Peroneal Tendon Tears: Débridement and Repair

Typically presents with pain and swelling posterior to the distal fibula, or, at the level of the peroneal tubercle of the calcaneus.

There is often a history of an ankle sprain or repeated ankle sprains that never fully resolved.

Activity modification, bracing, nonsteroidal antiinflammatory drugs, ice physical therapy, and possible a 4–6 week trial of immobilization in a cast or controlled ankle movement (CAM) walker should be attempted. Patients who do not improve, or who experience a recurrence of their symptoms and demonstrate tendon subluxation, pseudosubluxation, tears on magnetic resonance imaging (MRI), or point tenderness at an often prominent peroneal tubercle, are candidates for tendon débridement and tubularization, and repair of the peroneal retinaculum with fibula groove deepening if tendon subluxation is present.

A subtle cavovarus foot predisposes to the inversion-type ankle injury associated with the formation of these tears.

• The subtle cavovarus foot is associated with a high arch and the “peek-a-boo” heel sign when standing.

• Circumduction of the foot may elicit pain along the course of the peroneal tendons, plus or minus painful peroneal tendon subluxation and snapping associated with a torn or attenuated peroneal tendon sheath.

• Resisted foot eversion may also elicit pain and/or weakness relative to the uninjured foot.

Chronic ankle sprains are likely to have chronic tenderness of the anterior tibiofibular ligament, calcaneofibular ligament, and lateral gutter. Associated ankle instability may be present and elicited with an anterior drawer sign or inversion stress test. These may be performed both clinically and radiographically. There may also be associated talar dome osteochondral injury.

Plain weight-bearing radiographs of the foot/ankle may demonstrate a cavus foot with an increased talar first metatarsal angle on the lateral view with a relatively posterior fibula.

• Anterior drawer or varus stress radiographs may show joint subluxation and instability.

• Ankle radiographs may demonstrate a fleck of bone off the fibula if there was a traumatic tendon sheath avulsion.

MRI

• On T2 weighted or short tau inversion recovery sequences, increased fluid signal may be present with the peroneal tendon sheath. T1 weighted sequences may show retinacular tears, tendon tears, or intrasubstance degeneration of the peroneal tendons.

The peroneus longus and brevis comprise the lateral compartment of the leg ( Fig. 67.1 ).

• The peroneus longus originates on the proximal fibula and inserts on the plantar aspect of the base of the first metatarsal and cuneiform. It acts to evert and plantar flex the foot.

• The peroneus brevis originates from the distal half of the fibula and inserts on the tuberosity of the fifth metatarsal, where it acts to evert and dorsiflex the foot.

• Both are innervated by the superficial branch of the peroneal nerve.

• In the distal leg the peroneus brevis can be recognized by its lower lying muscle belly and its apposition to the posterior distal fibula where it runs in a groove. The peroneus longus runs posterior to the peroneus brevis at the level of the ankle joint, and both are encased in a retinacular sheath. Occasionally a slip of accessory muscle tissue, or peroneus quartus, may also be found within the sheath.

• The superior and inferior peroneal retinaculum prevent peroneal tendon dislocation or subluxation over the posterior edge of the fibula ( Fig. 67.2 ).

  • The superior peroneal retinaculum runs from the fibula to the posterior calcaneal tuber.

  • The inferior peroneal retinaculum is an extension of the inferior extensor retinaculum of the foot.

  

• There is a common peroneal tendon sheath running from the level of the ankle joint to just inferior to the fibula, which bifurcates at the peroneal tubercle along each tendon.

• The peroneus brevis is the tendon most frequently torn with longitudinal tears occurring at the level of the distal fibula, likely due to traumatic subluxation over the edge of the fibular groove ( Fig. 67.3 ).

  

• The peroneus longus passes under the peroneal tubercle of the calcaneus and wraps under the cuboid on its way to the base of the first metatarsal and may sustain injuries at either of these points. Tears and tenosynovitis of the peroneus longus may be associated with chronic friction over a hypertrophic peroneal tubercle ( Fig. 67.4 ). Alternatively, an os peroneum may be present within the peroneus longus as it passes around the cuboid, and there may be associated fractures or pathology at this point.