Outcomes following excision of Morton's interdigital neuroma: a prospective study

Safety and Efficacy of Percutaneous Morton Neuroma Cryoneurolysis Under Ultrasound Guidance

PURPOSE

To assess the technical success, safety and early efficacy of Morton neuroma (MN) cryoneurolysis.

MATERIALS AND METHODS

Retrospective review of 54 consecutive patients with MN treated with cryoneurolysis after failure of conservative treatment, from September 2022 to June 2023. Outcomes measurements included technical success (defined a successful ultrasound-guided placement of the cryoprobe), procedural safety according to Cirse classification and change in 6 months post-procedure by pain numeric rating scale (pNRS).

RESULTS

A total of 59 MN were treated during 55 procedures. Mean procedure duration was 47 min, all patients were discharged 2 h after the intervention. Technical success was 98.1%. No Cirse grade 3, 4 or 5 complication was reported. Three grade 2 complication occurred, including two chilblain-type lesions and one bone insufficiency fracture. At 6 months post-procedure, pNRS score was significantly decreased (2.7 ± 2.2 vs 7.1 ± 1.1) (p < 0.0001), with a mean score decrease of 4.1points. Thirty-two patients (60.4%) reported a complete pain relief, 15 (28.3%) a partial pain relief and 6 (11.3%) no pain relief, or increased pain.

CONCLUSION

Cryoneurolysis seems to be safe for the treatment of Morton neuroma. Six-month pain relief is promising and needs to be confirmed at long term.

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.

Association Between Fulfillment of Preoperative Expectations and Diagnosis in Foot and Ankle Surgery

BACKGROUND

There has been growing interest in patient-reported outcomes in foot and ankle surgery, and the fulfillment of patient expectations is a potentially powerful tool that compares preoperative expectations and perceived postoperative improvement. Prior work has validated the use of expectation fulfillment in foot and ankle surgery. However, given the wide spectrum of pathologies and treatments in foot and ankle, no study has examined the association between expectation fulfillment and specific diagnosis.

METHODS

This is a retrospective cohort study consisting of 266 patients who completed the Foot & Ankle Expectations Survey and the Foot and Ankle Outcome Survey (FAOS) preoperatively and 2 years postoperatively. A fulfillment proportion (FP) was calculated using the pre- and postoperative Foot & Ankle Expectations Survey scores. An estimated mean fulfillment proportion for each diagnosis was calculated using a multivariable linear regression model, and pairwise comparisons were used to compare the FP between diagnoses.

RESULTS

All diagnoses had an FP less than 1, indicating partially fulfilled expectations. Ankle arthritis had the highest FP (0.95, 95% CI 0.81-1.08), whereas neuromas and mid/hindfoot diagnoses had the lowest FPs (0.46, 95% CI 0.23-0.68; 0.62, 95% CI 0.45-0.80). Higher preoperative expectations were correlated with lower fulfillment proportions.

CONCLUSION

FP varied with diagnosis and preoperative expectations. An understanding of current expectation fulfillment among different diagnoses in foot and ankle surgery helps highlight areas for improvement in the management of expectations for presumed diagnoses.

LEVEL OF EVIDENCE

Level III, retrospective review of prospective cohort study.

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.

Treatment of Morton's neuroma with minimally invasive distal metatarsal metaphyseal osteotomy (DMMO) and percutaneous release of the deep transverse metatarsal ligament (DTML): a case series with minimum two-year follow-up

BACKGROUND

The optimal treatment of symptomatic Morton's neuroma remains unclear; conservative methods are sometimes ineffective and neurectomy has significant rates of patient dissatisfaction. The aim of this study was to evaluate the outcome of minimally invasive distal metatarsal metaphyseal osteotomy (DMMO) and percutaneous release of the deep transverse metatarsal ligament (DTML) in patients with Morton's neuroma.

METHODS

Between January 2018 and November 2019, 27 patients (29 feet) diagnosed with Morton's neuroma after clinical and radiological evaluation underwent DMMO and percutaneous DTML release. The primary clinical outcomes were pain (VAS) and function (AOFAS score). Secondary outcomes included patient satisfaction, complications, and radiographic outcomes. Patients were followed up for a minimum of two years.

RESULTS

The median age of the participants was 66 years (range 48-79) and the follow-up time was 28 months (24-47). There was a decrease of 5.7 points in the VAS for pain (p < .001) and an increase of 19.9 in AOFAS (p < .001) after the surgical procedure. There was one case of superficial infection and one patient required resection of the neuroma (neurectomy). The majority of patients (89.7%) were satisfied and considered the procedure outcome as excellent or good.

CONCLUSION

Treatment of Morton's neuroma with minimally invasive distal metatarsal metaphyseal osteotomy and percutaneous release of the deep transverse metatarsal ligament showed significant improvement in pain and function with a low incidence of complications and a high rate of personal satisfaction.

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.

Isolated Intermetatarsal Ligament Release as Primary Operative Management for Morton's Neuroma: Short-term Results

BACKGROUND

Although the precise pathoetiology of Morton's neuroma remains unclear, chronic nerve entrapment from the overlying intermetatarsal ligament (IML) may play a role. Traditional operative management entails neuroma excision but risks unpredictable formation of stump neuroma.

MATERIALS AND METHODS

Medical records were examined for adult patients who failed at least 3 months of conservative treatment for symptomatic and recalcitrant Morton's neuroma and who then underwent isolated IML decompression without neuroma resection.

RESULTS

A total of 12 patients underwent isolated IML decompression for Morton's neuroma with an average follow-up of 13.5 months. Visual Analog Pain Scale averaged 6.4 ± 1.8 (4-9) preoperatively and decreased to an average of 2 ± 2.1 (0-7) at final follow-up (P = .002). All patients reported significant improvement.

CONCLUSION

Isolated IML release of chronically symptomatic Morton's neuroma shows promising short-term results regarding pain relief, with no demonstrated risk of recurrent neuroma formation, permanent numbness, or postoperative symptom exacerbation.

LEVEL OF EVIDENCE

Level IV: Case series.

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.

"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.

The Management of Multiple Morton's Neuromas in the Same Foot: A Systematic Review

The optimal treatment strategy for the presentation of multiple Morton's neuromas in adjacent intermetatarsal spaces of the same foot is yet to be determined. We aimed to summarize and assess the efficacy of current treatment strategies. A systematic review, adhering to PRIMSA guidelines was performed. A computer base search was completed in PubMed, Embase, Cinahl, ISI Web of Science, Scopus and Emcare, for articles reporting the treatment of multiple neuromas in the same foot. The review is registered in the international prospective register of systematic reviews (CRD42020213631). A total of 253 articles were identified, with 7 articles being included in the review. The most common treatment strategy reported was simultaneous neuroma excision using a single incision, while 2 studies each describe simultaneous excision with 2 separate incisions and delayed excision respectively. There is no strong evidence favoring use of delayed excision or multiple incisions. Further high-quality research is required to make more definitive conclusions and future research should investigate other strategies such as non-operative treatment.

Ultrasound-guided Injection Treatments versus Surgical Neurectomy for Morton Neuroma: A Cost-effectiveness Analysis

Background: Morton neuroma is a common, painful disorder of the foot with multiple treatment options of varying cost and effectiveness. Objective: The aim of this study was to determine the most cost-effective treatment pathway for symptomatic Morton neuromas that have failed conservative management. Methods: An incremental cost-utility analysis was performed comparing a direct to surgical neurectomy strategy with three injection selective strategies in which one or more ultrasound-guided injection therapies was tried first prior to surgery for non-responders. The three injection selective strategies included: (1) steroid selective (2) alcohol selective, and (3) steroid/alcohol selective in which both steroid injections and alcohol sclerosing injections were trialed successively prior to surgical neurectomy. The direct to surgery approach was compared with the three different injection selective strategies, and with a no-treatment strategy, in a decision-analytic model for a hypothetical group of patients with symptomatic Morton neuromas that had failed conservative management. Model parameters including treatment costs, effectiveness, complication rates, and health utility states were estimated from the literature, reimbursement databases, and expert opinion. The outcome was cost per quality adjusted life year (QALY) with a time horizon of three years. A societal cost perspective was adopted with a willingness to pay threshold of $100,000 per QALY. Sensitivity analyses for key model parameters were performed. Results: For the base input values, the steroid/alcohol selective strategy was dominant and yielded an incremental cost-effectiveness ratio of $4401/QALY compared to no treatment. The probabilistic sensitivity analysis supported this strategy in 74% of 10,000 simulated trials. Results were robust with low sensitivity to most input parameters. However, when the probability of successful alcohol injection treatment dropped below 40%, the steroid selective strategy became most cost-effective. Conclusion: A trial of ultrasound-guided injection therapies for Morton neuroma is a cost-effective strategy compared to proceeding directly to surgical neurectomy. Clinical Impact: Ultrasound-guided injection therapies are indicated as a first line treatment for patients with symptomatic Morton neuromas that have failed conservative management.

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.

Medium-Term Results of Corticosteroid Injections for Morton's Neuroma

BACKGROUND

The objective of this study was to evaluate the medium-term results of corticosteroid injections for Morton's neuroma.

METHODS

This was a prospective follow-up study of a previous randomized controlled trial (RCT). Forty-five neuromas in 36 patients were injected with a single corticosteroid injection either with or without ultrasound guidance. As the results of the RCT showed no difference in outcomes between techniques, the data were pooled for the purpose of this study. Questionnaires were sent out and responses were collected via mail or telephone interview. Results were available in 42 out of 45 neuromas. There was a sex split of 68% female/32% male with a mean age of 62.6 years (SD, 12 years).

RESULTS

At mean follow-up of 4.8 years (SD, 0.91 years), the original corticosteroid injection remained effective in 36% (n = 16) of the patients. In these cases, the visual analog scale (VAS) pain score (P < .001) and Manchester-Oxford Foot Questionnaire Index (MOxFQ Index) (P = .001) remained significantly better than preintervention scores. The remaining cases underwent either a further injection or surgery. Fifty-five percent of the 11 neuromas that received a second injection continued to be asymptomatic in the medium term. Overall, 44% (n = 20) of the initial cohort underwent surgical excision by the medium-term follow-up. The VAS score, MOxFQ Index, and satisfaction scale score across all groups were not significantly different.

CONCLUSION

Corticosteroid injections for Morton's neuroma remained effective in over a third of cases for up to almost 5 years. A positive outcome at 1 year following a corticosteroid injection was reasonably predictive of a prolonged effect from the injection.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

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.

Patient-Related Outcome Measures (PROMs) With Nonoperative and Operative Management of Morton's Neuroma

BACKGROUND

Morton's neuroma is associated with chronic pain and disability. There is a paucity of literature regarding patient-related outcome measures (PROMs) in patients managed nonoperatively. We sought to investigate nonoperative and operative management of Morton's neuroma using PROMs in patients with follow-up to 1 year.

METHODS

We conducted a prospective observational study and collected data on all patients with a new diagnosis of Morton's neuroma treated from February 2016 until April 2018. Primary outcome measures were the Manchester-Oxford Foot Questionnaire (MOXFQ) for pain, EuroQoL (EQ) time trade-off (TTO), and EQ visual analog scale (VAS) taken preoperatively and at 52 weeks postoperatively. Forty-four patients were treated nonoperatively and 94 patients were treated operatively.

RESULTS

Pretreatment and 52-week scores were 55.7 and 43.10 (nonoperative) and 63.7 and 40.1 (operative) for MOXFQ (pain), 0.72 and 0.82 (nonoperative) and 0.68 and 0.82 (operative) for EQ-TTO, and 71.5 and 76.2 (nonoperative) and 73.1 and 68.7 (operative) for EQ-VAS. There was a statistically significant improvement in MOXFQ (pain) in nonoperative (P = .02) and operative groups (P < .001). There was a statistically significant improvement in EQ-TTO in the operative group only (P = .01).

CONCLUSION

This is the largest study investigating outcomes to 12 months of both nonoperative and operatively managed patients with Morton's neuroma. Both nonoperative and operative management lead to symptom improvement at 12 months.

LEVEL OF EVIDENCE

Level III, comparative study.

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.

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.

Can percutaneous alcoholization of Morton's neuroma with phenol by electrostimulation guidance be an alternative to surgical excision? Long-term results

BACKGROUND

Percutaneous alcoholization with phenol by electrostimulation guidance for the treatment of Morton's neuroma is proposed to determine a permanent chemical neurolysis.

METHODS

115 patients for 125 Morton's neuromas were treated. Ten patients were affected by multiple neuromas. Visual Analogue Scale and AOFAS score were used for the clinical assessment.

RESULTS

The mean follow-up was 8,3 years. The pre-alcoholization VAS was 85.84 ± 12.00, while at follow-up scored 28.85 ± 31.35, showing a significant decrease improving in 113/125 cases (90.4%). Treatment was considered successful with a reduction of the VAS value superior to 50% in 89 out of 125 patients (71.2%). The mean overall AOFAS score at -up was 85.09 ± 13.41.

CONCLUSIONS

Needle-electrode guided percutaneous alcoholization is an outpatient, minimally invasive procedure with low rate of complications. Better results of those obtained with traditional conservative treatments and comparable with those reported with other alcohols injections or surgical nerve excision were observed.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Mallet Toes, Hammertoes, Neuromas, and Metatarsophalangeal Joint Instability: 40 Years of Development in Forefoot Surgery

BACKGROUND

Today's foot and ankle surgeon has an enhanced understanding of forefoot pathology and treatment options compared to surgeons who practiced in previous decades. This paper summarizes developments in forefoot surgery in the past 40 years, specifically in treatments for mallet toe, hammertoe, neuroma, and metatarsophalangeal joint instability.

MATERIALS AND METHODS

A review of the literature was conducted using the PubMed search engine, with key terms including, "mallet toe," "hammertoe," "neuroma," "metatarsophalangeal joint instability," "plantar plate," and "forefoot surgery." Chapters in major orthopaedic textbooks covering these topics were also reviewed. We then chronicled the history of the diagnosis and treatment of these pathologies, with a focus on the past 40 years.

CONCLUSIONS

There have been major advances in understanding and treating forefoot pathologies in the past four decades; however, there remain areas for improvement both in the diagnosis and treatment of these problems.

LEVEL OF EVIDENCE

Level V, meta-synthesis.

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.

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.

The role of the width of the forefoot in the development of Morton's neuroma

AIMS

Morton's neuroma is common condition of the forefoot, but its aetiology remains unclear. Our aim was to evaluate the relationship between the width of the forefoot and the development of a Morton's neuroma.

PATIENTS AND METHODS

Between January 2013 and May 2016, a total of 84 consecutive patients (17 men, 67 women) with a unilateral Morton's neuroma were enrolled into the study. The involved and uninvolved feet of each patient were compared. A control group of patients with symptoms from the foot, but without a neuroma who were matched for age, gender, affected side, and web space location, were enrolled. The first to fifth intermetatarsal distance, intermetatarsal angle and intermetatarsal distance of involved web space on standing radiographs were assessed.

RESULTS

The inter- and intra-observer reliability was excellent. The three parameters did not differ significantly between the involved and uninvolved feet. Neither did they differ significantly between the patients and the controls.

CONCLUSION

We conclude that there is no significant relationship between the width of the forefoot and the development of a Morton's neuroma. Cite this article: Bone Joint J 2017;99-B:365-8.