Introduction

Peroneal tendon pathology frequently coexists with, or is secondary to chronic lateral ankle instability. Chronic ankle pain in ballet dancers and runners is often caused by these disorders. Peroneal tendon pathology is not always recognized as a cause of post-traumatic ankle pain. It was found that only 60% of peroneal tendon disorders were accurately diagnosed at the first clinical evaluation. Considering their stabilizing function, there is more strain on the peroneal tendons in chronic ankle instability. This may result in hypertrophic tendinopathy, tenosynovitis and ultimately tendon tears. Apart from the aforementioned tendon pathology the most common peroneal tendon problems consist of dislocation or subluxation and (subtotal) rupture or snapping of one or both of the peroneal tendons. These account for the majority of symptoms at the posterolateral aspect of the ankle.

Anatomy

The peroneus brevis, and the peroneus longus muscle are located in the lateral or peroneal compartment of the leg. Both are innervated by the superficial peroneal nerve. Blood flow is supplied through separate vinculae by the peroneal and medial tarsal arteries. The peroneus brevis muscle is situated dorsomedially to the peroneus longus muscle from its proximal aspect up to the fibular tip. Here, the peroneal brevis tendon is still relatively flat. Proximal of the lateral malleolus tip the peroneus longus tendon is located dorsally to the peroneus brevis tendon. Distal of the lateral malleolus tip, the peroneus brevis tendon becomes rounder, and crosses the round peroneus longus tendon. The distal posterolateral part of the fibula forms a fibrocartilaginous sliding channel for the two peroneal tendons. The tendons lie constrained in the malleolar groove by the superior peroneal retinaculum and distally by the inferior peroneal retinaculum. After crossing the foot sole obliquely, the peroneus longus tendon inserts into the lateral side of the base of the first metatarsal bone and the lateral side of the medial cuneiform bone. The peroneus brevis tendon inserts into the tuberosity on the lateral side of the proximal part of the fifth metatarsal bone.
In 1803 Monteggia was the first to describe peroneal tendon dislocation in a female ballet dancer. The tendons dislocate if the superior peroneal retinaculum ruptures, this occurs frequently due to an inversion/dorsiflexion trauma of the foot with contracted tendons. Peroneal tendon dislocation may also occur if the retinaculum is congenitally weak or absent.
Another cause is explained through the size of the cartilaginous rim, influencing the overall groove depth. The rim is located lateral of the fibular groove; the tendons are more likely to dislocate if this rim is flat or absent. 

History & Physical Examination

Tendinopathy of the peroneal tendons frequently coexists with a lateral ankle sprain. The diagnosis in a patient with a recent painful lateral ankle trauma can therefore be difficult. Careful history taking must focus on the trauma mechanism. Other conditions associated with (peroneal) tendon problems must be taken into account. These include rheumatoid arthritis, psoriasis, hyperparathyroidism, diabetic neuropathy, calcaneal fractures, fluorquinolone use and local steroid injections.
The anterior drawer test and varus stress tests are applied routinely to detect ankle ligament laxity. Crepitus and recognizable tenderness over the tendons are present in tendinopathy.
In recurrent peroneal tendon dislocations, patients typically complain of lateral ankle instability, giving way and sometimes a popping or snapping sensation over the lateral aspect of their ankle. During physical examination the tendons can be subluxed by active dorsiflexion and eversion, thereby provoking the recognizable pain.

Diagnostic Imaging

Peroneal tendon dislocation is a clinical diagnosis and does not need additional diagnostics.
However, as multiple pathological conditions can coexist, routine weight bearing radiographs in the anteroposterior and lateral direction are made if posterolateral ankle pain persists after a trauma.
Additional radiographic imaging, such as MRI and US, may be helpful in diagnosing (partial) tears of the peroneal tendons. Both are considerably accurate and precise.

Post-operative rehabilitation

The patient can be discharged the same day of surgery and weightbearing is allowed as tolerated. The patient is instructed to perform active dorsiflexion of the ankle to the neutral position (knee slightly bent). This exercise should be performed 2 or 3 days times per hour for the first days after surgery. The patient is instructed to elevate the foot when not walking to prevent edema. The dressing is removed 3 days post-operative. Normal walking without crutches at 4 - 5 days post surgery. Patients with limited range of motion are directed to a physiotherapist. Running can be started when range of motion is normal and in absence of swelling. This can on avarage be expected at 3 weeks post surgery. Sport resumption can on average be expected at 6 weeks post surgery. 

Recommended literature

Van Dijk CN, Fievez AWFM, Heijboer MP, et al. Arthroscopy of the ankle. Acta Orthop Scand 1993;64(suppl. 253):9.

Van Dijk CN, Scholte D. Arthoscopy of the Ankle Joint. Arthroscopy: The journal of Arthroscopic and Related Surgery, 1997;13(1):90-96.

Van Dijk, Verhagen RAW, Tol JL. Arthroscopy for problems after ankle fracture. J Bone Joint Surg (Br) 1997;79B(2):280-284.