A note on this column: This article is general medical information, not a description of a service offered at this practice. Dr. Ishiguro's surgical practice is focused on hip and knee conditions — he does not treat or perform surgery for tarsal tunnel syndrome or other peripheral nerve compressions of the foot and ankle. This column is written to help readers understand a lesser-known cause of foot pain and know when and how to seek the right specialist, typically a foot and ankle surgeon or a neurologist.
What tarsal tunnel syndrome actually is
The posterior tibial nerve runs down the inside of the leg and passes behind the medial malleolus — the bony bump on the inner ankle — through a narrow passage called the tarsal tunnel. This tunnel is bordered by the flexor retinaculum above and the talus, calcaneus, and distal tibia below, and it also carries the posterior tibial artery, vein, and the tendons of three muscles. When the tibial nerve or one of its branches (the medial and lateral plantar nerves) becomes compressed within this space, the result is tarsal tunnel syndrome — sometimes called posterior tibial nerve dysfunction.
It is often described as the foot's counterpart to carpal tunnel syndrome in the wrist, though it is considerably less common and, by most accounts, under-recognized. Because the nerve supplies sensation to the sole of the foot, symptoms typically appear as burning, tingling, numbness, or an electric "pins and needles" sensation on the bottom of the foot and toes, sometimes radiating up toward the ankle. Robust epidemiological data are limited, and true prevalence is thought to be underestimated, in part because the condition is frequently mistaken for plantar fasciitis or a general polyneuropathy.
Why it happens
In roughly 60–80% of cases a specific structural cause can be identified — this is called secondary tarsal tunnel syndrome. Reported causes include an intra- or extraneural ganglion cyst, an accessory flexor muscle, varicose veins around the ankle, an old fracture or ankle sprain that has altered local anatomy, bone spurs, and structural foot deformities such as flat feet (which stretch the nerve) or an unusually high arch. The remaining 20–40% of cases have no identifiable structural cause and are classified as idiopathic.
Certain factors appear to raise the risk of developing the condition, including obesity, prolonged standing or walking, frequent running or jogging, and systemic conditions that make peripheral nerves more vulnerable to compression, such as diabetes, hypothyroidism, rheumatoid arthritis, and chronic kidney disease requiring dialysis. One frequently cited study found tarsal tunnel syndrome in just over 40% of a diabetic patient cohort, although this figure is likely influenced by the presence of diabetic neuropathy as an overlapping risk factor rather than compression alone.
Recognizing the symptoms
The hallmark complaint is burning pain, numbness, or tingling confined to the plantar surface of the foot — as opposed to the stocking-like distribution typical of a general peripheral neuropathy. Symptoms are frequently aggravated by standing or walking for extended periods, and in some patients they are instead worse at rest or at night, thought to relate to reduced venous return around the nerve while lying down.
Common features of tarsal tunnel syndrome
- Burning, tingling, or numbness on the sole of the foot, sometimes extending into the toes or up toward the inner ankle
- Symptoms worsened by mechanical load — prolonged standing, walking, or running
- A positive Hoffmann-Tinel sign — tapping over the tarsal tunnel reproduces tingling into the sole of the foot
- A positive dorsiflexion-eversion test — holding the ankle bent upward and outward for 5–10 seconds reproduces symptoms by tensioning the nerve
- Often mistaken for plantar fasciitis, since both can cause plantar foot pain, though plantar fasciitis pain is typically most severe with the first steps in the morning rather than burning or tingling in nature
- Weakness or clawing of the toes in longer-standing, more severe cases, due to involvement of the small muscles the nerve supplies
How the diagnosis is made
There is no single test that confirms tarsal tunnel syndrome with certainty, and to date no formal gold standard has been established. Diagnosis relies on correlating the clinical history and examination with electrodiagnostic testing and, increasingly, high-resolution nerve ultrasound.
On examination, a positive Hoffmann-Tinel sign over the tarsal tunnel has a reported sensitivity of roughly 50–60% and specificity of 80–90%, though it becomes less reliable when a coexisting polyneuropathy is present. The dorsiflexion-eversion test, which stretches the nerve by combining ankle dorsiflexion, foot eversion, and toe extension, has been described in the literature as having notably higher sensitivity and specificity when performed correctly.
Nerve conduction studies of the tibial nerve, including its medial and lateral plantar branches, remain the traditional mainstay for confirming the diagnosis, but published sensitivity for routine testing ranges widely — from around 50% up to roughly 82% — which means a normal nerve conduction study does not reliably rule out the condition in a patient with a convincing clinical picture.
What the evidence shows: A 2022 study of patients with suspected tarsal tunnel syndrome found that routine nerve conduction studies of the medial and lateral plantar nerves had only 60.9% sensitivity, missing 18 of 46 clinically symptomatic feet. The authors developed novel provocative testing positions — performing the same nerve conduction studies while standing, and with the foot held in combined eversion and dorsiflexion — which raised sensitivity to 82.6% and 78.3% respectively when either branch was tested alone, and to 100% when both branches were tested together using the new positions (Hasab ElNaby, Abdel Rahman & Ibrahim, Egyptian Rheumatology and Rehabilitation, 2022). This suggests that a negative standard nerve conduction study performed with the patient lying still should not automatically exclude the diagnosis in someone with a convincing clinical picture, and that biomechanically challenging test positions may uncover milder or intermittent nerve compression.
High-resolution ultrasound is being used with increasing frequency because it can directly visualize nerve swelling and identify structural causes such as a cyst or varicosity that electrodiagnostic testing cannot see. Unlike most other compressive neuropathies, where the nerve tends to swell just proximal to the site of compression, tarsal tunnel syndrome appears to be something of an exception: swelling is typically seen at the level of the compression itself, within the tunnel.
What the evidence shows: A 2026 study of 26 feet with clinically and electrophysiologically confirmed tarsal tunnel syndrome found that nerve ultrasound, using a commonly cited cross-sectional-area cutoff of 11.8 mm² for the tibial nerve, had a moderate sensitivity of 65% — meaning ultrasound was unremarkable in roughly a third of confirmed cases (Holtz, Ceanga, Behnert, Marquardt, Geis & Axer, Journal of Clinical Medicine, 2026). A separate, smaller earlier study proposed a cross-sectional-area increase of 5 mm² compared with the nerve segment further up the leg as a criterion, reporting 81% sensitivity and 100% specificity for that particular threshold. Taken together, the evidence suggests ultrasound is a useful complementary tool — particularly for identifying a treatable structural cause — but on its own it cannot definitively rule the condition in or out, and is best interpreted alongside the clinical exam and electrodiagnostic findings rather than as a stand-alone test.
What the evidence says about treatment
Conservative treatment is the standard first step for most patients, particularly those without a clearly identifiable structural cause requiring surgical correction, or without significant weakness or muscle wasting.
Commonly used conservative measures
- Activity and load modification — reducing prolonged standing, walking, or running that aggravates symptoms
- Foot orthoses — custom arch supports, particularly for patients whose flat feet or foot deformity contribute to nerve tension
- Physical therapy — stretching and strengthening programs; one study found improvement in both pain and range of motion in patients who completed a structured six-week program of stretching, muscle strengthening, and arch support use
- NSAIDs and corticosteroid injections — most often useful when an inflammatory cause, such as tenosynovitis or rheumatoid arthritis, is contributing
- Night splints, heel cups, and padding — used by some clinicians, though evidence for these specific measures remains limited
What the evidence shows: A 2022 systematic review of the published literature on tarsal tunnel syndrome treatment found only three studies specifically reporting clinical outcomes of conservative management, each describing acceptable results as a reasonable first-line approach, alongside fourteen studies on surgical outcomes and only limited case-series-level evidence for minimally invasive options such as pulsed radiofrequency (Vij, Kaley, Robinson et al., Orthopedic Reviews, 2022). The review's authors noted that surgical evidence, while confined to a carefully selected group of patients whose symptoms fail conservative treatment, was considerably more robust than the evidence supporting minimally invasive alternatives, and that patients with an identifiable cause such as a cyst or history of trauma tend to do better after surgery than those with idiopathic disease. Comorbid obesity and diabetes were both associated with a lower likelihood of a good surgical outcome.
When conservative treatment fails, or when there is a clear structural cause such as a space-occupying cyst, surgical decompression of the tarsal tunnel is considered. Traditionally this has been performed as open surgery, releasing the flexor retinaculum and, where indicated, the fascia over the medial and lateral plantar tunnels further along the nerve's course; more recently, ultrasound-guided minimally invasive techniques have also been described.
| Approach | What it involves | Notes |
|---|---|---|
| Open decompression | Surgical incision to release the flexor retinaculum and, if needed, the distal medial and lateral plantar tunnels | Long-established approach; allows direct inspection for a structural cause such as a cyst |
| Ultrasound-guided release | Decompression performed through small percutaneous access points under real-time ultrasound guidance | Less invasive; reported outcomes broadly comparable to open surgery in the hands of experienced practitioners |
What the evidence shows: A 2020 review of 81 patients who underwent ultrasound-guided release of the proximal and distal tarsal tunnel, most with a long-standing prior diagnosis of plantar fasciitis that had not responded to conservative care, reported excellent results in 76.5% of patients, good results in 13.6%, and poor results in 9.9% at a minimum of 18 months' follow-up, graded using the Takakura outcome scale (Iborra, Villanueva & Sanz-Ruiz, Journal of Orthopaedic Surgery and Research, 2020). Notably, patients with the longest duration of symptoms before surgery had the worst outcomes — the average symptom duration was under two years in those with excellent results, compared with more than six years in those with poor results — reinforcing that earlier evaluation and treatment tend to be associated with better recovery. Broader literature on surgical decompression for tarsal tunnel syndrome, across both open and minimally invasive techniques, reports success rates ranging widely from roughly 44% to 96%, a spread largely attributed to differences in patient selection, symptom duration, and whether a clear structural cause was present.
When to see a specialist
Because burning or numbness on the sole of the foot can also stem from plantar fasciitis, a general peripheral neuropathy (including diabetic neuropathy), or a nerve problem originating higher up such as lumbar spinal stenosis or sciatica, a proper clinical evaluation is worthwhile rather than assuming the cause based on symptoms alone — particularly if pain is burning or electric in quality rather than mechanical, if it doesn't respond to standard plantar fasciitis treatment, or if there is any associated weakness. As with most compressive neuropathies, earlier evaluation and treatment are generally associated with a better chance of full recovery.
References (PubMed / Journal)
Holtz BO, Ceanga M, Behnert A, Marquardt R, Geis C, Axer H. Nerve Ultrasound for the Diagnosis of Tarsal Tunnel Syndrome: Findings in 26 Clinically and Electrophysiologically Confirmed Feet. J Clin Med. 2026;15(5):1699. DOI: 10.3390/jcm15051699
Hasab ElNaby MM, Abdel Rahman AF, Ibrahim RA. Novel electrodiagnostic provocative techniques for the diagnosis of suspected tarsal tunnel syndrome. Egypt Rheumatol Rehabil. 2022;49(1):53. DOI: 10.1186/s43166-022-00151-z
Vij N, Kaley HN, Robinson CL, et al. Clinical Results Following Conservative Management of Tarsal Tunnel Syndrome Compared With Surgical Treatment: A Systematic Review. Orthopedic Reviews. 2022;14(3). DOI: 10.52965/001c.37539 · PMID: 36072502
Iborra A, Villanueva M, Sanz-Ruiz P. Results of ultrasound-guided release of tarsal tunnel syndrome: a review of 81 cases with a minimum follow-up of 18 months. J Orthop Surg Res. 2020;15(1):30. DOI: 10.1186/s13018-020-1559-1