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Peroneal tendon disorders are a cause of hindfoot and lateral foot pain. There are three primary disorders of the tendons; peroneal tendonitis, peroneal subluxation, and peroneal tendon tears; these conditions are a cause of lateral ankle pain and may lead to ankle instability. The peroneal tendons are in the lateral compartment of the leg and include the peroneus longus and peroneus brevis muscles. Both receive innervation from the superficial peroneal nerve and blood supply from the peroneal artery. The peroneus brevis originates on the lateral aspect of the distal fibula and intermuscular septum and inserts onto the base of the fifth metatarsal. The peroneus longus originates at the proximal fibula and lateral tibia and inserts at the base of the first metatarsal and the medial cuneiform. The tendons occupy a common synovial sheath that runs posterior to the distal fibula, once past the fibula they each have their own synovial sheath. They run in a tunnel bordered by the superior peroneal retinaculum, the posterior fibula that has a trimalleolar groove, and the calcaneofibular ligament.[rx] The tendon relationship at the level of the ankle is the peroneus brevis anterior and medial to the peroneus longus.[rx] Sometimes anomalous anatomy can lead to a peroneal disorder such as low lying Brevis muscle belly or the presence of peroneus Quartus muscle.[rx] The peroneus Quartus muscle most commonly runs form the peroneus brevis to the retrotrochlear eminence of the calcaneus and is associated with peroneus brevis tears, and subluxation.[rx]
Peroneal tendon pathology is often found in patients complaining of lateral ankle pain and instability. Conditions encountered include tendinosis; tendinopathy; tenosynovitis; tears of the peroneus brevis, peroneus longus, and both tendons; subluxation and dislocation; and painful os peritoneum syndrome. Injuries can be acute as a result of trauma or present as chronic problems, often in patients with predisposing structural components such as hindfoot varus, lateral ligamentous instability, an enlarged peroneal tubercle, and asymptomatic os perineum.
Pathophysiology
The peroneal muscles form the lateral compartment of the lower leg, and both are innervated by the superficial peroneal nerve. The peroneus brevis originates from the distal two-thirds of the fibula and intermuscular septum, becoming tendinous 2 cm to 3 cm proximal to the tip of the fibula. The peroneus longus arises from the proximal two-thirds of the lateral fibula, the intermuscular septum, and the lateral condyle of the tibia. The peroneus tertius is distinct to the brevis and longus, lying within the anterior compartment of the leg. It originates from the lower third of the anterior tibia, interosseous membrane, and intermuscular septum between it and the brevis posteriorly.
Both the peroneus brevis and longus tendons lie proximally in a common synovial sheath that extends from approximately 4 cm proximal to the tip of the lateral malleolus to 1 cm distal to it. The Brevis tendon is relatively flat, running directly posterior to the distal fibula. The peroneus longus is more rounded and lies posterior to the brevis tendon. Both are contained within the retro-malleolar groove, a fibro-osseous tunnel bounded by the superior peroneal retinaculum (SPR), the posterior talofibular ligament, calcaneofibular ligament and posterior inferior tibiofibular ligament. The retinaculum is composed of both fascia and a synovial sheath forming a superior and inferior band.
The primary function of the peroneal tendons is to evert and plantarflex at the ankle. Also, the peroneus longus will plantarflex the first ray leading to hindfoot varus during walking. Having pre-existing varus hindfoot alignment can increase tendon. সহজ বাংলা: মাংসপেশি/টেনডনে টান।" data-rx-term="strain" data-rx-definition="A strain is injury to a muscle or tendon. সহজ বাংলা: মাংসপেশি/টেনডনে টান।">strain on the peroneus longus tendon that can lead to infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, subluxation, and possible tears.[rx] The trimalleolar groove has different shapes; a cadaveric study showed out of 178 ankles the groove is concave in 82%, flat in 11 %, and convex in 7% with a non-osseous fibrocartilaginous ridge that is on the medial side of the groove.[rx]
Peroneal Tendonitis
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Lateral ankle instability can cause laxity, leading to the increased motion of the tendons around the fibula with stretched superior peroneal retinaculum
Peroneal Subluxation/Dislocation
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Instability can be acute from the rupture of the superior retinaculum or fibular groove avulsion or chronic. Chronic subluxation is associated with fibular groove flattening laxity of the superior retinacular ligament[rx]
Peroneal tendon tear
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Musculotendinous junction during forceful contraction or in the cuboid tunnel
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Most tears are longitudinal and result from chronic subluxation over the distal fibula[rx]
Causes of Peroneal Tendon Disorders
Acute injury with a sudden contraction of the peroneal tendons can lead to acute injuries such as a tear of the tendon, or superior peroneal retinaculum, or avulsion of the tendons or the retinaculum from their attachments. If the tendons are chronically subluxated, this can lead to infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation and irritation causing tendonitis. The tendons rubbing over the posterolateral fibula can also lead to longitudinal tears of the tendons.[rx] Chronic lateral ankle stability has also been shown to lead to subluxation and subsequent tears due to increased laxity and motion of the tendons.[rx] Anatomical variants of the fibular trimalleolar groove, hindfoot alignment or cavus foot can lead to abnormal movement of the tendon leading to a predisposition towards subluxation or dislocation.[rx]
Peroneal tendon injuries may be acute (occurring suddenly) or chronic (developing over a period of time). They most commonly occur in individuals who participate in sports that involve repetitive ankle motion. In addition, people with higher arches are at risk of developing peroneal tendon injuries. Basic types of peroneal tendon injuries are tendonitis, tears, and subluxation.
Tendonitis an inflammation of one or both tendons. The inflammation is caused by activities involving repetitive use of the tendon, overuse of the tendon, or trauma (such as an ankle sprain). Symptoms of tendonitis include:
- Pain
- Swelling
- Warm to the touch
Acute tears are caused by repetitive activity or trauma. Immediate symptoms of acute tears include:
- Pain
- Swelling
- Weakness or instability of the foot and ankle
As time goes on, these tears may lead to a change in the shape of the foot in which the arch may become higher.
Degenerative tears (tendonosis) – are usually due to overuse and occur over long periods of time, often years. In degenerative tears, the tendon is like taffy that has been overstretched until it becomes thin and eventually frays. Having high arches also puts you at risk for developing a degenerative tear. The symptoms of degenerative tears may include:
- Sporadic pain (occurring from time to time) on the outside of the ankle
- Weakness or instability in the ankle
- An increase in the height of the arch
A subluxation – means one or both tendons have slipped out of their normal position. In some cases, subluxation is due to a condition in which a person is born with a variation in the shape of the bone or muscle. In other cases, subluxation occurs following trauma, such as an ankle sprain. Damage or injury to the tissues that stabilize the tendons (retinaculum) can lead to chronic tendon subluxation. The symptoms of subluxation may include:
- A snapping feeling of the tendon around the ankle bone
- Sporadic pain behind the outside ankle bone
- Ankle instability or weakness
Early treatment of a subluxation is critical since a tendon that continues to sublux (move out of position) is more likely to tear or rupture. Therefore, if you feel the characteristic snapping, see a foot and ankle surgeon immediately.
Diagnosis of Peroneal Tendon Disorders
History and Physical
History is essential in differentiating the pathology of peroneal tendons. It is necessary to identify the timing, aggravating position or activity, any traumatic events if there is associated swelling, as well as a description of the pain. A common pertinent history finding is a description of snapping or popping at the lateral malleolus. Patients must undergo screening for prior steroid injections and a history of recent antibiotic use; Fluoroquinolones and steroids have associations with tendon disease.[rx]
- Physical exam – should begin with an inspection of the ankle and foot for erythema or swelling, muscle strength testing of eversion and plantar flexion. The examiner can isolate the peroneus longus tendon by resisting active eversion through applying pressure to the medial first metatarsal head. Palpation of the tendons during ROM of the ankle. Evaluation of hindfoot biomechanics such as varus and valgus alignment should take place with the patient standing.[rx] Ankle drawer test should be done to assess ankle ligamentous stability. Another physical exam technique is to have the patient lay prone with a knee to 90 degrees flexion and examine for peroneal tendon subluxation.[rx][rx]
Imaging
The primary imaging modality with any suspected peroneal tendon disorder
- X-rays of the ankle – X-rays should be weight-bearing and include standard AP, mortise, and lateral ankle views. Additional X-ray views are the axillary/Harris heel view and AP, lateral and oblique views of the foot to look for other fractures and foot alignment. Findings on the x-ray that indicate peroneal pathology are avulsion from the base of the fifth metatarsal, avulsion fracture of the distal fibular groove, os perineum, and trimalleolar groove flattening.[rx]
- Ultrasound – is a no radiation, inexpensive imaging modality that can provide an evaluation of the tendon in motion, as well as assist with injections. It has been shown to be effective in identifying tears as well with a sensitivity of 100 % and specificity of 85%.[rx]
- MRI – is the next step in evaluation with a high-quality view of the tendons with no exposure to radiation. The sensitivity is 83%, and specificity is 75% for peroneus brevis tears. Findings include fluid surrounding the tendons, discontinuity, edema of the bone, and any bony deformity.[rx]
- CT scanning – does expose the patient to radiation but provides better bony detail to evaluate possible bony deformity causing possible tendon dysfunction. If x-rays indicate the possibility of fracture, peroneal tubercle, or retro trochlear eminence CT scan would be useful and determine possible management.[rx]
Treatment of Peroneal Tendon Disorders
Nonoperative treatment
- Bracing – The surgeon may provide a brace to use for a short while or during activities requiring repetitive ankle motion. Bracing may also be an option when a patient is not a candidate for surgery.
- Nonsteroidal anti-inflammatory drugs – ice, rest or immobilization, and physical therapy. Immobilization can include cast or controlled ankle motion boot. Modification of shoe wear can also help unload the peroneal tendons with the use of a lateral heel wedge. If this does not provide any improvement steroid injection around the peroneal tendon sheath can help with pain as well as assist with diagnosis. [rx][rx]
- PRP injections – with ultrasound guidance have shown improved functional outcomes with tendinopathy in the study by Dallaudiere. Four hundred eight patients showed 23 patients with peroneal tendon disorders.[rx]
Non-operative treatment should be for 4 to 6 months to allow resolution of inflammation
Surgery
If conservative treatment has failed, operative management options of each type of disorder are as follows:
Peroneal Tendonitis
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Open Debridement and synovectomy
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Arthroscopic peroneal endoscopy
Peroneal tendon subluxation
Treatment depends on the cause of the subluxation or dislocation. Goals are to restore the fibrocartilaginous rim, the superior peroneal retinaculum, and periosteum to the fibula and obtain smooth gliding of the tendon with adequate space for motion.[rx][rx]
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If the superior peroneal retinaculum is torn then open or endoscopic repair or reconstruction is necessary.
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Avulsion fracture of the fifth metatarsal or fibular groove should entail fixation or repair.
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If the fibular groove is shallow endoscopic or open fibular groove deepening can be performed to provide a better structure for the peroneal tendons. This procedure usually addresses cases of chronic instability.
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If there is any hindfoot varus alignment, this should also be corrected to decrease stress on the peroneus longus with hindfoot osteotomy.
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Rerouting the peroneal tendons underneath the calcaneofibular ligament.[rx]
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Bone block procedures that involve performing osteotomy of the fibula lateralizing it to create a bony block for the tendons.[rx]
Peroneal tendon tears
Treatment depends on the degree of tendon torn and whether the tear is acute or chronic
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Debridement and tubularization- partial tears of less than 50%.
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Repair end to end of acute complete tears
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Side-to-side anastomosis or Pulvertaft weave with chronic tears
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Allograft reconstruction
Peroneal tendon rupture
Where both tendons are degenerate and reconstruction using the above methods not feasible, the options available include tendon transfer, auto, or allograft. If there sufficient peroneal muscle belly excursion exists, a hamstring autograft or allograft should be considered. If the muscle belly is scarred and fibrotic, tendon transfer using flexor hallucis longus (FHL) or flexor digitorum longus (FDL) is preferable. If the tendon sheath is fibrotic, a staged approach can be used: the first stage involves excising the scarred tissue and implanting a 6 mm silastic rod in the peroneal muscle bed, suturing it to the distal tendon. The second stage is performed six to 12 weeks later when a pseudosynovial sheath has formed.
FDL or FHL transfer
The patient is placed supine with a sandbag under the ipsilateral hip and a thigh tourniquet used. The flexor tendon is approached medially along the midfoot, inferior and distal to the navicular. This is harvested at the knot of Henry. A proximal incision 7 cm above the medial malleolus is made and the tendon pulled proximally. Corresponding incisions are made laterally and the tendon end passed into posterior to the tibia into the peronei sheath. It is pulled in to the lateral midfoot where it is repaired directly to the peroneus brevis tendon stump or through a drill hole in the fifth metatarsal base.
Autograft or allograft
Where the tendons are damaged but proximal muscle excursion remains, a hamstring or extensor tendon graft can be used. The extensor tendon can be harvested distally at the level of the metatarsophalangeal joints through a small incision. It is then passed through a small proximal incision at the ankle joint. The tendon size is assessed and can either be doubled up or additional tendons harvested to provide a graft of adequate size. The graft is attached to the proximal peroneus brevis and routed behind the lateral malleolus. The distal end is secured either to peroneus brevis tendon stump or through a drill hole in the fifth metatarsal base.
Painful os perineum syndrome
The peroneus longus tendon is exposed at the cuboid tunnel and a tagging suture placed in the distal portion. The os perineum is shelled out from the tendon and if a defect remains, a direct repair performed. If the repair is not achievable, a tenodesis of the longus to brevis should be performed proximally, excising the degenerate section of longus.
Treatment of associated pathology: varus hindfoot deformity
The majority of patients with atraumatic peroneal tendon symptoms have a varus heel. This should be assessed during the initial clinical examination and correction of hindfoot alignment considered in surgery. This can be addressed using a lateralizing calcaneal osteotomy, and a dorsiflexion osteotomy of the first ray. In our institution, the calcaneal osteotomy is performed through a ‘L’ shaped lateral hindfoot incision, although an oblique direct incision or minimally-invasive technique has also been described. Full-thickness flaps should be elevated to minimize the risk of iatrogenic injury to the sural nerve and to preserve the vascularity of the flap.
Treatment of associated pathology: valgus hindfoot deformity
The person can become entrapped between the fibular tip and lateral calcaneal wall. The foot should be assessed for a planovalgus deformity and correction considered in the form of a medialising calcaneal osteotomy and tibialis posterior tendon reconstruction.
Treatment of associated pathology: post-calcaneal fracture deformity
A widened heel with a varus or valgus deformity following calcaneal fracture, may leave the patient prone to tendon impingement. Exostectomy of the lateral calcaneal wall through a lateral approach, as described above, may be carried out and the tendons explored accordingly.
Post-operative care and rehabilitation
We generally advise a non-weight-bearing back slab until a two-week wound check. A cast, walking boot or brace will then be used depending on the procedure performed and physiotherapy will be commenced accordingly.
The diagnosis of peroneal tendon disorders is often missed in the evaluation of the patient with lateral ankle pain. Understanding the functional expectations of the patient is useful in selecting the best course of treatment. Patients with minimal symptoms and loss of function often do well with a non-surgical approach. In contrast, higher-demand patients with more loss of function, especially those involved in athletic activities, may benefit from surgical treatment. A thorough history and physical examination, combined with judicious use of imaging techniques, should aid in making the correct diagnosis. The peroneal tendon pathology, the associated ankle pathology and the correction of underlying foot morphology must all be considered when planning surgery. Awareness of these disorders, their characteristics, and treatment options provides a more rapid diagnosis for the patient and a more effective management algorithm.
