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.

[Ultrasound of nerves of the lower extremities]

The ability to visualize the nerves of the lower extremities differs from that of the upper extremities in sonography because the soft tissue cover is significantly larger in some cases. Landmarks are also defined for the lower extremities, which enable precise visualization of the nerves. Nerves and muscles are to be understood as a functional unit. In addition to the clarification of nerve compression syndromes, polyneuropathies and nerve tumors, sonography is also used to visualize muscle atrophy.

An anatomical approach to the tarsal tunnel syndrome: what can ankle's medial side anatomy reveal to us?

BACKGROUND

The heel is a complex anatomical region and is very often the source of pain complaints. The medial heel contains a number of structures, capable of compressing the main nerves of the region and knowing its anatomical topography is mandatory. The purpose of this work is to evaluate if tibial nerve (TN) and its main branches relate to the main anatomical landmarks of the ankle's medial side and if so, do they have a regular path after emerging from TN.

METHODS

The distal part of the legs, ankles and feet of 12 Thiel embalmed cadavers were dissected. The pattern of the branches of the TN was registered and the measurements were performed according to the Dellon-McKinnon malleolar-calcaneal line (DML) and the Heimkes Triangle (HT).

RESULTS

The TN divided proximal to DML in 87.5%, on top of the DML in 12,5% and distal in none of the feet. The Baxter's nerve (BN) originated proximally in 50%, on top of the DML in 12,5% and distally in 37.5% of the cases. There was a strong and significant correlation between the length of DML and the distance from the center of the medial malleolus (MM) to the lateral plantar nerve (LPN), medial plantar (MPN) nerve, BN and Medial Calcaneal Nerve (MCN) (ρ: 0.910, 0.866, 0.970 and 0.762 respectively, p <  0.001).

CONCLUSIONS

In our sample the TN divides distal to DML in none of the cases. We also report a strong association between ankle size and the distribution of the MPN, LPN, BN and MCN. We hypothesize that location of these branches on the medial side of the ankle could be more predictable if we take into consideration the distance between the MM and the medial process of the calcaneal tuberosity.

Tarsal tunnel ganglion cyst: intraneural or extraneural site?

Intraneural ganglion cysts are very uncommon lesions, whose diagnosis has increased since the articular theory and the description of the MRI findings were established. We present a case report of a 59-year-old man with symptoms of tarsal tunnel syndrome. Foot and ankle MRI demonstrated the presence of an intraneural cystic lesion in the posterior tibial neve and its connection with the subtalar joint through an articular branch. The identification of the specific radiological signs like the «signet ring sign» allowed establishing an adequate preoperative diagnosis, differentiating it from an extraneural lesion and facilitating the articular disconnection of the nerve branch during surgery.

Magnetic Resonance Neurography of the Foot and Ankle

Peripheral neuropathies of the foot and ankle can be challenging to diagnose clinically due to concomitant traumatic and nontraumatic or degenerative orthopedic conditions. Although clinical history, physical examination, and electrodiagnostic testing comprised of nerve conduction velocities and electromyography are used primarily for the identification and classification of peripheral nerve disorders, MR neurography (MRN) can be used to visualize the peripheral nerves as well as the skeletal muscles of the foot and ankle for primary neurogenic pathology and skeletal muscle denervation effect. Proper knowledge of the anatomy and pathophysiology of peripheral nerves is important for an MRN interpretation.

Unusual entrapment symptomatology treated in 115 cases by neurolysis of the common fibular nerve at the fibular head combined with neurolysis of the posterior tibial nerve at the tarsal tunnel

INTRODUCTION

Entrapment of the common fibular nerve (CFN) at the head of the fibula and entrapment of the posterior tibial nerve (PTN) at the tarsal tunnel are the most common nerve entrapment syndromes in the lower limb. Our aim was to study the results of combined neurolysis of the CFN and PTN for chronic lower limb pain. We hypothesized that combined neurolysis allowed a reduction of this chronic pain.

MATERIAL AND METHOD

This bi-centric retrospective study took place from January 2015 to November 2018, with a single senior surgeon. The inclusion criteria were all patients operated on for an idiopathic entrapment syndrome with neurolysis of the PTN at the tarsal tunnel, combined with neurolysis of the CFN at the head of the fibula. The primary endpoint was the pain evolution assessed on a numerical analogue scale (NAS) preoperatively and postoperatively on D+21, and at the last follow-up. The secondary endpoint was to determine the prognostic factors on the clinical outcome of neurolysis.

RESULTS

One hundred and fifteen neurolysis were included, comprising 64 women and 38 men with a mean age of 57±17.6 years. The preoperative pain (NAS0) was evaluated at 6±2.4 points. At D+21 postoperatively, there was a significant reduction in pain (NASD+21: 3±2.6 points, p<0.01). Similarly, at the last follow-up (with a mean follow-up of 37±8.4 months), there was a significant reduction in pain (NASLFU: 2±2.5, p<0.01). A history of systemic inflammatory disease was the only factor associated with a less significant decrease in pain at D+21, according to a multivariate analysis (p<0.01). There were 14 complications (12%) not requiring revision surgery.

CONCLUSION

This study is the first to demonstrate the efficacy of combined neurolysis of the CFN at the head of the fibula and the PTN at the tarsal tunnel, in the treatment of idiopathic nerve entrapment syndrome of the lower limb.

LEVEL OF EVIDENCE

IV; Retrospective comparative study.

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.

Symptomatic accessory soleus muscle: A cause for exertional compartment syndrome in a young soldier: A case report

BACKGROUND

Accessory soleus muscle (ASM) is a rare congenital variation that is almost asymptomatic, but several papers have recently described symptomatic ASM. The clinical features of this condition are similar to tarsal tunnel syndrome (TTS) and include pain and numbness around the medial side of the ankle. ASM commonly originates from the fibula or soleus muscle and inserts into the Achilles tendon or calcaneus. Usually, it is identified as posteromedial swelling and definitely diagnosed by magnetic resonance imaging. In most cases, treatment is observation, but surgical excision can be considered if symptoms are severe.

CASE SUMMARY

A 23-year-old male Korean soldier presented with complaints of bilateral foot and ankle pain and a swelling medial to the Achilles tendon that was more pronounced on the right side. Symptoms first occurred after playing soccer 10 mo before this presentation, worsened after physical exertion, and were relieved by rest. He had no medical history, and no one in his family had the condition. Laboratory results were non-specific. Several tests were performed to exclude common diseases such as tumors or TTS. However, MRI revealed a bulky accessory soleus muscle in both feet, though the patient complained of more severe pain on the right side during physical activity. Accordingly, surgical resection was adopted. At surgery, a large accessory soleus muscle was noted anterior to the Achilles tendon with distinctive insertion from a normal soleus muscle. At 12 mo after surgery, there was no pain, numbness, or swelling of the right foot or ankle, no evidence of recurrence, and the patient could do all sports activities.

CONCLUSION

Accessory soleus muscle should be added to the list of differential diagnosis if a patient has pain, sole numbness or swelling of the posteromedial ankle.

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.

An update on imaging of tarsal tunnel syndrome

Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the tibial nerve (TN) within the tarsal tunnel (TT) at the level of the tibio-talar and/or talo-calcaneal joints. Making a diagnosis of TTS can be challenging, especially when symptoms overlap with other conditions and electrophysiological studies lack specificity. Imaging, in particular MRI, can help identify causative factors in individuals with suspected TTS and help aid surgical management. In this article, we review the anatomy of the TT, the diagnosis of TTS, aetiological factors implicated in TTS and imaging findings, with an emphasis on MRI.

Predictive factors of effective tibial nerve release in tarsal tunnel syndrome

BACKGROUND

Factors that may affect surgical decompression results in tarsal tunnel syndrome are not known.

METHODS

A retrospective single-center study included patients who had undergone surgical tibial nerve release. The effectiveness of decompression was evaluated according to whether the patient would or would not be willing to undergo another surgical procedure in similar preoperative circumstances.

RESULTS

The patients stated for 43 feet (51%) that they would agree to a further procedure in similar circumstances. Six feet with space-occupying lesions on imaging had improved results, but neurolysis failed in 9 feet with bone-nerve contact. Neurolysis was significantly less effective when marked hindfoot valgus (p = 0.034), varus (p = 0.014), or fasciitis (p = 0.019) were present.

CONCLUSIONS

If imaging reveals a compressive space-occupying lesion, surgery has a good prognosis. In feet with static hindfoot disorders or plantar fasciitis, conservative treatment must be optimized. Bone-nerve contact should systematically be sought.

An unusual cause of tarsal tunnel syndrome: Schwannoma of the posterior tibial nerve; a rare cause and rare localization

INTRODUCTION

Schwannoma of the posterior tibial nerve is extremely rare.

CASE PRESENTATION

A 25-year-old female with a one-year history of left foot pain is presented. Clinical and radiological findings were in favor of a tarsal tunnel syndrome caused by a schwannoma of the posterior tibial nerve, prompting the patient to undergo surgery. We performed a complete excision of the tumor with the aid of a loupe magnification. At the last follow-up, the patient did well, with no recurrent pain and no neurological squeals.

DISCUSSION

The diagnosis of a tibial nerve schwannoma can often be difficult as, in the early stages, a mass may not be palpable and symptoms are often non-specific because of the slow-growing soft tissue mass.

CONCLUSION

Although schwannoma is a rare cause of tarsal tunnel syndrome, it should be kept in mind by physicians, especially in cases of chronic unexplained foot pain with a positive Tinel's test.

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.

A Rare Case of Flexor Digitorum Accessorius Longus Muscle Presenting as Tarsal Tunnel Syndrome

Tarsal tunnel syndrome (TTS) is a relatively uncommon nerve entrapment neuropathy. Many pathologies are reported as possible causes for TTS. The diagnosis of TTS can be difficult and often missed. We present a rare case of TTS due to an accessory flexor digitorum longus muscle. Together with a high index of suspicion, MRI is the investigation of choice in making the diagnosis. These patients are best managed with excision or transposition of the flexor digitorum accessorius longus (FDAL) and neurolysis of the posterior tibial nerve and its branches.

Can the axial cross-sectional area of the tibial nerve be used to diagnose tarsal tunnel syndrome? An ultrasonography study

INTRODUCTION

The axial cross-sectional area (CSA) of the tibial nerve can be measured with ultrasonography. In patients who have posteromedial tarsal tunnel syndrome (TTS), there is little information on the nerve's CSA even though this information could be useful for determining whether the nerve is damaged. This led us to carry out a case-control study in which the tibial nerve's axial CSA was measured in healthy patients and in patients with TTS.

HYPOTHESIS

The tibial nerve's axial CSA can be used as a diagnostic criterion for TTS.

METHODS

Twenty-three patients (27 feet) (11 men, 12 women, mean age=54±14 years), who had clinical and electroneuromyography signs of TTS, were compared to 21 healthy adults (8 men, 13 women, mean age 39±10 years). An ultrasonography examination was carried out to look for a source of nerve compression, then the axial CSA of the tibial nerve was measured 10cm above the tarsal tunnel (_lCSA) and inside the tunnel itself (_ttCSA). The difference between the two measurements was then calculated: _ΔCSA=_ttCSA-_lCSA. The data were analysed using correlation tests and non-parametric tests, a multivariate linear regression and ROC tests.

RESULTS

A compressive cause was found by ultrasonography in 13 patients. The mean values of _ttCSA and _ΔCSA were 20.1±8.8 mm² [6-42] vs. 10.3±2.3 mm² [8-14] (p=0.0001) and 9.8±6.7 mm² [0-29] vs. -0.2±1.8 mm² [-3-4] (p<0.0001) in the patients and the controls, respectively. The differences in _ΔCSA remained significant in the multivariate analysis after adjusting for age and weight. The best threshold for _ttCSA in the TTS group was 15 mm² with 74% sensitivity and 100% specificity. The best threshold for _ΔCSA was 5mm² with 81% sensitivity and 100% specificity.

DISCUSSION

The difference in the measured axial CSA of the tibial nerve by ultrasonography between the posteromedial tarsal tunnel and 10cm above the tunnel is a key data point for the diagnosis of tarsal tunnel syndrome with and without compressive etiology.

LEVEL OF EVIDENCE

III, diagnostic case-control study.

Unusual bilateral variation of the flexor digitorum accessorius longus muscle and its relation on tarsal tunnel syndrome

PURPOSE

During standard anatomical dissection for a medical anatomy course, we encountered an unusual bilateral variant of a unipennate flexor digitorum accessorius longus (FDAL) muscle, a supernumery muscle of the deep posterior leg and medial ankle.

METHODS

We documented the muscles course and measured the diameter and length of the FDAL muscle belly, as well as the full length of its tendinous attachments.

RESULTS

On both right and left legs, the FDAL originated from the proximal posterior fibula and distal one-third of the flexor hallucis longus muscle. The tendon had a distal attachment on the flexor digitorum longus (FDL) tendon and traveled with the FDL tendon as it inserted on the third distal phalanx. The left FDAL full length was 42.54 cm; the length of the muscle belly was 16.26 cm; and the circumference of the muscle belly was 4.44 cm. The right FDAL full length was 44.20 cm; the length of muscle belly was 12.06; and the circumference (belly) was 4.44 cm. Surrounding musculature and neurovasculature follow standard anatomical courses.

CONCLUSION

This anatomical documentation provides opportunities for clinicians to consider mechanical influences of the FDAL on plantar foot function and further consider the accessory ankle muscles that have the potential to cause compressive neuropathies such as tarsal tunnel syndrome.

Carpal, cubital or tarsal tunnel syndrome after SARS-CoV-2 infection: A causal link?

COVID-19 is a complex disease with many clinicopathological issues, including respiratory, gastrointestinal, neurological, renal, cutaneous, and coagulative ones; in addition, reactive arthritis has been reported by different authors. Here, we hypothesize that a peripheral microangiopathy involving nerve supply, a viral demyelination, or an immune-mediated irritating antigenic stimulus on synovial sheaths after SARS-CoV-2 infection may all induce a carpal, cubital or tarsal tunnel syndrome of variable entity in genetically predisposed subjects associated with myxoid nerve degeneration.

Tarsal Tunnel Syndrome

Tarsal tunnel syndrome is paresthesia and pain in the foot and ankle caused by entrapment and compression of the tibial nerve within the fibro-osseous tarsal tunnel beneath the flexor retinaculum. The most helpful diagnostic criteria are a positive Tinel sign at the ankle and objective sensory loss along the distribution of the tibial nerve. Treatment is designed to reduce the compression of the nerve, and surgical nerve release is indicated with failure of conservative options. It is important to identify the causative factor of the nerve compression and eliminate it to obtain excellent results.

Clinico-radiological review of peripheral entrapment neuropathies - Part 2 Lower limb

PURPOSE

This review discusses the relevant anatomy, etiopathogenesis, current notions in clinical and imaging features as well as management outline of lower limb entrapment neuropathies.

METHODS

The review is based on critical analysis of the current literature as well as our experience in dealing with entrapment neuropathies of the lower limb.

RESULTS

The complex anatomical network of nerves supplying the lower extremities are prone to entrapment by a heterogenous group of etiologies. This leads to diverse clinical manifestations making them difficult to diagnose with traditional methods such as clinical examination and electrodiagnostic studies. Moreover, some of these may mimic other common conditions such as disc pain or fibromyalgia leading to delay in diagnosis and increasing morbidity. Addition of imaging improves the diagnostic accuracy and also help in correct treatment of these entities. Magnetic resonance imaging is very useful for deeply situated nerves in pelvis and thigh while ultrasound is well validated for superficial entrapment neuropathies.

CONCLUSION

The rapidly changing concepts in these conditions accompanied by the advances in imaging has made it essential for a clinical radiologist to be well-informed with the current best practices.

A case of osteophyte excision and arthroscopic arthrodesis for tarsal tunnel syndrome with traumatic osteoarthritis of the ankle

•

We successfully treated tarsal tunnel syndrome (TTS) accompanied with traumatic osteoarthritis of the ankle.

•

Osteophyte excision for the TTS and arthroscopic for the osteoarthritis was effective for even TTS with traumatic osteoarthritis of the ankle.

•

There were many advantages in arthroscopic ankle arthrodesis, compared with open ankle arthrodesis.

Introduction

There are some reports of tarsal tunnel syndrome (TTS) entrapment/impingement from bony factors, including exostosis and fragment, but there are no reports on TTS with traumatic osteoarthritis of the ankle that were treated with osteophyte excision for TTS and arthroscopic arthrodesis for osteoarthritis of the ankle.

Presentation of case

A 61-year-old woman with left trimalleolar fracture had undergone surgery 3 years earlier and was referred to our hospital for further investigation of persistent left ankle pain and numbness around the left medial malleolus and plantar aspect of the foot. Clinical examination demonstrated plantar hypesthesia and a positive Tinel’s sign at the tarsal tunnel. Imaging showed severe osteoarthritic change in the ankle and an osteophyte of the posteromedial distal tibia that appeared to be impinging on the tibial nerve. We performed arthroscopic ankle arthrodesis, which is less invasive than the open procedure, with removal of the osteophyte as the cause of TTS. Tarsal tunnel exploration revealed a large osteophyte pushing on the tibial nerve, and the osteophyte was removed.

Discussion

About 8 weeks after surgery, bony union was achieved. At the 2-year follow-up visit, the patient could perform daily activities with almost no pain or numbness. This case offers further insight into the management of TTS with traumatic osteoarthritis of the ankle.

Conclusion

We report here successful treatment of a rare case of tarsal tunnel syndrome (TTS) accompanied with traumatic osteoarthritis of the ankle, treated with osteophyte excision for the TTS and arthroscopic for the osteoarthritis.

Surgical efficacy analysis of tarsal tunnel syndrome: a retrospective study of 107 patients

Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve or its terminal branches compressed by its fibro-osseous tunnel beneath the flexor retinaculum on the medial side of the ankle. The current study was a retrospective study of 107 cases of patients with TTS, in which the onset characteristics were summarized, the factors that might affect the surgical treatment effects of TTS were discussed and analyzed. The syndrome diagnoses and treatment experiences of TTS were extracted and analyzed. In our cohort, TTS was more often found in middle-aged and older women. And the medial plantar nerve bundle was the most frequently affected nerve structure. The efficacy of surgical treatment were correlated to the causes of the disease, involved nerve bundles, methods of operation, and whether neurolysis of the epineurium was performed. Neurolysis of the epineurium is was recommended for patients with an enlarged tibial nerve due to impingement. The Singh method was recommended to release the tibial nerve and its branches. Patients with negative preoperative EMG results should carefully be cautious when considering their decision to undergo surgical treatment.

Lower extremity entrapment neuropathies

Entrapment neuropathies are frequently encountered by rheumatologists, not only because they are common but also because of their association with certain rheumatological and systemic disorders. Recognizing entrapment neuropathy early can help avoid progressive neurological deficits, as well as facilitate appropriate treatment measures, which can effectively minimize a patient's symptoms. Entrapment neuropathies may be distinguished from other musculoskeletal causes of lower extremity pain by identifying characteristic patterns of weakness and/or sensory loss, so a focused bedside neurological examination is key for diagnosis. In this chapter, we review the most common entrapment neuropathies that occur in the lower extremities, review the relevant neuroanatomy, outline a diagnostic approach to distinguish them from other mimics, and highlight appropriate management options.

A case report

Objectives

The sensitivity of nerve conduction studies (NCSs) of the medial and lateral plantar nerves for the diagnosis of tarsal tunnel syndrome (TTS) is not high enough. The near nerve method (NNM) is a recording technique for NCSs that allows the recording of large, clear potentials. The NNM was reported to improve the sensitivity of diagnoses of TTS. However, the NNM requires special skill using electrical motor threshold in positioning a needle electrode correctly. Thus, we performed the NNM with the aid of ultrasound imaging (ultrasound-assisted). The aim of this case report is to show the utility of ultrasound-assisted NNM in the electrodiagnosis of TTS.

Case report

A 69-year-old woman presented with paresthesia on the lateral sole of her right foot. Ultrasound imaging showed a space occupying lesion (SOL) posterior to the medial malleolus, caused by tenosynovitis, as discovered after surgery. We performed an NCS of the medial and lateral plantar nerves with ultrasound-assisted NNM. Ultrasound-assisted NNM allowed us to easily determine the needle insertion site just proximal to the SOL and to avoid penetrating the SOL and the vessels, and, furthermore, simplified moving the needle electrode toward the target nerve. The results of the NCS revealed that there was severe injury to the lateral plantar nerve and no injury to the medial plantar nerve.

Conclusions

In the NCS of the medial and lateral plantar nerves with NNM to diagnose TTS, ultrasound-assisted NNM can be useful for simplicity and safety.

Tarsal tunnel syndrome secondary to osteochondroma of the calcaneus: a case report

Background

Tarsal tunnel syndrome is an entrapment neuropathy that can be provoked by either intrinsic or extrinsic factors that compresses the posterior tibial nerve beneath the flexor retinaculum. Osteochondroma, the most common benign bone tumor, seldom occur in foot or ankle. This is a rare case of tarsal tunnel syndrome secondary to osteochondroma of the sustentaculum tali successfully treated with open surgical excision.

Case presentation

A 15-year-old male presented with the main complaint of burning pain and paresthesia on the medial plantar aspect of the forefoot to the middle foot region. Hard mass-like lesion was palpated on the posteroinferior aspect of the medial malleolus. On the radiological examination, 2.5 × 1 cm sized bony protuberance was found below the sustentaculum tali. Surgical decompression of the posterior tibial nerve was performed by complete excision of the bony mass connected to the sustentaculum tali. The excised mass was diagnosed to be osteochondroma on the histologic examination. After surgery, the pain was relieved immediately and hypoesthesia disappeared 3 months postoperatively. Physical examination and radiographic examination at 2-year follow up revealed that tarsal tunnel was completely decompressed without any evidence of complication or recurrence.

Conclusions

As for tarsal tunnel syndrome secondary to the identifiable space occupying structure with a distinct neurologic symptom, we suggest complete surgical excision of the causative structure in an effort to effectively relieve symptoms and prevent recurrence.

Artery Transposition Using Indocyanine Green for Tarsal Tunnel Decompression

BACKGROUND

Surgery for idiopathic tarsal tunnel syndrome (TTS) is of limited effectiveness or ineffective. Using indocyanine green video angiography (ICG-VA), we treated idiopathic TTS by posterior tibial artery (PTA) decompression from the posterior tibial nerve (PTN) and evaluated postoperative patency of the PTA.

METHODS

We treated 12 patients (12 feet) with idiopathic TTS by PTA decompression from the PTN and transposed its location. Age range of patients was 70-87 years (mean 77.9 years); all patients were operated on under local anesthesia. After a 2-cm skin incision, the flexor retinaculum was resected, and the PTA was decompressed from the PTN. It was then sutured to the flexor retinaculum for decompression and to prevent compression recurrence. ICG-VA was used to confirm the absence of PTA flow disturbance and to inspect the vasa nervorum of the PTN.

RESULTS

We encountered no intraoperative or postoperative complications. Postoperatively, ICG-VA confirmed blood flow in the PTA and intactness of the vasa nervorum in all cases. One patient required adjustment of PTA position. All patients reported symptom improvement.

CONCLUSIONS

Our surgical method of treating idiopathic TTS under ICG-VA monitoring is simple, safe, and effective.

The natural history of tarsal tunnel syndrome in diabetic subjects

INTRODUCTION

Tibial nerve entrapment is highly prevalent in diabetic subjects, resulting in significantly more neuropathic complaints and concomitant sensory disturbances. The study aim was to assess the impact of tarsal tunnel syndrome (TTS) and sensory loss at baseline on incident diabetic foot ulceration (DFU) in diabetic patients, since decompressing the tibial nerve might change the natural history of the disease.

METHODS

In this study, 113 subjects with TTS (69 bilateral, 23 left-sided and 21 right-sided) participating in the prospective Rotterdam Diabetic Foot Study were compared to 303 diabetic controls without TTS, regarding incident DFU. Kaplan-Meier analysis and Cox's regression analysis were used to determine the independent hazard of baseline variables for new DFU.

RESULTS

The median observation period was 836.5 days (IQR, 459-1077.8). In bilateral TTS, 17.4% (95% CI: 8.4-26.3%) of subjects experienced DFU versus 8.3% (95% CI: 5.1-11.6%) in controls (left or right) during follow-up (p = 0.0036). In left-sided TTS, no subjects versus 6.2% (95% CI: 3.4-9.0%) in controls had DFUs (p = 0.243). Incident ulceration was seen in 14.3% (95% CI: -0.7% to -29.3%) of right-sided TTS subjects versus 4.1% (95% CI: 1.5-6.3%) in controls (p = 0.034). Besides HbA1c, diminished sensation at the hallux independently increased the risk of ulceration, in patients with (HR: 4.692, p = 0.003) and without (HR: 2.307, p = 0.002) prior DFU.

DISCUSSION

Elevated sensory thresholds in TTS render diabetic patients at a higher risk for DFU. With effective surgery, TTS is likely to be an amenable factor to potentially prevent diabetic foot disease and thereby reduce amputation risk.

LEVEL OF EVIDENCE

II.

Injection Techniques for Common Chronic Pain Conditions of the Foot: A Comprehensive Review

Purpose of Review

This is a comprehensive literature review of the available evidence and techniques of foot injections for chronic pain conditions. It briefly describes common foot chronic pain syndromes and then reviews available injection techniques for each of these syndromes, weighing the available evidence and comparing the available approaches.

Recent Findings

Foot and ankle pain affects 20% of the population over 50 and significantly impairs mobility and ability to participate in activities of daily living (ADLs), as well as increases fall risk. It is commonly treated with costly surgery, at times with questionable efficacy. Injection therapy is challenging when the etiology is anatomical or compressive. Morton’s neuroma is a budging of the interdigital nerve. Steroid, alcohol, and capsaicin injections provide some benefit, but it is short lived. Hyaluronic acid (HA) injection provided long-term relief and could prove to be a viable treatment option. Achilles tendinopathy (AT) is most likely secondary to repeat tendon stress—platelet-rich-plasma (PRP) and prolotherapy have been trialed for this condition, but more evidence is required to show efficacy. Similar injections were trials for plantar fasciitis and achieved only short-term relief; however, some evidence suggests that PRP injections reduce the frequency of required therapy. Tarsal tunnel syndrome, a compressive neuropathy carries a risk of permanent neural injury if left untreated. Injection therapy can provide a bridge to surgery; however, surgical decompression remains the definitive therapy. When the etiology is inflammatory, steroid injection is more likely to provide benefit. This has been shown in several studies for gout, as well as osteoarthritis of the foot and ankle and treatment-refractory rheumatoid arthritis. HA showed similar benefit, possibly due to anti-inflammatory effects. Stem cell injections may provide the additional benefit of structure restoration.

Summary

Chronic foot pain is common in the general population and has significant associated morbidity and disability. Traditionally treated with surgery, these are costly and only somewhat effective. Injections provide an effective alternative financially and some evidence exists that they are effective in pain alleviation. However, current evidence is limited and the benefit described from injection therapy has been short-lived in most cases. Further studies in larger populations are required to evaluate the long-term effects of these treatments.

Results of ultrasound-guided release of tarsal tunnel syndrome: a review of 81 cases with a minimum follow-up of 18 months

Background

This study aims to analyse the clinical results of ultrasound-guided surgery for the decompression of the tibial nerve, including its distal medial and lateral branches, to treat tarsal tunnel syndrome. These structures are the complete flexor retinaculum and the deep fascia of the abductor hallucis muscle, including individualised release of the medial and lateral plantar nerve tunnels.

Method

This is a retrospective review of 81 patients (36 men and 45 women) with an average age of 41 years old (32–62) and an average clinical course of 31 months (8–96) compatible with idiopathic tarsal tunnel syndrome, who underwent ultrasound-guided decompression of the proximal and distal tarsal tunnel between February 2015 and November 2017 (both months included), with a minimum follow-up of 18 months.

Results

Based on the Takakura et al. scale for the 81 patients, 76.54% obtained excellent results, 13.58% good results, and 9.87% poor results.

The patients with the longest course of symptoms displayed the worst results.

Conclusion

Although 9% of patients did not improve, ultrasound-guided tarsal tunnel release might be a viable alternative to conventional open approaches.

[Clinical analysis of ankle arthroscopy technique for treatment of tarsal tunnel syndrome]

Objective: To explore the effects of ankle arthroscopy technique in treating the tarsal tunnel syndrome. Methods: From May 2014 to May 2016, the ankle arthroscopy technique was used for surgical treatment of tarsal tunnel syndrome in the Department of Hand and Foot Microsurgery in Xuzhou Central Hospital. Twenty-two patients with 24 feet with tarsal tunnel syndrome were hospitalized for treatment, with 10 left feet and 14 right feet, aged 26-57 years. The disease duration ranged from 4 to 15 months (mean 8.3 months). The dual-portals ankle arthroscopic neurolysis and fiber membrane resection were performed. The Pfeiffer scoring system was used to evaluate the post-operative outcomes. Results: Primarily healing of the wound was achieved in all the patients. No postoperative infection was found during the follow-up. The postoperative hospitalization time was 2 to 5 days (mean 3.7 days). All patients were followed up for 12 to 24 months. At the final follow-up, all the patients had significant improvement in numbness and pain. According to the Pfeiffer scoring system, the results were excellent in 16 feet, good in 8 feet, with an excellent and good rate of 100%. Conclusion: The ankle arthroscopic neurolysis is a safe and easy treatment option for the tarsal tunnel syndrome and provides satisfactory results.

Entrapment Neuropathies of the Lower Extremity

Entrapment neuropathies in the lower limbs are a common neurologic problem and may present in any medical setting. Accurate identification and management of these nerve palsies can prevent pain, sensory loss, incoordination, and muscle weakness that may significantly affect a patient's functional mobility. In this article, the authors focus on the cause, signs and symptoms, diagnosis, and treatment of select entrapment neuropathies of the lower extremity, including palsies of the common peroneal, lateral femoral cutaneous, femoral, and posterior tibial nerves.

Ultrasound-guided decompression surgery of the tarsal tunnel: a novel technique for the proximal tarsal tunnel syndrome-Part II

Background

The aim of this study is to provide a safe ultrasound-guided minimally invasive surgical approach for a proximal tarsal tunnel release concerning nerve entrapments.

Methods and results

The study was carried out on ten fresh-frozen feet. All of them were examined by high resolution ultrasound at the medial ankle region. The surgical approach was marked throughout the course of the flexor retinaculum (laciniate ligament). Once the previous steps were done, the flexor retinaculum release technique was carried out with a 2-mm entry only. As a result, an effective and safe release of the flexor retinaculum was obtained in all fresh-frozen feet.

Conclusion

The results of our anatomic study indicate that our novel ultrasound-guided minimally invasive surgical approach for the release of the flexor retinaculum might be an effective, safe and quick decompression technique treating selected patients with a proximal tarsal tunnel syndrome.

Guiding Treatment for Foot Pain

In the electrodiagnostic (EDX) approach of the patient who presents with foot pain, numbness, and/or tingling, it is important to consider a broad differential diagnosis of both neuropathic and nonneuropathic conditions, including focal and systemic causes. This article assists the electromyographer in the selection and utilization of the most appropriate EDX studies for evaluation. The EDX findings and impression can then help guide potential treatment options for the patient with foot pain and other symptoms. Moreover, this discussion demonstrates the added value that EDX evaluation of the foot provides to the comprehensive assessment of foot pain.

Morphological characteristics and variations of the human quadratus plantae muscle

The quadratus plantae (QP) is a highly variable structure. A number of partly inexact descriptions of this entity have been provided in textbooks of anatomy. Although several authors have examined the QP, its exact site of origin and type of insertion have hitherto not been specified. The aim of this study has been to provide detailed qualitative and quantitative data about the number of heads, points of origin, and type of insertion of the QP. The QP in both feet of 50 formalin-fixed specimens of body donors (25 men and women) were analyzed by gross anatomical dissection. It was composed of one (34%), two (57%) or three heads (9%). The latter condition was observed only in men. The lateral head was absent in 31 feet, and the medial head only in one right foot of a man. The medial head arose, amongst others, in 100% of the examined cases from the medial calcaneal surface, in 93% from the long plantar ligament and in 80% from the plantar calcaneocuboid ligament. The lateral head arose, amongst others, from the long plantar ligament in 90%, and from the lateral process of the calcaneal tuberosity in 64% of the examined feet. The type of insertion was always a mixture of at least two of three types; i.e. muscular (84%), tendinous (89%) and aponeurotic (45%). As additional findings, the flexor digitorum accessorius longus (FDAL) and the peroneocalcaneus internus (PCI) were observed in 12% of all individuals and in 20% of men. The present investigation revealed that the QP may be classified according to the number of heads, but no classification can be given for its points of origin or type of insertion. The present data are mandatory for anatomical and surgical practice and will hopefully lead to further imaging and biomechanical studies.

Entrapment neuropathies in diabetes mellitus

Neuropathy is a common complication of diabetes mellitus (DM) with a wide clinical spectrum that encompasses generalized to focal and multifocal forms. Entrapment neuropathies (EN), which are focal forms, are so frequent at any stage of the diabetic disease, that they may be considered a neurophysiological hallmark of peripheral nerve involvement in DM. Indeed, EN may be the earliest neurophysiological abnormalities in DM, particularly in the upper limbs, even in the absence of a generalized polyneuropathy, or it may be superimposed on a generalized diabetic neuropathy. This remarkable frequency of EN in diabetes is underlain by a peculiar pathophysiological background. Due to the metabolic alterations consequent to abnormal glucose metabolism, the peripheral nerves show both functional impairment and structural changes, even in the preclinical stage, making them more prone to entrapment in anatomically constrained channels. This review discusses the most common and relevant EN encountered in diabetic patient in their epidemiological, pathophysiological and diagnostic features.

Entrapment Neuropathies of the Foot and Ankle

Posterior tarsal tunnel syndrome is the result of compression of the posterior tibial nerve. Anterior tarsal tunnel syndrome (entrapment of the deep peroneal nerve) typically presents with pain radiating to the first dorsal web space. Distal tarsal tunnel syndrome results from entrapment of the first branch of the lateral plantar nerve and is often misdiagnosed initially as plantar fasciitis. Medial plantar nerve compression is seen most often in running athletes, typically with pain radiating to the medial arch. Morton neuroma is often seen in athletes who place their metatarsal arches repetitively in excessive hyperextension.

Extensive Osteochondroma of Talus Presenting as Tarsal Tunnel Syndrome: Report of a case and Literature Review

Osteochondroma or exostosis is the most common benign bone tumor, and occurring frequently in the proximal humerus, tibia, and distal femur. It rarely affects talus. Osteochondroma of talus is a very rare etiology of tarsal tunnel syndrome (TTS). We report a rare case of extensive osteochondroma of the talus in a 60 year old female presenting with multiple swellings around the ankle and symptoms suggestive of tarsal tunnel syndrome. En-block excision of the multiple masses was done. Histopathological examination confirmed the diagnosis of osteochondroma. Although most of the osteochondromas are being treated conservatively, those presenting with multiple swellings, restriction of movements and compressive neuropathies should be treated with surgical excision. Excision is a successful method of treatment for symptomatic osteochondromas with low recurrence.

Proposed Sonographic Criteria for the Diagnosis of Idiopathic Tarsal Tunnel Syndrome

OBJECTIVE

To propose new sonographic criteria for the diagnosis of idiopathic tarsal tunnel syndrome (TTS).

DESIGN

Prospective case-control study.

SETTING

Academic referral center.

PARTICIPANTS

Adult healthy volunteers (n=17) and adult patients (n=14) with electrodiagnostically proven idiopathic TTS (mean age, 43.4±8.7y; height, 161.4±7.0cm; weight, 90.6±13.9kg) (N=31). The exclusion criteria were patients with diabetes, neurological disorders, associated ankle and/or foot disorders, electrodiagnostic evidence of a widespread lesion, or feet that were electrophysiologically negative for TTS or with structural abnormalities detected via ultrasound imaging.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Tibial nerve CSA at the proximal tarsal tunnel, tibial nerve CSA within the tunnel, within tunnel-to-proximal tunnel CSA ratio.

RESULTS

There was a significant difference in the within tunnel CSA and within tunnel-to-proximal tunnel CSA ratio between the TTS group and controls (P=.002 and P=.001, respectively). The optimum cutoff value was 19mm(2) for the within tunnel CSA and 1 for the within tunnel-to-proximal tunnel CSA ratio. Sensitivities were 61% and 74%, respectively.

CONCLUSIONS

The within tunnel-to-proximal tunnel CSA ratio and the within tunnel CSA are the most accurate sonographic parameters and can be helpful in the assessment of idiopathic TTS.

Tarsal tunnel syndrome-A narrative literature review

BACKGROUND

Tarsal tunnel syndrome is classified as a focal compressive neuropathy of the posterior tibial nerve or one of its associated branches individually or collectively. The tunnel courses deep to fascia, the flexor retinaculum and within the abductor hallucis muscle of the foot/ankle. The condition is rare and regularly under-diagnosed leading to a range of symptoms affecting the plantar margins of the foot. There are many intervention strategies for treating tarsal tunnel syndrome with limited robust evidence to guide the clinical management of this condition. The role of conservative versus surgical interventions at various stages of the disease process remains unclear, and there is a need for a structured, step-wise approach in treating patients with this syndrome based on derived empirical evidence. This narrative review attempts to scrutinize the literature to date by clarifying initial presentation, investigations and definitive treatment for the purpose of assisting future informed clinical decision and prospective research endeavours.

PROCESS

The literature searches that have been incorporated in compiling a rigorous review of this condition have included: the Cochrane Neuromuscular Group's Specialized Register (Cochrane Library 2013), the databases of EMBASE, AMED, MEDLINE, CINAHL, Physiotherapy evidence database (PEDRO), Biomed Central, Science Direct and Trip Database (1972 to the present). Reference listings of located articles were also searched and scrutinized. Authors and experts within the field of lower-limb orthopaedics were contacted to discuss applicable data. Subject-specific criteria searches utilizing the following key terms were performed across all databases: tarsal tunnel syndrome, tibial neuralgia, compression neuropathy syndromes, tibial nerve impingement, tarsal tunnel neuropathy, entrapment tibial nerve, posterior tibial neuropathy. These search strategies were modified with differing databases, adopting specific sensitivity-searching tools and functions unique to each. This search strategy identified 88 journal articles of relevance for this narrative literature review.

FINDINGS

This literature review has appraised the clinical significance of tarsal tunnel syndrome, whilst assessing varied management interventions (non-surgical and surgical) for the treatment of this condition in both adults and children. According to our review, there is limited high-level robust evidence to guide and refine the clinical management of tarsal tunnel syndrome. Requirements for small-scaled randomized controlled trials in groups with homogenous aetiology are needed to analyse the effectiveness of specific treatment modalities.

CONCLUSIONS

It is necessary that further research endeavours be pursued for the clinical understanding, assessment and treatment of tarsal tunnel syndrome. Accordingly, a structured approach to managing patients who have been correctly diagnosed with this condition should be formulated on the basis of empirical evidence where possible.

The prevalence of tarsal tunnel syndrome in patients with lumbosacral radiculopathy

PURPOSE

Tarsal tunnel syndrome (TTS) is a painful foot condition. Lumbosacral radiculopathy (LR) may also present with symptoms occurring in TTS. However, no studies have been reported to determine the possible coexistence of these two conditions. The aim of our study was to identify the prevalence of TTS in patients with confirmed LR and to analyze the clinical and electrodiagnostic features of patients with both TTS and LR.

METHODS

Medial and lateral plantar nerve mixed studies, peroneal motor studies and deep peroneal sensory studies were performed in 81 normal subjects and 561 patients with LR. The Tinel's test and other provocative tests were performed in the LR patient group, and the clinical symptoms of TTS were also analyzed. The frequency of TTS was investigated in all radiculopathy group patients with different nerve root lesions.

RESULTS

Concomitant TTS was found in 27 (4.8%) patients with LR. Abnormal results of sensory/mixed conduction tests were observed in 25/27 (92.6%) patients, and 11/27 (40.7%) patients had abnormal results of motor conduction tests. Positivity for the Tinel's test and special provocative tests was found in 15/27 (55.6%) and 17/27 (63.0%) patients, respectively. Overall, 9/27 (33.3%) patients had typical symptoms, and suspicious clinical symptoms were found in the other 14/27 (51.9%) patients. The frequency of coexisting TTS was not statistically different among the single-level L4, L5 or S1 radiculopathy, or between the single-level and multi-level radiculopathies (P > 0.05).

CONCLUSIONS

The findings suggest that the prevalence of TTS is significant in patients with LR. Thus, more caution should be paid when diagnosing and managing patients with LR due to the possible existence of TTS, as their management strategies are quite different.

Tarsal tunnel syndrome masked by painful diabetic polyneuropathy

•

The real cause of symptoms in patients with neuropathy may not be related with diabetes.

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It is essential to investigate the etiology of the disease with more localized pathologies in such complicated cases.

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Tarsal tunnel syndrome gives a more segmental clinical profile with nerve entrapment.

Introduction

Various causes influence the etiology of tarsal tunnel syndrome including systemic diseases with progressive neuropathy, such as diabetes.

Presentation of case

We describe a 52-year-old male patient with complaints of numbness, burning sensation and pain in both feet. The laboratory results showed that the patient had uncontrolled diabetes, and the EMG showed distal symmetrical sensory-motor neuropathy and nerve entrapment at the right. Ultrasonography and MRI showed the cyst in relation to medial plantar nerve, and edema- moderate atrophy were observed at the distal muscles of the foot.

Discussion

Foot neuropathy in diabetic patients is a complex process. So, in planning the initial treatment, medical or surgical therapy is selected based on the location and type of the pathology. Foot deformities can be corrected with resting, anti-inflammatory treatment, appropriate shoes, orthesis and socks, and if required, ankle stabilization can be attempted. If the patient is still unresponsive, surgical treatment may be applied.

Conclusion

It is essential to investigate more localized reasons like tarsal tunnel syndrome that may mimic diabetic neuropathy, should be treated primarily.

Results of surgical treatment of tarsal tunnel syndrome

BACKGROUND

The aim of our study is to evaluate retrospectively the prognostic factors affecting the final outcome of surgical treatment of tarsal tunnel syndrome.

MATERIAL AND METHODS

Surgical decompression were performed on 31 patients. All patients had EMG and anesthetic test confirmation. The results were evaluated according to VAS scale and modified AOFAS score. Follow-up was after 12 months.

RESULTS

22 patients received very good or good (71%), 7 satisfactory (22%), 2 poor (7%) results in the subjective and objective patient's assessment. The outcomes decreased from 5.19 (SD 1.01) points to 1.19 (SD 0.83) points according to VAS scale, and modified AOFAS increased from 31.77 (SD 9.08) points to 57.58 (SD 9.90). Patients with diagnosed cause, short period of time between onset of disease till surgery, and positive Tinel's sign achieved the best results.

CONCLUSION

Etiology of the tarsal tunnel syndrome has influence on the results. Immediate diagnosis and short period between occurrences of symptoms in surgical treatment improves the outcomes. Tinel's sign may be used as a prognostic factor.

A case of acute tarsal tunnel syndrome following lateralizing calcaneal osteotomy

Surgical correction of hindfoot varus is frequently performed with a lateral displacement calcaneal osteotomy. It has rarely been associated with iatrogenic tarsal tunnel syndrome in patients with pre-existing neurological disease. We report the first case of acute postoperative tarsal tunnel syndrome in a neurologically intact patient with post-traumatic hindfoot varus. Early diagnosis and emergent operative release afforded an excellent clinical outcome. Imaging studies can help outrule a compressive hematoma and assess for possible nerve transection; however it is paramount that a high index of suspicion is utilized with judicious operative intervention to minimize long-term sequelae.

Tarsal tunnel syndrome associated with a perforating branch from posterior tibial artery: a case report

Tarsal tunnel syndrome, a compressive neuropathy of the tibial nerve or its branches with in the tarsal tunnel, is an uncommon condition. Various etiologies of the syndrome have been described. We report a rare case of tarsal tunnel syndrome associated with a perforating branch from the posterior tibial artery. A 56-year-old woman presented with 1-year history of paresthesia and hypoesthesia in the medial and lateral plantar area of the left foot. Tinel's sign was elicited at the tarsal tunnel. Electrodiagnostic studies confirmed the diagnosis of left tarsal tunnel syndrome. Intraoperatively, the perforating branch from posterior tibial artery which traveled through a split in the tibial nerve was encountered. The patient's symptom improved significantly at 2 years after tarsal tunnel release and vascular ligation. Only a minor degree of paresthesia remains in the forefoot.

Branching patterns of medial and inferior calcaneal nerves around the tarsal tunnel

Objective

To demonstrate the bifurcation pattern of the tibial nerve and its branches.

Methods

Eleven legs of seven fresh cadavers were dissected. The reference line for the bifurcation point of tibial nerve branches was an imaginary horizontal line passing the tip of the medial malleolus. The distances between the reference line and the bifurcation points were measured. The bifurcation branching patterns were categorized as type I, the pattern in which the medial calcaneal nerve (MCN) branched most proximally; type II, the pattern in which the three branches occurred at the same point; and type III, in which MCN branched most distally.

Results

There were seven cases (64%) of type I, three cases (27%) of type III, and one case (9%) of type II. The median MCN branching point was 0.2 cm (range, -1 to 3 cm). The median bifurcation points of the lateral plantar nerves and inferior calcaneal nerves was -0.6 cm (range, -1.5 to 1 cm) and -2.5 cm (range, -3.5 to -1 cm), respectively.

Conclusion

MCN originated from the tibial nerve in most cases, and plantar nerves were bifurcated below the medial malleolus. In all cases, inferior calcaneal nerves originated from the lateral plantar nerve. These anatomical findings could be useful for performing procedures, such as nerve block or electrophysiologic studies.

Recurrent tarsal tunnel syndrome

Recurrence of tarsal tunnel syndrome after surgery may be due to inadequate release, lack of understanding or appreciation of the actual anatomy involved, variations in the anatomy of the nerve(s), failure to execute the release properly, bleeding with subsequent scarring, damage to the nerve and branches, persistent hypersensitivity of the nerves, and preexisting intrinsic damage to the nerve. Approaches include more thorough release, use of barrier materials to decrease adherence of the nerve to surrounding tissues to avoid traction neuritis, excisions of neuromas using conduits, and consideration of nerve stimulators and systemic medications to deal with persistent neural pain.

Study of the anatomy of the tibial nerve and its branches in the distal medial leg

Objective

Determine, through dissection in fresh cadavers, the topographic anatomy of the tibial nerve and its branches at the ankle, in relation to the tarsal tunnel.

Methods

Bilateral dissections were performed on 26 fresh cadavers and the locations of the tibial nerve bifurcation and its branches were measured in millimeters. For the calcaneal branches, the amount and their respective nerves of origin were also analyzed.

Results

The tibial nerve bifurcation occurred under the tunnel in 88% of the cases and proximally in 12%. As for the calcaneal branches, the medial presented with one (58%), two (34%) and three (8%) branches, with the most common source occurring in the tibial nerve (90%) and the lower with a single branch per leg and lateral plantar nerve as the most common origin (70%). Level of Evidence, V Expert opinion.

Accessory muscles around the foot and ankle presenting as chronic undiagnosed pain. An illustrative case report and review of the literature

The differential diagnosis of ankle pain is extensive. Pathology may be classified as intra- or extra-articular. Additionally, ankle pain may be traumatic or non-traumatic. One of the unusual differential diagnoses for pain in the ankle is an accessory muscle. Magnetic resonance imaging is the radiological investigation of choice. However, this is invariably reported as normal unless one specifically looks for an accessory muscle. The purpose of this report is to highlight important features of these muscles and to draw attention to this uncommonly reported condition.

Considerations in footwear and orthotics

This article is based on educating readers and physicians about the use of footwear and orthotics for themselves and their patients, to treat diseases and enhance functionality in sports and daily life.