Peroneal Tendon Injury

A peroneal tendon injury is damage to one or both of the two tendons that run behind the bony bump on the outer side of the ankle. It can be inflammation from overuse, a partial or complete tear, or the tendons slipping out of their groove. It causes pain, swelling and a feeling of weakness or giving way.

The two peroneal tendons (peroneus longus and brevis) connect muscles on the outer lower leg to the foot. They run together in a groove behind the lower end of the fibula, held in place by a band of tissue called the superior peroneal retinaculum. They steady the ankle during walking, running and side-to-side movement. The most common injury is a partial lengthways tear of the peroneus brevis tendon, sometimes with damage to the retinaculum.

What types of injury are there?

• Tendinitis: inflammation of the tendon from overuse
• Partial or complete tears: often following ankle sprains or chronic overuse
• Subluxation or dislocation: the tendons slip out of their groove behind the fibula

What are the symptoms?

• Pain and/or swelling on the outer side of the ankle
• A clicking or snapping sensation when moving the ankle
• Ankle weakness or giving way
• Tenderness behind the fibula
• In subluxation, a feeling of the tendon popping out of place

Some people can deliberately flick the tendons out of place and back again.

Who gets it, and what causes it?

The causes include:

• Acute ankle sprains, especially inversion (rolling-over) injuries
• Repetitive overuse in running or sports that involve changes of direction
• High-arched feet (pes cavus), which place extra stress on the tendons
• Laxity of the retinaculum that holds the tendons in place
• Degenerative changes over time

Peroneal tendon instability is often seen in younger, more athletic patients. A systematic review of peroneal tendon tear surgery (Mercer and colleagues, The Journal of Foot & Ankle Surgery) included 336 patients with a mean age of 46.

Examination may also reveal a heel that tilts inwards (a cavovarus hindfoot), looseness of the outer ankle ligaments, Charcot-Marie-Tooth disease or variations in the shape of the fibular groove.

How is it diagnosed?

Diagnosis is by clinical examination, confirmed with ultrasound or MRI. Ultrasound is especially useful because it can watch the tendons move and show them slipping out of place. MRI gives a detailed assessment of tears and of the ankle joint.

Ultrasound depends on the skill of the operator. MRI can also show related injuries, such as ligament tears or cartilage damage, and X-rays can show the alignment of the heel.

What are the non-surgical options?

• Rest, ice, compression and elevation (RICE) in the acute phase
• Immobilisation in a walking boot for 2–6 weeks
• Anti-inflammatory medication
• Physiotherapy for ankle strength, balance (proprioception) and tendon stability
• Custom orthotics or bracing

For acute tendon tears specifically, a period of immobilisation has been described, but many people still need further treatment.

When is surgery recommended?

If conservative treatment fails or the tendon is torn or unstable, the surgical options include:

• Tendon debridement and repair for partial tears
• Retinaculum repair or reconstruction to stabilise the tendons
• Tendon grafting or transfer for large or chronic tears
• Peroneal groove deepening to better contain the tendons

Repair of a partial tear may involve trimming the damaged tissue and rolling the tendon back into a tube (tubularisation). For a complete tear of peroneus brevis, the torn tendon may be stitched to peroneus longus. Surgery may also address predisposing factors such as a varus hindfoot; if hindfoot alignment is not corrected, these operations often fail. Possible complications include recurrence, injury to the sural nerve (which supplies feeling to the outer edge of the foot) and ongoing pain or swelling.

What does the research show?

A systematic review and meta-analysis of 31 studies of surgery for chronic peroneal tendon instability (Lootsma and colleagues, Archives of Orthopaedic and Trauma Surgery) found that all the techniques studied improved clinical results. Bony procedures gave more unsatisfactory results overall, and rerouting and bony procedures had higher complication rates. The authors noted that no high-quality studies were available.

The review of tear surgery by Mercer and colleagues included nine studies. In the studies that measured them, pain scores fell from an average of 4.7 to 1.2 on a 10-point scale, and foot function scores improved. The overall complication rate was 38.7% (130/336), and ankle pain was the most common minor complication. Repair without stitching the tendons together was associated with a higher complication rate than the other operations reviewed.

What is recovery like?

• 0–2 weeks: non-weight-bearing; bulky dressing or cast
• 2–6 weeks: the boot continues; wound review at two weeks
• 6–12 weeks: gradual weight-bearing in the boot; physiotherapy begins
• 3–6 months: return to high-impact sport, depending on healing

How Mr Hester can help

Mr Hester is a dual fellowship-trained foot and ankle surgeon (FRCS Tr&Orth), trained at Guy's and St Thomas' and in Toronto and Calgary, and a member of BOFAS and EFAS. He sees patients privately at The London Clinic, Cromwell Hospital, King Edward VII's Hospital and HCA The Shard. His NHS practice is at King's College Hospital.

Insured patients need a GP referral and an authorisation code from their insurer. Self-pay patients are welcome. To book, call 020 7046 8004.

Frequently Asked Questions

Sources

1. Lootsma J, Wuite S, Hoekstra H, Matricali GA. Surgical treatment options for chronic instability of the peroneal tendons: a systematic review and proportional meta-analysis. Arch Orthop Trauma Surg. 2023;143(4):1903–1913. PMID: 35260916. https://pubmed.ncbi.nlm.nih.gov/35260916/
2. Mercer NP, Gianakos AL, Mercurio AM, Kennedy JG. Clinical outcomes of peroneal tendon tears: a systematic review. J Foot Ankle Surg. 2021;60(5):1008–1013. PMID: 33785239. https://pubmed.ncbi.nlm.nih.gov/33785239/
3. Sprains and strains. NHS. https://www.nhs.uk/conditions/sprains-and-strains/