Przejdź do treściPain on the outer side of the ankle, particularly behind or just below the lateral malleolus, may come from the peroneal tendons. It often becomes more noticeable when walking on uneven ground, running, rising onto the toes or after an ankle sprain. Similar symptoms can also arise from ligaments, joint cartilage, bone or the sural nerve, so pain location alone is not a diagnosis.
What are the peroneal tendons?
The peroneus longus and peroneus brevis tendons run together behind the lateral malleolus. They help stabilise the foot and ankle, especially during weight bearing on uneven surfaces, and are held within their groove by the retinaculum. Problems can include tendinopathy, longitudinal splitting or tearing, tenosynovitis, or instability in which the tendons snap or move out of their normal position.
Which symptoms are typical?
- pain and tenderness behind the lateral malleolus or along the outer border of the foot,
- pain that increases on uneven ground, during running or with resisted eversion of the foot,
- swelling along the course of the tendons,
- a snapping sensation or audible click behind the ankle,
- recurrent feelings of instability after previous ankle sprains.
A sudden snap after injury can indicate retinacular damage with tendon subluxation. By contrast, persistent lateral ankle pain without one clear injury is more often associated with overload, foot alignment, recurrent sprains or chronic tendon damage.
What else can cause pain in the same area?
The differential diagnosis includes lateral ligament injury after a sprain, fracture of the ankle or the base of the fifth metatarsal, an osteochondral lesion of the talus, ankle impingement, sural nerve irritation and pain arising from more distal joints of the foot. After an acute injury, this is why an X-ray is often the first imaging test rather than ultrasound.
See also: Ankle Injuries.
How is the problem assessed?
Clinical examination
The exact site of tenderness, muscle strength, ankle stability, foot alignment and reproduction of pain with resisted movement all matter. When tendon snapping is suspected, the tendons should also be assessed while the ankle is moving.
X-ray
After a recent injury, radiographs help exclude a fracture. They may also show bony anatomy that contributes to impingement or chronic overload, but they do not usually assess the tendons themselves adequately.
Ultrasound
Ultrasound can show tendon continuity and structure, fluid within the tendon sheath and tendon behaviour during movement. Dynamic assessment is especially useful when snapping or subluxation behind the lateral malleolus is suspected. A normal ultrasound, however, does not exclude every subtle abnormality.
MRI
MRI can help define the extent of tendon injury while also assessing cartilage, ligaments, bone marrow and other deeper structures. The choice between ultrasound and MRI depends on the clinical question; the two tests can be complementary.
How are peroneal tendon problems treated?
Overuse-related symptoms and stable partial injuries are usually treated non-operatively first. Management may include temporarily reducing activities that provoke pain, progressive strengthening and ankle-control exercises, footwear modification and, in selected cases, an orthotic or a short period of immobilisation. Return to running should depend on strength, stability and the tendon’s response to loading rather than simply on the number of days that have passed.
Analgesic or anti-inflammatory medication may be appropriate for selected patients, but it does not repair a damaged tendon. Tendon-sheath injections are considered selectively; image guidance is advisable, and steroid should not be injected into the tendon itself. Evidence for injections in this region remains limited.
More about image-guided procedures: Injection Treatments.
When does an orthopaedic surgeon consider surgery?
Surgery is considered mainly for complete or extensive tendon tears, recurrent subluxation, persistent weakness or pain that continues despite appropriate non-operative treatment. The procedure depends on whether the main problem lies in the tendon itself, the retinaculum, the groove behind the lateral malleolus or associated ankle instability.
Warning signs
Earlier assessment is needed after an injury if the foot cannot be loaded, there is an obvious deformity, swelling is increasing rapidly, sensation or circulation is impaired, there is an open wound, fever develops with marked local redness, or a sudden snap is followed by clear weakness of the foot. The ability to take a few steps does not by itself rule out a significant injury.
Back to: Foot and Ankle Conditions
More about: Tendons and Enthesopathies
References
- van Dijk PAD, Miller D, Calder J, et al. The ESSKA-AFAS international consensus statement on peroneal tendon pathologies. Knee Surg Sports Traumatol Arthrosc. 2018;26(10):3096–3107. DOI: 10.1007/s00167-018-4971-x.
- Ghandour S, Mercer RW, Strahan JA, et al. Diagnostic accuracy of MRI and US for peroneal tendon tears: a systematic review and meta-analysis. Eur Radiol. 2025. DOI: 10.1007/s00330-025-11472-w. PubMed.
- Dombek MF, Lamm BM, Saltrick K, Mendicino RW, Catanzariti AR. Peroneal tendon tears: a retrospective review. J Foot Ankle Surg. 2003;42(5):250–258.
This material is educational and does not replace an individual medical consultation.
Content prepared by: Tomasz Poboży - orthopaedic surgeon.