Peroneal and Tibialis Posterior Tenosynovitis

Patients will complain of activity-related ankle pain with localised symptoms either in the medial or lateral ankle depending on the affected tendon/tendon sheath. Clinically, palpation of the tendons as they pass around the medial or lateral malleolus is often symptomatic. Repeated heel raises, resisted inversion or eversion can be provocative for the tibialis posterior and the peroneals respectively.

With the tibialis posterior tendon or, less commonly, the flexor hallucis longus (FHL) tendon, patients complain of medial ankle symptoms. In the case of overuse, symptoms are often attributed to developmental hindfoot valgus (the heel bone tilts outwards) and is a common cause of acquired flat foot deformity. This acquired ankle position puts the tibialis posterior tendon at a lengthened and disadvantageous position biomechanically, resulting in the tendon being overloaded in maintaining midfoot supination as we walk and run. This ultimately gives rise to the pathological change in the tendon and surrounding tendon sheath.Source: Posterior Tibial Tendon Dysfunction – StatPearls – NCBI Bookshelf (opens in a new tab)

On the lateral side of the ankle, the peroneal tendons can go through similar pathological changes. This is typically due to chronic ankle instability, where the peroneals can rub over the posterolateral fibula, causing irritation, especially in patients with injury to the superior peroneal retinaculum. Further underlying causes can be attributed to anatomical variances of the fibular retromalleolar groove or varus hindfoot alignment, leading to abnormal movement of the tendons and repetitive bony contact.Source: Peroneal Tendon Syndromes – StatPearls – NCBI Bookshelf (opens in a new tab)

Tenosynovitis may also be driven from autoimmune conditions such as rheumatoid arthritis, psoriatic arthritis and lupus due to systemic inflammation.Source: Tenosynovitis – StatPearls – NCBI Bookshelf (opens in a new tab)

The diagnosis will be made from a combination of your clinical history, examination findings and commonly with an ultrasound scan.

The patient will have symptoms as discussed previously. Ultrasound will often be used to confirm the diagnosis. This will allow real-time visualisation, assessing for signs of tendinosis, tenosynovitis, longitudinal split tears as well as ruptures, which will help guide treatment options. In certain cases MRI may be indicated; it has been shown to have a higher diagnostic accuracy, sensitivity and specificity when compared to ultrasound, especially in evaluating for longitudinal split tears.Sources: Ultrasound in the diagnosis of posterior tibial tendon pathology – PubMed (opens in a new tab); Diagnostic efficacy of posterior tibialis tendon dysfunction: a systematic review of literature – PubMed (opens in a new tab)

X-rays are not typically indicated but may be used to assess hindfoot alignment in surgical workup cases.

Treatment options are divided into conservative and surgical.

Conservative options

• Period of unloading (where appropriate), analgesia +/- NSAIDs may allow things to calm down.
• Podiatry input / foot orthotics. In patients with flexible pes planus, orthotics can be used to encourage the natural longitudinal arch of the foot, which may be helpful to unload the tibialis posterior tendon; however, their efficacy in altering load and impact forces through the medial ankle is still an area of debate.Sources: Orthotic treatment for stage I and II posterior tibial tendon dysfunction (flat foot): A systematic review – PubMed (opens in a new tab); Foot orthoses for adults with flexible pes planus: a systematic review – PMC (opens in a new tab)
• Progressive rehab exercise aimed at improving the capacity and tolerance of the tendons is the mainstay of treatment. This has been shown to be successful in reducing symptoms and allowing return to high-demand sporting activities.Source: Exercise for posterior tibial tendon dysfunction: a systematic review of randomised clinical trials and clinical guidelines – PMC (opens in a new tab)
• For refractory cases that have failed conservative options, an ultrasound-guided local anaesthetic and steroid injection into the tendon sheath of the tibialis posterior tendon or peroneal tendon sheath can be helpful at breaking the pain cycle and allowing further compliance with rehab. Patients will be advised to limit their activity for at least 2 weeks after the injection. In some cases, patients may be advised to wear an air cast boot to immobilise the ankle to offer further protection to the tendons.Sources: Clinical outcomes of posterior tibial tendon sheath ultrasound-guided corticosteroid injections – PubMed (opens in a new tab); Clinical Outcomes and Complications of Peroneal Tendon Sheath Ultrasound-Guided Corticosteroid Injection – PubMed (opens in a new tab)

Surgical options

• For patients with concurrent longitudinal split tears in the peroneal tendons that may also be driving symptoms, these can be repaired +/- the superior peroneal retinaculum, improving chronic tendon instability. The tibialis posterior tendon can be repaired/reconstructed in traumatic cases.Sources: The Surgical Procedure in Managing Peroneal Tendon Injury: A Case Series – PMC (opens in a new tab); A Novel Anatomic Reconstruction for Posterior Tibialis Tendon in Treatment of Flexible Adult-Acquired Flatfoot Deformity – PubMed (opens in a new tab)
• In the case of tibialis posterior dysfunction, other surgical techniques are aimed at improving the hindfoot alignment to reduce concurrent stress through the tendon. These may include a calcaneal osteotomy and lateral column lengthening depending on the main clinical features of the foot (hindfoot valgus and forefoot abduction respectively).Source: Surgical treatment of stage II posterior tibialis tendon dysfunction: ten-year clinical and radiographic results – PubMed (opens in a new tab)

Arthrodesis (fusion) of the subtalar joint is a further surgical option for severe cases that can be used in deformity correction to unload the tibialis posterior tendon.Source: Subtalar Joint Arthrodesis for Elective and Posttraumatic Foot and Ankle Deformities – PubMed (opens in a new tab)