Common Diagnoses:
Peroneal Tendon Sublux/Disloc

Overview

The peroneal tendons connect the peroneal muscles on the outside of your calf to the metatarsal bones in your foot.

The two tendons (peroneus brevis and peroneus longus) normally sit in a groove behind the bony lump at the base of your calf bone (fibula). They are held in place by a strong fibrous structure called the superior peroneal retinaculum (SPR).

The peroneal tendons can slip out of position if the SPR becomes torn or stretched. This is usually the result of a forceful twisting injury, or repeated ankle sprains.

Symptoms

Peroneal subluxation is also known as snapping ankle, due to the clicking sensation as the tendons slip in and out of place. Symptoms include:

  • Sensation of the peroneal tendons moving behind your ankle
  • Sharp pain around the outside of your ankle when your foot is pointed inwards or when you stand on it and rotate inwards
  • Tenderness behind the bone on the outside of your ankle
  • Popping or snapping sound
  • Instability and reduced range of motion
  • Swelling around the outside of your ankle
  • Tendon visibly moving across the bone on the outside of your ankle

Diagnosis

Your doctor will carry out a physical examination to review any tenderness and pain, lack of stability or visible signs of peroneal displacement. They will assess any history of ankle injury such as sprains or fractures.

Diagnostic scans, including x-ray and MRI, will be reviewed by your doctor. These imaging studies show the severity of the SPR damage, ensuring that you get the right treatment for your injury.

Treatment

Non-surgical treatment
Immobilisation: wearing a non-weight-bearing cast or taping the ankle for 4-6 weeks, while a torn SPR re-adheres to the bone.
Rehabilitation: strengthening and mobilisation exercises after non-weight-bearing period.
Injections: occasionally, injection therapy is used to reduce symptoms.

Operative treatment
Your doctor will use minimally invasive surgery, with reduced impact on the structures of your ankle, and quicker recovery times. Surgical procedures include:

  • Deepening the groove for the peroneal tendon
  • Reinforcing the SPR with graft tissue
  • Reattaching the SPR into the fibula
  • Rerouting the tendons behind a ligament to hold them in place

After surgery, you will spend four weeks in non-weight-bearing cast, followed by two weeks in a weight-bearing cast.