Pain at the back of the ankle is often caused by the Achilles tendon. Common conditions include Achilles tendonitis (tendinopathy), bursitis and tendon injuries. Achilles pain may develop gradually over time or occur suddenly. Understanding the cause is key to choosing the right treatment and recovery plan.
Did your Achilles tendon pain start suddenly or develop gradually?
Chronic Achilles tendon injuries usually develop gradually over time. The most common cause is Achilles tendinopathy, where the tendon becomes overloaded and weakened. You may not be able to pinpoint exactly when your symptoms began. Acute injuries occur suddenly and are often associated with a specific incident, although not always. In some cases, long-term Achilles pain can flare up and present like an acute injury.
Gradual onset (chronic) Achilles pain
The following injuries are common causes of gradual onset and chronic pain at the back of the ankle:
Achilles tendinopathy/tendinitis
Chronic Achilles tendon pain is most commonly caused by Achilles tendinopathy (also referred to as Achilles tendonitis or tendinosis). It is an overuse injury where the tendon becomes overloaded over time, leading to pain, stiffness and reduced function.
Symptoms typically include:
- Gradual onset of pain at the back of the ankle
- Pain that develops over days or weeks
- Stiffness and pain first thing in the morning or at the start of exercise
- Pain that eases as the tendon warms up, then returns later in the day
- Tenderness when squeezing the Achilles tendon from the sides
- A thickened area or small lump within the tendon
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Achilles tenosynovitis
Achilles tenosynovitis (also called paratenonitis) is an inflammatory condition affecting the sheath surrounding the Achilles tendon.
Symptoms are very similar to those of Achilles tendinopathy, and it is often difficult to distinguish between the two without MRI or ultrasound scans. In many cases, both conditions can occur together.
Symptoms may include:
- Pain when touching the Achilles tendon
- Pain when pushing up onto tiptoes or stretching the calf muscles
- Swelling or thickening of the tendon
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Sever’s Disease
Sever’s disease affects children aged 8 to 15 years, particularly during periods of rapid growth or in those who take part in regular sport.
Symptoms typically include:
- Pain and tenderness at the back of the heel, which worsens with activity
- Swelling or a lump at the back of the heel
- Tenderness when squeezing the sides of the heel
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Posterior impingement syndrome
Ankle impingement syndrome occurs when soft tissue becomes trapped or pinched between bones at the back of the ankle.
Symptoms typically include:
- Pain at the back of the ankle
- Tenderness behind the lower end of the fibula (outer ankle bone)
- Pain at the end range of movement, especially when the foot points down (plantar flexion)
- Pain when rising onto tiptoes
In some cases, an X-ray may show bony spurs on the talus or tibia.
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Insertional Achilles Tendonitis
Insertional Achilles tendinopathy occurs at the back of the heel, where the Achilles tendon attaches to the heel bone. It is similar to Sever’s disease in children but typically affects adults.
Symptoms include:
- Pain and tenderness at the back of the heel
- Symptoms that worsen with activity
- A visible lump or thickening at the tendon insertion on the calcaneus (heel bone)
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Achilles bursitis
Achilles bursitis, also known as retrocalcaneal bursitis, is common in athletes, particularly runners. It involves inflammation and swelling of a small fluid-filled sac (bursa) at the back of the heel.
- Pain, swelling, and tenderness at the back of the heel
- The bursa becomes inflamed, usually due to overuse
- More on Achilles bursitis
Haglund’s syndrome/deformity
Haglund’s syndrome occurs when retrocalcaneal bursitis and Achilles tendinopathy are present at the same time in the same leg. This leads to pain both at the back of the heel and within the Achilles tendon.
- More on Haglund’s syndrome
Referred Achilles tendon pain
Pain in the Achilles tendon may be caused by nerve injury or entrapment elsewhere in the body, such as the lumbar spine, sacroiliac joint, or hip.
The sciatic nerve can become compressed, causing pain that radiates down the back of the leg into the ankle.
Sudden onset (acute) Achilles tendon pain
The following are common acute (sudden onset) Achilles tendon injuries:
Achilles tendon rupture
A total rupture of the Achilles tendon is a complete tear. It most commonly affects men over the age of 40 who are active in sport.
Symptoms include:
- Sudden, sharp pain in the Achilles tendon, often described as being struck by an object
- A loud snapping or popping sound at the time of injury
- Pain when walking, although some people may still be able to limp
- A feeling of weakness or difficulty pushing off the foot
If a complete Achilles tendon rupture is suspected, seek urgent medical attention.
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Partial Achilles rupture
A partial Achilles tendon rupture is an incomplete tear. It can occur in athletes across a range of sports, particularly running, jumping, and racket sports.
Symptoms may include:
- Sharp pain in the Achilles tendon at the time of injury, although not always
- Pain that develops later, often after activity, when the tendon cools and stiffens
- Ongoing discomfort or stiffness during activity
More on Partial Achilles rupture
When should I see a doctor about my Achilles tendon pain?
If you suspect an Achilles tendon rupture, seek medical attention as soon as possible. Surgery is often recommended, particularly for active individuals and athletes. An Achilles tendon rupture is not always obvious, and Thompson’s test is commonly used to help diagnose a tear.
References & further reading
- Gabbett TJ. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med 2016;50(5):273–80.
- Robinson JM, Cook JL, Purdam C et al. The VISA-A questionnaire: a valid and reliable index of the clinical severity of Achilles tendinopathy. BJSM 2001;35(5):335-41
- Alfredson H, Lorentzon R. Chronic Achilles Tendinosis – recommendations for treatment and prevention. Sports Med 2000;29(2):135-46
- Alfredson H, Piettila T., Jonsson P et al. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. American Journal of Sports Medicine 1998;26(3):360-6
