Dynamic sonography of the forefoot in Morton’s syndrome: correlation with magnetic resonance and surgery

Diagnostic Considerations of Intermetatarsal Bursitis: A Systematic Review

Intermetatarsal bursitis (IMB) is an inflammation of the intermetatarsal bursas. The condition causes forefoot pain with symptoms similar to those of Morton's neuroma (MN). Some studies suggest that IMB is a contributing factor to the development of MN, while others describe the condition as a differential diagnosis. Among patients with rheumatic diseases, IMB is frequent, but the scope is yet to be understood. The aim of this paper was to investigate the diagnostic considerations of IMB and its role in metatarsalgia by a systematic review approach. We identified studies about IMB by searching the electronic databases Pubmed, Embase, Cochrane Library, and Web of Science in September 2022. Of 1362 titles, 28 met the inclusion criteria. They were subdivided according to topic: anatomical studies (n = 3), studies of patients with metatarsalgia (n = 10), and studies of patients with rheumatic diseases (n = 15). We conclude that IMB should be considered a cause of pain in patients with metatarsalgia and patients with rheumatic diseases. For patients presenting with spreading toes/V-sign, IMB should be a diagnostic consideration. Future diagnostic studies about MN should take care to apply a protocol that is able to differ IMB from MN, to achieve a better understanding of their respective role in forefoot pain.

Relationship Between Sensory Symptoms, Mulder's Sign, and Dynamic Ultrasonographic Findings in Morton's Neuroma

BACKGROUND

Morton's neuroma (MN) is often a diagnostic dilemma lacking a gold standard set of diagnostic criteria. Advanced imaging of MN is evolving including ultrasonography. The current study aimed to analyze the relationship between ultrasonographic findings and symptoms, clinical data, and operative findings in a subgroup of patients.

METHODS

We evaluated physical examination, ultrasonographic findings, symptoms, and in a subgroup, the operative findings for Morton's neuroma. We analyzed the symptoms, the findings on physical examination, and ultrasonography data and performed a statistical correlation between them. A total of 175 patients were seen for suspected Morton's neuroma during the last 7 years.

RESULTS

Neuropathic pain of the toes was reported in 63% of patients. Presence of ultrasonographic findings suggesting Morton's neuroma was observed in 77% of cases. A mild significant relationship between neuropathic pain and positive ultrasonographic findings was observed. We found a strong correlation between ultrasonographic and clinical evaluation, but more than half with clinical negative Morton's neuroma had positive findings at ultrasonography. In the subgroup of operatively treated patients (n = 44) surgery confirmed Morton's neuroma in all patients who had positive ultrasonography findings.

CONCLUSIONS

The current study suggests that the association of ultrasonographic evaluation and clinical evaluation can be very useful for the management of Morton's neuroma. Our study could help with the development of a multiperspective approach in the diagnosis of Morton's neuroma.

LEVEL OF EVIDENCE

Level II, prospective cohort survey study.

The effectiveness of shoe modifications and orthotics in the conservative treatment of Civinini-Morton syndrome: state of art

Civinini Morton’s Syndrome (CMS), better known as Morton’s Neuroma, is a benign enlargement that typically affects the third common digital branch of the plantar nerve. It is a common cause of metatarsalgia leading to debilitating pain. It prefers the female gender, with a female to male ratio of 5:1 and an average age of 50 years at time of surgery. Precise aetiology remains under debate, with four etiopathogenetic theories often cited in the literature. Clinical symptoms, physical exam and instrumental evidence are important in assessing and grading the disease. Biomechanics seem to play an important role, especially regarding the usefulness of correct footwear. The first approach in the early stages of this condition usually begins with shoe modifications and orthotics, designed to limit the nerve compression. In order to prevent or delay the development of CMS, shoes should be sufficiently long, comfortable, broad toe-boxed, should bear a flat heel and a sufficiently thick external sole which should not be excessively flexible. Most authors suggested that an insole with medial arch support and a retrocapital bar or pad, just proximal to the metatarsal heads, displaces the pressure sites and can be beneficial to relieve the pain from the pinched nerve. A threshold period of 4.5 months appears to emerge from the results of the analysed studies, indicating that, beyond this period and in neuromas larger than 5-6 mm, orthotics and/or shoes modifications do not seem to give convincing results, proving to be more a palliation for the clinical condition to allow an acceptable life with pain rather than a real treatment. (www.actabiomedica.it)

Mechanical Metatarsalgia as a Risk Factor for Relapse of Morton's Neuroma After Ultrasound-Guided Alcohol Injection

Although many treatment modalities are available for Morton's neuroma, the injection of the neuroma with alcohol has gained popularity. However, recently, some investigators have observed a progressive deterioration in pain scores for patients initially pain free after the treatment. The purpose of the present retrospective comparative study was to determine whether mechanical metatarsalgia is related to symptom recurrence. We included 104 consecutive cases of ultrasound-guided alcohol injection for Morton's neuroma in 92 patients. Of these 104 cases, 51 were in group A (49%; Morton's neuroma) and 53 in group B (51%; Morton's neuroma associated with mechanical metatarsalgia). We evaluated each patient using a visual analog scale and American Orthopaedic Foot and Ankle Society forefoot scale, and Johnson satisfaction scale, with a mean follow-up period of 24 (range 12 to 39) months. Concomitant functional and mechanical disorders have been identified and treated with orthopedic inserts. The present study compared the clinical results and recurrence of symptoms in patients with isolated Morton's disease or Morton's disease associated with mechanical metatarsalgia. Of the 104 cases, the patients for 93 cases (89%) were completely satisfied or satisfied with minor reservations. No major complications developed. Symptoms recurred in 6 patients (6%), in whom neuroma was associated with mechanical disorders (p = .0269). Ultrasound-guided alcohol injection of Morton's neuroma is a relatively safe and well-tolerated treatment. Symptom recurrence is often associated with mechanical metatarsalgia. The treatment of the concomitant anatomical and functional disorders that target the genesis of the neuroma has an important role in the prevention of recurrence of this pathology.

The role of fasciae in Civinini-Morton's syndrome

This study evaluates the pathogenetic role of the perineural connective tissue and foot fasciae in Civinini-Morton's neuroma. Eleven feet (seven male, four female; mean age: 70.9 years) were dissected to analyse the anatomy of inter-metatarsal space, particularly the dorsal and plantar fasciae and metatarsal transverse ligament (DMTL). The macrosections were prepared for microscopic analysis. Ten Civinini-Morton neuromas obtained from surgery were also analysed. Magnetic resonance images (MRIs) from 40 patients and 29 controls were compared. Dissections showed that the width of the inter-metatarsal space is established by two fibrous structures: the dorsal foot fascia and the DMTL, which, together, connect the metatarsal bones and resist their splaying. Interosseous muscles spread out into the dorsal fascia of the foot, defining its basal tension. The common digital plantar nerve (CDPN) is encased in concentric layers of fibrous and loose connective tissue, continuous with the vascular sheath and deep foot fascia. Outside this sheath, fibroelastic septa, from DMTL to plantar fascia, and little fat lobules are present, further protecting the nerve against compressive stress. The MRI study revealed high inter-individual variability in the forefoot structures, although only the thickness of the dorsal fascia represented a statistically significant difference between cases and controls. It was hypothesized that alterations in foot support and altered biomechanics act on the interosseous muscles, increasing the stiffness of the dorsal fascia, particularly at the points where these muscles are inserted. Chronic rigidity of this fascia increases the stiffness of the inter-metatarsal space, leading to entrapment of the CDPN.

Diagnostic Accuracy of Clinical Tests for Morton's Neuroma Compared With Ultrasonography

The aim of the present study was to assess the diagnostic accuracy of 7 clinical tests for Morton's neuroma (MN) compared with ultrasonography (US). Forty patients (54 feet) were diagnosed with MN using predetermined clinical criteria. These patients were subsequently referred for US, which was performed by a single, experienced musculoskeletal radiologist. The clinical test results were compared against the US findings. MN was confirmed on US at the site of clinical diagnosis in 53 feet (98%). The operational characteristics of the clinical tests performed were as follows: thumb index finger squeeze (96% sensitivity, 96% accuracy), Mulder's click (61% sensitivity, 62% accuracy), foot squeeze (41% sensitivity, 41% accuracy), plantar percussion (37% sensitivity, 36% accuracy), dorsal percussion (33% sensitivity, 26% accuracy), and light touch and pin prick (26% sensitivity, 25% accuracy). No correlation was found between the size of MN on US and the positive clinical tests, except for Mulder's click. The size of MN was significantly larger in patients with a positive Mulder's click (10.9 versus 8.5 mm, p = .016). The clinical assessment was comparable to US in diagnosing MN. The thumb index finger squeeze test was the most sensitive screening test for the clinical diagnosis of MN.

Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis

OBJECTIVES

To compare ultrasound (US) and magnetic resonance imaging (MRI) in the diagnosis of Morton's neuroma.

METHODS

Studies that assessed the diagnostic accuracy of US and MRI for Morton's neuroma were retrieved from major medical libraries independently by two reviewers up to 1 April 2014. Predefined inclusion and exclusion criteria were adopted.

RESULTS

277 studies were initially found, and the meta-analysis was conducted on 14 studies. US sensitivity was studied in five studies, MRI sensitivity in three studies, and bothin six studies. All studies used surgery as the reference standard. A high sensitivity (SE) of diagnostic testing was observed for both US (SE (95 % CI) = 0.91 (0.83-0.96)) and MRI (SE (95 % CI) = 0.90 (0.82-0.96)) with no significant differences between the two modalities in diagnosis (Q test p = 0.88). For MRI, specificity of test was 1.00 with a pooled estimation of 1.00 (0.73-1.00), while the pooled specificity was 0.854 (95 % CI: 0.41-1.00) for US. No differences were observed between US and MRI in study design (p = 0.76).

CONCLUSION

This meta-analysis shows that the SE of US (0.91) is equal to (p = 0.88) that of MRI (0.90) for identification of Morton's neuroma.

KEY POINTS

• For Morton's neuroma, US sensitivity is equal to MRI. • US is as accurate as MRI in diagnosing Morton's neuroma. • US may be the most cost-effective imaging method for Morton's neuroma.

The accuracy of ultrasonography and magnetic resonance imaging for the diagnosis of Morton's neuroma: a systematic review

AIM

To determine the accuracy of MRI versus ultrasound for Morton's neuroma.

MATERIALS AND METHODS

A search was undertaken for clinical studies published in any language in PubMed up to the date of December 2013. Studies assessing the accuracy of the ultrasound or MRI for the diagnosis of Morton's neuroma were included. Data were pooled for meta-analysis. Study selection, data collection, and extraction were performed independently by two authors. Meta-disc 1.4 and Revman 5.2 software were applied for statistical analysis.

RESULTS

The study included 12 studies; 217 patients underwent MRI and 241 underwent ultrasound examinations. There appeared greater diagnostic accuracy for ultrasound than MRI for the diagnosis of Morton's neuroma (ultrasound sensitivity 90%, specificity 88%, positive likelihood ratio 2.77, negative likelihood ratio 0.16 versus MRI sensitivity 93%, specificity 68%, positive likelihood ratio 1.89, negative likelihood ratio 0.19).

CONCLUSIONS

The available evidence suggests that ultrasound can provide better accuracy for the diagnosis of Morton's neuroma than MRI.

MRI and ultrasonography in Morton's neuroma: Diagnostic accuracy and correlation

BACKGROUND

The diagnosis of Morton's neuroma is based primarily on clinical findings. Ultrasonography (US) and magnetic resonance image (MRI) studies are considered complementary diagnostic techniques. The aim of this study was to establish the correlation and sensitivity of both techniques used to diagnose Morton's neuroma.

MATERIALS AND METHODS

Thirty seven patients (43 intermetatarsal spaces) with Morton's neuroma operated were retrospectively reviewed. In all cases MRI or ultrasound was performed to complement clinical diagnosis of Morton's neuroma. In all cases, a histopathological examination confirmed the diagnosis. Estimates of sensitivity were made and correlation (kappa statistics) was assessed for both techniques.

RESULTS

Twenty seven women and 10 men participated with a mean age of 60 years. Double lesions presented in six patients. The second intermetatarsal space was affected in 10 patients and the third in 33 patients. An MRI was performed in 41 cases and a US in 23 cases. In 21 patients, both an MRI and a US were performed. With regard to the 41 MRIs performed, 34 were positive for Morton's neuroma and 7 were negative. MRI sensitivity was 82.9% [95% confidence interval (CI): 0.679-0.929]. Thirteen out of 23 US performed were positive and 10 US were negative. US sensitivity was 56.5% (95% CI: 0.345-0.768). Relative to the 21 patients on whom both techniques were carried out, the agreement between both techniques was poor (kappa statistics 0.31).

CONCLUSION

Although ancillary studies may be required to confirm the clinical diagnosis in some cases, they are probably not necessary for the diagnosis of Morton's neuroma. MRI had a higher sensitivity than US and should be considered the technique of choice in those cases. However, a negative result does not exclude the diagnosis (false negative 17%).

Remission of severe restless legs syndrome and periodic limb movements in sleep after bilateral excision of multiple foot neuromas: a case report

Introduction

Restless legs syndrome is a sensorimotor neurological disorder characterized by an urge to move the legs in response to uncomfortable leg sensations. While asleep, 70 to 90 percent of patients with restless legs syndrome have periodic limb movements in sleep. Frequent periodic limb movements in sleep and related brain arousals as documented by polysomnography are associated with poorer quality of sleep and daytime fatigue. Restless legs syndrome in middle age is sometimes associated with neuropathic foot dysesthesias. The causes of restless legs syndrome and periodic limb movements in sleep are unknown, but the sensorimotor symptoms are hypothesized to originate in the central nervous system. We have previously determined that bilateral forefoot digital nerve impingement masses (neuromas) may be a cause of both neuropathic foot dysesthesias and the leg restlessness of restless legs syndrome. To the best of our knowledge, this case is the first report of bilateral foot neuromas as a cause of periodic limb movements in sleep.

Case presentation

A 42-year-old Caucasian woman with severe restless legs syndrome and periodic limb movements in sleep and bilateral neuropathic foot dysesthesias was diagnosed as having neuromas in the second, third, and fourth metatarsal head interspaces of both feet. The third interspace neuromas represented regrowth (or 'stump') neuromas that had developed since bilateral third interspace neuroma excision five years earlier. Because intensive conservative treatments including repeated neuroma injections and various restless legs syndrome medications had failed, radical surgery was recommended. All six neuromas were excised. Leg restlessness, foot dysesthesias and subjective sleep quality improved immediately. Assessment after 18 days showed an 84 to 100 percent reduction of visual analog scale scores for specific dysesthesias and marked reductions of pre-operative scores of the Pittsburgh sleep quality index, fatigue severity scale, and the international restless legs syndrome rating scale (36 to 4). Polysomnography six weeks post-operatively showed improved sleep efficiency, a marked increase in rapid eye movement sleep, and marked reductions in hourly rates of both periodic limb movements in sleep with arousal (135.3 to 3.3) and spontaneous arousals (17.3 to 0).

Conclusion

The immediate and near complete remission of symptoms, the histopathology of the excised tissues, and the marked improvement in polysomnographic parameters documented six weeks after surgery together indicate that this patient's severe restless legs syndrome and periodic limb movements in sleep was of peripheral nerve (foot neuroma) origin. Further study of foot neuromas as a source of periodic limb movements in sleep and as a cause of sleep dysfunction in patients with or without concomitant restless legs syndrome, is warranted.

Neurologic running injuries

Neurologic running injuries account for a small number of running injuries. This may be caused by misdiagnosis or underdiagnosis. Nerve injuries that have been reported in runners include injuries to the interdigital nerves and the tibial, peroneal, and sural nerves. In this article, the etiology, symptoms, diagnosis, and treatment of these injuries are reviewed. Differences between nerve injury and more common musculoskeletal injury have been presented to aid in differential diagnosis.