Overview
Problems affecting the two peroneal tendons that lie behind the outer ankle bone (lateral malleolus) are common in athletes. These problems mainly occur in the area where the two tendons glide within a fibrous tunnel behind the lateral malleolus. When these tendons become inflamed, their ability to glide within this tunnel is hampered and pain and irritation results.
Causes
Injury
Repetitive ankle motions
High arch
Symptoms
Pain in the outer part of the ankle or just behind the lateral malleolus
Pain that worsens with activity and eases with rest
Swelling
Pain that worsens when pressure is applied along the tendons
Diagnosis
Physical examination and medical history consultation
X-rays
MRI
Treatment
Rest
Immobilization
Physical therapy
Anti-inflammatory medications
Surgery
Source: https://www.orthogate.org/patient-education/ankle/85-peroneal-tendon-problems