In short
Peroneal tendonitis is pain in the two tendons that run behind the bony bump on the outside of the ankle. It is often mistaken for an ankle sprain that will not heal. It tends to follow repeated ankle sprains, a jump in activity, or a high-arched foot. Most cases settle with a period of reduced load, supportive footwear or a brace, and a strengthening program. Tears and tendons that slip out of place may need surgery.
On this page
What is peroneal tendonitis?
The peroneal tendons are two tendons that run down the outside of the lower leg, pass behind the bony bump on the outside of the ankle and attach to the foot. They turn the foot outwards and help keep the ankle stable.1
Peroneal tendonitis is pain and irritation in those tendons or in the sheath around them. It is an under-recognised cause of pain on the outside of the ankle and heel, and it can be hard to tell apart from an injury to the ankle ligaments.1
Doctors group peroneal tendon problems into three types:1
- Tendonitis and inflammation of the tendon sheath
- Slipping tendons, where a tendon moves out of its groove behind the ankle bone
- Splits and tears
Symptoms
- Pain behind or below the bony bump on the outside of the ankle, sometimes running along the outer edge of the foot
- Pain that builds with activity and eases with rest, the usual pattern for an overloaded tendon3
- Swelling or tenderness along the line of the tendons3
- Pain when you turn the foot outwards against resistance, which is one of the things a doctor checks1
- A snapping or flicking feeling at the back of the ankle bone, if a tendon is slipping out of place
Pain that keeps coming back?
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Peroneal tendonitis or an ankle sprain?
The two are easily confused, and they often occur together. One review noted that even foot and ankle specialists are far more likely to label a peroneal tendon problem as an ankle injury, and that slipped peroneal tendons are missed in up to 40 per cent of cases.2
A typical ankle sprain follows a definite roll of the ankle and usually heals in 4 to 6 weeks.4 Pain on the outside of the ankle that lingers well beyond that, or that came on gradually with no single injury, is worth having checked for a tendon problem.
What causes it?
Like other tendon problems, it comes from loading the tendon beyond what it can cope with, through repeated movement or a sudden increase in activity.3 Peroneal tendon problems are also linked to:1
- An unstable ankle, for example after repeated sprains
- Foot shape, such as a high-arched foot or a heel that tilts
- Anatomy. Some people have an extra muscle, or a muscle that sits lower than usual, beside the tendons
Unsuitable footwear and a quick jump in training are general risk factors for any tendon injury.3
How is it diagnosed?
A doctor or physiotherapist will examine the ankle. A thorough check includes the shape of the foot, pressing along the tendons behind the ankle bone while you push the foot up and out, and testing the ankle ligaments.1
X-rays, ultrasound and MRI can help confirm the diagnosis and show whether a tendon is torn or slipping.1,2
Treatment
There are no large trials of treatment for peroneal tendon problems. Two reviews both describe the recommendations as based mainly on case series and expert opinion.1,2 In practice, treatment follows the same principles as other tendon injuries:
- Reduce the load. Cut back the activity that brings on the pain. In the first two days, rest, ice, compression and elevation help.3
- Do not stop moving. Complete rest for more than 48 hours can slow recovery.3
- Support the ankle. A brace or supportive shoe takes strain off the tendons while they settle. Bracing also lowers the risk of another sprain.5
- Rebuild strength and balance. A physiotherapist can set a graded program. Balance and control training helps prevent repeat ankle sprains.5
- Check the feet. A podiatrist can assess foot shape and footwear, and may suggest shoe inserts.6
Steroid injections around tendons give short-term relief but worse results later, across tendon conditions in general.7
When surgery is considered
Surgery is mainly for tendons that are torn or keep slipping out of place, and for pain that has not responded to a proper trial of other treatment.1
How long does it take to heal?
It varies. Recovery from tendon problems differs widely between people, and early treatment leads to faster recovery.3 A tendon that has been sore for months usually takes months to settle.
When to see a doctor
- Outer ankle pain that has lasted more than a couple of weeks
- An ankle sprain that is not improving, or pain, swelling or stiffness that is getting worse4
- Snapping or a feeling of something moving at the back of the ankle bone
- An ankle that keeps giving way
- You cannot put weight on the ankle4
See also tendonitis, foot pain and extensor tendonitis.
Next step: talk to a doctor
Answer a few quick questions and you’ll get an email about your eligibility. A consultation doesn’t guarantee any particular treatment.
References
- Davda K, Malhotra K, O'Donnell P, et al. Peroneal tendon disorders. EFORT Open Rev. 2017;2(6):281-292.
- Sharma A, Parekh SG. Pathologies of the Peroneals: A Review. Foot Ankle Spec. 2021;14(2):170-177.
- healthdirect. Tendinopathy.
- healthdirect. Sprained ankle.
- Doherty C, Bleakley C, Delahunt E, et al. Treatment and prevention of acute and recurrent ankle sprain: an overview of systematic reviews with meta-analysis. Br J Sports Med. 2017;51(2):113-125.
- Better Health Channel (Victorian Government). Tendonitis.
- Coombes BK, Bisset L, Vicenzino B. Efficacy and safety of corticosteroid injections and other injections for management of tendinopathy: a systematic review of randomised controlled trials. Lancet. 2010;376(9754):1751-67.
This guide is general information, not medical advice. It doesn’t replace a consultation with a doctor who knows your history. In an emergency, call 000.