tendon also can partially tear or
completely tear (rupture). A partial tear may cause mild or no symptoms. But a
complete rupture causes pain and sudden loss of strength and movement.
Problems with the Achilles tendon may seem to happen
suddenly, but usually they are the result of many tiny tears to the tendon that
have happened over time.
What causes Achilles tendon problems?
Achilles
tendon problems are most often caused by overuse or repeated movements. These
movements can happen during sports, work, or other activities. For example, if
you do a lot of pushing off or stop-and-go motions when you play sports, you
can get microtears in the tendon. Microtears can also happen with a change in
how long, hard, or often you exercise. Microtears in the tendon may not be able
to heal quickly or completely.
Being out of shape or not warming
up before exercising may also cause Achilles tendon problems. So can shoes with
poor arch supports or rigid heels.
An Achilles rupture is most
often caused by a sudden, forceful motion that stresses the calf muscle. This
can happen during an intense athletic activity or even during simple running or
jumping. Middle-aged adults are especially likely to get this kind of
injury.
A rupture most often occurs in sports such as basketball,
racket sports (including tennis), soccer, and softball.1 A tendon already weakened by overstretching, inflammation,
or small tears is more likely to rupture.
What are the symptoms?
Symptoms of Achilles tendon
problems include swelling in the ankle area and mild or severe pain. The pain
may come on gradually or may only occur when you walk or run. You may have less
strength and range of movement in the ankle.
A rupture of the
Achilles tendon may cause a sudden, sharp pain. Most people feel or hear a pop
at the same time. Swelling and bruising may occur, and you may not be able to
point your foot down or stand on your toes.
How are Achilles tendon problems diagnosed?
Your
doctor can tell if you have an Achilles tendon problem by asking questions
about your past health and checking the back of your leg for pain and swelling.
The doctor may ask: How much pain do you have? How did your injury happen? Have
you had other injuries in the ankle area?
If your symptoms are
severe or do not improve with treatment, your doctor may want you to get an
X-ray,
ultrasound scan, or
MRI.
How are they treated?
Treatment for mild Achilles
tendon problems includes rest,
over-the-counter pain medicine, and stretching
exercises. You may need to wear well-cushioned shoes and change the way you
play sports so that you reduce stress on the tendon. Early treatment works best
and can prevent more injury.
Even in mild cases, it can take weeks
to months of rest for the tendon to repair itself. It's important to be patient
and not return too soon to sports and activities that stress the tendon.
Treatment for severe problems, such as a torn or ruptured tendon, may
include surgery or a cast, splint, brace, walking boot, or other device that
keeps the lower leg from moving. Exercise, either in physical therapy or in a
rehab program, can help the lower leg get strong and flexible again. The tendon
will take weeks to months to heal.
Although treatment for Achilles
tendon problems takes time, it usually works. Most people can return to sports
and other activities.
Overuse or repeated movements during sports,
work, or other activities. In sports, a change in how long, intensely, or often
you exercise, or a change in your environment (such as going from a flat
surface to a hill or from a paved road to a dirt road) can cause microtears in
the tendon that are unable to heal quickly and will eventually cause pain.
Injury from repeated push-offs or a stop-and-go motion, common in
such activities as running, basketball, tennis, or ballet dancing.
Poor conditioning or warm-up (as when you start a new activity or
have not stretched before and after an activity).
Shoes with poor
arch support or rigid heels that do not cushion the heel.
Sudden, forceful motion that stresses the calf
muscle, such as during an intense athletic activity or even during simple
running or jumping, especially in middle-aged adults. A
rupture most often occurs in sports such as
basketball, racket sports (including tennis), soccer, and softball.1
Overstretching the tendon during any activity
when the tendon is already damaged because of Achilles tendinopathy or another
condition.
Previous
corticosteroid injections (in the past, a common
treatment for overuse tendon injury). Corticosteroids can weaken or break down
tendon tissue, making it more likely to rupture.
A sudden, sharp pain that feels like a direct
hit to the Achilles tendon. There may be a pop when the rupture occurs. This
may be followed by swelling and bruising.
Heel pain (may be
severe).
Not being able to go on tiptoe with the hurt leg.
If you have a partial rupture (tear) of the Achilles
tendon, you may have near-normal strength and less pain after the initial
injury, compared to what you experience after a complete
rupture.
What Happens
Achilles tendinopathy
Achilles tendinopathy starts with repeated small tears in the tendon, causing no
obvious symptoms or mild to severe pain during movement. As the tearing
continues, the leg may weaken and the tendon pain may become constant. Abnormal
growths (nodules) may develop in the tendon, and it may thicken.
Resting and treating your injured Achilles tendon will likely reduce the pain.
Stretching and exercising in physical therapy or a rehabilitation program will
restore flexibility and strength in your lower leg. Warming up the lower leg
and Achilles tendon will help promote healing and keep the condition from
getting worse as you resume more intense activities, such as sports or stair
climbing.
Without rest and treatment of Achilles tendinopathy,
you may develop long-lasting (chronic) pain.
Achilles tendon tear or rupture
An Achilles tendon
can partially tear or
completely tear (rupture). If your Achilles tendon has
ruptured, your leg may be weak, and walking may be
difficult.
A tear usually occurs in the tendon about
1.5 in. (3.8 cm) to
2.5 in. (6.4 cm) above its
attachment to the heel bone. Some health professionals believe that this area
is most likely to tear or rupture because of a limited blood supply.
If you treat an Achilles rupture with:
Surgery followed by a rehabilitation program,
you will likely regain full movement and function.
A cast, brace,
splint, walking boot, or other device that keeps your lower leg from moving
(immobilization), the tendon will most likely heal but may not be as strong as
before the injury and may be more likely to rupture again. Exercising, in
physical therapy or in a rehabilitation program, will help restore flexibility
and strength in the lower leg.
If you do not treat an Achilles rupture, you will feel
weakness in the first steps when walking, with a feeling similar to that of
walking in the sand. Eventually, walking will become difficult.
Other Achilles tendon problems
Other conditions
can affect the Achilles tendon area alone or along with tendinosis. These other
conditions are caused by inflammation and include:
Achilles paratenonitis, which is an inflammation of the covering of the Achilles
tendon. Symptoms include tenderness, pain, and swelling in the Achilles area,
all of which are usually worse during activity. This is also called Achilles
peritendinitis.
Retrocalcaneal bursitis, which is an
inflammation of the small fluid-filled sac (bursa) between
the back of the heel bone and the Achilles tendon, just above the point where
the tendon connects to the bone. The inflammation causes swelling, tenderness,
and pain on the back of the foot. See an illustration of the
retrocalcaneal bursa.
Insertional Achilles tendinopathy, which is damage in
the area where the tendon attaches to the heel bone. Symptoms include
tenderness on the lower back of the heel and less ability to overflex the foot.
Pain tends to be worst after exercise and can eventually become constant. This
condition often develops along with retrocalcaneal bursitis.
Sports and physical activity. Because overuse and
repeated movements can cause injury and weaken the Achilles tendon, playing
sports increases the risk of an Achilles tendon injury. Activities at work
(such as in construction) and at home (such as gardening) may also increase
your risk.
Sports training errors. Not warming up before and
after running or other activities or suddenly changing your training program
can increase your risk for injury. Increasing your distance, running uphill
more often, or changing your ground surfaces (for example, from pavement to
sand) too quickly can increase your risk.
Age. As you age, the blood supply to the Achilles
tendon area decreases. Most cases of Achilles tendinopathy or rupture occur in
people older than 30.
Weight. If you are very heavy, you have a greater
risk of an Achilles tendon injury.
Being male. Men are more likely than women to have
an Achilles tendon injury.
High cholesterol. If
high cholesterol runs in your family, you have a
higher risk of Achilles tendon pain and problems.3
Corticosteroid injections in the
Achilles tendon, which can weaken the tendon.
Using quinolone
antibiotics, especially if you are older than 60 and/or are taking
corticosteroids by mouth.4 Quinolones include
ciprofloxacin and ofloxacin.
Having received
dialysis or having undergone a kidney
transplant.4
When To Call a Doctor
Call your health professional immediately if you think you have an
Achilles tendon problem (at or above the back of your ankle) and:
The back of your heel and ankle are very
painful.
You felt a sharp pain like a direct hit to the Achilles
tendon.
You heard a pop in your Achilles tendon when
injured.
You are unable to walk comfortably.
Your
Achilles tendon area has begun to swell.
You have signs of damage
to the nerves or blood vessels, such as numbness, tingling, a pins-and-needles
sensation in your foot, or pale or bluish skin.
If you have had an Achilles tendon injury in the past and
you have reinjured your Achilles tendon, call your health professional to find
out what you need to do. Rest your lower leg and foot until treatment
begins.
Watchful Waiting
Watchful waiting is a period of time during
which you and your health professional observe your symptoms or condition
without using medical treatment. Watchful waiting is not appropriate if you
have severe pain in the Achilles tendon area. If you think you have injured
your Achilles tendon, call your health professional. Early treatment is most
effective in healing the Achilles tendon.
If you think you have
Achilles tendinopathy, rest your lower leg and foot
for a couple of days and avoid any hard activity. Use ice and pain-relieving
medicines to reduce the pain and swelling, and follow the other steps in the
Home Treatment section of this topic. If you have weakness, cramping, or
constant pain in your Achilles tendon, call your health professional.
Who To See
Health professionals who can diagnosis and treat an
Achilles tendon problem include:
Your health professional will usually
diagnose an Achilles tendon problem through a
medical history and physical examination. During the
physical exam, he or she will:
Check for tenderness.
Achilles tendinopathy usually makes the tendon tender
to the touch.
Check your lower leg for gaps in your Achilles
tendon, thickening of the tendon, nodules on the tendon, or bony growths on the
heel bone.
Compare your legs to see what is normal motion and how
the injury (tendinosis or
rupture) has affected the lower leg and ankle. Your
health professional will check for changes not only in strength but also in
nerve and circulatory symptoms, such as lack of feeling in the area.
To help identify a tear or rupture, your health
professional will:
Squeeze your calves. How your feet move
when your calves are squeezed can help diagnose a rupture. A partial tear of
the Achilles tendon can be difficult to diagnose when there is minimal pain and
near-normal strength after the initial tear. If there is a partial tear, the
calf squeeze test may be normal, but a defect may be felt in the
tendon.
Observe how you stand and walk. A sign of a ruptured tendon
is not being able to walk on your toes. You may or may not be able to stand and
bear weight.
Further tests may be done to clarify a diagnosis or to
prepare for surgery. These tests include:
Treatment for Achilles tendinopathy
includes rest to allow the tendon to heal, and steps to increase strength and
flexibility to prevent further injury. Treatment for an Achilles tendon
rupture includes surgery or a cast, splint, brace,
walking boot, or other device that will keep your lower leg from moving
(immobilization). Early treatment usually results in better healing.
Follow any
physical therapy that your health professional has
prescribed, including stretching and strengthening exercises, massage, heat, or
ultrasound.
Your health professional may suggest that you wear a
night brace to keep your foot flexed, if your Achilles tendon shortens and
stiffens while you sleep.
If you continue to have pain or
stiffness in the ankle area, your health professional may prescribe a walking
boot or other device for 4 to 6 weeks to keep your lower leg and foot from
moving and allow the tendon to heal.
If you still have Achilles
tendon pain after more than 6 months of consistent treatment and rest, you
might need to consider surgery.
Achilles tendon rupture
Treatment for an Achilles
tendon rupture includes:
Surgery followed by
rehabilitation. This is the most common treatment. It
reattaches the torn ends of the tendon and can be done through one large
incision (open surgery) or several smaller incisions
(percutaneous).
Immobilizing your leg followed by
rehabilitation. This prevents movement of the lower
leg and ankle and allows the ends of the Achilles tendon to reattach and heal.
A cast, splint, brace, walking boot, or other device may be used to do
this.
What To Think About
Do not smoke or use other tobacco
products. Smoking slows healing because it decreases blood supply and delays
tissue repair.
If you have an Achilles tendon rupture, your
decision about whether to have surgery will depend in part on your:
Attitude toward reinjury and complications.
Immobilization using a cast or similar device is more likely than surgery to
result in another rupture but is less likely to result in complications, such
as wound infection.5
Level of activity. If
you are very active in sports or have a job that requires leg strength and you
want your leg to be as strong as it was before your injury, you may consider
surgery.
Age. If you are an older adult who does not participate in
activities that may result in another rupture and who does not want the added
risk of surgery, you may prefer using a cast or similar
device.
Medical condition. If you have another medical
condition-such as
diabetes or heart or lung disease-that raises the
risks associated with surgery, you may prefer using a cast or similar
device.
Time of injury. Surgery is generally recommended if the rupture
is more than 2 weeks old.
Most Achilles tendon injuries occur during
sports and can be prevented. If you had an Achilles tendon problem in the past,
it is especially important to try to prevent another injury by:
Warming up and stretching. Before any sport or
intense activity, gradually warm up your body by doing 5 to 10 minutes of
walking or biking and then do stretching exercises.
Calf stretches will stretch and strengthen the Achilles tendon and calf
muscles. More
general stretches target other muscles, such as the hamstrings and
groin.
Cooling down and doing more stretching. After intense
activity, gradually cool down with about 5 minutes of easy jogging, walking, or
biking, and 5 minutes of stretches.
Avoiding any sport or intense
activity that you are not in condition to do.
Wearing shoes that
cushion your heel during sports or any strenuous activity.
Wearing
heel pads or other
orthotics that are designed to reduce stress on the
Achilles tendon.
Home Treatment
Home treatment is often used for
Achilles tendinopathy and in
physical therapy or rehabilitation after an Achilles
tendon
rupture.
Achilles tendinopathy
If you have
Achilles tendinopathy, follow these steps to rest,
heal, and strengthen your Achilles tendon and prevent further injury:
Rest your Achilles tendon. Avoid all
activities that strain the tendon, such as stair climbing or running. While
allowing your tendon the days, weeks, or months it needs to heal, try
alternative activities, such as swimming. Your health professional will give
you information on what you can and cannot do.
Reduce pain by icing
your Achilles tendon and taking nonprescription pain relievers such as
acetaminophen or
nonsteroidal anti-inflammatory drugs (NSAIDs) as
directed. Examples of acetaminophen include Panadol and Tylenol. NSAIDs include
ibuprofen (Advil, Motrin) and aspirin. Do not give aspirin to anyone younger
than 20 because of the risk of
Reye syndrome.
Follow your
physical therapy program if one has been prescribed
for you, and do gentle stretching and strengthening exercises, especially
focusing on
calf stretches.
Do not smoke or use other tobacco products.
Smoking slows healing because it decreases blood supply and delays tissue
repair.
Wear footwear that protects the tendon while it is healing.
Quality athletic shoes that support your
arches and cushion your heels can make a big difference in your daily comfort
and the healing process. If necessary, talk to your physical therapist or
podiatrist about heel pads or
orthotics.
A bandage that keeps your foot
flexed can restrict the motion of the Achilles tendon.
A silicone
sleeve or pad can distribute pressure on the Achilles tendon.
Your health professional may suggest you wear a
night brace to keep your foot flexed, if your Achilles tendon shortens and
stiffens while you sleep.
Achilles tendon rupture
Whether you treat an
Achilles tendon rupture with surgery or use a cast, splint, brace, walking
boot, or other device to keep your lower leg from moving (immobilizing your
leg), after treatment it's important to follow the
rehabilitation program prescribed by your health
professional and physical therapist. This program helps your tendon heal and
prevents further injury.
Acetaminophen can relieve pain.
Examples include Panadol or Tylenol.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are also often used to treat pain from
Achilles tendinopathy or
rupture. However, because most tendon problems do not
involve inflammation, NSAIDs are not usually necessary. NSAIDS include
ibuprofen (Advil, Motrin) and aspirin. Do not give aspirin to anyone younger
than 20 because of the risk of
Reye syndrome.
Corticosteroid
injections, which sometimes are injected around tendons or into joints to
reduce pain and
inflammation, are not used to treat Achilles
tendinopathy because they may increase the risk of a tendon rupture.
Surgery
Achilles tendinopathy
Surgery usually is not
necessary to treat
Achilles tendinopathy. However, in rare cases, someone
might consider surgery when rubbing between the tendon and the tissue covering
the tendon (tendon sheath) causes the sheath to become thick and fibrous.
Surgery can be done to remove the fibrous tissue and repair any small tendon
tears. This may also help prevent an Achilles tendon
rupture.
Achilles tendon rupture
Surgery is often used to
reattach the ends of a ruptured Achilles tendon. It provides a better chance of
preventing the tendon from rupturing again compared to using a cast, splint,
brace, walking boot, or other device that will keep your lower leg from moving
(immobilization).5
The results of surgery for an Achilles tendon rupture are best when you
have the surgery soon after your injury. Recovering from surgery may take
months, and it requires a
rehabilitation program to help heal and strengthen the
tendon.
Surgery Choices
Surgery for an Achilles tendon rupture
can be open or percutaneous.
In open surgery, the surgeon makes a single
large incision in the back of the leg, and stitches the torn tendon back
together.
In percutaneous surgery, the surgeon makes several small
incisions rather than one large incision, and stitches the torn tendon back
together.
What To Think About
The differences in age and
activity levels of participants can make it difficult to determine if Achilles
tendon surgery is effective. The success of your surgery can depend on your
surgeon's experience, the type of surgical procedure used, the extent of tendon
damage, how soon after rupture the surgery is performed, how soon your
rehabilitation program starts after surgery, and how
well you follow your rehabilitation program.
In general:
Both open and percutaneous surgeries are
successful. The differences between the two lie in the potential for having
another rupture and wound complications.
Although percutaneous
surgery used to have a higher rate of repeat tendon ruptures than did open
surgery, studies now indicate that how often the tendon reruptures is
similar-up to 3% for open surgery and about 3% to 7% for percutaneous surgery,
depending on how soon you start using the tendon again (mobilization).5
Open repair is more likely to result in wound
healing problems than percutaneous repair is. However, damage to a nerve is
more likely with percutaneous surgery. Newer techniques for percutaneous
surgery may make nerve damage less likely than when older techniques are used.
Your decision about whether to have surgery or use a cast
or similar device to immobilize your leg may depend in part on your:
Attitude toward reinjury and complications.
Immobilizing your leg is more likely than surgery to result in another rupture
but is less likely to result in complications, such as wound infection.5
Level of activity. If you are very active in
sports or have a job that requires leg strength and you want your leg to be as
strong as it was before your injury, you may consider surgery.
Age.
If you are an older adult who does not participate in activities that may
result in another rupture, and who does not want the added risk of surgery, you
may prefer using a cast or similar device.
Medical condition. If
you have another medical condition-such as
diabetes or heart or lung disease-that raises the
risks associated with surgery,a cast or similar device may be a better
treatment for you.
Time of injury. Surgery is generally
recommended if the rupture is more than 2 weeks old.
Talk to your surgeon about his or her surgical
experience and success rate with the technique that would best treat your
condition.
Other treatments are often used
for
Achilles tendinopathy and
rupture. Before using other treatments, you most
likely will try rest and medicine to reduce pain and swelling.
Achilles tendinopathy
Common
physical therapy treatments for Achilles tendinopathy
include:
Massage, to help
increase flexibility and blood circulation in the lower leg and to help prevent
further injury.
Wearing a
night brace to keep your leg flexed and prevent your Achilles tendon from
tightening while you sleep. An Achilles tendon that often tightens at night is
not able to heal properly.
If other treatment does not reduce your Achilles
tendinopathy pain, your health professional may recommend using a cast, brace,
walking boot, splint, or other device for 4 to 6 weeks to prevent your lower
leg and foot from moving and to allow the tendon to heal. This is then followed
by physical therapy and modification of activities.
Achilles tendon rupture
A
cast or similar device can be used to immobilize a ruptured Achilles tendon,
allowing it time to heal on its own. A cast or similar device prevents the
lower leg and ankle from moving. Treatment with this type of device may take as
long as 6 months to completely heal a tendon. This is usually followed by a
rehabilitation program that helps you regain strength
and flexibility in the tendon and leg. The rehabilitation program may include
physical therapy as noted above.
Your decision about whether to
have surgery or use a cast-type device may depend in part on your:
Attitude toward reinjury and complications.
Immobilizing your leg is more likely than surgery to result in another rupture
but is less likely to result in complications, such as wound infection.5
Level of activity. If you are very active in
sports or have a job that requires leg strength and you want your leg to be as
strong as it was before your injury, you may consider surgery.
Age.
If you are an older adult who does not participate in activities that may
result in another rupture, and who does not want the added risk of surgery, you
may prefer immobilizing your leg.
Medical condition. If you have
another medical condition-such as
diabetes or heart or lung disease-that raises the
risks associated with surgery, immobilizing your leg may be a better treatment
for you.
Time of injury. Surgery is generally recommended if the
rupture is more than 2 weeks old.
Other Places To Get Help
Organizations
American Academy of Orthopaedic Surgeons
(AAOS)
6300 North River Road
Rosemont, IL 60018-4262
Phone:
1-800-346-AAOS (1-800-346-2267) (847) 823-7186
Fax:
(847) 823-8125
E-mail:
pemr@aaos.org
Web Address:
www.aaos.org
The American Academy of Orthopaedic Surgeons (AAOS) provides
information and education to raise the public's awareness of musculoskeletal
conditions, with an emphasis on preventive measures. The AAOS Web site contains
information on orthopedic conditions and treatments, injury prevention, and
wellness and exercise.
National Institute of Arthritis and Musculoskeletal and
Skin Diseases (NIAMS), National Institutes of Health
The National Institute of Arthritis and Musculoskeletal
and Skin Diseases (NIAMS) is a governmental institute that serves the public
and health professionals by providing information, locating other information
sources, and participating in a national federal database of health
information. NIAMS supports research into the causes, treatment, and prevention
of arthritis and musculoskeletal and skin diseases and supports the training of
scientists to carry out this research.
The NIAMS Web site provides
health information referrals to the NIAMS Clearinghouse, which has information
packages about diseases.
Mann JA, et al. (2006). Tendon injuries section of Foot and ankle injury. In HB Skinner, ed., Current Diagnosis and Treatment in Orthopedics, pp. 527-533. New York: McGraw-Hill.
Mazzone MF, McCue T (2002). Common conditions of the Achilles tendon. American Family Physician, 65(9): 1805-1810.
Beeharry D, et al. (2005). Familial hypercholesterolaemia commonly presents with Achilles tenosynovitis. Annals of Rheumatic Disease, 65: 312-315.
Van der Linden PD, et al. (2003). Increased risk of
Achilles tendon rupture with quinolone antibacterial use, especially in elderly
patients taking oral corticosteroids. Archives of Internal Medicine, 163(15): 1801-1807.
Wong J, et al. (2002). Quantitative review of
operative and nonoperative management of Achilles tendon ruptures.
American Journal of Sports Medicine, 30(4):
565-575.
Other Works Consulted
Haji A, et al. (2004). Percutaneous versus open tendo
Achilles repair. Foot and Ankle International, 25(4):
215-218.
Khan RJ, et al. (2004). Surgical interventions for
treating acute Achilles tendon ruptures. Cochrane Database of Systematic Reviews (3). Oxford: Update Software.
Schepsis AA, et al. (2002). Achilles tendon disorders in athletes. American Journal of Sports Medicine, 30(2): 287-305.
This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
Mann JA, et al. (2006). Tendon injuries section of Foot and ankle injury. In HB Skinner, ed., Current Diagnosis and Treatment in Orthopedics, pp. 527-533. New York: McGraw-Hill.
Mazzone MF, McCue T (2002). Common conditions of the Achilles tendon. American Family Physician, 65(9): 1805-1810.
Beeharry D, et al. (2005). Familial hypercholesterolaemia commonly presents with Achilles tenosynovitis. Annals of Rheumatic Disease, 65: 312-315.
Van der Linden PD, et al. (2003). Increased risk of
Achilles tendon rupture with quinolone antibacterial use, especially in elderly
patients taking oral corticosteroids. Archives of Internal Medicine, 163(15): 1801-1807.
Wong J, et al. (2002). Quantitative review of
operative and nonoperative management of Achilles tendon ruptures.
American Journal of Sports Medicine, 30(4):
565-575.