Posterior Ankle Impingement

Posterior Ankle Impingement Overview

Posterior ankle impingement refers to pain and pinching at the back of the ankle joint, particularly when the foot is pointed downward (plantarflexed). It occurs when soft tissue or bony structures at the back of the ankle become compressed during movement.

This condition is commonly seen in ballet dancers, footballers, and cricketers due to repetitive plantarflexion, but it can also occur following an ankle injury or fracture. In some people, it is caused by an extra bone called the os trigonum, or by bony spurs, loose fragments, or thickened soft tissue at the back of the ankle.

Posterior Ankle Impingement Symptoms and Diagnosis

Symptoms typically include:

• Pain at the back of the ankle, especially when pointing the toes or pushing off

• Pain during activities like sprinting, jumping, or going down stairs

• Swelling or tenderness at the back of the ankle

• Clicking or catching sensation in some cases

• Pain that worsens with activity and improves with rest

Diagnosis is made by clinical examination and confirmed with imaging. X-rays may show bony abnormalities such as an os trigonum or posterior spurs. MRI is helpful for assessing soft tissue structures, inflammation, or impinged tendons (such as the flexor hallucis longus). CT scanning may be used to assess fine bony detail prior to surgery.

Posterior Ankle Impingement Causes

Causes of posterior ankle impingement include:

• Os trigonum: A small accessory bone at the back of the talus that can become impinged

• Repetitive plantarflexion (e.g. ballet, football, kicking sports)

• Soft tissue impingement: Thickened joint lining, scar tissue, or tendon inflammation

• Posterior bony spurs or fragments after injury or wear

• Flexor hallucis longus (FHL) tendon irritation where it passes behind the ankle

• Previous ankle sprain or fracture

These structures may become pinched between the tibia and heel bone when the ankle is fully extended, causing pain and dysfunction.

Posterior Ankle Impingement Treatment and Prevention

Most cases are treated successfully without surgery. Conservative management may include:

• Activity modification, particularly avoiding extreme plantarflexion

• Anti-inflammatory medications to reduce pain and swelling

• Physiotherapy, focusing on ankle stability and range of motion

• Taping or bracing to limit painful movements

• Ultrasound-guided corticosteroid injection to reduce inflammation and improve symptoms

In mild to moderate cases, symptoms improve over time with rest and rehabilitation.

Posterior Ankle Impingement Surgery

If symptoms persist after conservative treatment or imaging shows significant impingement, surgical intervention may be recommended.

Surgical options include:

• Arthroscopic debridement (keyhole surgery) to remove soft tissue impingement or inflamed joint lining

• Os trigonum excision if an accessory bone is causing the problem

• Removal of bony spurs or loose fragments from the posterior ankle joint

• Release of the FHL tendon sheath if tendon entrapment is contributing to symptoms

These procedures aim to relieve compression, improve ankle motion, and allow a return to activity.

Mr Hester will discuss the specific surgical plan with you, including the most appropriate approach based on your imaging and activity level.

Posterior Ankle Impingement Surgery Recovery

Recovery after surgery typically involves:

• A short period in a protective boot, with partial weight-bearing for 1–2 weeks

• A wound check at 2 weeks, followed by physiotherapy

• Gradual increase in walking and mobility

• Return to low-impact activity from 6 weeks, with a return to sport typically by 10–12 weeks, depending on recovery and rehabilitation

Expected Recovery Timeline

0–2 weeks
Rest and elevation. Boot with partial weight-bearing.
2 weeks
Wound review. Begin gentle physiotherapy.
2–6 weeks
Increase walking. Improve range of motion.
6–12 weeks
Return to daily activity and sport as tolerated.
12+ weeks
Increasing activity as toloerated guided with pain with recovery reaching new baseline at 6-12 months