Achilles tendonitis occurs when the Achilles tendon, which connects the calf muscles in the lower leg to the heel bone, becomes inflamed causing pain and swelling symptoms.
Achilles tendonitis (also known as Achilles tendinopathy, tendinitis, or tendinosis) is classified as an overuse injury. If left untreated it can become a chronic (long-term) injury, requiring more intensive treatment. Achilles tendonitis can also increase the risk of sustaining an Achilles tendon rupture (tear).
Signs and symptoms
The onset of the symptoms of Achilles tendonitis tend to be gradual, usually developing over a period of several days, or even weeks. Symptoms may include:
- Pain - this may be mild at first and may only be noticeable after exercise. Over time the pain may become constant and severe
- Stiffness - this is usually relieved by activity
- Sluggishness in the leg
- Tenderness - particularly in the morning and most commonly felt just above where the tendon attaches to the heel bone
The Achilles tendon is a strong band of connective tissue that attaches the calf muscle to the heel bone. The tendon moves through a protective sheath and is made up of thousands of tiny fibres.
It is thought that Achilles tendonitis develops when these fibres tear, causing inflammation, pain and swelling. As the tendon swells it can begin to rub against the sheath surrounding it, irritating the sheath and causing it to also become inflamed and swollen.
The Achilles tendon has a poor blood supply, which can make it susceptible to injury and can make recovery from injury slow.
Factors that can lead to the development of Achilles tendonitis include:
- Tight or weak calf muscles
- Rapidly increasing the amount or intensity of exercise
- Hill climbing or stair climbing exercises
- Changes in footwear - particularly changing from wearing high-heeled shoes to wearing flat shoes
- Wearing inadequate, inappropriate or worn out shoes for the sporting activity being undertaken
- Not adequately warming up and stretching prior to exercise
- A sudden sharp movement that causes the calf muscles to contract and the stress on the Achilles tendon to be increased. This can cause the tendon fibres to tear.
- Older age (the Achilles tendon weakes with age)
- A side-effect of a certain class of antibiotics called fluoroquinolones
- Certain medical conditions that increase the risk of Achilles tendonitis, such as diabetes mellitus, psoriasis and rheumatoid arthritis.
Some of these risk factors can also contribute to the development of plantar fasciitis, which is inflammation of the ligaments that connect the heel with the base of the toes.
If Achilles tendonitis is suspected, avoid any exercise or activity that causes the pain. It is advisable to see a doctor or physiotherapist promptly so that an accurate diagnosis can be made and appropriate treatment recommended.
A doctor will ask about the nature and duration of the symptoms and perform a physical examination of the affected area. Ultrasound scanning may be used to assess damage to the tendon or surrounding structures.
Occasionally MRI (magnetic resonance imaging) may be recommended. X-rays may be taken to rule out other conditions that can cause symptoms similar to Achilles tendonitis.
Treatment will depend on the severity of the injury. In general terms, the longer the symptoms are present before treatment begins, the longer the timeframe until complete recovery is achieved. Complete recovery can take between three and nine months.
Initial treatment of Achilles tendonitis includes:
- Rest - to avoid further injury to the area
- Ice - to reduce inflammation
- Elevation - to reduce swelling
- Non-steroidal anti-inflammatory drugs to reduce pain and inflammation. (Cortisone (corticosteroid) injections to reduce inflammation are not usually recommended as they may weaken the tendon and increase the risk of rupture).
Physiotherapy generally focuses on two main areas – treatment and rehabilitation. Treatment may involve massage, ultrasound, acupuncture and gentle stretching. Rehabilitation predominantly involves strengthening.
Strengthening of the muscles surrounding the Achilles tendon helps to promote healing in the tendon itself. Strengthening is achieved through the use of specific exercises, which will be taught by the physiotherapist. One such exercise is eccentric loading (sometimes referred to as "heel drops", which involve lengthening the calf muscle and tendon while under tension or load). It is common for the rehabilitation programme to take up to three months.
Podiatry, including gait analysis and the fitting of orthotic devices to support the foot and reduce stress on the tendon, may be recommended.
For cases of Achilles tendonitis that do not respond to initial treatment, casting or splinting of the affected foot may be recommended to allow it to rest completely.
In cases of severe, long-term Achilles tendonitis the sheath may become thick and fibrous. In such cases surgery may be recommended. Surgery aims to remove the fibrous tissue and repair any tears in the tendon. A cast or splint will be required after the operation and a recovery programme including physiotherapy, specific exercises and a gradual return to activity will be planned.
The following measures can significantly reduce the risk of developing Achilles tendonitis:
- When beginning an exercise regimen, start slowly and gradually increase the duration and intensity
- Adequately warm up and stretch prior to exercise
- Warm down and stretch after exercise
- Choose footwear carefully and use footwear appropriate to the sport being undertaken
- Use orthotic devices in footwear to correctly support the foot
- Exercise within fitness levels and follow a sensible exercise programme
- Develop strong, flexible calf muscles by doing eccentric exercises (heel drops) and stretching daily.
American Academy of Orthopaedic Surgeons (2010). Orthoinfo: Achilles tendinitis (Web Page). Rosemont, Illinois: American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00147 [Accessed: 21/02/20]
Cleveland Clinic (2017). Achilles tendon injury (Web Page). Cleveland, OH: Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/15225-achilles-tendon-injury---including-achilles-tendinitis-and-achilles-tendon-rupture [Accessed: 21/02/20]Mayo Clinic (2019). Achilles tendinitis (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/diseases-conditions/achilles-tendinitis/basics/definition/con-20024518 [Accessed: 21/02/20] Saglimbeni, A.J. (2018) Achilles tendon injuries (Web Page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. http://emedicine.medscape.com/article/309393-overview [Accessed: 21/02/20]
Last reviewed – March 2020Go to our Medical Library Index Page to find information on other medical conditions.