Peroneal Tendinopathy and Tendonitis

Peroneal tendonitis refers to painful inflammation of the peroneal tendons located on the outer side of the foot, a little behind the ankle bump.

There are two peroneal muscles on the outer side of the lower leg. One long one, called the peroneal longus runs from the knee to the ankle, and one short one, called the peroneal brevis muscle runs from below the knee to the ankle. Both these muscles when they approach the ankle, convert into tendons, which are thick bands of fibers that connect muscle to bone. Both these tendons run side-by-side and curve behind the outer bump of the ankle, then run below the foot where they insert into the bones of the foot.

As the muscle contracts, these tendons pull the lower surfaces of these bones, pulling/bending the foot downward (plantarflexion) and outward (eversion).

Causes of peroneal tendonitis:

Peroneal tendonitis relates to inflammation of one or both of these tendons. Inflammation is a defensive response of the body to any traumatic or harmful change.

The Peroneal tendons can be traumatised by;

Acute injuries such as an ankle sprain or chronic repetitive stress, as occurs in sports involving repeated ankle movement such as tennis, basketball, skiing or hiking. These sports involve side-to-side play, jumping, running/climbing on uneven surfaces, all of which put an extra load on the peroneal tendons.

Factors that increase the risk of tendonitis include:

High foot arches

Weak, brittle tendons (as occurs in the elderly due to age-related changes)

Over pronation

Excessive eversion (outward rolling) of the foot (as occurs in running on sloping surfaces)

Tight calf muscles

Symptoms:

pain on the outside of ankle behind the bony prominence and at the location of the fifth metatarsal

pain aggravates on activity and also on moving the foot downward or outward

pain relieved with rest

swelling and warmth in the affected area

tendons are tender to the touch, pain can be elicited by pressing on the tendons

calf muscles may be stiff

In older individuals, repeated stress may lead to a slow degenerative tearing of the tendons called tendonosis. The tendon wears out and becomes loose, leading to recurrent pain and instability of the ankle joint.

Diagnosis

Diagnosis is mainly based on the basis of the physical symptoms. The doctor examines and moves the foot in different ways to check for the cause of the pain. An MRI shows swelling or tearing of tendons. X-rays are helpful to rule out any fractures in the area.

Tendons have a limited blood supply; blood is essential, not only for nutrition, but also to provide defence against infections and heal any damage caused by trauma. As tendons have a poor blood supply, their injuries take a long time to heal.

Treatment:

Relieving pain and swelling by:

Avoiding stressful activities and giving the sore tendon complete rest

Applying ice and compression

Using anti-inflammatory drugs

In case of persistent symptoms, steroids may be injected. However, with steroids, there is the risk of tendon rupture; therefore, physicians usually avoid using steroids.

Supporting the painful tendon by:

Avoiding walking barefoot or in flat footwear such as slippers, loafers, etc,

Using insole devices such as:

1. A heel lift; lifting the heel, decreases the stretch and thus the load on the peroneal tendons

2. A lateral heel wedge to support and lift the outer part of the heel

3. A lateral sole wedge on the inside or outside of the shoe, which decreases the outward rolling (eversion) of the foot and thus relieves the stress imposed on the peroneal tendons

In severe cases, a walking cast (fitted with a heel) may be applied for 2-4 weeks to immobilize the tendon. Surgery may be required to repair a torn tendon.

Once the symptoms ease, physiotherapy and stretching exercises help to strengthen and stabilize the ankle joint.