Orthopaedic Surgery - Peroneal Tendon Subluxation

Basics

Peroneal tendon subluxation is abnormal displacement of the peroneus longus and/or peroneus brevis tendons from their normal groove behind the lateral malleolus.

The two principal peroneal tendons are:

Peroneus longus

and

Peroneus brevis.

An accessory muscle, the:

Peroneus quartus

is variably present and has been reported in up to approximately 20% of individuals.

Anatomy

The peroneus longus and brevis pass posterior to the:

Lateral malleolus

within a common tenosynovial sheath.

They are stabilized by the:

Superior peroneal retinaculum

and more distally by the:

Inferior peroneal retinaculum.

The superior peroneal retinaculum is particularly important in maintaining the tendons within the:

Retromalleolar groove of the distal fibula.

Subluxation and Dislocation

When the superior peroneal retinaculum is torn, stretched, or developmentally insufficient, the tendons may translate:

Anteriorly over the lateral malleolus

during ankle motion.

This may produce:

Pain

Snapping

Clicking

or a:

Palpable tendon displacement.

The instability may be:

Acute after trauma

or

Chronic and recurrent.

Epidemiology

Peroneal tendon instability is:

Uncommon.

It is encountered most frequently in:

Active adolescents and adults, especially athletes.

Risk Factors

Athletic activities that place substantial stress on the lateral ankle increase risk.

Other predisposing factors include:

Generalized ligamentous laxity

Shallow or convex retromalleolar groove

Chronic ankle instability

Cavovarus or varus hindfoot alignment

Accessory peroneal musculature

Genetics

There is no established Mendelian inheritance pattern.

However, inherited anatomy such as:

Ligamentous laxity

or

Hindfoot alignment

may contribute indirectly.

Etiology

The classic acute mechanism involves:

Forceful ankle dorsiflexion

combined with:

Eversion

and strong contraction of the:

Peroneal muscles.

This can tear or strip the:

Superior peroneal retinaculum

from the distal fibula.

Sports Association

The injury is classically associated with:

Skiing

but may also occur in:

Running

Soccer

Basketball

Football

Dance

and other activities involving abrupt ankle loading.

Chronic or Spontaneous Instability

Some patients develop instability without a major traumatic event.

Predisposing anatomic factors may include:

A shallow fibular groove

Generalized ligamentous laxity

Varus hindfoot

Abnormal peroneal anatomy

Associated Conditions

Peroneal tendon subluxation may coexist with:

Chronic lateral ankle instability

Peroneus brevis split tear

Peroneal tenosynovitis

Cavovarus alignment

Generalized ligamentous laxity

Diagnosis

Diagnosis is based largely on:

History

Dynamic physical examination

and, when needed,

Imaging.

Because the tendons may be normally positioned at rest, dynamic evaluation is particularly important.

Signs and Symptoms

Patients commonly report:

Persistent posterolateral ankle pain

Pain with activity

Snapping or popping behind the fibula

A sensation of the tendons moving over the lateral malleolus

History

A typical history may involve:

A skier or running athlete

with:

Painful lateral ankle snapping

following an inversion/eversion-type injury or forceful dorsiflexion.

Patients may also report:

Repeated ankle sprains

or

Chronic instability.

Acute Presentation

Following an acute injury, there may be:

Swelling

Ecchymosis

Tenderness posterior to the lateral malleolus

Chronic Presentation

Chronic cases may have relatively little swelling but demonstrate:

Reproducible painful snapping

during active ankle movement.

Physical Examination

Inspection

Inspect the posterolateral ankle for:

Swelling

Bruising

Visible tendon displacement

Hindfoot alignment

Neurovascular Examination

Assess:

Distal pulses

Sensation

Motor function

because lateral ankle trauma can occasionally involve nearby neurologic structures.

Ankle Stability

Evaluate the lateral ligament complex using:

Anterior drawer testing

and

Talar tilt or inversion stress testing.

This is important because chronic peroneal instability may coexist with:

Lateral ligament instability.

Provocative Maneuver

The patient can be asked to move from:

Plantarflexion and eversion

into:

Dorsiflexion with active eversion.

This contracts the peroneal muscles and may reproduce:

Posterolateral pain

Snapping

or

Visible/palpable tendon subluxation.

Palpation

The examiner should palpate directly:

Behind the lateral malleolus

while the patient repeatedly:

Inverts and everts the foot

or performs resisted ankle motion.

The tendons may be felt moving:

Anteriorly over the fibula.

Normal Tendon Clicking

Peroneal tendons may occasionally:

Snap or click within their sheath

without actual instability.

Therefore, the finding is clinically meaningful when there is:

True displacement from the groove

together with:

Reproduction of the patient’s pain or symptoms.

Laboratory Tests

There are no specific laboratory tests for isolated peroneal tendon subluxation.

Imaging

Plain Radiographs

Initial ankle radiographs help assess for:

Fracture

Bony avulsion

Hindfoot alignment

A small avulsion fragment from the posterolateral distal fibula may indicate injury to the:

Superior peroneal retinaculum.

Historically, such avulsion fractures have been reported in approximately:

10% of acute cases.

CT

CT can define:

The shape and depth of the retromalleolar groove

and other bony anatomy.

It may be helpful for:

Preoperative planning

when groove morphology is abnormal.

MRI

MRI can demonstrate:

Superior peroneal retinacular tearing or attenuation

Peroneal tenosynovitis

Fluid within the tendon sheath

Peroneus brevis longitudinal split tear

Associated ligamentous injuries

MRI is also useful for identifying chronic tendon degeneration.

Dynamic Ultrasound

Dynamic musculoskeletal ultrasound is particularly useful because the tendons can be observed:

During active ankle movement.

It may directly demonstrate:

Subluxation or dislocation over the lateral malleolus.

Because instability may not be present at rest, dynamic ultrasound can sometimes be more informative than static imaging.

Diagnostic Injection

A local anesthetic injection into the:

Peroneal tendon sheath

may occasionally help determine whether pain originates from the peroneal tendons.

This can be useful when the diagnosis remains uncertain.

Pathological Findings

Possible findings include:

Shallow retromalleolar groove

Torn or attenuated superior peroneal retinaculum

Peroneal tenosynovitis

Longitudinal split tear of the peroneus brevis

Chronic Instability

Repeated subluxation can cause friction and progressive damage to the:

Peroneus brevis tendon, particularly a longitudinal split tear.

Differential Diagnosis

Important alternative diagnoses include:

Lateral ankle sprain

Chronic ankle instability

Lateral malleolar fracture

Peroneal tendon tear

Posterolateral ankle impingement

Osteochondral lesion of the talus

Sural nerve irritation

Treatment

General Principles

Treatment depends on whether the instability is:

Acute or chronic

and on the patient’s:

Activity level

Symptoms

Associated tendon injury

Acute Nonoperative Treatment

For a first-time acute injury, an initial period of nonoperative treatment may be attempted.

Options include:

Cast immobilization

Walking boot

Rest

Ice

NSAIDs when appropriate

Immobilization

Immobilization aims to allow the:

Superior peroneal retinaculum

to heal while preventing recurrent tendon displacement.

A period of immobilization is generally more effective for:

Acute injuries

than for established chronic instability.

Chronic Cases

Longstanding recurrent subluxation is less likely to respond to:

Casting or bracing alone.

Persistent painful instability often requires:

Operative stabilization.

Bracing and Taping

An ankle brace may reduce tendon excursion and improve symptoms.

Athletes may also use:

Taping

or

Lateral crescent/J-shaped pads

to help maintain the tendons behind the lateral malleolus.

These methods are primarily:

Symptom-control strategies

rather than definitive treatment for major structural instability.

Activity Modification

Reducing or avoiding the activity that provokes subluxation may help selected patients.

This is particularly reasonable when symptoms occur only with:

A specific high-demand movement or sport.

Physical Therapy

Physical therapy alone is generally insufficient to correct:

True mechanical peroneal tendon instability.

However, it is valuable for treating associated:

Weakness

Poor proprioception

Chronic ankle instability

and is especially important after surgery.

Rehabilitation Goals

Therapy should address:

Peroneal strengthening

Ankle range of motion

Balance

Proprioception

Neuromuscular control

Sport-specific function

Medication

NSAIDs may be used during the acute phase or rehabilitation to reduce:

Pain

and

Inflammation.

They do not correct the mechanical instability.

Surgery

Operative treatment is appropriate for:

Recurrent symptomatic subluxation

Failure of nonoperative treatment

Associated tendon tear

High-demand athletes requiring reliable stability

Competitive Athletes

High-level athletes may undergo earlier surgical treatment when recurrent instability is likely to interfere substantially with:

Return to play

and

Performance.

Surgical Principles

Surgery should address all contributing abnormalities rather than treating only the retinaculum.

Options include:

Superior peroneal retinacular repair

Peroneal tendon repair

Retromalleolar groove deepening

Correction of associated hindfoot malalignment when necessary

Retinacular Repair

When the superior peroneal retinaculum has been avulsed or torn, it can be:

Reattached or reconstructed

to restore the normal tunnel behind the fibula.

Groove Deepening

Patients with a:

Shallow or convex retromalleolar groove

may benefit from:

Fibular groove-deepening procedures

combined with retinacular repair.

This increases the bony containment of the tendons.

Tendon Repair

If a concomitant:

Peroneus brevis split tear

or other tendon lesion is present, treatment may include:

Debridement

Tubularization

or

Direct tendon repair.

Historical Procedures

Older procedures include:

Bone-block techniques

and

Tendon rerouting procedures beneath adjacent ligamentous structures.

These are now used less commonly because anatomic repair of the retinaculum and groove generally preserves more normal biomechanics.

Follow-Up

Postoperative rehabilitation is gradual.

Early treatment typically includes:

Immobilization

followed by progressive:

Range of motion

Strengthening

Proprioceptive training

Return to Activity

Patients may begin progressively increasing activity after approximately:

2–3 months, depending on healing and surgical technique.

Return to full competitive sports commonly requires approximately:

4–6 months, sometimes longer.

Prognosis

Chronic symptomatic instability has a relatively low likelihood of resolving permanently with conservative treatment alone.

Patients undergoing appropriate surgical stabilization generally achieve:

Good pain relief

Improved tendon stability

and

Return to athletic activity.

Complications

Potential surgical complications include:

Recurrent subluxation

Persistent pain

Peroneal tendon stiffness or adhesions

Sural nerve injury

Sural nerve entrapment

Sural neuroma

Recurrence

Recurrent instability may occur if:

Retinacular healing fails

Underlying groove abnormality is not corrected

Rehabilitation progresses too rapidly

Sural Nerve Injury

Because the sural nerve passes near the posterolateral ankle, surgery can result in:

Numbness

Neuropathic pain

or

Neuroma formation.

Patient Monitoring

Follow-up should assess:

Pain

Tendon stability

Range of motion

Peroneal strength

Ankle stability

Proprioception

Readiness to return to sport

Rehabilitation commonly requires renewed training in:

Ankle strengthening and proprioceptive control.

Key Principle

Peroneal tendon subluxation is dynamic instability of the peroneus longus and/or brevis tendons behind the lateral malleolus, usually caused by injury or insufficiency of the superior peroneal retinaculum.

The characteristic finding is:

Painful snapping with palpable or visible anterior displacement of the tendons over the distal fibula during ankle motion.

Acute injuries may be treated initially with immobilization, whereas:

Chronic, recurrent, or high-demand athletic cases frequently require surgical restoration of the retinaculum and associated anatomic abnormalities.