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The entrapment theory is the most commonly accepted theory concerning the development of interdigital neuroma; it incriminates the deep transverse metatarsal ligament as the major causative factor of the condition. This report presents a patient with interdigital neuroma in the second intermetatarsal space, which was strongly suspected to be caused by the metatarsophalangeal joint instability due to plantar plate injury. Surgical intervention revealed that the neuroma was located more distally and dorsally than the deep transverse metatarsal ligament and was pinched between the adjacent metatarsal heads, suggesting the involvement of the metatarsophalangeal joint instability and chronic trauma as etiologies in this case.

We present the case of a 20-year-old man with the chief complaint of right foot pain for the past three years presenting with focal bony prominence at dorsomedial aspect of right mid foot with interdigital pain. MRI demonstrated a metatarsal coalition with interdigital neuroma.

This was a retrospective study examining 60 surgically excised Morton's neuromas from 53 patients over a period of three years at Southend University Hospital, Essex. The initial diagnosis of Morton's neuroma was based on history and examination findings. In only one-third of cases was the neuroma palpable. However, many patients had difficulty localizing the pain and had atypical presentation. We attempted to assess the reliability of ultrasound in diagnosing Morton's neuroma in the 60 histologically confirmed cases. Our second objective was to assess whether size estimate of a neuroma seen on ultrasound correlated with subsequent real specimen measurement. In our study, preoperative ultrasound reliably diagnosed Morton's neuroma in 97% of the cases. In contrast, there was poor correlation in real specimen size measurements when compared with ultrasound reports.

Background: Using clinical and cadaver studies, we examined the relationship between the location of Morton interdigital neuromas and the surrounding structures, including the deep transverse metatarsal ligament (DTML), which has been suspected as a major causative factor in neuroma formation. Methods: Seventeen fresh-frozen cadavers were evaluated to determine the relationship between the location of Morton interdigital neuromas and the DTML at two phases of the gait cycle with 60 degrees of metatarsophalangeal dorsiflexion and with 15 degrees of ankle dorsiflexion. We measured the distance from the bifurcation of the common digital nerve in the foot to the anterior margin of the DTML and also measured the length of the DTML itself. Clinically, we checked the location of the Morton interdigital neuroma and its length during surgery in 32 feet. Results: In the second and third webspace, the mean distance from the bifurcation of the common digital nerve of the foot to the anterior margin of the DTML was 16.7 mm, 15.1 mm in the mid-stance position, and 15.9 mm and 14.6 mm in the heel-off position. The length of the second and third DTML averaged 12.8 mm and 10.6 mm. Clinically, all of the cases of Morton interdigital neuroma started at the bifurcation area of the common digital nerve, and the mean neuroma length was 7.5 mm (6 to 11). Conclusions: Morton interdigital neuromas were located more distally than the DTML in both the mid-stance and the heel-off stage during walking. The main lesion was located between the metatarsal head and the metatarsophalangeal joint and more distal than the DTML, questioning previous studies suggesting that the DTML is the major causative factor in development of Morton interdigital neuroma.

Aims This is the first prospective study to report the pre- and post-operative patient reported outcomes and satisfaction scores following excision of interdigital Morton’s neuroma. Patients and Methods Between May 2006 and April 2013, we prospectively studied 99 consecutive patients (111 feet) who were to undergo excision of a Morton’s neuroma. There were 78 women and 21 men with a mean age at the time of surgery of 56 years (22 to 78). Patients completed the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12 (SF-12) and a supplementary patient satisfaction survey three months pre-operatively and six months post-operatively. Results Statistically significant differences were found between the mean pre- and post-operative MOXFQ and the physical component of the SF-12 scores (p = 0.00081 and p = 0.00092 respectively). Most patients reported their overall satisfaction as excellent (n = 49, 49.5%) or good (n = 29, 29.3%), but ten patients were dissatisfied, reporting poor (n = 8, 8.1%) or very poor (n = 2, 2.0%) results. Only 63 patients (63%) were pain-free at follow-up: in eight patients (8.1%), the MOXFQ score worsened. There was no statistically significant difference in outcome between surgery on single or multiple sites. However, the MOXFQ scores were significantly worse after revision surgery (p = 0.004). Conclusions The patient-reported outcomes after resection of a symptomatic Morton’s neuroma are acceptable but may not be as good as earlier studies suggest. Surgery at several sites can be undertaken safely but caution should be exercised when considering revision surgery. Cite this article: Bone Joint J 2016;98-B:1376–81.

Background: Diagnosis of an interdigital neuroma (IDN) is clinically based on patient symptoms. During operative excision, it is common to send the excised specimen for routine histopathologic examination. The purpose of this study was to evaluate the accuracy of the clinical and intraoperative diagnosis of IDN and correlate these with the histopathologic results of IDN. Methods: Case logs of 3 fellowship-trained foot and ankle surgeons were reviewed to identify all neuroma excisions completed between 1997 and 2014. Charts were reviewed to identify the preoperative clinical diagnosis and intraoperative diagnosis as well as concern for pathology besides a neuroma. All results were compared to final histopathology to identify instances of discordance between diagnoses. A total of 123 patients with 133 neuromas were identified. Results: Of the total 133 neuromas, 5 cases included a clinical or intraoperative concern for a diagnosis other than neuroma. In these 5 instances surgeons accurately identified cysts and rheumatoid nodules. 132 of 133 histopathology reports indicated the presence of nerve tissue in their report. There were no reports of malignancy or abnormal nerve tissue. There were no changes to the postoperative protocol based on histopathology. Conclusion: The clinical, intraoperative, and histopathologic diagnosis of neuroma was in concordance 100% of the time. With a high level of clinical and intraoperative acumen in identifying a neuroma, we believe it is reasonable not to submit the specimen for histopathologic evaluation. In addition, limiting the amount of routine histopathologic evaluation could have saved approximately $480 per case. Level of Evidence: Level IV, case series.

Between November 1993 and September 1999, 60 patients (three bilateral) were consecutively treated with excision of interdigital neuroma. The clinical examination was preoperatively performed and a personal interview, physical examination, and routine radiographs were included. A specific clinical rating system was developed. The clinical results were excellent or good in 49 (78%) feet, fair in 12 (19%), and poor in two (3%). Prior to surgery, the clinical evaluation score was an average of 16 points. Postoperative average score was 67 points, with an average improvement of 50 points. Histopathologically, intraneural fibrosis and sclerohyalinosis were observed, as in the interstitium; furthermore, an increase of the elastic fibers in the stroma was also observed. The precise etiology of interdigital neuroma remains obscure.

Background: Previous studies have shown that the injection of dehydrated alcohol has been successful for the treatment of Morton’s neuroma in the foot. In this study, we determined the cellular effect of injection of alcohol into and around the sciatic nerve of rats and measured the extent of cell necrosis and/or any associated histologic or inflammatory changes. Methods: Twenty-two male (~375 g) Wistar rats were randomized into 2 groups each receiving alcohol injections into or around the sciatic nerve after nerve exposure under sterile technique. Group 1 rats were injected with a 0.5 ml solution of 0.5% Marcaine in the left sciatic nerve as a control group. In the right sciatic nerve a 0.5 ml solution of 4% ethanol with 0.5% Marcaine was injected. Group 2 rats received 0.5 ml of 20% ethanol with 0.5% Marcaine injected into the left sciatic nerve and 0.5 ml of 30% ethanol with 0.5% Marcaine injected into the right sciatic nerve. In each group, the rats were placed in 3 subgroups: intraneural, perineural, perimuscular injections. All rats were sacrificed and tissue harvested for histologic evaluation at day 10 post injection. Results: No evidence of alcohol-associated cell necrosis, apoptosis, or apparent inflammation was observed in histologic specimens of any injected nerves, perineural tissue, or muscles in controls or experimental groups regardless of concentration of ethanol injected on day 10. Conclusion: We concluded that alcohol injection (≤30% ethanol) into and/or around the sciatic nerve or the adjacent muscle of rats has no histologic evidence of necrosis or inflammation to the nerve or surrounding tissue. There was no observable histological change in apoptosis, or cell number, in response to the alcohol injection. Clinical Relevance: The lack of any measureable changes in nerve or adjacent muscle histology with ethanol injection into the rat sciatic nerve (and surrounding tissues) raises questions about the efficacy of using ethanol injections in the treatment of Morton’s neuroma in human clinical practice.

This prospective, randomized study compares the treatment of an interdigital neuroma (IDN) by the standard resection operation with a technique in which the IDN is transposed into the inter-muscular space between the adductor hallucis and the interossei muscles after division of the digital nerves distal to the IDN. The resection group contained 22 patients and 22 neuromas and the transposition group contained 22 patients and 23 neuromas. An interviewer, blinded as to the operative technique used, telephoned each patient preoperatively, and at 1 month, 3 months, 6 months, 12 months, and 36–48 months postoperatively. The interviewer recorded the patient's reported pain level on a numerical rating scale of 0 to 100. In the resection group the average pain level was slightly lower through the first 6 month period, but at the 12 month review the resection group had a slightly higher average pain level. At the 36–48 month survey the resection group again reported a greater average pain level and fewer asymptomatic patients.It was concluded that it is unnecessary to excise the IDN to obtain excellent relief of pain. It was also concluded that transposition of the IDN into an intermuscular position between the adductor hallucis and the interossei muscles produced significantly better long term results than did the standard resection operation.

Background: We sought to evaluate the safety and effectiveness of extracorporeal shockwave therapy as a therapeutic treatment for destroying Morton’s neuroma. Methods: Twenty-five patients (25 feet) were included in the study. Indications for participation were more than 8 months of conservative care with a visual analog scale pain score of 4 or greater. The mean overall pain score on a modified visual analog scale was 6.9 preoperatively. Results: Thirteen patients were randomized to the active group and 12 to the sham group. Two patients in the sham group were lost to follow-up. Post-treatment evaluations were performed at 1, 6, and 12 weeks by a blinded investigator (L.W.). The end point evaluation parameter was the reduction in visual analog scale score. The treatment group showed a significant difference before and after extracorporeal shockwave therapy (P < .0001). The sham group did not have a significant difference after 12 weeks (P = .1218). Conclusions: Extracorporeal shockwave therapy is a possible alternative to surgical excision for Morton’s neuroma. (J Am Podiatr Med Assoc 99(3): 191–193, 2009)

We carried out a prospective study with 40 patients diagnosed of interdigital neuroma of the foot and who had undergone surgery over a 9 year period. We analysed the advantages of two surgical techniques (neurectomy and neurolysis). The results were similar in both groups. No recurrence occurred in the group where neurectomy was carried out. There were two cases of clinical recurrence in the group where neurolysis was carried out. We concluded that neurectomy was our preferred technique for its simplicity, the shorter surgical time necessary and the reduced risk of relapse.

Interdigital neuroma requires thorough clinical evaluation to ensure an accurate diagnosis. For cases refractory to conservative treatment, a neurectomy and release of the transverse metatarsal ligament is performed through a dorsal approach. Recurrent pain is a common complication, but its incidence may be minimized by diagnostic precision and meticulous surgical technique.

It is generally accepted that an interdigital neuroma (Morton's neuroma) is a clinical diagnosis. If the diagnosis is equivocal, other investigations such as ultrasound (US), MRI Scan, a local anaesthetic with or without hydrocortisone or electromyographic nerve conduction studies can be used. The aim of this retrospective study is to compare the accuracy of ultrasound versus a "cocktail" of hydrocortisone (HCI)/local anaesthetic injection (LAI), as an adjuvant investigation in the diagnosis of interdigital neuroma. The results showed that both these investigations are excellent in confirming an interdigital neuroma.

A total of 117 patients with suspected interdigital neuroma (IDN) were investigated with ultrasound scan and 90 (68%) IDN cases were demonstrated. From this group, histological analysis confirmed that 88 cases (98%) were IDN. Three cases with persistent symptoms despite a negative ultrasound scan were surgically explored and two cases had histological confirmation of an IDN. The sensitivity of ultrasound scan in the diagnosis of IDN was 98% and its specificity was 95%. The most common anatomical site was the third interspace (80%). There were a higher proportion of females diagnosed with this condition. Ultrasound appears to be an accurate and effective technique in diagnosing and localizing an IDN when applied as an adjunct to clinical symptoms and signs in cases of metatarsalgia.

To examine morphological differences in Morton's interdigital neuroma between two elderly human populations, we conducted comparative study using 40 Japanese (27 males, 13 females; mean age, 81.2 years) and 21 Finnish (6 males, 15 females; mean age, 80.5 years) cadavers. We defined the neuroma as a thickening of the nerve of at least two-fold relative to the non-pathological proximal part. The incidence of this neuroma was 25% (10/40) in the Japanese and 33.3% (7/21) in the Finnish cadavers. Moderate or severe hallux valgus (with an angle of more than 20 degrees) was seen in half of the 40 Japanese cadavers (7 males, 13 females), but was absent in the Finnish cadavers. Such hallux valgus was present in 7 (5 males, 2 females) of the 10 Japanese cadavers with neuroma. Moreover, in 2 Japanese cadavers, a paper-like, specialized type of neuroma was associated with the deformity. Pathogenesis of Morton's neuroma might be different between human populations with or without hallux valgus.

Background: Although many treatment modalities are available for Morton’s neuroma (MN), studies looking at the long-term effectiveness of most forms of treatment are scarce. The injection of MN with alcohol has gained popularity over the past 10 years with widespread media coverage. Many surgeons have anecdotally questioned the long-term effectiveness of this treatment. We reviewed a cohort of patients at an average 5-year follow-up to assess the medium-term results of alcohol injection. Methods: We used the modified Johnson score and visual analogue scales to assess 45 of the original cohort of patients with an average follow-up of 61 months (range, 33-73 months). Any complications from the procedure were also noted. Results: Our results indicated that by 5 years, 16 of 45 patients had undergone surgical treatment and a further 13 patients had return of symptoms. Only 29% (13/45) remained symptom free. The visual analog scale and modified Johnson scores showed statistically significant deterioration in patients’ symptoms at 5 years following alcohol injection. Conclusion: Injection with alcohol sclerosant for MN has been marketed as a definitive management option comparable to surgical excision. Our investigation illustrated that although short-term results are encouraging, alcohol injection does not offer permanent resolution of symptoms for most patients and can be associated with considerable morbidity. Our investigation provides the only long-term data for alcohol injection treatment of MN. Level of Evidence: Level II, prospective case series.

Background:Injection for interdigital neuroma (IDN) may not selectively target the common digital nerve. We investigated the anatomical localization and extent of extravasation with injection for IDN.Methods:Two fellowship-trained foot and ankle surgeons injected radiopaque contrast into the third webspace of 49 cadaveric specimens (29 with 2 mL and 20 with 1 mL). Computed tomography scan of each specimen was obtained. An independent blinded foot and ankle surgeon analyzed the scans.Results:All injections were accurate. Contrast was found in the second (greater than 70%) and fourth (greater than 30%) webspaces in both injection volume groups. No contrast was found within the third metatarsophalangeal joint. Extravasation extent was significantly greater with 2 mL versus 1 mL of solution in the medial to lateral (27.9 [7.8] mm vs 23.7 [6.0] mm; P = .05) and distal to proximal (52.1 [13.7] mm vs 40.4 [16.1] mm; P = .01) planes. No differences were observed in extravasation extent between surgeons.Conclusion:Injection for IDN was accurate, and extravasation extended into adjacent webspaces in a large percentage of specimens with both solution volumes. Lower extent of extravasation with 1 mL of solution did not indicate better selectivity of injection.Clinical Relevance:Steroid injections for interdigital neuroma were accurate for therapeutic purposes but not diagnostic, except potentially for distinguishing webspace pain from joint pain.

One hundred fifteen patients with signs and symptoms of Mortons' interdigital neuroma were studied in an attempt to evaluate the efficacy of a staged treatment program. The first stage consisted of patient education, footwear modifications, and metatarsal head relief. The second stage consisted of a steroid/local anesthetic injection into the affected interspace. The third stage was surgical excision of the inflamed interdigital nerve. Overall, 97 of 115 patients (85%) believed that they had improved with the treatment program. Twenty-four patients (21%) eventually required surgical excision of the nerve and 23 of 24 patients (96%) had satisfactory results. The results of the staged treatment protocol were very satisfactory and patient satisfaction was high.

Subtle compressive neuropathies of the foot and ankle can cause weakness in the foot that affects athletic performance, especially in runners or jumpers. Detection of these syndromes requires a knowledge of the sensory distribution and anatomic course of the peripheral nerves in the foot and ankle. Most compressive neuropathies can be treated with standard conservative measures; however, if chronic pain causes significant disability, surgical treatment may be indicated.

To The Editor: In regard to "Operative Treatment of Interdigital Neuroma. A Long-Term Follow-up Study" (2001;83:1321-8), by Coughlin and Pinsonneault, we would like to congratulate the authors on the large number of patients that they have treated surgically and on their high rate of satisfactory results. Nevertheless, we think that they should have included some imaging studies (echography or magnetic resonance imaging, with or without gadolinium) that could positively demonstrate the existence of an interdigital neuroma1. While these tests are not totally exact, echography has shown a sensitivity of 100% and a specificity of 83.3%2, and magnetic resonance imaging has demonstrated a correlation with the operative findings in 84% of cases3. These studies are even more necessary for the assessment of surgically treated lesions with unsatisfactory results. Another omission in the article involved the pathological reports of the histological findings in the removed tumors. This information would have been interesting, since some authors hold …

Recurrent or persistent symptoms following surgical neurectomy for an interdigital neuroma are quite common, because of incorrect initial diagnosis, true neuroma formation, nerve stump adhesions, accessory nerve branches, or an adjacent web space neuroma. The clinical presentation of a recurrent neuroma is similar to the initial presentation. Recurrent symptoms usually occur within the first 12 months after surgery. The physical examination coupled with diagnostic nerve blocks is critical for diagnosis. Conservative therapy, although not particularly effective in treating true recurrent neuromas, may help to alleviate pain. With proper isolation of the instigating neuroma, revision surgical excision can be effective.

Morton's neuroma, known also as intermetatarsal or interdigital neuroma, is a common foot injury that often curtails athletic activity. Nerve compression involving adjacent metatarsal heads and the transverse intermetatarsal ligament appears implicated in injury onset. Diagnosis is made clinically, and the condition typically causes initial symptoms of dull cramping or burning pain and more persistent sharp pain with nerve deterioration. Depending on injury severity, treatment is either conservative or surgical.

Fifteen patients (17 feet) with symptoms suggestive of plantar interdigital neuroma underwent magnetic resonance (MR) imaging at 1.5 T with a solenoid forefoot coil with an 8-cm field of view. Surgery was subsequently performed on six feet. Fifteen interdigital masses were identified with MR imaging. Five of these, in feet that underwent surgery, were pathologically confirmed neuromas. In the remaining foot that underwent surgery, flexor tendon injury with probable inflammatory reaction was demonstrated with MR imaging but was interpreted as indeterminate for neuroma. No neuronal was identified at surgery, which otherwise confirmed the MR imaging findings. Neuromas were most conspicuous on T1-weighted images as foci of decreased signal intensity well demarcated from adjacent fat tissue. The lesions were poorly seen on T2-weighted images, where they appeared isointense or slightly hypointense to fat tissue in all cases. Prominent regions of increased signal intensity, presumably representing fluid in intermetatarsal bursae, were seen proximal to 10 of the 15 masses found with MR imaging.

We studied 366 feet in 313 patients who underwent surgical treatment for a primary interdigital neuroma through a dorsal web-splitting incision. Three hundred five feet in 259 patients were available for follow up, which averaged 5.9 years (range: 2.8 to 13); 45.2% of these patients were completely satisfied, 33.8% were satisfied with minor reservations, 9.2% were satisfied with major reservations, and 11.8% were dissatisfied after the surgical procedure. Patient satisfaction was directly related to the size of the neuroma found at the time of operation. Bilateral procedures were associated with a higher rate of dissatisfaction. The third web space accounted for 91% of the neuromas.

To describe the procedure of ultrasound-guided Morton's neuroma and recurrent stump neuroma injections and early clinical outcomes after a single injection.Retrospective review of 44 percutaneous ultrasound-guided neuroma injections in 24 patients who had completed clinical outcomes questionnaires. A 10-point pain scale [scale of 1 (no pain) to 10 (severe pain)] in a 7-day pain log format was distributed to patients at the time percutaneous neuroma injection was performed.Neuromas were clearly visualized with sonography as hypoechoic nodules and were distinguishable from other causes of forefoot pain, such as metatarsophalangeal joint synovitis and intermetatarsal bursae. The sizes of the neuromas injected ranged between 4 and 19 mm. Postinjection, all neuromas displayed increased echogenicity and/or the appearance of fluid surrounding it, confirming localization of the therapeutic mixture. We arbitrarily subdivided the pain ratings into symptomatic (greater than 4) and asymptomatic (less than or equal to 4) for statistical analysis. Average pain level pre injection was 5.2 and average pain level was 3.7 at 7 days post single injection, with 62% of the initially symptomatic patients asymptomatic on day 7 (p0.000001). Overall, 76% of the total number of neuromas injected once were asymptomatic on day 7.Ultrasound can be used to accurately target Morton's neuromas and, therefore, appropriately direct therapeutic interventions, with good short-term clinical results.

Background: We examined a large cohort of patients who had interdigital neurectomy and evaluated their clinical outcomes by using a previously developed scoring system as well as a visual analog scale (VAS). In addition, we wanted to identify risk factors that may lead to poorer outcomes. Materials and Methods: A retrospective review identified 232 patients who had neuroma excision between 1994 and 2004, after failure of conservative treatment. Each patient was contacted via mail and given a Neuroma Clinical Evaluation Score survey as well as a visual analog score. Each patient received a unique identification number, allowing the evaluation process to be single-blinded. Results: Of the 232 patients contacted, 120 (52%) returned their completed surveys. The average Giannini neuroma score was 53: 61 feet (51%) had good or excellent results, 12 (10%) had fair results, and 48 (40%) had poor results. The average VAS score was 2.5. The only significant ( p = 0.027) difference in outcome was the location of the neuroma: second webspace had worse outcomes than third webspace neuromas on both the VAS and neuroma score. Conclusion: This retrospective review identified location in the second webspace as a possible prognostic indicator of poor outcome, but the more important finding may be that outcomes of neuroma excision do not appear to be as successful at long-term followup as previously reported

The purpose of this study is to evaluate the effectiveness of sonography to accurately identify interdigital neuromas. Twenty patients, all complaining of interdigital neuroma type pain, underwent sonographic evaluation of the symptomatic intermetatarsal space and adjacent interspaces. Each patient subsequently had surgical exploration of the symptomatic site. Fourteen patients had sonographic evidence of neuromas which were confirmed surgically; one patient had sonographic evidence of a neuroma that was not confirmed surgically. The remaining five patients did not have sonographic or surgical evidence of neuroma in spite of clinical signs and symptoms. No adjacent neuromas were appreciated. The correlation of sonography and clinical measurements was determined using Pearson's product moment correlation coefficient (r = 0.804, p < 0.001). Measurements performed with ultrasound were highly correlated with surgical findings. The mean size (standard deviation) of neuromas identified with ultrasound and during surgical inspection was 5.35 mm. (1.36) and 5.43 mm. (1.04). Ultrasound demonstrated a sensitivity of 100% and a specificity of 83.3%. Ultrasound was able to accurately predict the presence, size, and location of Morton's neuromas.

Several reports demonstrated that the interdigital neuroma is a form of entrapment neuropathy. Nonoperative measures may provide satisfactory results to some patients, but surgical treatment seems to provide more predictable results and lasting pain relief. Neurectomy remains the most commonly used procedure for the treatment of interdigital neuritis through a plantar or a dorsal approach. Outcome results after neurectomy note a failure rate of 2% to 35%.

Introduction: An interdigital neuroma is a common source of forefoot pain, and while second metatarsophalangeal joint instability is a less common entity, it can be a concomitant source of pain. The purpose of this study was to evaluate the long-term clinical course and surgical outcomes of the treatment of these concomitant problems.Methods: 121 consecutive patients (131 feet and 136 neuromas) were evaluated and treated for a symptomatic interdigital neuroma from 1981 to 1997. Of these, 24 patients (20%) had a concurrent interdigital neuroma (IDN) and second metatarsophalangeal (MTP) capsular instability that underwent surgical treatment. At the final follow-up examination, 20 patients (21 feet) were evaluated by an independent orthopaedic surgeon with a standardized clinical and radiographic examination, patient self-assessment and outcome measures.Results: Overall, there were 18 females and two males (21 feet) treated with an average age of 54 years at the time of surgery that returned for examination and follow-up at an average of 80 months (48 to 108 months) following surgery. Seventeen patients (85%) rated their result as good or excellent and three as fair. Six patients had mild continued symptoms referable to the second toe and none to the neuroma. Simultaneous neuroma excision and second MTP stabilization was performed in 15 cases and in six cases a staged repair was performed. The mean visual analog pain score was 1.4 (0 = no pain, 10 = severe pain) and mean MHAQ score was 1.13 (1–1.625) with activity modification stemming from hip, back and knee complaints.Conclusion: With careful patient selection and preoperative assessment, resection of an interdigital neuroma and stabilization of second metatarsophalangeal joint instability resulted in a high percentage of successful results at greater than four years following the procedure. Objective results were comparable to previous reports on the surgical treatment of isolated interdigital neuroma and crossover second toe reconstruction. Subjective patient satisfaction was high but both subjective and objective results were lower in patients with persistent symptoms of MTP instability.

We retrospectively reviewed the records of 20 patients (21 feet) with previous interdigital neuroma resections and symptoms suggestive for, but not diagnostic of, recurrent neuroma. Sonography was performed when clinical findings supplemented by local anesthetic block did not conclusively confirm the presence of recurrent neuroma. Studies performed in 13 patients (14 feet) were positive for recurrent neuromas. Three studies were indeterminate. The remaining four studies were negative for recurrent neuroma. The ultrasound studies were performed at an average of 19.2 months (range, 2–82 months) after the resection. Nine patients with 11 previous interdigital neuromas underwent ultrasonographic examination of the forefoot and subsequent revision neuroma resection. At surgery, gross and histologic findings were consistent with recurrent neuroma in 10 of 11 cases; one patient was found to have metatarsal-phalangeal synovitis. Ultrasonography appears to be a useful means for confirming neuroma recurrence in patients with symptoms after interdigital neurectomy when the diagnosis is not clear on physical examination.

Between 1984 and 1990, 172 plantar incisions were used in 137 patients. Eighty-nine of these patients returned for a personal interview and examination, twenty-six were interviewed by telephone, and twenty-two were lost to follow-up. Of the eighty-nine patients (124 incisions) who returned for follow-up examination at an average of twenty-five months (range, six to seventy-seven months), eighty-five (96 per cent) were pleased with the result of the plantar incision. None of these patients had altered their activities, and only three had modified their selection of footwear. Of the twenty-six patients who were interviewed by telephone, twenty-five (96 per cent) were pleased with the result. Thus, 110 (96 per cent) of 115 patients (150 plantar incisions) were satisfied with the result. The plantar incision may be used for resection of an interdigital neuroma (primary or recurrent); drainage of an abscess; removal of a foreign body; sesamoidectomy; lateral release of the first metatarsophalangeal joint; or excision of an invaginated keratotic plug (intractable plantar keratosis), a metatarsal head, the plantar aspect of a metatarsal head, or an intermetatarsal bursa.

In a series of 89 neurectomies, the occurrence of a second primary interdigital neuroma was less than 4%. The clinical presentation and results of surgery were similar to those of a single interdigital neuroma. Two of five patients with a suspected second neuroma in the same foot did not have this entity, but instead had had the incorrect interspace operated on by the previous surgeon. The entity of a second neuroma is truly rare, especially if careful evaluation for correct diagnosis and interspace is done.

Dissections of the common digital nerve and its branches were performed in the second and third web spaces in five fresh-frozen cadaveric feet. Plantarly directed nerve tetherings, which were histologically demonstrated to be nerve branches, were consistently present along the course of each common digital nerve. These plantarly directed nerve branches were found in highest concentration in the distal aspect of the common digital nerve proximal to the bifurcation into the proper digital branches. The presence of these nerve branches may contribute to the high incidence of Morton's neuroma recurrence either due to traumatic neuroma formation in the branches or to failure of proximal retraction of the more distally resected nerve stump.

Malignant Schwannoma is a rare tumour of nerve sheath origin commonly associated with neurofibromatosis. A solitary tumour of plantar digital nerves in the absence of neurofibromatosis is even rarer and only one such case has been previously reported. 1 We present the case of a patient who presented with symptoms and signs clinically diagnostic of a Morton's interdigital neuroma localized in the web space between the hallux and the index toe. The patient had no external features of Von Recklinghausen's neurofibromatosis (VRN) yet excisional biopsy revealed a malignant Schwannoma.