Weight-bearing Ultrasound to Diagnose Talar Dislocation Causing Tarsal Tunnel Syndrome.

The neuropathic compression of the tibial nerve and/or its branches on the medial side of the ankle is called tarsal tunnel syndrome (TTS). Patients with TTS presents pain, paresthesia, hypoesthesia, hyperesthesia, muscle cramps or numbness which affects the sole of the foot, the heel, or both. The clinical diagnosis is challenging because of the fairly non-specific and several symptomatology. We demonstrate a case of TTS caused by medial dislocation of the talar bone on the calcaneus bone impacting the tibial nerve diagnosed only by ultrasound with the patient in the standing position.

Common Peroneal Nerve and Tarsal Tunnel Release Surgery in an Adolescent Male with Hunter Syndrome: Illustrative Case.

BACKGROUND: Children with Hunter syndrome have a high prevalence of nerve compression syndromes given the buildup of glycosaminoglycans in the tendon sheaths and soft tissue structures. These are often comorbid with orthopedic conditions given joint and tendon contractures due to the same pathology. While carpal tunnel syndrome and surgical treatment has been well-reported in this population, the literature on lower extremity nerve compression syndromes and their treatment in Hunter syndrome is sparse. OBSERVATIONS: We report the case of a 13-year-old male with a history of Hunter syndrome who presented with toe-walking and tenderness over the peroneal and tarsal tunnel areas. He underwent bilateral common peroneal nerve and tarsal tunnel releases, with findings of severe nerve compression and hypertrophied soft tissue structures demonstrating fibromuscular scarring on pathology. Post-operatively, the patient's family reported subjective improvement in lower extremity mobility and plantar flexion. LESSONS: In this case, peroneal and tarsal nerve compression were diagnosed clinically and treated effectively with surgical release and postoperative ankle casting. Given the wide differential of common comorbid orthopedic conditions in Hunter syndrome and the lack of validated electrodiagnostic normative values in this population, the history and physical examination and consideration of nerve compression syndromes are tantamount for successful workup and treatment of gait abnormalities in the child with Hunter syndrome.

Lateralizing calcaneal osteotomy performed with a percutaneous burr results in a significantly lower increase in tarsal tunnel pressure.

PURPOSE: Tarsal tunnel syndrome is well documented following lateralizing calcaneal osteotomy to manage varus hindfoot deformity. Traditionally, calcaneal osteotomy is performed with an oscillating saw. No studies have investigated the effect of alternative surgical techniques on postoperative tarsal tunnel pressure. The purpose of this study was to investigate the difference in tarsal tunnel pressures following lateralizing calcaneal osteotomy performed using a high-torque, low-speed "minimally invasive surgery" (MIS) Shannon burr versus an oscillating saw. METHODS: Lateralizing calcaneal osteotomy was performed on 10 below-knee cadaveric specimens. This was conducted on 5 specimens each using an oscillating saw (Saw group) or MIS burr (Burr group). The calcaneal tuberosity was translated 1 cm laterally and transfixed using 2 Kirschner wires. Tarsal tunnel pressure was measured before and after osteotomy via ultrasound-guided percutaneous needle barometer. Mean pre/post-osteotomy pressures were compared between groups. Differences were analyzed using Student's t test. RESULTS: The mean pre-procedure tarsal tunnel pressure was 25.8 ± 5.1 mm Hg in the Saw group and 26.4 ± 4.3 mm Hg in the Burr group (p = 0.85). The mean post-procedure pressure was 63.4 ± 5.1 in the Saw group and 47.8 ± 4.3 in the Burr group (p = 0.01). Change in tarsal tunnel pressure was significantly lower in the Burr group (21.4 ± 4.5) compared to the Saw group (37.6 ± 12.5) (p = 0.03). The increase in tarsal tunnel pressure was 43% lower in the Burr group. CONCLUSION: In this cadaveric study, tarsal tunnel pressure increase after lateralizing calcaneal osteotomy was significantly lower when using a burr versus a saw. This is likely because the increased width ("kerf") of the 3 mm MIS burr, compared to the submillimeter saw blade width, causes calcaneal shortening. Given the smaller increase in tarsal tunnel pressure, using the MIS burr for lateralizing calcaneal osteotomy may decrease the risk of postoperative tarsal tunnel syndrome. Future research in vivo should explore this.

Ganglia-Induced Tarsal Tunnel Syndrome.

BACKGROUND: Tarsal tunnel syndrome (TTS) is a common entrapment neuropathy that is sometimes elicited by ganglia in the tarsal tunnel. METHODS: Between August 2020 and July 2022, we operated on 117 sides with TTS. This retrospective study examined data from 8 consecutive patients (8 sides: 5 men, 3 women; average age 67.8 years) with an extraneural ganglion in the tarsal tunnel. We investigated the clinical characteristics and surgical outcomes for these patients. RESULTS: The mass was palpable through the skin in 1 patient, detected intraoperatively in 1 patient, and visualized on MRI scanning in the other 6 patients. Symptoms involved the medial plantar nerve area (n = 5), lateral plantar nerve area (n = 1), and medial and lateral plantar nerve areas (n = 2). The interval between symptom onset and surgery ranged from 4 to 168 months. Adhesion between large (≥20 mm) ganglia and surrounding tissue and nerves was observed intraoperatively in 4 patients. Of the 8 patients, 7 underwent total ganglion resection. There were no surgery-related complications. On their last postoperative visit, 3 patients with a duration of symptoms not exceeding 10 months reported favorable outcomes. CONCLUSIONS: Because ganglia eliciting TTS are often undetectable by skin palpation, imaging studies may be necessary. Early surgical intervention appears to yield favorable outcomes.

The Effectiveness of Indonesia's Seven - Step Return to Work Assessment on a Distal Tarsal Tunnel Syndrome : A Case Report Study.

Tarsal tunnel syndrome (TTS) is a nerve entrapment of the posterior tibial nerve. This uncommon condition frequently goes undiagnosed or misdiagnosed even though it interferes with the daily activities of workers. Here we discuss the return to work status of a 37-year-old male patient who manages a manufacturing plant. He was identified as having Tarsal Tunnel Syndrome as a result of a foot abnormality and improper shoe wear. He had moderate pes planus and underwent tarsal tunnel release on his right foot. What are the determinant factors in defining a patient's status for returning to work after a tarsal tunnel release? We conducted a literature review using PubMed, Science Direct, and Cochrane. The Indonesian Occupational Medicine Association used the seven-step return-to-work assessment as a protocol to avoid overlooking the process. Duration of symptoms, associated pathology, and the presence of structural foot problems or a space-occupying lesion are factors affecting outcome. Post-operative foot scores, including Maryland Foot Score (MFS), VAS, and Foot Function Index, can be used to evaluate patient outcomes. Early disability limitation and a thorough return-to-work assessment are needed.

Lessons in clinical reasoning - pitfalls, myths, and pearls: a case of tarsal tunnel syndrome caused by an intraneural ganglion cyst.

OBJECTIVES: Intraneural ganglionic cysts are non-neoplastic cysts that can cause signs and symptoms of peripheral neuropathy. However, the scarcity of such cases can lead to cognitive biases. Early surgical exploration of space occupying lesions plays an important role in identification and improving the outcomes for intraneural ganglionic cysts. CASE PRESENTATION: This patient presented with loss of sensation on the right sole with tingling numbness for six months. A diagnosis of tarsal tunnel syndrome was made. Nerve conduction study revealed that the mixed nerve action potential (NAP) was absent in the right medial and lateral plantar nerves. The magnetic resonance imaging (MRI) found a cystic lesion measuring 1.4×1.8×3.8 cm as the presumed cause of the neuropathy. Surgical exploration revealed a ganglionic cyst traversing towards the flexor retinaculum with baby cysts. The latter finding came as a surprise to the treating surgeon and was confirmed to be an intraneural ganglionic cyst based on the histopathology report. CONCLUSIONS: Through integrated commentary by a case discussant and reflection by an orthopedician, this case highlights the significance of the availability heuristic, confirmation bias, and anchoring bias in a case of rare disease. Despite diagnostic delays, a medically knowledgeable patient's involvement in their own care lead to a more positive outcome. A fish-bone diagram is provided to visually demonstrate the major factors that contributed to the diagnostic delay. Finally, this case provides clinical teaching points in addition to a pitfall, myth, and pearl related to availability heuristic and the sunk cost fallacy.

Prevalence of Obesity in High Tarsal Tunnel Syndrome: A Cross-Sectional Study.

BACKGROUND: Tarsal tunnel syndrome (TTS) occurs when an individual suffers from tibial nerve compression at the tarsal tunnel. Symptoms of TTS may include pain, burning, or tingling on the bottom of the foot and into the toes. Tarsal tunnel syndrome can be divided into distal and proximal TTS. Furthermore, a high tarsal tunnel syndrome (HTTS) has also been described as a fascial entrapment proximal to the laciniate ligament at the level of the high ankle. Multiple risk factors, including obesity, have been said to be associated with TTS. This study aimed to determine the frequency of obesity in the form of body mass index (BMI) with HTTS. METHODS: A cross-sectional descriptive study using a nonprobability sampling method retrospectively surveyed the BMI of 73 patients whose clinical presentation suggested HTTS or TTS, and in which electrodiagnostic testing found HTTS. The age of the patients ranged from 25 to 90 years (mean, 56.4 years). Thirty-five patients were men and 38 patients were women. RESULTS: Based on BMI, nine patients with HTTS had normal weight (12.9%), 17 patients were overweight (23.3%), and the remaining 47 patients were obese (64.3%). CONCLUSIONS: The frequency of obesity in the form of BMI was 64.3% in patients with HTTS, which is a significantly high correlation.

Distal Tibial Mononeuropathy From Compression by the Posterior Tibial Artery: Clinical-Electrophysiological-Ultrasonographic Correlations.

SUMMARY: The tibial nerve is bound tightly to the posterior tibial artery in the tarsal tunnel where expansion capacity is limited. Therefore, the nerve may be vulnerable to, and damaged by chronic pulsatile trauma from an atypically positioned overriding artery, labeled "punched-nerve syndrome". In this article, we present a 49-year-old woman who presented with two months of severe burning pain in the left medial ankle and sole of the foot without antecedent trauma. Neurological examination identified dysesthetic sensation to light touch in the left medial sole of the foot, and both active and passive dorsiflexion worsened the painful paresthesia. Nerve conduction studies demonstrated a reduced left medial plantar mixed nerve action potential amplitude, 50% less than the right. High-resolution ultrasound (HRUS) showed an increased left tibial nerve cross-sectional area of 26 mm2 (normal <22.3 mm2) at the level of the ankle with side-to-side difference of 6 mm2 (normal <5.7 mm2). The distal tibial nerve and its medial plantar branch were atypically positioned immediately deep to the left posterior tibial artery and abnormally flattened with focal enlargement of the nerve on longitudinal view. Dynamic analysis demonstrated the nerve being compressed with each pulsation of the tibial artery immediately above. Active dorsiflexion of the ankle narrowed the space underneath the flexor retinaculum resulting in further compression of the nerve against the artery. In conclusion, HRUS as an adjunct to electrophysiological studies identified punched-nerve arterial compression as an etiology of tarsal tunnel syndrome.

Injection of the Abductor Hallucis Muscle in the Diagnosis and Treatment of Distal Tarsal Tunnel Syndrome.

BACKGROUND: Tarsal tunnel syndrome (TTS) can be divided into proximal TTS and distal TTS (DTTS). Research on methods to differentiate these two syndromes is sparse. A simple test and treatment is described as an adjunct to assist with diagnosing and providing treatment for DTTS. METHODS: The suggested test and treatment is an injection of lidocaine mixed with dexamethasone administered into the abductor hallucis muscle at the site of entrapment of the distal branches of the tibial nerve. This treatment was studied with a retrospective medical record review in 44 patients with clinical suspicion of DTTS. RESULTS: The lidocaine injection test and treatment (LITT) was positive in 84% of patients. Of patients available for follow-up evaluation (35), 11% of those with a positive LITT test (four) had complete lasting symptom relief. One-quarter of patients with initial complete symptom relief at LITT administration (four of 16) maintained this level of symptom relief at follow-up. Thirty-seven percent of patients evaluated at follow-up (13 of 35) who had a positive response to the LITT experienced partial or complete symptom relief. No association was found between level of symptom relief maintenance and the immediate level of symptom relief (Fisher exact test = 0.751; P = .797). The results showed no difference in the distribution of immediate symptom relief by sex (Fisher exact test = 1.048; P = .653). CONCLUSIONS: The LITT is a simple, safe, invasive method to help diagnose and treat DTTS, and it provides an additional method to assist with differentiating DTTS from proximal TTS. The study also provides additional evidence that DTTS has a myofascial etiology. The proposed mechanism of action of the LITT suggests a new paradigm in diagnosing muscle-related nerve entrapments that may lead to nonsurgical treatments or less invasive surgical interventions for DTTS.

Bilateral Flexor Digitorum Accessorius Longus Precipitating Bilateral Tarsal Tunnel Syndrome: A Case Report.

CASE: A 29-year-old woman presented with bilateral tarsal tunnel syndrome caused by bilateral flexor digitorum accessorius longus, experiencing immediate relief of symptoms after surgical intervention through 1 year. CONCLUSION: Accessory muscles can cause compressive neuropathies in multiple areas of the body. In patients who have FDAL as the cause of their tarsal tunnel syndrome, surgeons should have a high index of suspicion of bilateral FDAL if the same patient develops similar contralateral symptoms.

The bifurcation and topography of the posterior tibial artery within the tarsal tunnel.

PURPOSE: The tarsal tunnel (TT) is a fibro-osseous anatomical space coursing from the medial ankle to the medial midfoot. This tunnel acts as a passage for both tendinous and neurovascular structures, including the neurovascular bundle containing the posterior tibial artery (PTA), posterior tibial veins (PTVs) and tibial nerve (TN). Tarsal tunnel syndrome (TTS) is the entrapment neuropathy that describes the compression and irritation of the TN within this space. Iatrogenic injury to the PTA plays a significant role in both the onset and exacerbation of TTS symptoms. The current study aims to produce a method to allow clinicians and surgeons to easily and accurately predict the bifurcation of the PTA, to avoid iatrogenic injury during treatment of TTS. METHODS: Fifteen embalmed cadaveric lower limbs were dissected at the medial ankle region to expose the TT. Various measurements regarding the location of the PTA within the TT were recorded and multiple linear regression analysis performed using RStudio. RESULTS: Analysis provided a clear correlation (p < 0.05) between the length of the foot (MH), length of hind-foot (MC) and location of bifurcation of the PTA (MB). Using these measurements, this study developed an equation (MB = 0.3*MH + 0.37*MC - 28.24 mm) to predict the location of bifurcation of the PTA within a 23° arc inferior to the medial malleolus. CONCLUSIONS: This study successfully developed a method whereby clinicians and surgeons can easily and accurately predict the bifurcation of the PTA, to avoid iatrogenic injury that would previously lead to an exacerbation of TTS symptoms.

Botulinum Toxin Injection for the Treatment of Compression of Lateral Plantar Nerve by Flexor Digitorum Accessorius Longus.

ABSTRACT: The flexor digitorum accessorius longus is an anomalous muscle with a reported prevalence of 1.6%-12.2% in cadaveric studies. Flexor digitorum accessorius longus courses through the tarsal tunnel and has been reported as an etiology of tarsal tunnel syndrome in previous case reports. The flexor digitorum accessorius longus is intimately related to the neurovascular bundle and may impinge on the lateral plantar nerves. However, very few cases of lateral plantar nerve compression by the flexor digitorum accessorius longus have been reported. Herein, we report a case of lateral plantar nerve compression caused by the flexor digitorum accessorius longus muscle in a 51-year-old man who complained of insidious pain at the lateral sole and hypoesthesia at the left third-fifth toe and lateral sole, and the pain improved after treatment of botulinum toxin injection into the flexor digitorum accessorius longus muscle.

Tortuosity and Pulsatility of the Tibial Artery - Two Case Reports of a Rare Etiology of Tarsal Tunnel Syndrome.

Tarsal tunnel syndrome is a neuropathic compression of the tibial nerve and its branches on the medial side of the ankle. It is a challenging diagnosis that constitutes symptoms arising from damage to the posterior tibial nerve or its branches as they proceed through the tarsal tunnel below the flexor retinaculum in the medial ankle, easily forgotten and underdiagnosed. Neural compression by vascular structures has been suggested as a possible etiology in some clinical conditions. Tibial artery tortuosity is not that rare, but only that it affects the nerve can cause tarsal tunnel syndrome. Therefore, a study care must be taken to avoid false-positive errors.

How Common is Subsequent Posterior Tibial Tendon Dysfunction or Tarsal Tunnel Syndrome After Ankle Sprain Injury?

Posterior tibial tendon dysfunction (PTTD) and tarsal tunnel syndrome (TTS) are debilitating conditions reported to occur after ankle sprain due to their proximity to the ankle complex. The objective of this study was to investigate the incidence of PTTD and TTS in the 2 years following an ankle sprain and which variables are associated with its onset. In total, 22,966 individuals in the Military Health System diagnosed with ankle sprain between 2010 and 2011 were followed for 2 years. The incidence of PTTD and TTS after ankle sprain was identified. Binary logistic regression was used to identify potential demographic or medical history factors associated with PTTD or TTS. In total, 617 (2.7%) received a PTTD diagnosis and 127 (0.6%) received a TTS diagnosis. Active-duty status (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.70-2.79), increasing age (OR 1.03, 95% CI 1.02-1.04), female sex (OR 1.58, 95% CI 1.28-1.95), and if the sprain location was specified by the diagnosis (versus unspecified location) and did not include a fracture contributed to significantly higher (p < 0.001) risk of developing PTTD. Greater age (OR 1.06, 95% CI 1.03-1.09), female sex (OR 2.73, 95% CI 1.74-4.29), history of metabolic syndrome (OR 1.73, 95% CI 1.03-2.89), and active-duty status (OR 2.28, 95% CI 1.38-3.77) also significantly increased the odds of developing TTS, while sustaining a concurrent ankle fracture with the initial ankle sprain (OR 0.45, 95% CI 0.28-0.70) significantly decreased the odds. PTTD and TTS were not common after ankle sprain. However, they still merit consideration as postinjury sequelae, especially in patients with persistent symptoms. Increasing age, type of sprain, female sex, metabolic syndrome, and active-duty status were all significantly associated with the development of one or both subsequent injuries. This work provides normative data for incidence rates of these subsequent injuries and can help increase awareness of these conditions, leading to improved management of refractory ankle sprain injuries.

Anatomy of the tibial nerve in relation to the tarsal tunnel: A cadaveric study.

BACKGROUND: Tarsal tunnel syndrome (TTS) is typically caused by an anatomical variant or mechanical compression of the tibial nerve (TN) with variable success after surgical treatment. METHOD: 40 lower-leg specimens were obtained. Dissections were appropriately conducted. Extremities were prepared under formaldehyde solution. The tibial nerve and branches were dissected for measurements and various characteristics. RESULTS: The flexor retinaculum had a denser consistency in 22.5% of the cases and the average length was 51.9 mm. The flexor retinaculum as an independent structure was absent and 77.2% of cases as an undistinguished extension of the crural fascia. The lateral plantar nerve (LPN) and abductor digiti minimi (ADM) nerve shared same origin in 80% of cases, 34.5% bifurcated proximal to the DM (Dellon-McKinnon malleolar-calcaneal line) line 31.2% distally and 34.3% at the same level. CONCLUSION: Understanding the tibial nerve anatomy will allow us to adapt our surgical technique to improve the treatment of this recurrent pathology.

Acute Tarsal Tunnel Syndrome After Total Ankle Arthroplasty With Varus Deformity.

Background: A 54-year-old woman presented with varus ankle arthritis, which was corrected with total ankle arthroplasty (TAA). Immediately postoperatively, she was insensate throughout the plantar foot. After seven weeks, she underwent tarsal tunnel release, and the tibial nerve was found to be intact. Plantar sensation improved by one week after exploration with neurolysis and was completely intact at one year. Conclusion: Loss of plantar sensation can occur following TAA for varus arthritic deformity. One potential cause is tibial nerve compression from tightening the laciniate ligament, resulting in acute tarsal tunnel syndrome. The condition can be remedied with early recognition and tarsal tunnel release. Level of Evidence: V.

Tarsal tunnel syndrome secondary to accessory or variant muscles: a clinical and anatomical systematic review.

PURPOSE: Many etiologies are known to lead to a tarsal tunnel syndrome (TTS). One rare cause is mass-occupying lesions, and particularly accessory or variant muscles (AVM). This study aimed to systematically collect published clinical cases of TTS caused by AVM. METHODS: An electronic literature search was conducted from inception to April 2021. The diagnosis of AVM should be reported in one of the following methods: ultrasonography, magnetic resonance imaging (MRI), or per-operatively. Data extraction included types and prevalence of accessory muscles, clinical presentation and diagnosis, and treatment modalities. Twenty-five studies were identified with a total 39 patients (47 ankles). RESULTS: The prevalence of TTS was reported in only two studies (9%). Forty-nine AVM were identified with the accessory flexor digitorum longus being the most common (52%). The most common sign/symptoms were tenderness (78.7%), pain (82.9%), dysesthesia (57.4%), Tinel sign (44.6%), and a swelling (25.5%). Decompression and excision were the most commonly performed procedures. Four accessory/variant muscles in the ankle have the potential to induce a tarsal tunnel syndrome. CONCLUSION: This review highlights the clinical and imagery specificities of TTS secondary to accessory or variant muscles. Mass-occupying etiology should be included in the list of differential diagnoses whenever a posterior tibial nerve compression is suspected.

Accessory Flexor Digitorum Longus Presenting as Tarsal Tunnel Syndrome: A Case Series.

ABSTRACT: Tarsal tunnel syndrome (TTS) typically occurs from extrinsic or intrinsic sources of compression on the tibial nerve. We present 3 cases of patients, all of whom have a prolonged time to diagnosis after evaluation with multiple specialties, with foot pain ultimately secondary to an accessory flexor digitorum longus muscle causing TTS. The literature describing the association between TTS and accessory musculature has been limited to single case reports and frequently demonstrate abnormal electrodiagnostic testing. In our series, 2 cases had normal electrodiagnostic findings despite magnetic resonance imaging (MRI) that later revealed TTS and improvement with eventual resection. A normal electromyogram should not preclude the diagnosis of TTS and MRI of the ankle; it should be considered a useful diagnostic tool when examining atypical foot pain.

Electrophysiological Study of the Tibial Nerve Across the Tarsal Tunnel in Distal Symmetric Diabetic Polyneuropathy.

OBJECTIVE: The aim of the study was to demonstrate abnormalities of motor conduction of the tibial nerve across the tarsal tunnel in type 2 diabetes. DESIGN: One hundred twenty-four consecutive patients (mean age = 66.6 yrs, 62.1% male) with distal symmetric diabetic polyneuropathy clinically diagnosed were prospectively enrolled. Nerve conduction studies of deep peroneal, tibial, superficial peroneal, medial plantar, and sural nerves and standard needle electromyography in the lower limbs were performed. Demographic, anthropometric, and clinical findings were collected. RESULTS: Motor conduction velocity of the tibial nerve across tarsal tunnel was slowed in 60.5% of patients; another 4% showed conduction block across tarsal tunnel without reduction of motor conduction velocity. Overall percentage of abnormalities across tarsal tunnel (64.5%) exceeds that of the sensory conduction velocities of proximal sural and superficial peroneal nerves. Abnormal tibial motor conduction velocity across tarsal tunnel represents the most common abnormality among all motor nerve conduction study parameters and significantly correlates with hemoglobin level, diabetic neuropathic index score, and diabetic complications frequency. CONCLUSIONS: Tibial conduction abnormalities across tarsal tunnel are the most sensitive motor parameter in distal symmetric diabetic polyneuropathy, second only to conduction abnormalities of sensory/mixed distal nerves of the feet. The use of nerve conduction studies across tarsal tunnel of the tibial nerve may be useful in the electrophysiological protocol to confirm the diagnosis of distal symmetric diabetic polyneuropathy.

Tarsal Tunnel Syndrome: An Ultrasound Pictorial Review.

Tarsal tunnel syndrome may be idiopathic or may be caused by various conditions: bone disease, thickening of the retinaculum, hematoma, or iatrogenic nerve damage; tendinopathy or tenosynovitis; the presence of supernumerary muscles such as an accessory soleus, peroneocalcaneus internus, or accessory flexor digitorum muscle; bone or joint disorders; expansile tumors or cysts; and venous aneurysm or kinking of the tibial artery. The purpose of this article is to describe and illustrate most of the causes of tarsal tunnel syndrome, as diagnosed by ultrasound, which is a practical, inexpensive method.