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.

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.

Tarsal Tunnel Syndrome Associated With a Bipartite Talus.

BACKGROUND: Talus bipartitus is a rare skeletal anomaly that may be mistaken for an os trigonum, a relatively common accessory ossicle found posterior to the talus. Both are believed to be formed similarly with the failed fusion of the talus with a second ossification center. Os trigonum is often diagnosed incidentally or found on radiographs obtained in symptomatic patients with signs of os trigonum syndrome, which presents with posterolateral ankle pain. A bipartite talus may also present with similar symptoms but may be differentiated through its articular involvement. CASE: In this article, we describe the rare presentation of tarsal tunnel syndrome in a patient caused by a bipartite talus. The patient underwent surgical decompression with the removal of the posterior fragment. CONCLUSION: A bipartite talus is a rare entity that may be mistaken for an os trigonum, a common accessory ossicle. In this article, we describe an outcome of a bipartite talus fragment removal due to tarsal tunnel syndrome and illustrate a rare pathological consequence of a bipartite talus. We further highlight the importance of early surgical management in patients presenting with an identifiable structure contributing to tibial nerve compression.

Anterior Tarsal Tunnel Syndrome: Entrapment of the Articular Branch of Deep Peroneal Nerve: A Case Report.

CASE: A 28-year-old male patient who injured his ankle 2 years ago presented with unilateral ankle pain, tingling, and numbness for 1 year. Clinically, tenderness and positive Tinel sign were localized on anterior aspect of ankle. On exploration, deep peroneal nerve and mainly its articular branch were encased in fibrotic tissue. Decompression of both nerves resulted in symptomatic relief after surgery. CONCLUSION: High index of suspicion, a thorough medical history, meticulous clinical examination, complete knowledge of nerve anatomy, proper radiological studies, and careful surgical decompression are all necessary for the diagnosis and management of such atypical cases.

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.

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.

Impact of Dynamic Change of Meandering of Parallel Artery to the Idiopathic Tarsal Tunnel Syndrome.

In idiopathic tarsal tunnel syndrome (TTS), walking seems to make symptoms worse. The findings imply that an ankle movement dynamic component may have an impact on the etiology of idiopathic TTS. We describe how the ankle movement affects the nerve compression caused by the surround tissue, particularly the posterior tibial artery. We enrolled 8 cases (15 sides) that had TTS surgery after tarsal tunnel (TT) MRI preoperatively. Dorsiflexion and plantar flexion were the two separate ankle positions used for the T2* fat suppression 3D and MR Angiography of TT. Based on these findings, we looked at how the two different ankle positions affected the posterior tibial artery's ability to compress the nerve. Additionally, we assessed the posterior tibial artery's distorted angle. We divided the region around the TT into four sections: proximal and distal to the TT and proximal half and distal half to the TT. Major compression cause was posterior tibial artery. Most severe compression point was proximal half in the TT in all cases without one case. In each scenario, the nerve compression worsens by the plantar flexion. The angle of the twisted angle of the posterior tibial artery was significantly worsened by the plantar flexion. In idiopathic TTS, deformation of posterior tibial artery was the primary compression component. Nerve compression was exacerbated by the plantar flexion, and it was attributable with the change of the distorted angle of the posterior tibial artery. This could be a contributing factor of the deteriorating etiology by walking in idiopathic TTS.

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.

A retrospective magnetic resonance imaging analysis of bone and soft tissue changes associated with the spectrum of tarsal coalitions.

We aimed to investigate the bone and soft tissue changes accompanying tarsal coalition (TC) and aimed to evaluate their association with the location and type of coalition. Ankle magnetic resonance imagings of 65 patients with TC were included. The relationship between the location and type of coalition and bone marrow edema, subchondral cysts, sinus tarsi syndrome, tarsal tunnel syndrome, posterior impingement syndrome, accessory bone, tibiotalar effusion, talar osteochondritis dissecans, ganglion cysts, and calcaneal spur were evaluated. Twenty-nine patients without coalition were selected as the control group, and the distribution of these variables between the two groups was analyzed. There were 33 females and 32 males in the coalition group (mean age: 42.0 ± 15.63 years), and 22 females and seven males in the control group (mean age: 44.79 ± 12.33 years). Coalition was most common in the talocalcaneal joint (n = 33, 50.8%), and the most common coalition type was non-osseous (n = 57, 87.6%). We find no significant difference between the pathologies defined in terms of coalition location and type. Sinus tarsi syndrome, tarsal tunnel syndrome, subchondral cysts, and tibiotalar effusion were found to be more common in the coalition group (p = 0.028, p = 0.010, p = 0.023, and p = 0.006, respectively). The presence of coalition increased the probability of developing tarsal tunnel syndrome 9.91 times (95% CI: [1.25-78.59]; p = 0.029), and sinus tarsi syndrome 3.66 times (95% CI: [1.14-11.78]; p = 0.029). Tarsal coalition may predispose bone and soft tissue changes. In this study, sinus tarsi syndrome, tarsal tunnel syndrome, subchondral cysts and tibiotalar effusion were found to be more common in the coalition group.

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.

Magnetic Resonance Imaging Findings in Patients with Tarsal Tunnel Syndrome.

Tarsal tunnel syndrome (TTS) is a common entrapment syndrome whose diagnosis can be difficult. We compared preoperative magnetic resonance imaging (MRI) and operative findings in 23 consecutive TTS patients (28 sides) whose mean age was 74.5 years. The 1.5T MRI sequence was 3D T2* fat suppression. We compared the MRI findings with surgical records and intraoperative videos to evaluate them. MRI- and surgical findings revealed that a ganglion was involved on one side (3.6%), and the other 27 sides were diagnosed with idiopathic TTS. MRI visualized the nerve compression point on 23 sides (82.1%) but failed to reveal details required for surgical planning. During surgery of the other five sides (17.9%), three involved varices, and on one side each, there was connective tissue entrapment or nerve compression due to small vascular branch strangulation. MRI studies were useful for nerve compression due to a mass lesion or idiopathic factors. Although MRI revealed the compression site, it failed to identify the specific involvement of varices and small vessel branches and the presence of connective tissue entrapment.

[An unusual cause of tarsal tunnel syndrome in a 15-year-old girl: about a case]. / Cause inhabituelle de syndrome du canal tarsien chez une fille de 15 ans: à propos d'un cas.

Tarsal tunnel syndrome is a multifaceted condition caused by the compression or lesion of the posterior tibial nerve (PTN) that passes through a retromalleolar osteofibrous canal, the so-called tarsal tunnel. It has multiple etiologies, including peripheral nerve tumors, which must be suspected when this syndrome is resistant to medical treatment and infiltrations. We here report the original case of a 15-year-old girl presenting with tarsal tunnel syndrome revealing neurofibroma of the PTN, misdiagnosed as plantar fasciculitis and S1 radiculopathy.

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.

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.

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.

[Clinical anatomical study on the treatment of tarsal tunnel syndrome with four-point vertical acupotomy].

OBJECTIVE: To explore safety and accuracy of four-point acupotomy for the treatment of tarsal tunnel syndrome regarding release of ankle tunnel flexor retinaculum to provide an anatomical basis of clinical treatment. METHODS: Twenty-nine adult specimens (15 males and 14 females) fixed with 10% formalin, aged from 47 to 98 years old with an average age of (81.10±11.14) years old, 29 on the right side and 29 on the left side, which were selected for the study from September 2020 to October 2020. Simulate the operation of loosening flexor retinaculumt with a needle knife on the human specimen, and place the specimen on the frog position of lower limbs with medial malleolus upward to determine the center of medial malleolus. Choose 4 different positions near the flexor retinaculum to insert the needle so that the needle body was perpendicular to skin and cutting edge direction was perpendicular to the running direction of the flexor retinaculum. The needle knife penetrates the skin and explores slowly. When the flexor retinaculum was reached, the needle tip may touch the tough tissue. At this time, the cutting is loosened for 4 times. After acupotomy release operation was completed, make a lateral incision on the skin surface along acupotomy direction, open the area of the exposed flexor retinaculum, dissecting layer by layer, observe and record the needle knife and its surrounding anatomical structure. The length of acupotomy cutting marks of flexor retinaculum was measured by electronic vernier caliper. The safety and accuracy of acupotomy loosening of ankle canal flexor retinaculum were evaluated by observing the number and degree of ankle canal contents such as tendons and nerves injured by needle knife. The safety is to count the number of cases of acupotomy injury to the contents of the ankle canal, and to calculate the injury rate, that is, the number of injury cases/total cases × 100%. The effective release was defined as the release length L ≥ W/2(W is the width of the flexor retinaculum, defined as 20 mm). RESULTS: For safety, there were no acupotomy injuries to nerves or blood vessels in 58 cases, 26 cases injuried to posterior tibial tendon which 17 of these tendon injury cases, the tendon was penetrated and severely injured, and flexor digitorum longus tendon was injured in 12 cases. Among these cases, tendon was penetrated and severely injured in 4 cases, and total injury rate was 32.14%. No nerve and vessel injury on c3 and c4 point. For accuracy, 58 specimens were successfully released. The length Lc of releasing trace for acupotomy was (10.40±1.36) cm, and length range 6.38 to 12.88 cm. Among all cases, the length of releasing trace was ≥10 mm in 37 cases. The overall success rate of release was 100.00%. Layered structure of ankle tube flexor retinaculumt:fiber diaphragm from flexor retinaculum divides contents of ankle tube into different chambers inward, and fiber diaphragm meets here to synthesize a complete flexor retinaculum at the midpoint of the line between the medial malleolus tip and calcaneal tubercle(above the neurovascular course). CONCLUSION: Four-point needle-knife method of releasing flexor retinaculum for the treatment of tarsal tunnel syndrome is performed at the attachment of the two ends of flexor retinaculum;the tendon, but not the nerves and blood vessels, is easily damaged. It is safe to insert needle on the side of calcaneus. The extent of release is relatively complete, but due to the "layered" structure of the flexor retinaculum, classic surgical technique could only release one layer of flexor retinaculum when a needle is inserted at the edge of the bone and cannot achieve complete release of the full thickness of the flexor. Therefore, it remains to be determined whether the desired effect can be achieved clinically.