Anterior tarsal tunnel syndrome

Extensor Retinaculum Syndrome of the Ankle: An Adult Case Series

Background

Extensor retinaculum syndrome (ERS) is a relatively rarely diagnosed compartment syndrome-like entity caused by elevated pressures in the tissues deep to the superior extensor retinaculum (SER). ERS is identified as out-of-proportion anterior ankle pain, pain with passive toe plantarflexion, elevated SER pressures (>40 mm Hg), and ultimately toe extension weakness and first web space numbness. Although previously described in a pediatric population, this case series is the first to our knowledge in an adult population.

Methods

Seven nonconsecutive cases over 18 years from 2 surgeons are reported who underwent complete SER release for ERS either through the direct lateral approach to the fibula or the anterolateral approach to the distal tibia. All were associated with traumatic injuries including 3 bimalleolar ankle fractures, 3 tibial pilon fractures, and 1 distal tibial/fibular shaft fracture. All patients developed writhing anterior ankle pain worsened with passive toe plantarflexion. SER compartment pressures ranged from 50 to >135 mm Hg. Five cases displayed decreased first web space sensation.

Results

The diminished or absent first web space sensation uniformly improved post-release. Complications included 1 patient with complex regional pain syndrome type 1, 1 patient required hardware removal, and 2 had persistent but improved first web space sensation changes.

Conclusion

Clinical suspicion for possible ERS should arise after distal tibial/fibular fractures when the excruciating pain localizes to the ankle instead of the classic anterior leg muscle bellies. If pain is worsened with passive toe plantarflexion, this diagnosis should be considered. Recommended treatment involves complete release of the SER anywhere on the anterior surface between the tibia and fibula depending on the approach needed for fixation of the associated fracture.

Level of Evidence

Level IV, case series.

Unravelling the Anatomy of the Anterior Tarsal Tunnel and Its Clinical Implications

BACKGROUND

Anterior tarsal tunnel (ATT) syndrome is caused by the compression of the deep fibular nerve (DFN) within the ATT beneath the inferior extensor retinaculum, bounded by the tendons of the extensor hallucis longus (EHL) and extensor digitorum longus (EDL). Compression may result from direct trauma, repetitive mechanical irritation, and thrombosis of the dorsalis pedis artery. Injury to the contents of ATT could occur during ankle arthroscopy. Therefore, this study was undertaken to provide a detailed description of the anatomy of the ATT and its clinical implications.

MATERIALS AND METHODS

Ten formalin-fixed cadavers were utilized for the study. The ATT was identified between the tendons of the EHL and EDL. The length at the medial and lateral boundaries and the width at the proximal end, middle, and distal end of the ATT were measured using a digital Vernier calliper.

RESULT

The mean length of the medial border of the tunnel was 31.42±8.44 mm, while the lateral border was 20.39±4.39 mm. The width of the ATT increased from the proximal to the distal end. DFN was related to the DPA laterally in 15 limbs and medially in five limbs within the tunnel.

CONCLUSION

The present study not only describes the intricate anatomy of the ATT but also describes the patterns of DFN and DPA within the tunnel. Understanding the anatomy of ATT is crucial, as it paves the way for safe and efficient surgical interventions, thereby significantly reducing the risk of neurovascular damage during surgical procedures.

Foot Deformity in Patients With Ankylosing Spondylitis: Is It Associated With Functionality and Disease Activity?

Foot involvement affects mobility and functionality in patients with ankylosing spondylitis but it remains unknown if foot deformities in ankylosing spondylitis patients affect functionality, disease activity, and quality of life. The aim of this study was to evaluate in detail the presence of a relationship between radiologically detected foot deformities in ankylosing spondylitis patients and both clinical and electrophysiological findings. The cross-sectional study included 110 patients with ankylosing spondylitis who were diagnosed according to the Assessment in Spondyloarthritis International Society criteria and were followed in our hospital. Demographic and clinical data of all patients were recorded. Bilateral lateral foot x-rays and electrophysiology examinations were evaluated in all subjects. The arch in the dominant foot of the patients was classified in 3 groups as pes cavus, pes planus, or normal. The clinical outcomes, physical examination and electrophysiological findings were compared between the groups, and correlations were examined of the foot deformities with these parameters. Foot deformities were determined at a high rate (74.5%). These deformities affected foot pain, disability and quality of life. Pes cavus deformity was found to be associated with hip pain and enthesopathy. In the electrophysiological studies, the presence of pes planus was found to be associated with the findings of the tibial and sural nerve conduction studies, and the presence of pes cavus with the findings of the peroneal nerve conduction study. In conclusion, foot deformities may have an effect on the quality of life and functionality in ankylosing spondylitis patients.

Partial anterior tunnel syndrome: a retrospective analysis of ultrasound findings in four surgically proven cases

We present the cases of four patients (two men and two women, mean age of 48.5 years) with surgically confirmed partial anterior tarsal syndrome, diagnosed by ultrasound. All patients reported pain in the dorsal aspect of the forefoot radiating to the first intermetatarsal space. Ultrasound showed compression of the medial branch of the deep fibular nerve by the extensor hallucis brevis tendon at the level of the Lisfranc joint, associated with a hypoechoic neuroma. The ultrasound allowed a correct diagnosis to be obtained, which was not evident from clinical examination or by standard radiographs (four patients) or MRI (three patients). Surgery confirmed the sonographic findings, and all patients showed complete recovery.

Mid-foot retinaculum: an unrecognized entity

Retinacula are thickenings of deep fascia in the region of joints that hold down the tendons preventing them from bowing out of position. In the region of ankle, number of such retinacula have been described. Retinacula like superior and inferior extensor retinacula have been described which hold down the tendons of leg muscles passing to the foot beneath them. As the extensor tendons of the leg have more distal attachment to the toes, the present study was conducted to ascertain the presence of any additional retinaculum in the mid-foot region, which would tie down the tendons for their effective action at the distal joints. The aim was also to determine the attachments of the retinaculum, if present as well as the structures passing beneath them. Fifty cadaveric feet were dissected carefully for this purpose. Presence of an additional extensor retinaculum distal to the inferior band of inferior extensor retinaculum in the mid-foot region was found in 22 feet. Besides the extensor tendons, medial terminal branch of deep peroneal nerve and dorsalis pedis artery was found to pass beneath the retinaculum. A partial or complete mid-foot retinaculum existed in the mid-foot region covering the tarsometatarsal joints in about half of study population. Functionally, this retinaculum may prevent bowstringing of the extensor tendons, clinically it may predispose to entrapment of deep peroneal nerve mimicking anterior tarsal tunnel syndrome.

Role of sonography in the diagnosis and treatment of a ganglion cyst compressing the lateral branch of deep peroneal nerve

Selective compression neuropathy of the lateral branch of the deep peroneal nerve is rare. A 55-year-old woman with ankle instability and mild weakness of extension of the toes was examined with sonography (US), which revealed the presence of a ganglion cyst compressing selectively the lateral branch of the deep peroneal nerve. US-guided aspiration of the cyst resulted in nerve decompression and progressive resolution of symptoms. This case demonstrates the importance of examining the deep peroneal nerve and its branches when performing US in the clinical setting of ankle instability. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:108-111, 2017.

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.

Bilateral anterior tarsal tunnel syndrome variant secondary to extensor hallucis brevis muscle hypertrophy in a ballet dancer: a case report

We present a case of bilateral anterior tarsal tunnel syndrome secondary EHB hypertrophy in a dancer, with successful treatment with bilateral EHB muscle excisions for decompression. The bilateral presentation of this case with the treatment of EHB muscle excision is the first of its type reported in the literature.

Endoscopic anterior tarsal tunnel release: a case report

Anterior tarsal tunnel syndrome is a rare entrapment neuropathy of the deep peroneal nerve beneath the inferior extensor retinaculum of the ankle. We report a patient with anterior tarsal tunnel syndrome who was successfully treated with endoscopic anterior tarsal tunnel release. Our endoscopic technique, because it preserves the inferior extensor retinaculum, is potentially less traumatic than traditional surgical techniques for repairing this entrapment neuropathy.

Anterior tarsal tunnel syndrome: a misunderstood and a misleading entrapment neuropathy

Anterior tarsal tunnel syndrome (ATTS) is a rare entrapment neuropathy of the deep peroneal nerve beneath the extensor retinaculum on the top of the ankle. ATTS is often asymptomatic or olygosymptomatic. There are few reports describing the ATTS. We describe the clinical and electrophysiological features of 85 patients with unilateral or bilateral ATTS prospectively collected between January 2000 and December 2010 in our laboratory of Clinical Neurophysiology. This entrapment neuropathy remains poorly diagnosed and it might be misleading when performing a diagnostic EMG-ENG examination for suspected polyneuropathy or lumbosacral radiculopathy.

Clinical importance of the lateral branch of the deep peroneal nerve

Persistent recalcitrant dorsolateral foot pain after ankle sprain cannot always be explained by known anatomic nerve pathways. To determine whether an impingement of a lateral branch of the deep peroneal nerve might be responsible for atypical pain, we conducted a cadaveric anatomic study to identify the anatomy and course of the nerve. Furthermore, using this information, we conducted a clinical study to determine if targeted treatment to a lateral branch of the deep peroneal nerve would resolve these symptoms. We dissected 22 cadaveric feet to identify a large lateral branch of the deep peroneal nerve. This nerve arborized into five main branches. We identified two areas of compression in the lateral branch of the deep peroneal nerve. We also performed a prospective clinical study including 11 consecutive patients with a 1-year minimum followup. Pain and clinical findings corresponded to the anatomic compression sites in all 11 patients. All patients responded to a local anesthetic injection or surgical release of the lateral branch of the deep peroneal nerve. We identified a previously unreported complex course of the lateral branch of the deep peroneal nerve that correlated with clinical impingement syndrome and responded to specifically targeted treatment.

Anterior tarsal tunnel syndrome

Compression of the deep peroneal nerve is commonly referred to as anterior tarsal tunnel syndrome. Although rare, this syndrome remains poorly diagnosed. The syndrome is characterized by pain, weakness, and sensory changes of the foot and ankle. Non-operative measures should be attempted to reduce or remove the external compression along the anterior aspect of the foot and ankle. Other options include shoe modifications, cortisone injections,and physical therapy. If conservative management fails to relieve the symptoms, surgical decompression of the entrapped nerve can be performed. The deep peroneal nerve is released from compressive forces in the entrapment site. This can be performed at the more proximal level at the extensor retinaculum or more distally at the level of the tarsal metatarsal site.

Medial (cutaneous) branch of deep common peroneal nerve: recording technique and a case report

An isolated lesion of the medial branch of the deep common peroneal nerve is rare and so far there do not appear to have been any reports of a recording method or normative data for this sensory action potential (SAP). Just such a case is described along with an appropriate recording technique. Control data were subsequently obtained from 50 normal volunteers.