Peroneal tendinopathy

Peroneal tendinopathy is caused by repeated tension stress on the tendon of the muscles that run down the outer side of the leg – the peroneal muscles. These muscles attach to the outer leg bone (fibula) and have tendons that run down the fibula, behind the bony prominence on the outside of the ankle (lateral malleolus) and under the foot to attach to foot bones (the first and fifth metatarsal and cuniform bones).  

Peroneal tendinosis is a condition involving degradation and weakness of the collagen that make up the peroneal tendons. This makes them vulnerable to painful straining and tearing. Because these tendons pass very close to the outer ankle joint, peroneal tendinosis can easily be mistaken for lateral ankle strain. In fact, they often occur concurrently.

These muscles act to turn the foot outwards (eversion), prevent the foot from rolling inwards and help point the foot downwards (plantar flexion). They play an important role in centering and stabilising the body’s weight over the foot in weight bearing on one foot.

Tendinopathy often develops over years without symptoms. It may be triggered by a sudden increased force or symptoms may develop gradually for no apparent reason.

Symptoms include sporadic or ongoing pain on the outside of the ankle, foot and/or lower leg, especially during and/or after activity especially walking or running on slopes, hard or uneven surfaces, or sporting activity requiring frequent change of direction or jumping.

This condition leads to a feeling of weakness or instability in the ankle. Firmly touching the affected peroneal tendon will cause pain. The tendons are held in place by a band of tough connective tissue called a “retinaculum.” Often painful tender lumps form here due to over compression of the tendon between the bone and the retinaculum.