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

The comparison of postoperative outcomes in Morton's neuroma excision between plantar versus dorsal approach: A systematic review and meta-analysis

BACKGROUND

Current literature lacks comprehensive information comparing the clinical outcomes of plantar and dorsal approaches for Civinini-Morton syndrome, also known as Morton's neuroma. This systematic review and meta-analysis was conducted to evaluate and compare the clinical outcomes of neurectomy for Morton's neuroma, focusing on the differences between the plantar and dorsal approach.

METHODS

Our comprehensive literature review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and utilized databases including PubMed, Embase, Web of Science, and the Cochrane Library. Data investigated in this study included postoperative sensory loss, scar tenderness, reoperation, histopathology, complications, pain score, patient satisfaction, functional scores, and time to weight bearing.

RESULTS

Total eight studies were included in this study. In aggregate, 237 neuromas underwent excision using the plantar approach, while 312 neuromas were treated via the dorsal approach. A significantly higher rate of postoperative reduced sensory was found in the dorsal group: 48.5 % (64/132) Vs. 62.0 % (80/129) with the relative ratio (RR) of 0.79 (95 % CI, 0.64-0.97). A significantly higher rate of postoperative scar tenderness was noted in the plantar group: 16.7 % (32/192) Vs. 6.2 % (14/225) with the RR of 2.27 (95 % CI, 1.28-4.04). Regarding the histopathology, 99.3 % (143/144) and 97.1 % (134/138) accuracy rate was confirmed in the plantar approach and dorsal approach, respectively, with the RR of 1.02 (95 % CI, 0.98-1.07). Overall reoperations and complications were not different between groups at 5.3 % (10/189) and 8.8 % (19/216) in the plantar group versus 6.1 % and 12.0 % (35/291) in dorsal group.

CONCLUSIONS

We recommend detailed discussions with patients prior to surgery to weigh the advantages and disadvantages of each approach.

Sonographic anatomy and technique to image the plantar digital nerves and aid identification of a Morton's neuroma

Introduction

The anatomy of the forefoot is complex, and the sonographic assessment to image the plantar digital nerves and exclude, diagnose or discriminate between a Morton's neuroma and intermetatarsal bursitis can be challenging.

Topic description and discussion

A good appreciation of the sonographic anatomy, technique, normal and abnormal appearances is required to undertake a sonographic assessment of the forefoot and its interspaces, particularly the plantar digital nerves. This is unpacked in this paper with associated pictorial aids. Muscles, tendons, and ligaments of the interspaces and the nearby metatarsophalangeal joints and their associated soft-tissue structures are helpful sonographic landmarks to guide imaging and assessment of the common and proper plantar digital nerves and the intermetatarsal bursa. These need to be appreciated from both dorsal and plantar sonographic approaches, in both short- and long-axis imaging planes.

Conclusion

Improved understanding of the anatomy and sonographic appearances of the interspace structures can enhance the sonographic assessment of the forefoot and improve diagnosis of a Morton's neuroma and/or intermetatarsal bursitis when present to guide patient management.

Treatments for Morton's neuroma

BACKGROUND

Morton's neuroma (MN) is a painful neuropathy resulting from a benign enlargement of the common plantar digital nerve that occurs commonly in the third webspace and, less often, in the second webspace of the foot. Symptoms include burning or shooting pain in the webspace that extends to the toes, or the sensation of walking on a pebble. These impact on weight-bearing activities and quality of life.

OBJECTIVES

To assess the benefits and harms of interventions for MN.

SEARCH METHODS

On 11 July 2022, we searched CENTRAL, CINAHL Plus EBSCOhost, ClinicalTrials.gov, Cochrane Neuromuscular Specialised Register, Embase Ovid, MEDLINE Ovid, and WHO ICTRP. We checked the bibliographies of identified randomised trials and systematic reviews and contacted trial authors as needed.

SELECTION CRITERIA

We included all randomised, parallel-group trials (RCTs) of any intervention compared with placebo, control, or another intervention for MN. We included trials where allocation occurred at the level of the individual or the foot (clustered data). We included trials that confirmed MN through symptoms, a clinical test, and an ultrasound scan (USS) or magnetic resonance imaging (MRI).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. We assessed bias using Cochrane's risk of bias 2 tool (RoB 2) and assessed the certainty of the evidence using the GRADE framework.

MAIN RESULTS

We included six RCTs involving 373 participants with MN. We judged risk of bias as having 'some concerns' across most outcomes. No studies had a low risk of bias across all domains. Post-intervention time points reported were: three months to less than 12 months from baseline (nonsurgical outcomes), and 12 months or longer from baseline (surgical outcomes). The primary outcome was pain, and secondary outcomes were function, satisfaction or health-related quality of life (HRQoL), and adverse events (AE). Nonsurgical treatments Corticosteroid and local anaesthetic injection (CS+LA) versus local anaesthetic injection (LA) Two RCTs compared CS+LA versus LA. At three to six months: • CS+LA may result in little to no difference in pain (mean difference (MD) -6.31 mm, 95% confidence interval (CI) -14.23 to 1.61; P = 0.12, I2 = 0%; 2 studies, 157 participants; low-certainty evidence). (Assessed via a pain visual analogue scale (VAS; 0 to 100 mm); a lower score indicated less pain.) • CS+LA may result in little to no difference in function when compared with LA (standardised mean difference (SMD) -0.30, 95% CI -0.61 to 0.02; P = 0.06, I2 = 0%; 2 studies, 157 participants; low-certainty evidence). (Function was measured using: the American Orthopaedic Foot and Ankle Society Lesser Toe Metatarsophalangeal-lnterphalangeal Scale (AOFAS; 0 to 100 points) - we transformed the scale so that a lower score indicated improved function - and the Manchester Foot Pain and Disability Schedule (MFPDS; 0 to 100 points), where a lower score indicated improved function.) • CS+LA probably results in little to no difference in HRQoL when compared to LA (MD 0.07, 95% CI -0.03 to 0.17; P = 0.19; 1 study, 122 participants; moderate-certainty evidence), and CS+LA may not increase satisfaction (risk ratio (RR) 1.08, 95% CI 0.63 to 1.85; P = 0.78; 1 study, 35 participants; low-certainty evidence). (Assessed using the EuroQol five dimension instrument (EQ-5D; 0-1 point); a higher score indicated improved HRQoL.) • The evidence is very uncertain about the effects of CS+LA on AE when compared with LA (RR 9.84, 95% CI 1.28 to 75.56; P = 0.03, I2 = 0%; 2 studies, 157 participants; very low-certainty evidence). Adverse events for CS+LA included mild skin atrophy (3.9%), hypopigmentation of the skin (3.9%) and plantar fat pad atrophy (2.6%); no adverse events were observed with LA. Ultrasound-guided (UG) CS+LA versus non-ultrasound-guided (NUG) CS+LA Two RCTs compared UG CS+LA versus NUG CS+LA. At six months: • UG CS+LA probably reduces pain when compared with NUG CS+LA (MD -15.01 mm, 95% CI -27.88 to -2.14; P = 0.02, I2 = 0%; 2 studies, 116 feet; moderate-certainty evidence). (Assessed with a pain VAS.) • UG CS+LA probably increases function when compared with NUG CS+LA (SMD -0.47, 95% CI -0.84 to -0.10; P = 0.01, I2 = 0%; 2 studies, 116 feet; moderate-certainty evidence). We do not know of any established minimum clinical important difference (MCID) for the scales that assessed function, specifically, the MFPDS and the Manchester-Oxford Foot Questionnaire (MOXFQ; 0 to 100 points; a lower score indicated improved function.) • UG CS+LA may increase satisfaction compared with NUG CS+LA (risk ratio (RR) 1.71, 95% CI 1.19 to 2.44; P = 0.003, I2 = 15%; 2 studies, 114 feet; low-certainty evidence). • HRQoL was not measured. • UG CS+LA may result in little to no difference in AE when compared with NUG CS+LA (RR 0.42, 95% CI 0.12 to 1.39; P = 0.15, I2 = 0%; 2 studies, 116 feet; low-certainty evidence). AE included depigmentation or fat atrophy for UG CS+LA (4.9%) and NUG CS+LA (12.7%). Surgical treatments Plantar incision neurectomy (PN) versus dorsal incision neurectomy (DN) One study compared PN versus DN. At 34 months (mean; range 28 to 42 months), PN may result in little to no difference for satisfaction (RR 1.06, 95% CI 0.87 to 1.28; P = 0.58; 1 study, 73 participants; low-certainty evidence), or for AE (RR 0.95, 95% CI 0.32 to 2.85; P = 0.93; 1 study, 75 participants; low-certainty evidence) compared with DN. AE for PN included hypertrophic scaring (11.4%), foreign body reaction (2.9%); AE for DN included missed nerve (2.5%), artery resected (2.5%), wound infection (2.5%), postoperative dehiscence (2.5%), deep vein thrombosis (2.5%) and reoperation with plantar incision due to intolerable pain (5%). The data reported for pain and function were not suitable for analysis. HRQoL was not measured.

AUTHORS' CONCLUSIONS

Although there are many interventions for MN, few have been assessed in RCTs. There is low-certainty evidence that CS+LA may result in little to no difference in pain or function, and moderate-certainty evidence that UG CS+LA probably reduces pain and increases function for people with MN. Future trials should improve methodology to increase certainty of the evidence, and use optimal sample sizes to decrease imprecision.

Predictive factors for foot pain in the adult population

BACKGROUND

Foot pain has been associated to factors like: fat, body mass index, age increased, female gender and the presence of pathologies. Although evidence is limited. The purpose is to determine the predictive factors for foot pain in the adult population.

METHODS

From January to December 2021, 457 patients were > 18 years, gave signed informed consent to take part to this cross sectional study. All completed demographic data and various questionnaires related to pain: Foot Function Index, EuroQoL-5D and Visual Analogue Scale (foot pain). Anthropometric measurements were obtained using McPoil platform and foot posture was assessed by the Foot Posture Index (FPI). To determine whether a volume change is a predictive factor for foot pain, a parameter was established: the volumetric index for footwear (VIF). Factors linked to the presence of pain, including the considered VIF variables, were analyzed through multivariable logistic regression.

RESULTS

Among the study population, 40.7% were male and 59.3% female. The mean age of 39.06 years and a body mass index of 25.58 Kg/cm2. The logistic regression model had a classification capability of 72.4%, a sensitivity of 72.3% and a specificity of 73%, in which, the predictors considered were the variables found to have a significant association with FFI-pain > 45 points,, showed that younger women, with a higher BMI, higher values of right FPI (pronation), poorer overall perceived health and with problems in walking were more likely to experience foot pain.

CONCLUSION

Predictive factors for foot pain in the adult population include gender, age, Body Mass Index, FPI on the right foot, perceived health and mobility. Clinical implication, the presented measure aids physicians in assessing their patients´ foot pain likelihood.

Effect of surgical approach on the treatment of Morton's neuroma: a systematic review and meta-analysis

BACKGROUND

Surgical resection of Morton's neuroma includes dorsal and plantar approaches. However, there is no consensus on the choice of approach in clinic. The purpose of this study was to conduct a systematic review and meta-analysis to compare the surgical results of dorsal and plantar approaches.

METHODS

The literatures of PubMed, Cochrane library, Embase and Web of Science were searched on April 26th, 2023. A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The data were extracted after screening the literature and evaluating the quality of the methodology included in the study. The RevMan5.4 software was used to analyze and calculate the OR value and 95% confidence interval.

RESULTS

A total of 7 randomized controlled trials and comparative studies were published, of which only 5 were included. There were 158 feet via plantar approach (plantar group, PG) and 189 via dorsal approach (dorsal group, DG). There was no significant difference between PG and DG in overall adverse events, sensory problems, incision infection and deep vein thrombosis (p > 0.05). In terms of scar problems, PG showed more than DG (OR, 2.90[95%CI, 1.40 to 5.98]; p = 0.004). Other outcome indicators such as visual analogue scale (VAS) scores and American Orthopedic Foot and Ankle Society (AOFAS) scores were difficult to be included in the comparison.

CONCLUSIONS

Based on the relatively low quality and small amount of available evidence, the meta-analysis conducted produces a hypothesis that the frequency of adverse events in surgical treatment of Morton's neuroma, dorsal approach and plantar approach may be the same, but the types are different. More high-level evidence is needed to further verify this hypothesis.

Rheumatoid nodule presenting as a Morton's neuroma in the foot: An important differential diagnosis to consider

A 51-year-old lady with a background of rheumatoid arthritis presented to the foot and ankle clinic with pain and a typical history of Morton's neuroma. Examination revealed a palpable swelling over the right foot in the third intermetatarsal space. Following failed conservative management, the patient underwent excision of the neuroma. Histology revealed of necrotizing granulomas with peripheral palisading and no evidence of features specific to a neuroma. This has rarely been described previously and supports the concept of rheumatoid synovitis and nodules producing symptoms mimicking Morton's neuroma/metatarsalgia. Level of clinical evidence: 4.

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.

Anatomy of the Plantar Intermetatarsal Tunnel: A Cadaveric Study

The contents of the plantar intermetatarsal tunnel (PIMT) and the relationship between the common plantar interdigital nerve (CPIN) and the PIMT were recorded. The width of the PIMT was measured at the metatarsal neck (MTN), metatarsophalangeal (MTP) joint and the base of the proximal phalanx (BPP). The length of the deep transverse metatarsal ligament (DTML), the PIMT and the intracapsular ligament (ICL) were also measured. The PIMT was revealed to be a narrow osseofibrous tunnel divided into 3 segments by the DTML: the distal section, the area under the DTML (middle) and the proximal section. The length of the middle section was 12.77 mm in the second intermetatarsal (IM) space and 10.18 mm in the third IM space. The lengths of the distal sections were 15.52 and 14.95 mm in the second and third IM spaces, respectively. There was some soft tissue between the CPIN and PIMT, and the CPIN was observed not to glide freely within the tunnel. The widths of the PIMT at the MTN, MTP joint and BPP were respectively 2.87, 2.56, and 3.42 mm in the second IM space and 3.10, 2.68 and 3.61 mm in the third IM space. The ICL lies between the capsules of the MTP joint, and the length of the ICL was 2.76 and 3.03 mm in the second and third IM spaces, respectively. The PIMT was found to be a complex spatial structure, and the ICL might prevent the CPIN from being squeezed into the IM space.

Targeted Muscle Reinnervation for Treatment of Postresection Interdigital Neuroma: A Cadaveric Feasibility Study

BACKGROUND

Symptomatic postresection interdigital neuroma is a frustrating problem that causes debilitating foot pain. Implementing the concepts of targeted muscle innervation, this study offers a novel nerve transfer involving the resected third common plantar digital nerve (CPDN) to the motor nerve branch of the third dorsal interosseous muscle (DIMB) to improve postresection pain.

METHODS

Ten fresh feet from seven cadaveric donors were used for this study. CPDN and DIMB lengths and diameters were measured, along with nerve overlap after the transfer with ankle in neutral position and in maximal dorsiflexion. Motor entry point to the calcaneal tuberosity and to the fifth metatarsal tuberosity were measured and used to evaluate the ratio relative to foot length. Means, standard deviations, and P values were calculated for each measure and between sexes and feet (right and left).

RESULTS

In all specimens, the nerve transfer was technically feasible, without notable size mismatch between the donor and recipient nerves. CPDN, DIMB, and important anatomical reference points were identifiable in all specimens. Average CPDN length was 30.1 ± 8.2 mm. The average DIMB length was 14.4 ± 3.9 mm. The overlap between the donor and recipient in neutral ankle position at the transfer site was 6.4 ± 1.8 mm.

CONCLUSIONS

Given their anatomical locations, a nerve transfer between the third CPDN and third DIMB is surgically feasible. This novel technique is a viable option that can be used instead of the conventional technique of muscle implantation or more proximal re-resection for symptomatic postresection interdigital neuroma.

A Method for Entubulating Exposed Nerve Ends Following Neurectomy Using a Porcine Extracellular Matrix Nerve Cap

Compression and irritation at the plantar aspect of the transverse intermetatarsal ligament may lead to a compressive neuropathy called Morton's neuroma. There are many treatment options for Morton's neuroma, with the most common surgical option being traction neurectomy. While there has been success in many surgical procedures, up to 35% of patients treated with traction neurectomy have recurrent pain and up to one-third of these patients have a recurrent stump neuroma. These neuromas are caused by abnormal axonal growth during regeneration, leading to an unorganized mass of fibrotic collagenous tissues, Schwann cells, and axons. More recent surgical treatments of neuromas have included nerve capping, which has been proposed to prevent painful neuroma formation by isolating the nerve end from external chemosignaling and reducing disorganized axonal outgrowth. An off-the-shelf, biocompatible porcine small intestine submucosa (pSIS) derived nerve cap with internal chambering has been investigated in a rodent study, which showed less pain sensitivity and less axonal swirling indicative of reduced likelihood of neuroma formation. Furthermore, a recent clinical study indicated that patients experienced a significant reduction in pain 3 months after Morton's neuroma excision followed by repair using a nerve cap. This article describes the surgical technique of the aforementioned clinical study to mitigate neuroma formation, where a Morton's neuroma is excised, and the remaining proximal nerve stump is inserted within a nerve cap and buried in the surrounding muscle.Level of Evidence: Level V: Expert opinion.

Patient reported outcomes following revision neurectomy through a dorsal approach for recurrent interdigital neuroma

Interdigital neuroma is one of the commonest causes of metatarsalgia. The reported success rate after excision of a primary neuroma is 74%. Recurrent symptoms after neurectomy can be due to a recurrent interdigital neuroma. Recurrent interdigital neuromas can be diagnosed using sound clinical examination and ultrasonography. Surgical excision is the best treatment modality with varying success reported in the literature. We report on the clinical outcome following surgical excision of recurrent interdigital neuromas through a dorsal approach. All patients who had undergone excision of a recurrent interdigital neuroma by a single surgeon between 01/2010 and 12/2019 were identified. Inclusion criteria included patients having a preoperative ultrasound and postoperative histology report. The exclusion criteria were preexisting neuropathy or tarsal tunnel syndrome. Demographic data was collected, and a self-reported foot and ankle score questionnaire (SEFAS) was completed by the patient at their most recent follow-up. Twenty-three patients (25 feet) were included in the study. Mean time of follow-up was 75 (range 14-189) months. The mean age was 49 (range 15-71) years. Eleven (44%) recurrent neuromas were excised from the second webspace and 14 (56%) were excised from the third webspace. All excised masses were confirmed as recurrent neuromas histologically. Regarding the SEFAS score, 17 (73.93%) patients scored as excellent, one (4.34%) as good, three (13.04%) as fair, and two (8.69%) as poor. This long term follow-up study on outcomes after surgery for recurrent interdigital neuroma suggests that excision through a dorsal approach is an effective treatment option with a high patient satisfaction.

Longitudinal Plantar Approach for Excision of Morton's Neuroma: Long-Term Results

Longitudinal plantar approaches are generally considered at risk for wound healing problems. Thus, we wanted to investigate long-term outcomes after a primary Morton's neuroma excision through a longitudinal plantar approach. A retrospective study of patients with primary neuroma excision was conducted. Twenty-four patients (28 feet) were evaluated at a mean 9-year follow-up (range, 6-14) by a single trained examiner using a specific postoperative evaluation protocol, including AOFAS Forefoot subjective and objective scores. Good-to-excellent outcomes were reported in 25 (89.3%) cases. A hypertrophic scar formation and keratosis occurred in only 2 cases (7.1%). All the patients, with a single exception, achieved full weightbearing with a postoperative shoe from the first day after the operation. A longitudinal plantar approach can lead to long-term, good-to-excellent outcomes with no case of recurrence or reoperation. Accurate wound closure and immediate weightbearing with a postoperative shoe can minimize the rate of complications. This approach should be considered for primary resection of Morton's neuromas.

Intermetatarsal ligament section assisted with sonography for the percutaneous surgery of Morton's disease: Cadaveric study

BACKGROUND

Surgical treatment of Morton's neuroma remains controversial. Several surgical techniques have been described including percutaneous transection of the deep metatarsal transverse ligament (DMTL).

PURPOSE

To evaluate the efficacy and safety of percutaneous release of the DMTL under ultrasound guidance for the treatment of Morton's syndrome.

MATERIALS AND METHODOLOGY

Percutaneous release of the DMTL was performed with ultrasound guidance in 48 intermetatarsal spaces of 16 cadaveric specimens. Specimens were then dissected to assess the completion of the release and the presence of any injuries of the neurovascular and tendinous adjacent structures.

RESULTS

The DMTL was visualized with ultrasound in all cases. Complete release of the ligament was achieved in 87.5% (42/48) cases. One case of interdigital nerve injury was found.

CONCLUSION

Percutaneous release of DMTL with ultrasound guidance for the treatment of Morton's disease has an acceptable rate of complications but care must be taken to ensure the complete release of the ligament.

Microsurgical Neurectomy for Morton’s Neuroma

Introduction “Morton’s neuroma” is one of the common causes of forefoot pain. If conservative therapy fails, surgical treatment should be performed. Microscopy is often used to operate on the digital nerve in the hand. However, to our knowledge, there has only been one report on the use of microsurgical technique. In this study, we describe a new microsurgical technique for Morton’s neuroma and discuss the advantages of this procedure.

Materials and Methods Ten patients with Morton’s neuroma underwent surgical neurolysis or neurectomy using microsurgical technique. All patients were females with a mean age of 53 years (range = 35–65). The average follow-up time after surgery was 18 months (range = 6–24 months).

Results Four cases initially underwent microsurgical neurolysis, but the patient’s symptoms did not improve. Two of these cases were then referred for revision surgery by microsurgical neurectomy. Following neurectomy, the mean preoperative pain and functional score improved significantly. In five cases, histopathology showed the neuroma was surrounded by metatarsal bursitis. In three cases, the nerve was sutured because each stump was easily reached.

Conclusion Microsurgical technique allows careful visualization of the plantar digital nerve even through a dorsal approach. Separation of the digital nerve from the adhesive fibrous tissue can be performed quite readily under the microscope and Morton’s neuroma can then be completely removed en block. In some cases, microsurgical nerve repair may also be possible. A microsurgical approach is a reliable and useful tool for neurectomy of Morton’s neuroma.

High-Resolution Ultrasound of the Forefoot and Common Pathologies

Forefoot pain is common in clinical practice. Careful history taking and routine physical examination are initially performed for diagnosis, but imaging can confirm the clinical suspicion and play a key role in management. Ultrasound (US) can provide a visualization of the fine anatomy of the forefoot and is a useful method for evaluating various lesions causing forefoot pain. In this review, we provide the detailed anatomical structures of the forefoot and their normal appearances on US. We also focus on the most common pathologies affecting the forefoot, including plantar plate tear, sesamoiditis, bone fracture, synovitis, tenosynovitis, bursitis, Morton’s neuromas, and foreign bodies.

"The Feasibility of Targeted Muscle Reinnervation for the Management of Morton's Neuroma"

BACKGROUND

Despite multiple surgical modalities available for the management of Morton's neuroma, complications remain common. Targeted muscle reinnervation (TMR) has yet to be explored as an option for the prevention of recurrence of Morton's neuroma. The purpose of the present investigation was to determine the consistency of the relevant foot neurovascular and muscle anatomy and to demonstrate the feasibility of TMR as an option for Morton's neuroma.

METHODS

The anatomy of 5 fresh-tissue donor cadaver feet was studied, including the course and location of the medial and lateral plantar nerves (MPNs and LPNs), motor branches to abductor hallucis (AH) and flexor digitorum brevis (FDB), as well as the course of sensory plantar digital nerves. Measurements for the locations of the muscular and sensory branches were taken relative to landmarks including the navicular tuberosity (NT), AH, FDB, and the third metatarsophalangeal joint (third MTPJ).

RESULTS

The mean number of nerve branches to FDB identified was 2. These branch points occurred at an average of 8.6 cm down the MPN or LPN, 9.0 cm from the third MTPJ, 3.0 cm distal to AH distal edge, and 4.8 cm from the NT. The mean number of nerves to AH was 2.2. These branch points occurred at an average of 6.3 cm down the MPN, 11.9 cm from the third MTPJ, 0.8 cm from the AH distal edge, and 3.8 cm from the NT.

CONCLUSIONS

Recurrent interdigital neuroma, painful scar, and neuropathic pain are common complications of operative management for Morton's neuroma. Targeted muscle reinnervation is a technique that has demonstrated efficacy for the prevention and treatment of neuroma, neuropathic pain, and phantom limb pain in amputees. Herein, we have described the neuromuscular anatomy for the application of TMR for the management of Morton's neuroma. Target muscles, including the AH and FDB, have consistent innervation patterns in the foot, and consequently, TMR represents a viable option to consider for the management of recalcitrant Morton's neuroma.

LEVELS OF EVIDENCE

V.

Diagnostic and Therapeutic Challenge of Metatarsalgia in a Patient With Rheumatoid Arthritis

A 63-year-old female patient, with a past history of rheumatoid arthritis, presented with insidious pain on the left foot second and third metatarsophalangeal joints, associated with swelling and morning stiffness (mean time: four hours). Physical examination evidenced a tender and soft nodularity in the third intermetatarsal space, along with sharp pain, consistent with Morton’s neuroma. Foot ultrasound suggested Morton’s neuroma, but not excluding the possibility of rheumatoid arthritis involvement. Foot magnetic resonance imaging suggested the possibility of extensive synovitis of the third metatarsophalangeal joint, but not excluding the coexistence of Morton’s neuroma because of the mass effect. Finally, the patient underwent an ultrasound-guided needle biopsy of the nodule, which confirmed metatarsophalangeal joint synovitis. The foot is a common location of rheumatoid arthritis manifestation, and metatarsophalangeal joint synovitis can mimic Morton’s neuroma. After a definite diagnosis, the patient recovered lower limb functional impairment after introducing adalimumab and a rehabilitation program. This case highlights the importance of an accurate differential diagnosis, pharmacological rheumatoid arthritis control, and physical medicine and rehabilitation programs to optimal clinical and functional improvement.

To Be or Not to Be (A Morton's/Interdigital Neuroma): That Is the Question-A Case Series of Lateral Forefoot Pain Localized to the Proper Digital Nerve of the Fifth Toe

We present 2 cases where the initial history and examination were similar to a Morton's/interdigital neuroma. In both cases, however, diagnostic ultrasound revealed symptomatic snapping of the proper digital nerve of the fifth toe. The anatomy of the proper digital nerve of the fifth toe may predispose it to a snapping phenomenon. Clinical awareness of this atypical cause of forefoot pain can help guide the diagnosis and treatment in those patients with persistent and refractory lateral forefoot pain and paresthesias.

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.

Endoscopic Resection of a Toe Web Fibroma That Was Mimicking a Morton's Neuroma

Fibroma of tendon sheath is a rare benign tumor originating in the tendon or tendon sheath. It most commonly occurs in upper extremity and rarely presents in the foot. In this report, a case of fibroma of tendon sheath in the web space with Morton's neuroma-like symptoms was presented. The tumor was resected endoscopically with preservation of the interdigital nerve. Post-operatively, the symptoms were subsided and the toe sensation was preserved. There was no sign of recurrence of the tumor at the end of 3-year-period of follow-up.

Ultrasound-guided treatment of Morton's neuroma

Morton’s neuroma is a painful lesion of the interdigital nerve, usually at the third intermetatarsal space, associated with fibrotic changes in the nerve, microvascular degeneration, and deregulation of sympathetic innervation. Patients usually present with burning or sharp metatarsalgia at the dorsal or plantar aspect of the foot. The management of Morton’s neuroma starts with conservative measures, usually with limited efficacy, including orthotics and anti-inflammatory medication. When conservative treatment fails, a series of minimally invasive ultrasound-guided procedures can be employed as second-line treatments prior to surgery. Such procedures include infiltration of the area with a corticosteroid and local anesthetic, chemical neurolysis with alcohol or radiofrequency thermal neurolysis. Ultrasound aids in the accurate diagnosis of Morton’s neuroma and guides the aforementioned treatment, so that significant and potentially long-lasting pain reduction can be achieved. In cases of initial treatment failure, the procedure can be repeated, usually leading to the complete remission of symptoms. Current data shows that minimally invasive treatments can significantly reduce the need for subsequent surgery in patients with persistent Morton’s neuroma unresponsive to conservative measures. The purpose of this review is to present current data on the application of ultrasound for the diagnosis and treatment of Morton’s neuroma, with emphasis on the outcomes of ultrasound-guided treatments.

Minimally invasive neurectomy for Morton's neuroma with interdigital approach. Long term results

BACKGROUND

"Morton's Neuroma" is a frequent cause of chronic forefoot pain. It can affect general population, including athletes, and can lead to progressive foot pain and discomfort for daily life activities and sports.

HYPOTHESIS/PURPOSE

Our objective is to evaluate the long-term results in a series of 85 feet, operatively treated with minimally invasive interdigital approach for neurectomy.

STUDY DESIGN

Case series.

METHOD

83 patients (85 feet) were treated between January 2003 and December 2019. The AOFAS score and VAS scale were used to evaluate the patients pre and postoperatively. Results were analyzed using the JASP software.

RESULTS

Mean age was 50.58 years (range 23-77). Eleven (11) were men, and seventy-four (74) women, with two bilateral cases. Mean follow up was 49 months. Our series was evaluated with AOFAS and VAS scores, both showing statistically significant improvement posterior to the operative procedure.

CONCLUSIONS

A series of 85 feet operatively treated for Morton's neuroma with minimally invasive interdigital approach for neurectomy is presented. Long term results were similar to other published series with different approaches, with the advantage of minimal incision, minimum soft tissue dissection and no need to release intermetatarsal ligament, immediate weightbearing and quick return to daily activities and sports. It is concluded that minimally invasive neurectomy with interdigital approach is a safe procedure for Morton's neuroma treatment with similar results that other operative procedures.

LEVEL EVIDENCE

Level IV.

Treating Morton's neuroma by injection, neurolysis, or neurectomy: a systematic review and meta-analysis of pain and satisfaction outcomes

BACKGROUND

Individual evidence suggests that multiple modalities can be used to treat entrapment pathology by Morton's neuroma, including injection, neurolysis, and neurectomy. However, their impacts on patient pain and satisfaction have yet to be fully defined or elucidated. Correspondingly, our aim was to pool systematically identified metadata and substantiate the impact of these different modalities in treating Morton's neuroma with respect to these outcomes.

METHODS

Searches of 7 electronic databases from inception to October 2019 were conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. The incidences of outcomes were extracted and pooled by random-effects meta-analysis of proportions.

RESULTS

A total of 35 articles satisfied all criteria, reporting a total of 2998 patients with Morton's neuroma managed by one of the three modalities. Incidence of complete pain relief after injection (43%; 95% CI, 23-64%) was significantly lower than neurolysis (68%; 95% CI, 51-84%) and neurectomy (74%; 95% CI, 66-82%) (P = 0.02). Incidence of complete satisfaction after injection (35%; 95% CI, 21-50%) was significantly lower than neurolysis (63%; 95% CI, 50-74%) and neurectomy (57%; 95% CI, 47-67%) (P < 0.01). The need to proceed to further surgery was significantly greater following injection (15%; 95% CI, 9-23%) versus neurolysis (2%; 95% CI, 0-4%) or neurectomy (5%; 95% CI, 3-7%) (P < 0.01). Incidence of procedural complications did not differ between modalities (P = 0.30).

CONCLUSIONS

Although all interventions demonstrated favorable procedural complication incidences, surgical interventions by either neurolysis or neurectomy appear to trend towards greater incidences of complete pain relief and complete patient satisfaction outcomes compared to injection treatment. The optimal decision-making algorithm for treatment for Morton's neuroma should incorporate these findings to better form and meet the expectations of patients.

Management of acute lesser toe pain

Patients with foot pain commonly present to their primary care physicians for their initial management and treatment. These patients and their respective foot or lesser toe pain can present the physician with a complex problem with a long differential list. Depending on the timing of the pain and underlying pathology, these differentials can be divided into acute and acute exacerbation of chronic conditions. This review categorizes the history, physical exam, radiological findings, conservative treatment, and surgical management for each major cause of lesser toe pain, whether acute or chronic. The acute conditions surrounding lesser toe pain in the adult population discussed are toe fractures, toe dislocations, and metatarsal head and neck fractures. The chronic pathologies surrounding lesser toe pain in the adult population evaluated in this review include metatarsalgia, Morton's neuroma, Freiberg infraction, brachymetatarsia, bunionettes, and lesser toe disorders.

Common Complaints of the Hands and Feet

Primary care providers frequently care for complaints of the hands and feet. Here, the author describes the typical presentations of hand osteoarthritis, carpal tunnel syndrome, ganglion cysts, plantar fasciitis, onychomycosis, and Morton neuroma. Useful physical examination techniques are described. The history and physical examination are usually sufficient to diagnose these conditions without the need for more advanced testing. All of these conditions have evidence-based therapy that can be initiated by the primary care provider. These treatments as well as reasons to refer to a specialist are reviewed.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Anatomic basis for a new ultrasound-guided, mini-invasive technique for release of the deep transverse metatarsal ligament

Introduction

Morton's neuroma is an entrapment neuropathy of the third common plantar digital nerve, caused by the deep transverse metatarsal ligament (DTML). Minimally invasive or percutaneous surgery is a very common procedure, but surgical effectivity of this technique remains controversial. The goal of our study was to prove the effectiveness and safety of a new ultrasound‐guided technique for DTML‐release in a cadaver model.

Materials, Methods, and Results

The DTML was visualized in 10 fresh frozen donated body to science‐feet (eight male and two females, five left and five right) using an US device (GE Logic R7; 13 MHz linear probe, Madrid, Spain). Consecutively, minimally invasive ultrasound‐guided surgery was performed. Exclusion criteria of the donated bodies to science were previous history of forefoot surgery and space occupying mass lesions. The complete release of the ligament was achieved in all specimens without damage of any important anatomical structures as proven by anatomical dissection.

Conclusions

The results of this study indicate that our novel approach of an ultrasound‐guided release of the DTML is safer and more effective compared to blind techniques. The DTML could reliably be visualized and securely cut through a dorsal, minimally invasive surgical incision of only 2 mm.

The effects of a combined physical therapy approach on Morton's Neuroma. An N-of-1 Case Report

INTRODUCTION

There is a lack of supporting evidence for conservative treatments involving Morton's Neuroma, which has often a clinical presentation with many associated complications such as functional impairment and chronic pain. This case study assessed the effects of a combined physical therapy treatment for Morton's Neuroma, an injury often referred for surgery.

METHODS

The patient suffered a long-standing Morton's Neuroma and received 6 combined physical therapy sessions that included soft-tissue massage, joint mobilization, strengthening therapeutic exercises and pain education. Values for pain with deep pressure, pain maladaptive beliefs and functionality were taken using clinical testing and questionnaires.

RESULTS

After the intervention was successfully completed, pain when applying deep pressure resolved. Functionality involving the toe-to-wall test showed an improvement in ankle dorsiflexion and better results were found in both the LEFS and FAAM questionnaires. Pain maladaptive beliefs, assessed with the Pain Catastrophizing Scale and the Pain Awareness Questionnaire also reflected an improvement.

CONCLUSION

A combined physical therapy approach shows encouraging results in the treatment of Morton's Neuroma.

Revision of Recurrent Neuromas

Forefoot neuromas are a common pathology that is seen in a wide variety of patients. Although conservative treatment is successful with modification of shoes/inserts or injections, surgical intervention is occasionally needed to alleviate the discomfort. Most surgical procedures for neuromas have a good outcome. There are times when the outcome is not optimal and revision surgery may be needed. This article describes revision surgery techniques that may lead to an improved outcome. Also discussed is the opportunity to reduce recurrence through the understanding of neuroma biology, diagnosis, and treatment options.

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)

Five Centimeters Morton's Neuroma in a 46-Year-Old Woman Affected by Macrodactily

The present article described the case of a voluminous Morton's neuroma of the third intermetatarsal space in a patient affected by macrodactily. The case was unique because of its dimensions, the uncommon surgical approach which was needed for removal, the association with macrodactily of the fourth toe with Raynaud's phenomenon, and the postoperative defect in the intrinsic muscles. The patient was operated in February 2016 by transverse plantar approach. Twelve months after surgery, the patient complained for hypoesthesia on third and fourth toes with inability to actively spread the toes and enlargement in the second interdigital space. The dimensions of the lesions may be explained with the presence of macrodactily in the fourth toe with occasional Raynaud's phenomenon, which may have caused an abnormal arrangement of the nerve branches for the fourth interspace with related microtrauma. A plantar approach was highly recommended as the size of the lesion forced it to the plantar surface of the foot. The inability to actively spread the toes and the enlargement of the second interdigital space are likely to be related to a deficiency of the interosseous muscles, innervated by the deep branch of the lateral plantar nerve, which had probably been sacrificed because of the size of the lesion and the subversion of the surrounding anatomical relationships.

Nerve decompression according to A.L. Dellon in Morton's neuroma - A retrospective analysis

BACKGROUND

First reported by Dellon et al. in 1992, nerve decompression by dissecting the deep transversal intermetatarsal ligament through a dorsal incision appears to be a reliable method for treating Morton's neuroma by addressing its underlying pathomechanism, since it should rather be considered as Morton's entrapment. As there are no current studies dealing with Dellon's surgical technique, we carried out a retrospective analysis with the aim of showing that nerve decompression is an effective method to treat Morton's neuroma, and one that considers its true pathology.

MATERIALS AND METHODS

All patients with a clinical diagnosis of Morton's neuroma, verified by MRI and treated by nerve decompression were included in this study in the years from 2010 to 2018 at our department. Follow-up was performed at least six months post-intervention; pain and function history were ascertained using the VAS (visual analogue scale) score and the German foot function index. Skin sensitivity testing was performed using Semmes-Weinstein monofilaments.

RESULTS

A total of 12 patients were treated and followed-up during the study period. Postoperatively, there was significant improvement in the values of the VAS score both under strain (p-value: 0.0021) and at rest (p-value: 0.0062), as well as in the foot function index (p-value: 0.0022). There was no significant difference in skin sensitivity of the innervation areas of the interdigital nerves of the affected foot compared with the healthy reference foot (p-value: 0.0968).

CONCLUSION

Dellon's decompression method yielded a highly positive outcome, and based on our findings, we consider it a reliable, technically simple and promising approach to treat Morton's neuroma. It is a minimally invasive technique that addresses the pathomechanism of peripheral nerve entrapment and has a low rate of complication as well as rapid patient recovery.

Constitutional risk factors for focal neuropathies in patients referred for electromyography

BACKGROUND AND PURPOSE

It is well established that patient-related constitutional features predispose to focal peripheral neuropathies. Some of these risk factors were investigated in common focal neuropathies encountered in patients referred for electromyography.

METHODS

Gender, age, height and body mass index (BMI) were analysed retrospectively as risk factors for 11 focal neuropathies. In all, 9686 patients (age range 18-96 years; 58% women) were included from three different centres, with identical methods and equipment.

RESULTS

High BMI was related to carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), combined CTS and UNE, meralgia paraesthetica and lumbar radiculopathy. In women, CTS and Morton's metatarsalgia were more common, whilst long thoracic neuropathies, suprascapular neuropathies and UNE were more common in men. Older age increased the risk for CTS, UNE, Morton's metatarsalgia and radiculopathies.

CONCLUSIONS

Age, gender and BMI are important risk factors for many common focal neuropathies.

Effectiveness of customized insoles in patients with Morton's neuroma: a randomized, controlled, double-blind clinical trial

OBJECTIVE

To assess the effectiveness of customized insole in patients with Morton's neuroma.

DESIGN

Double-blind randomized controlled trial with intent-to-treat analysis.

SETTING

Outpatients, University Hospital.

SUBJECTS

A total of 72 patients with Morton's neuroma met the inclusion criteria and were randomly allocated to either the study group (n = 36) or the control group (n = 36).

INTERVENTIONS

The study group was assigned to use a customized insole with metatarsal and arch support made of ethyl vinyl acetate and the control group received a flat insole of the same material, color, and density.

MAIN MEASURES

The primary outcome measure was walking pain intensity measured by the visual analogue scale. The secondary outcomes were as follows: pain at rest, palpation, and paresthesia (visual analogue scale); functional disability (6-minute walk test, Foot Function Index, and Foot Health Status Questionnaire); quality of life (Health Survey Short Form-36 (SF-36)); and foot pressure (AM Cube FootWalk Pro program).

RESULTS

In the comparison between the groups over time, a statistically significant difference, with improvement in favor of the experimental group, was found for pain during walking (P = 0.048); in the general health domains (P < 0.001) and physical activity (P = 0.025) of the Foot Health Status Questionnaire; in the general Foot Function Index score (P = 0.012); and in the functional capacity domain of the SF-36 questionnaire (P = 0.046). For the other parameters, no difference was found between groups.

CONCLUSION

The study demonstrated that customized insole with metatarsal and arch support relieved walking pain and improved patient-reported measures of function in patients with Morton's neuroma.

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.

Forefoot disorders and conservative treatment

Forefoot disorders are often seen in clinical practice. Forefoot deformity and pain can deteriorate gait function and decrease quality of life. This review presents common forefoot disorders and conservative treatment using an insole or orthosis. Metatarsalgia is a painful foot condition affecting the metatarsal (MT) region of the foot. A MT pad, MT bar, or forefoot cushion can be used to alleviate MT pain. Hallux valgus is a deformity characterized by medial deviation of the first MT and lateral deviation of the hallux. A toe spreader, valgus splint, and bunion shield are commonly applied to patients with hallux valgus. Hallux limitus and hallux rigidus refer to painful limitations of dorsiflexion of the first metatarsophalangeal joint. A kinetic wedge foot orthosis or rocker sole can help relieve symptoms from hallux limitus or rigidus. Hammer, claw, and mallet toes are sagittal plane deformities of the lesser toes. Toe sleeve or padding can be applied over high-pressure areas in the proximal or distal interphalangeal joints or under the MT heads. An MT off-loading insole can also be used to alleviate symptoms following lesser toe deformities. Morton's neuroma is a benign neuroma of an intermetatarsal plantar nerve that leads to a painful condition affecting the MT area. The MT bar, the plantar pad, or a more cushioned insole would be useful. In addition, patients with any of the above various forefoot disorders should avoid tight-fitting or high-heeled shoes. Applying an insole or orthosis and wearing proper shoes can be beneficial for managing forefoot disorders.

The effectiveness of non-surgical interventions for common plantar digital compressive neuropathy (Morton's neuroma): a systematic review and meta-analysis

Background

Morton’s neuroma (MN) is a compressive neuropathy of the common plantar digital nerve. It is a common compressive neuropathy often causing significant pain which limits footwear choices and weight bearing activities. This paper aims to review non-surgical interventions for MN, to evaluate the evidence base for the clinical management of MN.

Methods

Electronic biomedical databases (CINAHL, EMBASE, MEDLINE and Cochrane) were searched to January 2018 for studies evaluating the effectiveness of non-surgical interventions for Morton’s neuroma. Outcome measures of interest were treatment success rate (SR) (binary) and pain as measured using 100-point visual analogue scale (VAS) (continuous). Studies with and without control groups were included and were evaluated for methodological quality using the Downs and Black Quality Index. Results from randomised controlled trials (RCT) were compared between-groups, and case series were compared pre- versus post-treatment. Effect estimates are presented as odds ratios (OR) for binary data or mean differences (MD) for continuous data. Random effects models were used to pool effect estimates across studies where similar treatments were used. Heterogeneity was assessed using the I² statistic.

Results

A total of 25 studies met the inclusion criteria, seven RCTs and 18 pre/post case series. Eight different interventions were identified, with corticosteroid or sclerosing injections being the most often reported (seven studies each). Results from a meta-analysis of two RCTs found corticosteroid injection decreased pain more than control on VAS (WMD: -5.3, 95%CI: -7.5 to − 3.2). Other RCTs reported efficacy of: manipulation/mobilisation versus control (MD: -15.3, 95%CI: -29.6 to − 1.0); extracorporeal shockwave therapy versus control (MD: -5.9, 95%CI: -21.9 to 10.1). Treatment success was assessed for extracorporeal shockwave therapy versus control (OR: 0.3, 95%CI: 0.0 to 7.1); and corticosteroid injection vs footwear/padding (OR: 6.0, 95%CI: 1.9 to 19.2). Sclerosing and Botox injections, radiofrequency ablation and cryoneurolysis have been investigated by case series studies, however these were of limited methodological quality.

Conclusions

Corticosteroid injections and manipulation/mobilisation are the two interventions with the strongest evidence for pain reduction, however high-quality evidence for a gold standard intervention was not found. Although the evidence base is expanding, further high quality RCTs are needed.

Electronic supplementary material

The online version of this article (10.1186/s13047-019-0320-7) contains supplementary material, which is available to authorized users.

Morton's interdigital neuroma: instructional review

The terminology ‘Morton’s neuroma’ may represent a simplification of the clinical condition as the problem may not be a benign tumour of the nerve, but neuropathic foot pain associated with the interdigital nerve.

Foot and ankle pathomechanics leading to metatarsalgia, clinical examination and differential diagnosis of the condition and imaging of the condition, for differential diagnosis, are discussed.

Nonoperative management is recommended initially. Physiotherapy, injections (local anaesthetic, steroid, alcohol), cryotherapy, radiofrequency ablation and shockwave therapy are discussed.

Operative treatment is indicated after nonoperative management has failed. Neuroma excision has been reported to have good to excellent results in 80% of patients, but gastrocnemius release and osteotomies should be considered so as to address concomitant problems.

Key factors in the success of surgery are correct diagnosis with recognition of all elements of the problem and optimal surgical technique.

Cite this article: EFORT Open Rev 2019;4:14-24. DOI: 10.1302/2058-5241.4.180025.