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

Ultrasound identification of hand and wrist anatomical structures by hand surgeons new to ultrasonographic techniques

PURPOSE

Ultrasound is becoming an essential tool for hand surgeons, but most of them are trained on the job, without any diploma or dedicated training. The aim of this study was to assess the ability of hand surgeons new to ultrasound to identify hand and wrist anatomical structures.

METHODS

A monocentric study was conducted from January 2022 to April 2022. Ten residents and five attending hand surgeons, ultrasound novices, were involved in this study. The participants underwent two tests, wherein they were required to identify 17 anatomical structures using ultrasound, on the same subject. The second test was similar and carried out 2 to 6 weeks later by all participants. The number of structures successfully identified and if it was the case, the detection time per structure, were recorded. The correlations between participants age, years of surgical experience, surgical background (orthopedic or plastic) and the ability to perform immediately during the first test or to progress between the two tests were also assessed.

RESULTS

The average number of structures identified during the first test (T1) was 14.1+/-2.1 (82.9%), versus 16.2+/-0.8 (95.3%) structures during the second test (T2) (p = 0.001). The mean detection time per structure was 53.4 +/- 18.9 s during T1 versus 27.7 +/- 7.2 s during T2 (p < 0.0001). A moderate negative correlation between the progression in the number of anatomical structures identified between the two tests and the years of surgical experience (ρ=-0.56; p = 0.029) was found. The other parameters were neither correlated with the ability to perform at the first test nor with the progression between the two tests.

CONCLUSION

Hand surgeons new to ultrasound are most of the time able to identify hand and wrist anatomical structures. Comparison of their first and second tests showed significant potential for improvement in anatomical structure identification and detection time of those, especially in surgeons with limited surgical experience.

What is the place of ultrasound in MSK imaging?

During the past four decades, ultrasound has become popular as an imaging modality applied to the musculoskeletal (MSK) system, particularly outside the USA, due to its low cost, accessibility, and lack of ionizing radiation. A basic requirement in performing these examinations is to have a core group of radiologists and ultrasound technologists with expertise in MSK ultrasound. The extent to which ultrasound will be part of the imaging offered by a particular radiology practice or in an academic institution will vary according to expertise, availability, and reimbursements. A brief discussion of the technical capabilities of the current generation of ultrasound scanners will be followed by a description of some of the more prevalent MSK ultrasound imaging applications. The extent to which training to perform these exams within and outside of Radiology plays a role is discussed. Applications that are unique to ultrasound, such as dynamic evaluation of musculoskeletal anatomy and some, US-guided interventions are an important part of MSK imaging. Ultrasound is increasingly important in the assessment of superficial structures, such as tendons, small joints, and peripheral nerves. These applications help to establish the place of ultrasound as an important part of the Radiologists approach to MSK imaging. Outside of radiology, for a variety of clinical subspecialties, ultrasound already plays an integral role in MSK imaging.

Post-traumatic radial nerve neuroma: A case report

Introduction

Radial nerve neuromas (RNNs) are mostly post-traumatic conditions that occur after a complete or partial section of a nerve. Here we report a case of post-traumatic RNN with good functional progression after intense physical rehabilitation.

Case presentation

A 49 years old patient with a post-complete section of the radial nerve underwent intensive physical rehabilitation with two sessions of ultrasound-guided injections of 10 % glucose saline around the neuroma. 12 months later, the patient improved his wrist and hand finger extension functions.

Conclusion

Several surgical and non-surgical therapies have been proposed for the treatment of neuromas. However, no consensus currently exists, and management is frequently adapted to each patient.

Comparing Clinical Examination and Radiological Evaluation in the Preoperative Diagnosis and Location of Symptomatic Interdigital (Morton's) Neuroma

This study investigates whether clinical examination is as sensitive as ultrasound and magnetic resonance imaging (MRI) in the diagnosis and localization of symptomatic interdigital neuroma. A retrospective cohort study was conducted at two tertiary centers on all consecutive patients who underwent excision by a single foot and ankle specialist surgeon for a presumed interdigital neuroma between January 2008 and December 2020. Investigators collected preoperative clinical findings, radiological investigations, and postoperative outcomes. Sensitivity and positive predictive values were calculated and Z-score for 2 populations proportions was performed. One hundred fourteen consecutive patients were operated on for 131 suspected interdigital neuroma. Thirteen patients were excluded due to lack of adequate clinical documentation. Of the remaining 101 patients with 118 suspected interdigital neuroma, 115 were confirmed histologically (97.5%). The sensitivity of clinical assessment to accurately diagnose and place an interdigital neuroma in the correct space was calculated as 96.5%. The most common preoperative clinical feature was pain (99.2%). The calculated sensitivity for ultrasound to accurately diagnose an interdigital neuroma was 83.6%, and to correctly locate neuroma was 79.5% respectively, which were both statistically different compared to clinical assessment (p value: <.001 and p value: <.001). The calculated sensitivity for MRI to accurately diagnose an interdigital neuroma was 93.6%, which was statistically different to clinical assessment (p value: .005). Preoperative clinical assessment has the highest sensitivity to accurately diagnose interdigital neuroma when compared to MRI and ultrasound. Preoperative clinical assessment has higher sensitivity to accurately locate interdigital neuroma when compared to ultrasound.

Regenerative peripheral nerve interface reduces the incidence of neuroma in the lower limbs after amputation: a retrospective study based on ultrasound

BACKGROUND

Amputees suffer from symptomatic neuroma and phantom limb pain. Regenerative peripheral nerve interface (RPNI) has recently been regarded as an effective method to prevent neuroma after amputation. However, the verifications of RPNI efficacy are mostly based on subjective evaluation, lacking objective approaches. This study aims to unveil the effect of RPNI on preventing neuroma formation and provide evidence supporting the efficacy of RPNI based on ultrasound.

METHODS

Amputees of lower limb at Peking University People's Hospital from July 2020 to March 2022 were analyzed retrospectively. The clinical data collected consisted of general information, pathology of primary disease, history of limb-salvage treatment, amputation level of nerve, pain scales such as the Numerical Rating Scale (NRS) and the Manchester Foot Pain and Disability Index (MFPDI). Three months after amputation, the transverse diameter, anteroposterior diameter, and cross-sectional area of neuromas in stump nerves at the end of residual limbs were measured using ultrasound and compared to adjacent normal nerves.

RESULTS

Fourteen patients were enrolled in the study, including 7 in the traditional amputation group (TA group) and 7 in the RPNI group. There was no significant difference in basic information and amputation sites between the two groups. The NRS and MFPDI scores of patients in RPNI group were significantly lower than those in TA group, and decreased with the follow-up time increasing, indicating that RPNI could reduce symptomatic neuroma pain. The comparison of preoperative ultrasound and postoperative pathology showed ultrasound could reflect the size of neuroma in vivo. Independent-sample t tests indicated that the ratios of anteroposterior diameter, transverse diameter and area of the cross section of both the neuroma and adjacent normal nerve obtained via ultrasound were significantly reduced in the RPNI group.

CONCLUSION

This study suggested that RPNI can effectively prevent the formation of symptomatic neuroma after amputation using ultrasound.

Is Morton's neuroma in a pes planus or pes cavus foot lead to differences in pressure distribution and gait parameters?

Morton's neuroma (MN) is a compressive neuropathy of the common digital plantar nerve causing forefoot pain. Foot posture and altered plantar pressure distribution have been identified as predispoing factors, however no studies have compared individuls with different foot postures with MN. Thus, we aimed to compare the effect of MN on spatiotemporal gait parameters and foot-pressure distribution in individuals with pes planus and pes cavus. Thirty-eight patients with unilateral MN were evaluated between June and August 2021. Nineteen patients with bilateral pes planus and 19 age and gender-matched patients with pes cavus who had no prior surgery were recruited. A Zebris FDM-THM-S treadmill system (Zebris Medical GmbH, Germany) was used to evaluate step length, stride length, step width, step time, stride time, cadence, velocity, foot-pressure distribution, force and whole stance phase, loading response, mid stance, pre-swing and swing phase percentages. There were no significant differences between the groups in spatiotemporal gait parameters (p > 0.05). Patients with pes planus displayed the following results for step length (49.36 ± 8.38), step width (9.05 ± 2.12), stance phase percentage (65.92 ± 2.11), swing phase percentage (34.08 ± 2.12), gait speed (2.96 ± 0.55), and cadence (100.57 ± 8.84). In contrast, patients with pes cavus displayed the following results for step length (49.06 ± 8.37), step width (8.10 ± 2.46), stance phase percentage (64.96 ± 1.61), swing phase percentage (34.79 ± 1.60), gait speed (2.95 ± 0.65), and cadence (99.73 ± 13.81). Foot-pressure distribution values showed no differences were detected in force, forefoot, and rearfoot pressure distribution, except for midfoot force (p < 0.05). The forefoot, midfoot, and rearfoot pressure values for the pronated group were 32.14 ± 10.90, 13.80 ± 3.03, and 22.78 ± 5.10, and for the supinated group were 33.50 ± 11.49, 14.23 ± 3.11 and 24.93 ± 6.52. MN does not significantly affect spatiotemporal gait parameters or foot-pressure distribution in patients with pes cavus or pes planus.

Differential Diagnosis of Metatarsalgia

Lesser (or central) metatarsalgia is defined as pain in the forefoot under or around the lesser metatarsals and their respective metatarsophalangeal joints. Two common causes of central metatarsalgia are Morton's neuroma (MN) and plantar plate (PP) injury. Because both clinical and imaging features overlap, establishing the correct differential diagnosis may be challenging. Imaging has a pivotal role in the detection and characterization of metatarsalgia. Different radiologic modalities are available to assess the common causes of forefoot pain, so the strengths and weakness of these imaging tools should be kept in mind. It is crucial to be aware of the pitfalls that can be encountered in daily clinical practice when dealing with these disorders. This review describes two main causes of lesser metatarsalgia, MN and PP injury, and their differential diagnoses.

MR Imaging–Ultrasonography Correlation of Acute and Chronic Foot and Ankle Conditions

Foot and ankle injuries are common musculoskeletal disorders. In the acute setting, ligamentous injuries are most common, whereas fractures, osseous avulsion injuries, tendon and retinaculum tears, and osteochondral injuries are less common. The most common chronic and overuse injuries include osteochondral and articular cartilage defects, tendinopathies, stress fractures, impingement syndromes, and neuropathies. Common forefoot conditions include traumatic and stress fractures, metatarsophalangeal and plantar plate injuries and degenerations, intermittent bursitis, and perineural fibrosis. Ultrasonography is well-suited for evaluating superficial tendons, ligaments, and muscles. MR imaging is best for deeper-located soft tissue structures, articular cartilage, and cancellous bone.

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.

The Vulcan salute sign: a non-sensitive but specific sign for Morton's neuroma on radiographs

OBJECTIVES

To assess the value of the divergence of toes on conventional radiographs of the foot for diagnosing Morton's neuroma.

METHODS

This retrospective case-control study was approved by the local ethics committee. In 100 patients with MRI-proven Morton's neuroma 2/3 or 3/4 (study group) and 100 patients without (control group), conventional weight-bearing dorso-plantar view radiographs were evaluated for the subjective presence of interphalangeal divergence, called the Vulcan salute sign or V-sign, by two blinded, independent musculoskeletal radiologists. Interphalangeal angles (2/3 and 3/4) and intermetatarsal angle I/V were measured. The t test and chi-squared test were used to compare the groups. Diagnostic performance was calculated. Interobserver reliability was assessed using κ statistics and intraclass correlation coefficient (ICC).

RESULTS

The difference between the groups was significant (P < 0.05) regarding the presence of the V-sign, which was found in 30 of 100 patients with Morton neuroma and in 3 of 100 control patients, with a sensitivity of 30% and a specificity of 97%. The differences between interphalangeal angles were significant (P < 0.05) between the groups. The interphalangeal angle 2/3 mean values were 7.9° (± 4.8) for the study group vs 5.4° (± 2.6) for the controls; the 3/4 angle values were 6.5° (± 3.8) and 3.4° (± 2.5), respectively. There was no significant difference between the groups in the intermetatarsal angle I/V. Interobserver agreement was substantial for the V-sign, with a κ value of 0.78. The ICC was excellent concerning angle measurements, with all values ≥ 0.94.

CONCLUSION

The Vulcan salute sign on conventional radiographs is specific for Morton's neuroma.

The interphalangeal angle as a novel radiological measurement tool for Morton's neuroma - a matched case-control study

BACKGROUND

The aim of this retrospective study was to examine if a correlation between Morton's Neuroma (MN) and an increased interphalangeal angle (IPA) or intermetatarsal angle (IMA) can be found in preoperative weightbearing dorsal-plantar X-rays of the foot.

METHODS

Forty-five patients with forty-nine MN in the interspaces 2/3 or 3/4 and 49 controls were recruited for this study. Every MN was matched with an asymptomatic control without history of metatarsalgia. The diagnosis was made by clinical examination, magnetic resonance imaging (MRI) and positive histopathology after operative resection. IMA 1/5, 2/3, 2/4, 2/5, 3/4 and IPA 2/3, 3/4 were measured for both groups.

RESULTS

The IPA 3/4 was significantly enlarged by 2.8 degrees (p < 0.001) with Area under the curve (AUC) 0.75 (p < 0.001), sensitivity of 73% and specificity of 67% in feet with MN compared to controls. The IMA 3/4 was significantly enlarged by 1 degree (p < 0.048) with AUC 0.64 (p < 0.031), sensitivity of 71% and specificity of 43% in feet with MN compared to controls. No difference between IMA 2/4, 2/5, 1/5 or correlation between IPA or IMA and the size of the MN in the MRI was found.

CONCLUSION

The results confirm the clinical observation of an increased IPA in patients with MN. An increased IPA should therefore be considered in the diagnosis of MN.

A problem-based approach in musculoskeletal ultrasonography: central metatarsalgia

Ultrasonography (US) is a useful diagnostic method that can be easily applied to identify the cause of metatarsalgia. The superficial location of structures in the foot, dynamic capability of US, and the ability to perform direct real-time evaluations of the pain site are also strong advantages of US as a modality for examining the foot. Moreover, knowing the possible pain sources to investigate when a patient has a specific site of pain will enhance the diagnostic quality of US, and will help radiologists to perform US efficiently and effectively. The purpose of this article is to review the common etiologies of metatarsalgia including Morton’s neuroma, plantar plate injury, synovitis, tenosynovitis, bursitis, and metatarsal fractures, and to discuss their US features.

Fascial Manipulation Technique in the Conservative Management of Morton's Syndrome: A Pilot Study

Background and Objective: Morton’s syndrome (MS) is a common cause of neuropathic chronic forefoot pain, characterised by the development of a swelling of the common digital plantar nerve, whose aetiology is not fully known. There is currently no gold standard of treatment; nonoperative management commonly involves manual therapies, orthoses therapy and infiltrative techniques, while surgery is indicated after failure of conservative measures. The present preliminary study prospectively evaluates patients affected by MS treated by Fascial Manipulation technique (FM), a noninvasive manual therapy, focused on the release of the deep fascia, reducing its stiffness. Materials and Methods: Patients with clinical and sonographic diagnosis of MS with at least a 4-month history of neuropathic symptoms underwent a cycle of three weekly FM sessions. Clinical follow-up, including VAS and AOFAS scores, was performed 21 days (T1) and 3 months (T2) after treatment. Results: Nine patients, among 28 recruited initially, completed the manual therapy sessions and relative follow-up points. This noninvasive pain treatment led to significant improvement of VAS (p = 0.0034) and AOFAS scores (p = 0.0240) at the first follow-up (T1). At 3-month follow-up (T2), both scores decreased slightly, remaining however superior to the pre-treatment values. Only VAS was still significant (p = 0.0184). Conclusions: Despite the small size of the case series, this pilot study is unique in supporting Fascial Manipulation in the nonoperative treatment of MS. Further studies are needed with a large cohort of gender balanced patients to confirm the encouraging results obtained.

Neuromas and postamputation pain

Postamputation stump and phantom pain are highly prevalent but remain a difficult condition to treat. The underlying mechanisms are not fully clarified, but growing evidence suggests that changes in afferent nerves, including the formation of neuromas, play an important role. The main objective of this cross-sectional study was to investigate whether ultrasound-verified neuroma swellings are more frequent in amputees with postamputation pain than in amputees without pain (primary outcome). Sixty-seven amputees were included. Baseline characteristics including the frequency and intensity of spontaneous stump and phantom pain were obtained, and sensory characteristics and evoked responses were assessed. A high-frequency ultrasound examination of the amputated extremity was performed to obtain information on the presence, size, and elasticity of swollen neuromas and pressure pain thresholds. Swollen neuromas were present in 53 (79.1%) of the 67 amputees included in the study, in 47 (82.5%) of 57 amputees with pain and in 6 (60.0%) of 10 amputees without pain (P = 0.2). No difference was found in stump pain intensity (P = 0.42) during the last week or in phantom pain intensity in the last month (P = 0.74) between amputees with and without swollen neuromas. Our findings suggest that it is not the presence of swollen neuromas itself that drives postamputation pain. However, changes in the transected nerve endings may still be crucial for driving postamputation pain because a positive Tinel sign was significantly more frequent in amputees with pain, irrespectively of the degree of neuroma swelling.

First webspace Morton's neuroma case report with literature review

Morton's neuromas are benign lesions of the inter-digital nerves within the foot. They are most commonly found in the second and third webspace. Morton's neuroma of the first webspace is very rare. A case of a 42-year-old female who presented complaining of long standing forefoot pain is presented. The patient was diagnosed with a soft tissue tumor in the 1st webspace. An excisional biopsy of the tumour confirmed a Morton's neuroma. Very few cases of Morton's neuroma in the first webspace have been reported in the literature.

[Sonography of the foot in rheumatology : Ultrasound diagnostics of the ankle joint and foot in the rheumatological routine]

Ultrasound examination of the joints is an essential component of diagnostics in rheumatology. Due to its easy accessibility, excellent image definition of soft tissue and bone surfaces with standardized scan sections and scoring systems, ultrasound examination of the joints enables decisions to be made on early and differential diagnostics, treatment monitoring and prognosis. Involvement of the ankle and foot is a common problem in both inflammatory and degenerative rheumatological diseases. Persisting inflammatory processes and bone destruction increase the burden of disease by causing a loss of mobility due to pain. As treatment is often prolonged it is an important issue for both the quality of life of affected patients and a burden on the resources of the healthcare system. The anatomical characteristics of the foot make it difficult to draw diagnostic conclusions by physical examination only. These diagnostic gaps in the remaining rheumatological questions can often be answered by ultrasound examination of the joint.

Morton's neuroma: review of anatomy, pathomechanism, and imaging

Morton's neuroma is a commonly encountered cause of forefoot pain, which may limit weight-bearing activities and footwear choices. Although the aetiology and pathomechanism of this condition is controversial, the histological endpoint is well established as benign perineural fibrosis of a common plantar digital nerve, typically within the third intermetatarsal space. The diagnosis of Morton's neuroma is mainly based on characteristic symptoms and clinical findings, but may be confirmed by ultrasonography. Although ultrasound is a highly accurate diagnostic tool for Morton's neuroma, it is subject to interoperator variability due to differences in technique and level of experience. In this paper, the authors review the anatomy of the common plantar digital nerves and surrounding structures in the forefoot, which are deemed relevant to the understanding of Morton's neuroma, especially from a sonographic point of view. Several theories of the pathomechanism of Morton's neuroma are briefly discussed. The main purpose of this article is to illustrate the ultrasound techniques for evaluating Morton's neuroma and performing ultrasound-guided corticosteroid injections.

ACR Appropriateness Criteria® Chronic Foot Pain

Chronic foot pain is a frequent clinical complaint, which can significantly impact the quality of live in some individuals. These guidelines define best practices with regards to requisition of imaging studies based on specific clinical scenarios, which have been grouped into different variants. Each variant is accompanied by a brief description of the usefulness, advantages, and limitations of different imaging modalities. The present narrative is the result of an exhaustive assessment of the available literature and a thorough review process by a panel of experts on Musculoskeletal Imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Ultrasound-Guided Decompression of the Intermetatarsal Nerve for Morton's Neuroma: A Novel Closed Surgical Technique

BACKGROUND

This study describes the technique for decompression of the intermetatarsal nerve in Morton's neuroma by ultrasound-guided surgical resection of the transverse intermetatarsal ligament. This technique is based on the premise that Morton's neuroma is primarily a nerve entrapment disease. As with other ultrasound-guided procedures, we believe that this technique is less traumatic, allowing earlier return to normal activity, with less patient discomfort than with traditional surgical techniques.

METHODS

We performed a pilot study on 20 cadavers to ensure that the technique was safe and effective. No neurovascular damage was observed in any of the specimens. In the second phase, ultrasound-guided release of the transverse intermetatarsal ligament was performed on 56 patients through one small (1- to 2-mm) portal using local anesthesia and outpatient surgery.

RESULTS

Of the 56 participants, 54 showed significant improvement and two did not improve, requiring further surgery (neurectomy). The postoperative wound was very small (1-2 mm). There were no cases of anesthesia of the interdigital space, and there were no infections.

CONCLUSIONS

The ultrasound-guided decompression of intermetatarsal nerve technique for Morton's neuroma by releasing the transverse intermetatarsal ligament is a safe, simple method with minimal morbidity, rapid recovery, and potential advantages over other surgical techniques. Surgical complications are minimal, but it is essential to establish a good indication because other biomechanical alterations to the foot can influence the functional outcome.

Ginkgoblatt oder Pfifferling – Sonomorphologie von Morton-Neuromen

Bei der Morton-Metatarsalgie handelt es sich um ein chronisches Kompressionssyndrom der distalen Nn. digitales plantares des N. tibialis zwischen den Köpfchen der Mittelfuβknochen. Betroffen sind am häufigsten die Nervenäste zwischen den Ossa metatarsalia III und IV, weniger häufig II und III, noch seltener in den übrigen Zwischenräumen. Das pathologische Korrelat dieser Störung sind die sog. Morton-Neurome als gutartige Verdickungen der kleinen Nerven in diesem Bereich. Sinnvolle elektrophysiologische Untersuchungen zur Diagnostik der daraus resultierenden Morton-Metatarsalgie existieren nicht, sodass den bildgebenden Verfahren eine besondere Bedeutung zukommt, neben der Kernspintomografie besonders die Nervensonografie, die mit relativ geringem Aufwand kostengünstig auch in einer neurologischen Praxis oder einer Funktionsabteilung durchgeführt werden kann. Die Sensitivität von Nervensonografie und Kernspintomografie scheint etwa gleich hoch zu sein, möglicherweise ist die Nervensonografie sogar in der Spezifität überlegen 1 5.

Interdigital Commissural Approach for Morton's Neuroma

BACKGROUND

Morton's neuroma is a frequent cause of metatarsalgia. Operative treatment is indicated if nonoperative management has failed. The objective of the present study was to describe a technique of Morton's neuroma excision by a minimally invasive commissural approach and evaluate the long-term outcome and complications.

METHODS

A retrospective study of 108 patients with Morton's neuroma treated surgically with a commissural approach between September 1990 and December 2010 was performed. The surgical technique is described. Clinical outcomes and complications were evaluated. The average follow-up was 121 months. Eleven patients were men and 97 women. The average age was 49.4 years; 56.8% neuromas were at the third space and 43.2% at the second space. Six patients presented 2 neuromas in the same foot, and 9 patients had bilateral neuroma.

RESULTS

The visual analog scale (VAS) average pain score was 5.4 points preoperatively and 0.2 points at the final follow-up. The author found a significant difference between the VAS scores preoperatively and postoperatively (P < .01). Excellent and good satisfaction outcomes were achieved in 93.6%. The postoperative complication incidence was 3%.

CONCLUSION

The author believes a minimally invasive commissural approach has advantages over a dorsal or plantar incision. It is a simple and reproducible technique, with satisfactory outcomes, low complication rates, and a quick return to usual activities.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Anterocentral Portal in Ankle Arthroscopy

BACKGROUND

The anterocentral portal is not a standard portal in anterior ankle arthroscopy due to its proximity to the anterior neurovascular bundle. However, it provides certain advantages, including a wide field of vision, and portal changes become redundant. The purpose of this study was to evaluate the neurovascular complications after anterior ankle arthroscopy using the anterocentral portal.

METHODS

We retrospectively identified patients who had undergone anterior ankle arthroscopy with an anterocentral portal at our institution from 2013 to 2018. Medical record data were reviewed and patients were invited for clinical follow-up, where a clinical examination, quantitative sensory testing for the deep peroneal nerve, and ultrasonography of the structures at risk were performed. A total of 101 patients (105 arthroscopies) were identified and evaluated at a mean follow-up of 31.5 ± 17.7 months.

RESULTS

Leading indications to surgery were heterogeneous and included anterior impingement (48.6%), osteochondral lesions of the talus (24.8%), chronic ankle instability (14.3%), and fractures (8.6%). The overall complication rate was 7.6%, and no major complications were observed. In 1.9% (2/105) of the cases, the complications were associated with the anterocentral portal and included injury to the medial branch of the superficial nerve (1/105) and to the deep peroneal nerve (1/105). Injury to the deep peroneal nerve was associated with a loss of detection and nociception. There were no injuries to the anterior tibial artery. In 41.9% (44/105) of the cases, only 1 working portal was used in addition to the anterocentral portal, and in 19% (20/105) the anterolateral portal could be avoided. Ultrasonography confirmed the integrity of the deep peroneal nerve, the medial branch of the superficial peroneal nerve, and the anterior tibial artery in all patients. Patients with nerve injuries associated with the anterocentral portal showed no signs of neuroma or pseudoaneurysm.

CONCLUSION

Using a standardized technique, the anterocentral portal in ankle arthroscopy is safe with a low number of neurovascular injuries and can be recommended as a standard portal. The anterolateral portal remains associated with a high number of injuries to the superficial peroneal nerve.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Intra- and Interobserver Reliability of Size Measurement of Morton Neuromas on Sonography

OBJECTIVES

Sonography is often used for analysis of Morton neuromas, but the measurement reliability is unknown. The aim of this study was to determine the intra- and interobserver reliability and precision of sonographic measurement of Morton neuromas.

METHODS

Three observers with different levels of sonography experience (observer A, expert; observer B, intermediate; observer C, beginner) performed repeated measurements of the size of Morton's neuroma in 20 patients. Intraclass correlation coefficient and limit of agreement were used to evaluate reliability and measurement precision.

RESULTS

The intraclass correlation coefficient for intraobserver reliability was 0.80, 0.71, and 0.43 (limit of agreement, 20%, 18%, and 47%) in observers A, B, and C, respectively. The intraclass correlation coefficient for interobserver reliability was 0.72, 0.38, and 0.38 (limit of agreement, 25%, 36%, and 35%) between observers A/B, A/C, and B/C, respectively.

CONCLUSIONS

The intra- and interobserver reliability values for sonographic measurement of Morton neuroma size were dependent on observer experience. Experienced observers had higher reliability, while observers who were less familiar with sonography showed moderate to low reliability.

Value of Preoperative Imaging and Intraoperative Histopathology in Morton's Neuroma

BACKGROUND

Recent studies have demonstrated that clinical diagnosis of Morton's neuroma is highly correlated with operative and histopathologic diagnosis, whereas others have questioned the cost-effectiveness of intraoperative histopathology of excised specimens. The purpose of this study was to determine the utility of both preoperative imaging and intraoperative histology in the treatment of Morton's neuroma in making an accurate diagnosis, guiding treatment decisions, and altering clinical outcomes.

METHODS

A retrospective review was performed on all patients who underwent operative resection suspected Morton's neuroma with 4 fellowship-trained foot and ankle surgeons between 2007 and 2017. Procedures were excluded from the study if the pathology report was not available for review. Diagnoses were made either by clinical examination and/or by the results of preoperative imaging. All pathology reports were reviewed to determine the final diagnosis, considered the "gold standard." Postoperative chart notes were reviewed to determine if any treatment regimen was altered based on the pathology report revealing an alternate diagnosis other than Morton's neuroma. Two hundred eighty-seven procedures in 269 patients with 313 clinically suspected neuromas met inclusion criteria.

RESULTS

Of the 313 suspected neuromas, 309 (98.7%) were confirmed Morton's neuromas on histopathologic examination. For no patient did the results of the pathology report alter the postoperative treatment course. Preoperative imaging results were available for 179 (57.2%) suspected neuromas, with magnetic resonance imaging (MRI) and ultrasonography used to preoperatively image 121 and 71 suspected neuromas, respectively, including 13 using both. The total estimated cost of histopathologic analysis for the cohort was $143 667, and the estimated combined cost of preoperative imaging and intraoperative histopathology in our cohort totaled $278 567.

CONCLUSION

Our study found that the diagnosis of Morton's neuroma could be made clinically with extreme accuracy and positive predictive value, calling into question the utility and costs of other imaging modalities and intraoperative sampling for histopathologic diagnosis.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Prediction of Clinical Prognosis according to Intermetatarsal Distance and Neuroma Size on Ultrasonography in Morton Neuroma: A Prospective Observational Study

OBJECTIVES

This study aims to evaluate the clinical importance of intermetatarsal distance, size of neuroma, and proportion of neuroma in the intermetatarsal space in examinations of Morton neuroma using ultrasonography.

METHODS

Clinical prognosis was observed prospectively after corticosteroid injections in 136 patients with Morton neuroma, and the results were compared with ultrasonographic parameters of intermetatarsal distance, size of neuroma, and proportion of neuroma in the intermetatarsal space.

RESULTS

Twenty-one patients (15%) did not respond to corticosteroid injections and underwent surgical treatment for Morton neuroma. Logistic regression analysis and receiver operating characteristic curve analysis showed that the size of the neuroma was the sole predictor of failure of corticosteroid injections (P = .002). No other factors were significant for the prediction of clinical prognosis (P > .05).

CONCLUSIONS

The size of the neuroma on ultrasonography is the sole predictor of corticosteroid injection failure, while intermetatarsal distance and proportion of neuroma in the intermetatarsal space are not significant when predicting clinical prognosis of Morton neuroma.

Role of imaging methods in diagnosis and treatment of Morton's neuroma

Among the many causes of forefoot pain, Morton's neuroma (MN) is often suspected, particularly in women, due to its high incidence. However, there remain controversies about its relationship with symptomatology and which diagnostic and treatment choices to choose. This article mainly focuses on the role of the various imaging methods and their abilities to support an accurate diagnosis of MN, ruling out other causes of forefoot pain, and as a way of providing targeted imaging-guided therapy for patients with MN.

Short term comparison between blind and ultrasound guided injection in morton neuroma

OBJECTIVE

The aim of this work is to compare the effectiveness of blind and ultrasound-guided injection for Morton's neuroma (MN) to determine which is more appropriate as the initial procedure in conservative treatment.

METHODS

This is an evaluator-blinded randomised trial. Of the 56 included patients, 27 were assigned to the blind group (A) and 29 to the ultrasound-guided group (B). Injection includes 1 ml of 2% mepivacaine and 40 mg of triamcinolone in each web space with MN. The included patients were assessed clinically by VAS score and the Manchester Foot Pain and Disability Score (MFPDS). The follow-up was performed at 15 days, 1 month, 45 days, 2 months, 3 months and 6 months after the initial injection.

RESULTS

No differences in age or clinical measurements were found at presentation between group A and group B. At the follow-up, the ultrasound-guided group showed greater symptomatic relief at several stages of the follow-up: 45 days (VAS 3.0 ± 0.5 versus 5.5 ± 0.5, p = 0.001; MFPDS: 32.2 ± 1.8 versus 38.8 ± 2.0, p = 0.018), 2 months (VAS: 3.1 ± 0.5 versus 5.6 ± 0.5, p = 0.002; MFPDS: 31.5 ± 1.9 versus 38.5 ± 2.1, p = 0.020) and 3 months (VAS: 3.1 ± 0.4 versus 5.2 ± 0.6, p = 0.010; MFPDS: 31.2 ± 1.9 versus 37.7 ± 2.4, p = 0.047).

CONCLUSION

Injection of MN under ultrasound guidance provides a statistically significant improvement at some stages of the follow-up (45 days, 2 and 3 months), compared with blind injection.

KEY POINTS

• Ultrasound-guided steroid injections in Morton's neuroma provide short-term pain relief to over 60% of the patients. • Ultrasound-guided injections in Morton's neuroma lead to a higher percentage of short-term pain relief than blind injections. • Ultrasound-guided injections in Morton's neuroma lead to a lower percentage of skin side effects than blind injections.

Plantar Pressure Measurements and Geometric Analysis of Patients With and Without Morton's Neuroma

BACKGROUND

The purpose of this research was to see if there were any differences in peak pressure, contact time, pressure-time integrals, and geometric variables such as forefoot width, foot length, coefficient of spreading, and arch index between subjects with Morton's neuroma (MN) and control subjects.

METHODS

Dynamic peak plantar pressure, contact time, pressure-time integral, and geometric data were extracted using the EMED-X platform in 52 subjects with MN and 31 control subjects. Differences in peak pressure, contact time, pressure-time integral, and geometric data between participants with and those without MN were determined using independent-samples t tests. There were no significant differences in age, weight, height, and body mass index between patients with MN and control subjects.

RESULTS

There were no significant differences in the peak pressures of all masked areas and pressure-time integrals under metatarsal 2 to 4 heads between patients with MN and control subjects. In addition, no significant differences were observed between patients with MN and control subjects in geometric measurements of forefoot length, width, coefficient of spreading, foot progression angle, and arch index.

CONCLUSION

No relationship was found in this study between peak pressure, contact time, and pressure-time integral under the metatarsal heads, forefoot width, foot length, coefficient of spreading, and foot progression angle in a symptomatic MN group compared with a control group. The need to perform osteotomies to treat MN not associated with other lesser metatarsal phalangeal joint pathologies is questionable.

LEVEL OF EVIDENCE

Level III, Case-Control Study.

Clinical Utility of High-Frequency Musculoskeletal Ultrasonography in Foot and Ankle Pathology: How Ultrasound Imaging Influences Diagnosis and Management

The use of high-frequency (high-resolution) musculoskeletal ultrasonography is increasing and has shown promising utility in many areas of medicine. The utility of musculoskeletal ultrasonography for foot and ankle complaints has not been widely investigated, however. Although some conditions of the foot and ankle are easily diagnosed by physical examination, others can have nonspecific examination findings, making optimal treatment decisions difficult. We hypothesized that high-resolution musculoskeletal ultrasound scanning of the foot and ankle can affect the diagnosis and/or treatment for patients presenting with foot or ankle complaints. Retrospectively, the cases of 98 patients who had undergone musculoskeletal ultrasound scanning of the foot or ankle were reviewed. The pre-ultrasound clinical diagnosis and treatment were compared with the post-ultrasound diagnosis and treatment. In 64% of the patients, the diagnosis or treatment changed after the ultrasound examination. In 43% of patients, both the diagnosis and the treatment changed after ultrasound scanning. For those patients for whom the diagnosis and treatment were unchanged after the ultrasound examination, the ultrasound findings were concordant with the pre-ultrasound clinical diagnosis for 100% of the patients. These results suggest that in a large proportion of patients, high-resolution musculoskeletal ultrasonography of the foot or ankle can facilitate appropriate diagnosis and management.

Morton's interdigital neuroma of the foot: A literature review

Morton's neuroma is one of the most common causes of metatarsalgia. Despite this, it remains little studied, as the diagnosis is clinical with no reliable instrumental diagnostics, and each study may deal with incorrect diagnosis or inappropriate treatment, which are difficult to verify. The present literature review crosses all key points, from diagnosis to surgical and nonoperative treatment, and recurrences. Nonoperative treatment is successful in a limited percentage of cases, but it can be adequate in those who want to delay or avoid surgery. Dorsal or plantar approaches were described for surgical treatment, both with strengths and weaknesses that will be scanned. Failures are related to wrong diagnosis, wrong interspace, failure to divide the transverse metatarsal ligament, too distal resection of common plantar digital nerve, an association of tarsal tunnel syndrome and incomplete removal. A deep knowledge of the causes and presentation of failures is needed to surgically face recurrences.

Is Histopathological Analysis of Interdigital Morton's Neuroma Necessary?

BACKGROUND

Interdigital neuroma (IN), otherwise known as Morton's neuroma, is a common cause of metatarsalgia presenting to the elective foot and ankle clinic. Surgical excision of the IN in patients who fail to respond to nonoperative measures is considered to be the gold standard of care in many centers. The Royal College of Pathologists UK recommend that all excised interdigital Morton's neuromas are sent for formal histopathological analysis. We present a study correlating clinical and radiological diagnosis with histopathologic appearances of IN following surgical excision, and question if routine histopathological analysis is warranted.

METHODS

A retrospective study was carried out in a single center. Ninety-six operative records were reviewed to identify all the cases of IN surgically resected between January 2007 and July 2016. The histopathology result of the resected IN specimen, that had a clinical and radiological diagnosis of IN, was analyzed.

RESULTS

A total of 85 patients met the inclusion criteria and were included in the final analysis. We found that 100% of patients with a clinical, radiographic, and intraoperative diagnosis of a Morton's neuroma had a histopathological report confirming a Morton's interdigital neuroma.

CONCLUSION

In our single-surgeon series, histopathologic diagnosis is in complete agreement with clinical and radiological diagnosis. We therefore recommend that routine histopathological analysis of IN is not necessary, saving resources and providing a cost benefit. Histopathologic examination should be reserved only in cases where intraoperative findings do not concur with clinical and radiological features.

LEVELS OF EVIDENCE

Level IV: Case series.

Radiographic Analysis of Feet With and Without Morton's Neuroma

BACKGROUND

The aim of this research was to investigate the association of various structural measurements of the forefoot with Morton's neuroma (MN).

METHODS

Weightbearing anteroposterior and lateral foot radiographs of subjects attending the University of Western Australia (UWA) Podiatry Clinic and the first author's private practice were included in this study. A single assessor measured the following angles: lateral intermetatarsal angle (LIMA), intermetatarsal angle (IMA), hallux valgus angle (HVA), digital divergence between the second and third digits (DD23), digital divergence between the third and fourth digits (DD34) and relative metatarsal lengths of the first to fifth metatarsals (Met1-5), and the effect of MN size as measured by ultrasonograph on digital divergence. Intratester reliability of all radiographic measurements was assessed on all radiographic measurements. The study included 101 subjects, of whom 69 were diagnosed with MN and 32 were control subjects without MN. The mean (± standard deviation) age of MN subjects was 52 (±15) years and for control subjects, 48 (±12) years.

RESULTS

When comparing all feet, there were no significant differences in the LIMA, HVA, IMA, digital divergence angles and the relative metatarsal distances between subjects with MN and control subjects. No relationship between MN size and digital divergence was found in either foot, or in either neuroma location.

CONCLUSION

We were unable to demonstrate any relationship in this study between radiographic metatarsal length and angular measurements in a symptomatic MN group compared to a control group. In addition, we did not find any correlation between the size of MN as measured from ultrasonographic images and radiographic evidence of digital divergence.

LEVEL OF EVIDENCE

Level III, case control study.

Ultrasound Evaluation of Morton Neuroma Before and After Laser Therapy

OBJECTIVE

The objective of our study was to retrospectively assess for differences in imaging appearances of Morton neuromas before and after laser therapy using diagnostic ultrasound (US).

MATERIALS AND METHODS

A retrospective review was performed to identify patients who underwent US imaging to evaluate for Morton neuroma during the study period (June 1, 2013-July 1, 2014); of the 42 patients identified, 21 underwent US evaluations before and after laser therapy. US reports and images were reviewed and correlated with clinical history. The final study group consisted of 21 patients who had a total of 31 Morton neuromas evaluated using US after treatment. A retrospective review was then performed to characterize the appearances of these lesions before and after therapy followed by an analysis of variables.

RESULTS

Retrospective US review of 31 pretreatment Morton neuromas showed fusiform, heterogeneously hypoechoic masses with well-defined borders in most cases and that pain was reported when transducer pressure was applied in 97% (30/31) of cases. After treatment, lesions showed ill-defined borders (23/31), and pain with application of transducer pressure was either significantly decreased or absent (29/31); these findings were concordant with the clinical findings. Both of these characteristics were statistically significant (p < 0.0001). In addition, more Morton neuromas occurred in the second intermetatarsal space than in the third intermetatarsal space (p < 0.0001).

CONCLUSION

US may be used to identify posttreatment changes after laser therapy of Morton neuromas. Posttreatment changes include ill-defined borders and less pain or the absence of pain with the application of transducer pressure. These criteria may be applied in future clinical studies evaluating the efficacy of laser therapy for Morton neuroma.

Sonography of Morton Neuromas: What Are We Really Looking At?

OBJECTIVES

To determine what accounts for the sonographic appearance of a Morton neuroma by correlating preoperative sonograms with the sonographic appearance of the resected surgical specimen, the surgical findings, and the pathologic examination.

METHODS

Ten Morton neuromas that had preoperative sonograms underwent postoperative specimen sonography and histologic evaluation. The appearance and size of the neuromas were compared between the preoperative and postoperative specimen images and were compared to the surgical and pathologic appearances.

RESULTS

Preoperative images showed a fibrillar echogenic nerve coursing into a heterogeneous hypoechoic mass measuring 14.3 mm in average length (range, 9.0-24.0 mm) that contained a round, mildly echogenic mass within it measuring 7.6 mm in average length (range, 4.5-12.0 mm). Surgically, the specimens showed scarred intermetatarsal bursas and tangled vessels surrounding the nerve. Specimen sonography showed echogenic focal enlargement of the nerve at the site of the neuroma, measuring 6.8 mm in average length (range, 3.5-11.0 mm). The size of the resected neuroma was smaller than the hypoechoic mass on the presurgical images (P < .001). Within the hypoechoic mass, the small echogenic focus showed no difference in size compared to the specimen (P = .40), but the shape of the echogenic specimen was fusiform, whereas the preoperative appearance was round. Histologically, the resected specimens showed sclerosis and mucoid degeneration of the nerve fascicles and fibrotic thickening of the perineurium.

CONCLUSIONS

The hypoechoic heterogeneous mass that is referred to as a Morton neuroma sonographically is really a "neuroma-bursal complex" that is much larger than the actual neuroma itself.

Correlation of Clinical, Operative, and Histopathologic Diagnosis of Interdigital Neuroma and the Cost of Routine Diagnosis

BACKGROUND

Diagnosis of an interdigital neuroma (IDN) is clinically based on patient symptoms. During operative excision, it is common to send the excised specimen for routine histopathologic examination. The purpose of this study was to evaluate the accuracy of the clinical and intraoperative diagnosis of IDN and correlate these with the histopathologic results of IDN.

METHODS

Case logs of 3 fellowship-trained foot and ankle surgeons were reviewed to identify all neuroma excisions completed between 1997 and 2014. Charts were reviewed to identify the preoperative clinical diagnosis and intraoperative diagnosis as well as concern for pathology besides a neuroma. All results were compared to final histopathology to identify instances of discordance between diagnoses. A total of 123 patients with 133 neuromas were identified.

RESULTS

Of the total 133 neuromas, 5 cases included a clinical or intraoperative concern for a diagnosis other than neuroma. In these 5 instances surgeons accurately identified cysts and rheumatoid nodules. 132 of 133 histopathology reports indicated the presence of nerve tissue in their report. There were no reports of malignancy or abnormal nerve tissue. There were no changes to the postoperative protocol based on histopathology.

CONCLUSION

The clinical, intraoperative, and histopathologic diagnosis of neuroma was in concordance 100% of the time. With a high level of clinical and intraoperative acumen in identifying a neuroma, we believe it is reasonable not to submit the specimen for histopathologic evaluation. In addition, limiting the amount of routine histopathologic evaluation could have saved approximately $480 per case.

LEVEL OF EVIDENCE

Level IV, case series.

Ultrasound-guided intervention in the ankle and foot

In this comprehensive review, we discuss the main interventions performed in the foot and ankle for Achilles tendinopathy, Morton's neuromas and Plantar fasciitis as well as techniques for intra-articular and peritendinous injections. We present the different imaging techniques and injectable agents that can be used in clinical practice, trying to help the reader decide the most appropriate way of managing the patient with a problem in the ankle and foot.