Introduction

Did you know that the Achilles tendon is the strongest and largest in the human body?¹ This band of tissue connects the calf muscles to the heel bone enabling us to run, walk, and jump. However, when the tendon is repeatedly overloaded, it can become inflamed and painful, leading to a condition known as Achilles tendinitis. 

The first-line treatment for Achilles tendinitis typically involves conservative therapies such as eccentric exercises, activity modification, ice, and physical therapy. Some evidence suggests that additional therapies, including shockwave and laser treatments, may also be beneficial. Surgery is generally considered only when all other options have failed. It‘s important to remember that recovery from Achilles tendinitis takes time, with most rehabilitation programmes focusing on a recovery period of 12 weeks or more. 

Anatomy and physiology of the achilles tendon

The Achilles tendon is formed from both the gastrocnemius and soleus muscles and inserts onto the heel bone, known as the calcaneus. When we walk, run, or jump, the gastrocnemius and soleus muscles contract, transmitting force through the tendon, which causes plantar flexion of the foot. As the tendon attaches to the heel, it turns 90 degrees medially; this configuration is thought to be one of the reasons why it is susceptible to Achilles tendinitis.² 

Achilles tendinitis refers to acute inflammation within the tendon. This condition can quickly develop into tendinosis, where chronic inflammation occurs within the tendon. Therefore, the term Achilles tendinopathy is often used to encompass both conditions.

What are the causes of achilles tendinitis?

The main cause of Achilles tendinitis is overuse, which places excessive stress on the tendon, leading to inflammation and structural changes. This condition is commonly found in people who engage in high-impact exercises such as running, tennis, or dance. Triggers can include:³

• An increase in training
• Muscle imbalances
• Hard training surfaces 
• Poor footwear 
• Inadequate warm-up 

Other factors can predispose you to Achilles tendinitis. These include:

• Ageing 
• Being overweight 
• Long-term health conditions
• Problems with foot biomechanics 
• Certain medications, including antibiotics and steroids.³ 

What are the symptoms of achilles tendinitis?

Symptoms of Achilles tendinitis often start mildly, with more pain first thing in the morning or after activity. Sufferers typically experience the following:

• Pain in the heel 
• Pain that worsens after exercise
• Pain and stiffness in the area in the morning upon waking 
• Pain when touching the tendon 
• Swelling and redness over the tendon, sometimes with thickening 
• Difficulty standing on tiptoes

How is achilles tendinitis diagnosed?

Achilles tendinitis is predominantly diagnosed through physical examination. Your clinician may assess for signs of pain, swelling, and stiffness in the tendon in both standing and lying down positions. The following specific tests are commonly used:

• Arc Sign: The clinician palpates the swelling or nodules in the tendon while moving the ankle up and down. The test is considered positive if the swelling or nodules move within the range of motion.² If the nodules or swelling remain in one position, the cause of pain is likely para tendinopathy.
• Royal London Hospital Test: The clinician palpates the most tender area of the tendon while the ankle is in a neutral position. The patient then dorsiflexes the ankle to stretch the tendon; with Achilles tendinitis, the tenderness in that area should decrease.⁴
• Ankle Range of Motion: In Achilles tendinitis, pain will increase with passive dorsiflexion of the ankle. 

Other tests, such as hopping or heel raising, may also be used to assess the function of the Achilles tendon. 

Is imaging useful for achilles tendinitis?

MRI and ultrasound scans can be used to assess the condition of the tendon, while CT scans can help rule out any structural changes to the heel bone.² However, guidelines strongly recommend that imaging is unnecessary in most cases of Achilles tendinitis.⁵ 

What treatment options are there for achilles tendinitis?

Conservative (non-surgical) treatments 

Conservative therapies should always be the first-line treatment for Achilles tendinitis, with surgical options considered only if conservative measures fail.⁶ Active treatments are generally recommended over a “wait and see” approach.⁷ Treatment options include:

• Reduce or Modify Activity: Achilles tendinitis is often caused by overuse, particularly in high-impact activities such as running or jumping. Reducing or modifying painful activities can help relieve stress on the tendon and allow it to begin healing. This does not mean you cannot exercise; non-weight-bearing exercises, such as swimming or cycling, may be less painful. 
• Ice: While it does not cure tendinitis, applying ice to the area may help relieve some of the pain.³ Be sure to wrap the ice in a cloth or towel before applying it to your skin to prevent burns. 
• NSAIDs: The use of non-steroidal anti-inflammatory drugs (NSAIDs) is debated. NSAIDs may help relieve pain in the very acute phase of the condition but are unlikely to be beneficial if the pain has persisted for a longer period.³ This is because inflammatory cells are typically no longer present in the tendon after the initial phase. 
• Eccentric Exercises: Eccentric exercises are one of the most effective treatments for  Achilles tendinitis.⁸ They allow you to gradually increase the stress on the tendon, which causes structural changes and promotes healing. Eccentric exercises involve lowering your body weight through the muscle in a controlled manner. For example, one eccentric exercise for Achilles tendinitis is to stand on a step and lower your body weight slowly through the Achilles tendon off the edge of the step. The NHS provides good examples of eccentric exercises. These exercises are typically done daily for at least 12 weeks. It may initially seem like there is no improvement, but it is important to persist, as it takes time to see results. 
• Physiotherapy: Physiotherapy may aid recovery from Achilles tendinitis. A physiotherapist can assess any biomechanical issues contributing to your pain and design a rehabilitation programme to support your recovery. Deep friction massage and stretching of the tendon can also help to speed up recovery.^9,10 
• Ultrasound: Ultrasound treatment was once regularly prescribed for Achilles tendinitis. However, current evidence suggests that it provides no clinical benefit.¹¹ 
• Laser Therapy: Low-level laser therapy uses a single wavelength of light to reduce inflammation and promote healing. There is some evidence suggesting it can be effective in treating Achilles tendinitis.¹² However, it is most effective when combined with a rehabilitation programme. 
• Extracorporeal Shockwave Therapy (ESWT): In ESWT, shockwaves from a special device are passed through the skin into the Achilles tissue. Usually, at least three sessions every week are recommended. Evidence regarding this treatment is mixed, but recent reviews suggest it may benefit pain and function in Achilles tendonitis.¹³ However, the greatest benefits are seen in combining shockwave treatment with eccentric exercises. It is also considered a very safe treatment method with few side effects.
• Platelet-Rich Plasma (PRP) Injection: A PRP injection involves injecting blood plasma, rich in platelets, into the injured tendon. A small amount of blood is drawn from the patient, processed to separate the platelet-rich plasma, and then re-injected into the tendon. This is thought to stimulate the healing of soft tissues. Unfortunately, current evidence suggests that this treatment is not effective for Achilles tendinitis.¹⁴ 
• Corticosteroid Injections: Corticosteroid injections involve injecting anti-inflammatory medication directly into the tendon. While corticosteroid injections may provide some short-term benefit, ³ overall evidence suggests they are not effective as a treatment for Achilles tendinitis.¹⁵ Furthermore, there is a high incidence of adverse effects, including tendon atrophy, rupture, and decreased strength.³ 

Surgical treatments

Surgery for Achilles tendonitis is considered only when conservative treatments have failed. The type of surgery depends on the location of the tendinitis: whether it is non-insertional (in the middle of the tendon) or insertional (where the tendon attaches to the bone). 

Non-insertional treatment may involve removing degenerative tissue, stimulating healing through low-grade trauma to the tendon, or even grafting. 

Insertional Achilles tendinopathy surgery typically involves removing the degenerated tendon tissue and any calcification at the bone attachment, removing the inflamed bursa, and reattaching the tendon. If more than 50% of the tendon is removed, anchors may be required to secure the tendon. 

Long-term results for surgery are promising, but there can be significant side effects and recovery is often substantial.³ 

Summary

If you are suffering from Achilles tendinitis, there are many treatment options available, including eccentric exercises, activity modification, ice, and physical therapy. Some evidence suggests that therapies such as shockwave and laser may also be beneficial. Surgery is considered only when all other options have failed. It is important to remember that recovery from Achilles tendinitis takes time, and most rehabilitation programmes will focus on a recovery period of 12 weeks or more.