Introduction

Peroneal tendons and muscles are essential for daily activities, particularly for athletes. They play a crucial role in providing stability to the feet and ankles during walking, running, and sporting activities. They also help reduce the risk of ankle sprains. Therefore, any injury or condition affecting the tendons can hinder an individual’s day-to-day life. One such condition is peroneal tendonitis.¹

What is peroneal tendonitis?

Peroneal tendonitis is a condition more prevalent amongst athletes. It can be either acute or chronic (peroneal tendinopathy), involving inflammation of the two tendons, the peroneus longus and peroneus brevis, that run down the outside of the lower leg and are located behind the bone on the outside of the ankle. Noticeable signs of inflammation can be redness, swelling and pain at the site.^2,3,4

An injury that causes a tendon tear, a rip in the superior peroneal retinaculum (SPR), or the tendon pulling off a fragment of bone can all cause peroneal tendonitis. The tendons may become irritated and inflamed if they are often moved out of their natural position. 

However, the problem can also arise in the absence of an acute injury, for instance, when the tendon is repeatedly stressed and compressed, such as when standing, walking, or engaging in other activities.³

Diagnosis

To diagnose peroneal tendonitis, radiography (such as X-rays), computed tomography (CT) scans, magnetic resonance imaging (MRI), or ultrasound can be used. A CT scan can show the degree of inflammation. In tendonitis, the peroneal tendon appears less contrasted than normal, losing its usual hyperdense image compared to a healthy tendon. CT scans can also reveal whether the tendon is trapped at the calcaneal (heel bone) or fibular (calf bone) fracture site and the presence of tendon dislocation.⁵

Acute vs. chronic peroneal tendonitis

Onset

• Acute peroneal tendonitis: is classified as a tendon injury that occurs suddenly due to an injury or poor foot positioning, causing immediate and sharp pain. Acute cases have an onset within zero to six weeks. Sub-acute cases are classified when the condition persists between six and twelve weeks
• Chronic peroneal tendonitis: develops due to overuse and recurrent instability of the tendon. The pain is gradual, dull, and progressively worsens over time. Chronic cases involve symptoms persisting for more than three months^6,7

Symptoms

Both acute and chronic peroneal tendonitis present with pain, particularly during movement. Movement may be limited, and signs of inflammation (redness, swelling, and warmth) are common. ⁸

• Acute peroneal tendonitis: may present with a grating or crackling sensation upon movement 
• Chronic peroneal tendonitis: can develop into peroneal tendinopathy, presenting with swelling and pain at the injury site, where pain may radiate above, below or behind the outside of the ankle bone. Patients may also experience joint weakness, a “popping” or slipping sensation as the tendon moves in and out of the groove behind the ankle and a burning sensation

Treatment

Initial management

For initial treatment of the swelling and pain, physiotherapy and joint immobilisation are considered first-line interventions, with improvement often seen within four to six weeks. The R.I.C.E method is highly recommended for a speedy recovery:

• Rest: limit or cease movement of the affected tendon for two to three days
• Ice: apply an ice pack wrapped in a towel to the affected area for up to twenty minutes to relieve pain and reduce inflammation
• Compression: support the affected area with an elastic bandage, tubular bandage, or soft brace, ensuring that it sits comfortably and not too tightly
• Elevation: elevate the injured joint above heart level to reduce swelling

Supportive devices (braces or bandages) should be removed before sleeping. Once movement is pain-free, regular mobility should be encouraged to prevent stiffness. Strengthening exercises can also be implemented to help with pain relief, increase your balance and stability in the tendons.⁸

Acute peroneal tendonitis often resolves with initial management using the RICE method, physiotherapy, and joint immobilisation. Painkillers such as paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen may be used to relieve pain and inflammation.

Chronic peroneal tendonitis, on the other hand, may persist despite initial management. In these cases, surgical intervention may be required, along with additional therapies such as radial extracorporeal shock wave therapy (ESWT) and sclerotherapy.⁹

Surgery

Different surgical procedures are implemented depending on the tendon’s integrity. If there is no tendon dislocation, direct tendon repair can be performed. Nevertheless, a tenodesis surgery is necessary if the tendon damage extends beyond half of the tendon. This procedure entails severing the injured peroneal tendon and suturing it to the neighbouring, intact tendon. 

If the tendon has been dislocated, reconstruction of the superior peroneal retinaculum is necessary, along with repositioning of the peroneal tendons.⁵

Radial extracorporeal shock wave therapy

Extracorporeal shock wave therapy (ESWT) is a non-invasive treatment. It is recommended when symptoms persist for at least three to six months despite other treatments and medications. The treatment involves sending shockwaves to the affected area, which increases blood circulation and accelerates the body’s natural healing process. The shockwaves can also overstimulate nerves, providing pain relief and reducing pain sensitivity.¹⁰

Sclerotherapy

In sclerotherapy, a sclerosant injection is used on the affected site. Polidocanol is used to narrow the blood vessels and interrupt normal blood flow within the tendon. Consequently, the small blood vessels are blocked off and undergo sclerosis (scarring). However, although sclerotherapy can effectively eliminate the nerve fibres responsible for pain in peroneal tendonitis, its role in tendon healing remains unclear.^7,9

Other treatment options

If symptoms persist and conventional treatments are exhausted, other treatment options are available. These include passive physiotherapy such as:

• Therapeutic ultrasound
• Acupuncture
• Deep transverse friction massage (DTFM)

Additional options include:

• Botulinum toxin injections
• Platelet-rich plasma (PRP) therapy
• Topical glyceryl trinitrate therapy
• Matrix metalloproteinase (MMP) inhibitors
• Stem cell or gene therapy⁷

Summary

Peroneal tendonitis can present as either an acute or chronic condition, significantly impacting individuals with active lifestyles. It can result from inflammation due to tendon tears, dislocation, positional changes of the tendon, or excessive strain from physical activity. In acute peroneal tendonitis, symptoms can often be resolved through the RICE method, physiotherapy exercises, joint immobilisation, and the use of painkillers and anti-inflammatory medicines. However, in chronic peroneal tendonitis, pain may persist, and recovery can take longer. Additional treatments such as surgical intervention, ESWT and sclerotherapy may be required to manage the condition.