Expert Patient Guide · London & North London

Peroneal Tendon ProblemsPeroneal Tendon Dislocation & Peroneal Tendon Tears

A comprehensive patient guide by Mr Matthew Welck, Consultant Orthopaedic Foot & Ankle Surgeon at the Royal National Orthopaedic Hospital (RNOH) Stanmore and Honorary Associate Clinical Professor at UCL — treating sports injuries, ankle instability and complex ankle reconstruction across London and North London.

Overview

Peroneal Tendon Problems Explained

The peroneal tendons run down the outside of the ankle, just behind the bony bump on the outer ankle (the fibula). They are the main tendons that turn the foot outwards and act as key stabilisers of the lateral ankle.

Problems with these tendons are a common but often overlooked cause of persistent outer-ankle pain, and are frequently mistaken for an ordinary ankle sprain. This guide covers the two most important patterns: peroneal tendon dislocation and peroneal tendon tears.

Part 1 · Peroneal Tendon Dislocation

At a Glance — Dislocation

At a Glance

Condition
The peroneal tendons slip out of their normal groove behind the outer ankle bone.

Typical Patient
Younger, active adults and athletes; often follows a sports injury.

Main Cause
A forceful upward-and-outward twist of the ankle that tears the retaining tissue (superior peroneal retinaculum).

Diagnosis
Clinical examination, ultrasound (dynamic), MRI, and X-ray to look for a tell-tale ‘fleck’ of bone.

Non-Surgical Care
Cast or boot immobilisation for around six weeks in suitable cases.

Surgery
Repair of the retaining ligament, groove-deepening, and treatment of any tendon damage.

Specialist
Mr Matthew Welck — RNOH Stanmore & UCL, London

Understanding the Condition

What Is Peroneal Tendon Dislocation?

Normally the two peroneal tendons sit in a shallow groove at the back of the fibula, held in place by a strong band of tissue called the superior peroneal retinaculum. In a dislocation, this band is damaged and the tendons can flick forwards over the bone, either momentarily or persistently.

The first medical description dates back to 1803, yet it remains one of the most commonly missed lateral ankle injuries.

How common is it in the UK? Acute peroneal dislocations are genuinely under-recognised — studies show they are misdiagnosed as a simple lateral ankle sprain in up to 40% of cases. They are seen most often in active, sporting adults, which is why expert assessment by a foot and ankle surgeon matters when outer-ankle pain does not settle as expected.

Causes

What Causes Peroneal Tendon Dislocation?

  • Sudden sporting injury — a forceful dorsiflexion (foot pulled up) with the muscles contracting, common in skiing, football and racket sports.
  • A shallow or convex groove — some people are simply born with a flatter groove that offers less restraint.
  • A high-arched (cavovarus) foot or heel that turns inward — this alters loading through the tendons.
  • A previous ankle sprain — stretching of the retinaculum can leave the tendons unstable.
Symptoms

What Are the Symptoms?

  • A painful snapping, clicking or popping sensation on the outer ankle.
  • A feeling that something ‘flicks’ over the bone when the ankle moves.
  • Swelling and tenderness just behind the outer ankle bone.
  • Instability or apprehension, especially on uneven ground or in sport.
  • Symptoms that can be reproduced by turning the foot up and out against resistance.
Diagnosis

What Investigations Might You Need?

  • Weight-bearing X-rays — may reveal a small ‘fleck’ of bone pulled off the fibula, which is a strong sign of a torn retinaculum.
  • Dynamic ultrasound — uniquely able to show the tendons actually slipping in real time as the ankle moves.
  • MRI — assesses the retinaculum, the tendons and any associated ankle damage.
  • CT / weight-bearing CT — useful to study the shape of the groove and overall foot alignment before surgery.
Treatment

Treating Peroneal Tendon Dislocation

Non-Surgical Treatment Options

For a first-time (acute) dislocation in a less active patient, a trial of cast or boot immobilisation for about six weeks is reasonable, followed by physiotherapy to rebuild strength and balance.

Patients should be aware that non-surgical treatment carries a meaningful risk of the problem returning — roughly one in two — and that later surgery is not compromised by trying a conservative route first.

Surgical Options

Surgery aims to keep the tendons securely in their groove. In expert hands it is highly effective, particularly for athletes who wish to return to sport. Depending on the findings, Mr Welck may combine:

  • Retinaculum repair — re-attaching and tightening the retaining band that failed.
  • Groove-deepening — gently deepening the bony groove so the tendons sit more securely; routinely recommended for athletes.
  • Tendon repair — dealing with any splits or tears found at the same time.
  • Correcting foot shape — addressing a high arch or inward-turning heel where this is driving the problem. This may need to be discussed if applicable in order to reduce recurrence rate.
Part 2 · Peroneal Tendon Tears

At a Glance — Tears

At a Glance

Condition
A split or tear within one or both peroneal tendons, usually running along the tendon’s length.

Typical Patient
Active adults; strongly linked to a high-arched (cavovarus) foot and chronic ankle instability.

Main Cause
Repetitive overload, ankle instability and rubbing of the tendon against the bone.

Diagnosis
Ultrasound and MRI are both excellent; X-rays assess foot shape.

Non-Surgical Care
Bracing, orthotics, activity change and physiotherapy for milder cases.

Surgery
Debridement and tubularisation, tenodesis, or grafting, plus correction of foot alignment.

Specialist
Mr Matthew Welck — RNOH Stanmore & UCL, London

Understanding the Condition

What Are Peroneal Tendon Tears?

A peroneal tendon tear is usually a longitudinal (lengthwise) split — the tendon frays and splits along its length rather than snapping cleanly across. The peroneus brevis tendon is torn far more often than the peroneus longus. Because the tendon can still work partially, symptoms are frequently put down to a stubborn sprain, delaying the correct diagnosis.

How common is it in the UK? Cadaveric studies suggest peroneal tendon tears are present in roughly 11–38% of ankles, though only a proportion ever cause symptoms. One MRI study found peroneal abnormalities in around a third of people with no symptoms at all — which is exactly why an experienced foot and ankle surgeon is needed to decide what is relevant and what is not.

Causes

What Causes Peroneal Tendon Tears?

  • A high-arched (cavovarus) foot — found in the great majority of patients treated for tears; it overloads the outer ankle.
  • Chronic ankle instability — repeated sprains stretch the retinaculum and let the tendon rub over the bone edge.
  • Crowding behind the ankle — an extra muscle (peroneus quartus), a low-lying muscle belly or a prominent bony bump can ‘overstuff’ the tunnel.
  • Repetitive sporting load — common in running and pivoting sports.
Symptoms

What Are the Symptoms of a Tear?

  • Aching pain along the outer ankle and hindfoot, worse with activity and better with rest.
  • Swelling and tenderness that follows the line of the tendons.
  • A sense of weakness or giving way when pushing off.
  • Sometimes a palpable thickening or nodule that moves with the tendon.
Diagnosis

What Investigations Might You Need?

  • Weight-bearing X-rays — show overall foot shape, such as a high arch, which must be corrected for a durable result.
  • Ultrasound — a dynamic, real-time look at the tendons with high accuracy for tears.
  • MRI — maps the exact size and position of the tear and reveals any associated ankle damage.
Treatment

Treating Peroneal Tendon Tears

Non-Surgical Treatment Options

Many patients improve without surgery, especially early on. Sensible first steps include:

  • Activity modification and a period of rest from aggravating sport.
  • Anti-inflammatory medication and physiotherapy.
  • Custom orthotics (insoles) or a lateral heel wedge to offload the outer ankle.
  • A brace or, for a flare-up, a short spell in a walking boot.

Surgical Options

If symptoms persist, surgery is tailored to how much healthy tendon remains and to the shape of the foot. Options include:

  • Debridement and tubularisation — cleaning out the split, cutting out frayed degenerate parts, and reshaping the tendon when enough good tissue remains; return to activity is typically excellent.
  • Tenodesis — joining the damaged tendon to its healthy neighbour when repair is not feasible.
  • Graft reconstruction — using a tendon graft for more extensive damage.
  • Correcting foot alignment — a high arch or inward heel is realigned at the same time so the repair is not overloaded again.
Why Choose Mr Welck

Why Choose Mr Welck?

Mr Matthew Welck is a Consultant Orthopaedic Foot & Ankle Surgeon at the Royal National Orthopaedic Hospital (RNOH) Stanmore — the UK’s leading orthopaedic hospital — and Honorary Associate Clinical Professor at UCL. His practice is dedicated exclusively to the foot and ankle, with particular expertise in sports injuries, lateral ankle instability, complex hindfoot reconstruction and total ankle replacement.

He has authored over 50 peer-reviewed publications, holds double international fellowship training, and is a pioneer of weight-bearing CT imaging for precise diagnosis. Patients are seen across London and North London with rapid access to ultrasound, MRI and weight-bearing CT, and every treatment plan is individualised.

Questions & Answers

Frequently Asked Questions

Who is the best foot and ankle surgeon in North London for peroneal tendon problems?

Mr Matthew Welck is a Consultant Foot & Ankle Surgeon at the RNOH Stanmore in North London and UCL, with a specialist interest in sports injuries and ankle instability. He treats both NHS and private patients across London and North London.

Is a peroneal tendon injury the same as an ankle sprain?

No — but it is very commonly mistaken for one. Outer-ankle pain, clicking or instability that does not settle after a ‘sprain’ should be assessed by a foot and ankle specialist, as peroneal problems are missed in a large proportion of cases.

Can peroneal tendon problems heal without surgery?

Many tears and some first-time dislocations improve with bracing, orthotics, physiotherapy and activity change. Surgery is considered when symptoms persist or for athletes wanting a reliable return to sport.

How long is recovery after peroneal tendon surgery?

It varies with the procedure, but many patients return to activity by around 12 weeks after tendon repair, with a graded physiotherapy programme. Mr Welck will give you a personalised timeline.

Why does my high-arched foot matter?

A high-arched (cavovarus) foot overloads the outer ankle and is strongly linked to peroneal tears. Correcting the foot shape at the time of surgery gives a more durable, longer-lasting result.

Where can I see Mr Welck?

NHS patients are seen at the Royal National Orthopaedic Hospital (RNOH) Stanmore. Private appointments are available across London and North London — call 07547 395270 or email secretary@matthewwelck.com.

Get in Touch

Book a Consultation

If you have ongoing outer-ankle pain, clicking, instability or a suspected sports injury, early specialist assessment gives you the widest range of treatment options and the best long-term result. Book a private or NHS consultation with Mr Matthew Welck, Consultant Foot & Ankle Surgeon.

Email: secretary@matthewwelck.com
Call: 07547 395 270
Website: matthewwelck.com

Written by: Matthew Welck | Consultant Orthopaedic Foot & Ankle Surgeon London — last updated 9 July 2026

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