Highlights

• Peroneal tendonitis is the inflammation of the tendons that support your lower leg and foot, often caused by excessive use, sprains, or injury
• Clinical evaluation involves patient history and physical examination to assess pain, swelling, movement, and muscle strength
• Imaging tests such as X-rays, ultrasound, MRI, and CT scans help identify tendon tears, fluid buildup, and bone problems
• Accurate diagnosis is crucial to avoid confusing peroneal tendonitis with other conditions like ankle sprain, fractures, or Achilles tendonitis
• Treatment options include rest, physiotherapy, medications, and sometimes surgery, with recovery time varying from weeks to months
• Preventive measures include gradual training, stretching exercises, proper footwear, ankle braces, and weight management

Introduction

There are connective tissues in your body known as tendons. They can be found between your bones and muscles. Any force generated from your muscles is taken up by the tendons, transferred to your bones, and a movement is generated. 

Your lower leg and foot are connected by two such tendons. These tendons offer balance to your foot and ankle and increase their stability. They also serve to protect your foot and ankle from getting injured. 

Peroneal tendonitis is the inflammation of these tendons that support your lower leg and foot. It could affect only one tendon or both. Excessive use of these tendons as in vigorous physical activity or sports, is the main cause of peroneal tendonitis. Other injuries to the ankle, such as a sprain, can also be a cause.

It is important to get an accurate diagnosis for peroneal tendonitis and not confuse it with other foot and ankle injuries such as bone fracture, arthritis and sprain. Timely diagnosis helps prevent further damage to the foot and ankle. 

Brief description of the peroneal tendons

Image created by ChatGPT with DALL·E, OpenAI (2025).

Tendons serve as a connection between your muscles and your bones. They offer stabilisation to your joints and cause them to move. You have two peroneal tendons, which you can also call fibular tendons. 

Peroneal tendons are traced from muscles found in the outer part of your lower leg, called the fibularis brevis and the fibularis longus. They turn the foot outward (evert) and are housed in a groove behind your fibula. The Peroneal tendons:

• Stabilise the ankle joint
• Makes ankle movement possible
• Maintains the normal shape of the ankle

Clinical evaluation of peroneal tendonitis

Your healthcare provider will take time to gather information about your lifestyle and medical issues. This is called history taking. A thorough physical assessment will also be conducted on you. All these help your healthcare provider to make informed decisions about your diagnosis, treatment and care. 

Patient history

This is an essential part of the clinical evaluation your healthcare provider will perform. You may be required to provide information such as:

• The symptoms you have: for example, pain, swelling or any other experience
• How you describe the pain: for example, if the pain is sharp or aching, or any other description
• Any activity or posture that makes the pain worse
• If you had a fall or hit your foot or ankle
• If you are currently taking any medication
• If this is your first time experiencing this or not

Physical examination

Your healthcare provider will perform a physical examination, usually after history taking. What you should expect includes:

• Observation
  • To check the normal position of your leg and ankle
  • To see if there is any swelling on your ankle

• Touch examination (Palpation)
  • Your healthcare provider will press on the area to feel for warmth around your ankle
  • There is usually pain and stiffness due to tense muscles

• Ability to move (range of motion)
  • This examination will reveal limited movement in your ankle joint
  • An attempt to move the foot up or down makes the pain worse

• Check for muscle strength
  • This will reveal a decline in the strength of your ankle muscles

• Specific test for tendon problems
  • Your healthcare provider will press gently on the tendons behind your ankle bone, while you lift and move your foot outward (at 90 degrees)
  • A clicking sensation and increased pain occur if you have peroneal tendonitis

Imaging studies for peroneal tendonitis

To diagnose peroneal tendon problems, your healthcare provider may use any of the following imaging tests:

• X-rays: This is important in showing bone alignment and possible fractures. It is important to rule out any other cause of ankle problems
• Ultrasound: This can reveal the extent of tendon movement. You are not exposed to radiation in ultrasound, unlike X-rays. Your healthcare provider can also use the help of an ultrasound to give injections
• Magnetic resonance imaging (MRI): This gives a better view of the tendons. It reveals any fluid collection around the tendons and bone problems. Also, no exposure to radiation
• Computed Tomography scan (CT): This can reveal any bone problem, and if it is the cause of tendon dysfunction. No exposure to radiation also

These tests help your healthcare provider identify tendon tears, fluid buildup, or bone issues.

Differential diagnosis

Accurate diagnosis is important to guide your healthcare provider in making the best treatment option available for you. Other ankle problems that may appear like peroneal tendonitis are:

• Ankle Sprain: You will find this form of ankle problem most common in sports people or people who exercise rigorously. The primary difference between ankle sprain and peroneal tendonitis is that there is damage to the ligament in ankle sprain, not tendon inflammation. Both present with similar pain and swelling
• Fracture to the ankle: This can be ruled out through X-ray or MRI
• Severe long-standing ankle pain: Other causes of pain in the ankle should be ruled out to avoid confusing it with peroneal tendonitis
• Peroneal tendon tear: Pain is a primary symptom of peroneal tendon tear, but imaging tests such as MRI will reveal it is not peroneal tendonitis
• Ankle instability: This occurs when you keep having ankle sprains and do not treat them properly. The ligaments in your ankle would not be strong enough to support you when you walk or run. Imaging tests like MRI are used to differentiate this from peroneal tendonitis
• Peroneal tendon dislocation (subluxation): When the peroneal tendons shift from their normal position, it can also cause pain
• Achilles tendonitis: The Achilles tendons can become inflamed and cause pain at the back of the heel. This should not be confused with peroneal tendonitis, where the pain is at the outer foot and ankle

Frequently asked questions about peroneal tendonitis

What are the causes of peroneal tendonitis? 

Causes of peroneal tendonitis include:

• Repetitive stress on your ankles
• Ankle injury
• Tendon friction
• Poor training approach

How is peroneal tendonitis treated? 

Treatment typically involves:

• Adequate rest
• Physiotherapy
• Prescribed medications
• Surgical approach (sometimes) 

What is the recovery time for peroneal tendonitis? 

Your willingness to follow the treatment plan prescribed and how serious the condition may be can greatly affect recovery time. It may take days, which may extend to weeks or even months. 

What are the complications of peroneal tendonitis? 

Complications include:

• Tendon tear
• Damage to nerves
• Ankle instability

How can I prevent peroneal tendonitis? 

Peroneal tendonitis can be prevented when you do the following:

• You should begin training mildly and increase the intensity gradually
• Perform stretch exercises for your knee and ankle muscles
• Keep your body weight in check
• Use braces to support your ankles
• Wear well-fitted shoes

Can I engage in any physical activity after the treatment of peroneal tendonitis? 

When you engage in physical activities such as running or even walking, the peroneal tendons feel the stress, and the pain worsens. It is important to follow your treatment plan as outlined by your healthcare provider. It is possible to return to your normal physical activities with proper treatment. 

Summary 

Peroneal tendonitis can be quite painful and can limit your physical activities. It is important for your healthcare provider to take every detail into consideration, including your symptoms and imaging tests, in order to reach an accurate diagnosis. Care must be taken, as other ankle problems can mimic the appearance of peroneal tendonitis. 

Early diagnosis helps your healthcare provider to begin treatment on time and helps prevent further damage to your foot and ankle. Arrange a visit to your healthcare provider if you have any symptoms that may suggest peroneal tendonitis.