Peroneal Tendons

The peroneal muscles (peroneus brevis and peroneus longus) lie in the lateral (outside) part of the lower leg. They form tendons which lie within a sheath which restrains them as they pass behind the outer bone of the ankle joint (fibula) before attaching to bones in the foot. The peroneal tendons are responsible for pulling the foot downwards and outwards and contribute to stabilising the ankle joint.

Most patients remember a traumatic episode - most commonly an ankle sprain. A few patients cannot recall a traumatic incident. Certain conditions also predispose to peroneal tendon injuries such as cavo-varus (high-arch) foot, rheumatoid arthritis, psoriasis, diabetes and a steroid injection. The tendons may become inflamed (tendinosis/tenosynovitis) or torn. Repetitive trauma may also cause tendon rupture. The injured tendon will cause pain along the outside of the ankle/foot and possibly weakness of the ankle which may predispose the ankle to giving-way easily on uneven ground. Occassionally the sheath surrounding the tendons may be damaged enabling the tendons to dislocate round the side of the fibula during ankle movements. This may once again give rise to a feeling of ankle weakness and a painful 'clicking" feeling along the outside of the ankle as the tendons dislocate from their normal positions.

Most peroneal tendon injuries may be diagnosed by careful examination. X-rays are usually taken to assess the ankle region for arthritis or traumatic changes that may contribute to the pain. An ultrasound or MRI scan may also be required.

The primary reason for treating these disorders is pain. Non-surgical treatment is usually attempted first - this includes anti-inflammatory medication to reduce pain and inflammation. Activity modification, footwear changes and temporary immobilisation may also help. Acute injuries and inflammation of the tendon sheath frequently respond to non-operative therapy.

Tendon tears and dislocating tendons, however, often require surgery. This requires opening the sheath and repairing any tendon tear. A severely damaged tendon may need to be excised and re-attached to one of the other tendons so that its function may be preserved. If the sheath has been damaged and the tendons are dislocating then the sheath may be reconstructed. After surgery the ankle is normally placed in a plaster cast for 4-6 weeks before physiotherapy is commenced.

Surgery for tendon tears has 80-90% good or excellent results with patients able to return to previous recreational and sporting activities. Although reconstruction of the tendon sheath for chronic dislocation has a longer rehabilitation process a high percentage of satisfactory results can be expected. Complications of surgery include infection, recurrent injury and injury to nerves in the region (sural nerve). Blood clots (DVT and PE) are uncommon with foot and ankle surgery.