The peroneus longus and brevis muscles which make up the Peroneal tendon are located on the outside portion of the lower leg course along the outside ankle bone or fibula attaching on the bottom of the arch as well as the outside portion of the foot on the fifth metatarsal bone.

Both of these muscles function to stabilize the foot on the ground during walking and resist the forces that cause ankle sprains. When these muscles function under stress inflammation can result. This Inflammation or tendonitis is the cause of pain to the outside portion of the foot and ankle. Prior ankle sprains, walking on irregular terrain or excessive curvature of the lower leg are a few of the potential causes of Peroneal Tendonitis. PersistentPeroneal Tendonitis may indicate a tendon tear or attenuation might be present. Attenuation can occur after just one ankle sprain or may occur slowly while the tendons are under stress from excessive lower leg curvature. The diagnosis of Peroneal Attenuation can be confirmed by a MRI study. Pain in both of these conditions is usually worse with initial standing from a sitting position and may be associated with swelling.

Treatment including rest, anti-inflammatory medications and ankle bracing may be required. If the pain is significant the use of a removable boot or CAM boot or an ankle sports brace may be required to rest the tendon. Shoes can have a tremendous impact on the development as well as recovery for this condition. The sole of the shoe should be firm and wide to decrease the stress on the outside ankle. An orthotic or shoe insert with padding modification can be used to help support the ankle thus reducing stress on the tendons.

Peroneal Tendonitis: Causes, Diagnosis, and Treatment