Morton’s Neuroma Injections
Ross A. Hauser, MD. Danielle R. Steilen-Matias, MMS, PA-C.
Morton’s Neuroma Injections
Many of the foot pain patients that we see in our clinic, come in with an extensive history of what they did to try to treat their foot problems. They are extensive because many of these people work at jobs that require a lot of physical demand including being on their feet all day, or they are competitive or recreational runners who are still trying to run through the pain. Some patients are women who have foot pain and numbness after a lifetime of tight shoes and high heels. Women are also more prone to suffering from Morton’s Neuroma if they are overweight. (1)
These patients will tell us about foot pain accompanied by tingling or numbness or a sensation like they have a pebble in their shoe. They will further describe a pain in the center of their foot that becomes acute upon “foot strike,” or “putting weight on it.” Sometimes they will describe a snapping or cracking sensation and a shooting burning kind of nerve pain. When they describe these symptoms to us, we start to suspect Morton’s Neuroma. This means that the nerves that travel in between the bones of the foot have become impinged or squeezed.
Morton’s Neuroma: When foot bones collide
The bones in the foot are unstable forces, meaning that the connective tissues that are holding them together and in place have been weakened. When the bones collide, they squeeze everything between them including the nerves. If those bones are moving so much that they are putting continuous pressure on the nerves, the nerve will swell. Thus, Morton’s neuroma occurs in a digital nerve in the foot, often between the third and fourth toes. The foot bone instability, which may be a result of ligament or tendon weakness., can cause a thickening of tissue around a digital nerve.
In this video, Ross Hauser, MD. describes instability in the metatarsal joints as a common cause for foot problems including Morton’s Neuroma.
- On physical examination, when instability in the metatarsal joints is suspected, we commonly hear a clicking sound when the toes or the metatarsal joints are compressed, or in this examination, gently squeezed together. When we hear the clicking sounds, this is our first sign that there is instability in the foot causing hypermobility in the joint. This compression action is called a Mulder’s Sign, the noise a Mulder’s Click.
- At 1:07 of the video and ultrasound examination displays the foot instability.
- We treat this problem with simple dextrose Prolotherapy. The treatment is explained in detail below. Prolotherapy addresses the instability by strengthening the connective tissue, the ligaments, that hold the bones in place. Typical 2 – 5 treatments will be needed to resolve Morton’s Neuroma.
- As we mentioned above, Morton’s neuroma is typically diagnosed from the symptom of burning pain in a toe or toes. Although this burning pain and numbness may be due to nerve entrapment, it may also find its origins in problems of damaged ligaments and tendons.
A typical patient that we suspect of having Morton’s Neuroma will usually describe their medical history as:
- A series of x-rays, scans, ultrasounds, and MRIs basically pained an “inconclusive picture.”
- Trips to the general practitioner, referral to the podiatrist, referral to the orthopedic surgeon, and the ultimate recommendation for surgery.
- To delay or see if surgery can be avoided, a series of “conservative care recommendations” are offered.
- Avoid walking barefoot
- A steady regiment of icing
- Shoe inserts and pads
- New shoes, especially extra wide shoes
- Walking boot
While some of these recommendations may be effective in providing symptom relief, they may not do enough. Many patients have graduated onto more extensive conservative care treatments. This would include:
- Physical therapy
- Shockwave therapy
These conventional therapies, and more including rest, weight loss, massage therapy, manipulation, analgesics, non-steroidal anti-inflammatory drugs, anti-depressant medications, trigger point injections often result in residual pain for the patients.
Why is treatment Morton’s Neuroma ineffective? “The condition is degenerative rather than neoplastic”
As pointed out Morton’s Neuroma can be a controversial diagnosis. This is pointed out in an August 2021 update (2) to the United States Library of Congress’ medical publication STAT PEARLS. “Morton’s neuroma is a compressive neuropathy of the forefoot interdigital nerve. Neuropathy is chiefly due to compression and irritation at the plantar aspect of the transverse intermetatarsal ligament. It is not a true neuroma as the condition is degenerative rather than neoplastic (being caused by abnormal tissue growth as in cyst or tumor or other overgrowths).
Many people get relief from the various treatments we mentioned above. This article is for people who did not get relief or have the varying diagnoses that may describe a common foot problem. Those being as described in the above publication: “Morton metatarsalgia, interdigital neuritis, Morton entrapment, interdigital neuralgia, interdigital neuroma, interdigital nerve compression syndrome, and intermetatarsal neuroma.”
It is quite common for people with the diagnosis of a neuroma, or nerve entrapment, to undergo multiple surgeries attempting to alleviate the entrapment. One individual came to us with a history of 15 surgeries. Multiple surgeries occur primarily because most physicians incorrectly believe numbness is equated with a pinched nerve. Ligament and tendon weakness in the limb also cause chronic numbness in an extremity.
Despite years of experimental research and clinical investigation, the painful neuroma has remained difficult to prevent or to treat successfully when it occurs. More than 150 physical and chemical methods for treating neuromas have been utilized including suturing, covering with silicone caps, injecting muscle or bone with chemicals such as alcohol, and many others.
Morton’s Neuroma treatments: Cortisone and beyond
Cortisone is given to reduce the inflammation on the nerve. While successful cortisone injections have side effects. Among the most common are skin atrophy, skin depigmentation, and damage to soft tissue around the neuroma such as the ligaments.
Doctors in the United Kingdom (3) assessed patients who received a cortisone injection for their Morton’s neuroma problem. They were looking for factors in the treatments that would allow them to predict who would need more treatments within 2 years of the single ultrasound-guided corticosteroid injection the patients received.
Of the treated feet:
54 patients (57 feet) were reviewed:
- 51% required further treatment within 2 years (11 repeat injections, 18 surgical excisions).
- Larger neuromas and younger patients were more likely to need further treatments.
In June 2017, hospital and university researchers in Barcelona published their findings on cortisone in the medical journal Foot and Ankle International. (4)
Here they write that the effectiveness of corticosteroid injection for the treatment of Morton’s neuroma is unclear and to see if they could make it clearer that reviewed 41 patients with a diagnosis of Morton’s neuroma.
- The 41 patients were randomized to receive 3 injections of either a corticosteroid plus a local anesthetic or a local anesthetic alone.
- The results they found was that there were no significant between-group differences in terms of pain and function improvement at 3 and 6 months after treatment completion in comparison with baseline values.
- At the end of the study, 17 (48.5%) patients requested surgical excision of the neuroma: 7 (44%) in the experimental group and 10 (53%) in the control group.
- The injection of a corticosteroid plus a local anesthetic was not superior to a local anesthetic alone in terms of pain and function improvement in patients with Morton’s neuroma.
In November 2019, foot specialists from the University Hospitals of Leicester in the United Kingdom published a comparison review of “nine different non-operative treatment modalities (for Morton’s Neuroma); Corticosteroid injection, Alcohol injection, Extra-corporeal Shockwave therapy (ESWT), Radiofrequency Ablation (RFA), Cryoablation, Capsaicin injection, Botulinum toxin, Orthosis, and YAG Laser Therapy, in the European Journal of Foot and Ankle Surgery. (5) When compared against the other 8 treatments the researchers: “would recommend the use of corticosteroid injections to treat Morton’s neuromas.”
Side-effects and only short-term relief with cortisone injections for Morton’s Neuroma
In June 2021 doctors publishing in the journal Clinics in Orthopedic Surgery (6) offered an assessment of cortisone injections for Morton’s Neuroma. The highlights of their findings were as noted:
- “Corticosteroid injections showed a satisfactory clinical outcome in patients with Morton’s interdigital neuroma although (the researchers) found that 140 subjects out of 469 study patients (29.85%) eventually underwent surgery after receiving corticosteroid injections due to persistent pain.
The initial success of treatment:
- “At three to twelve months of follow-up, corticosteroid injections provided satisfactory outcomes based on (standard) satisfaction scores.
- Standard pain scores showed that maximal pain reduction appeared at 1 week to 3 months.
- After 3 months, the cortisone benefits ended as patient-reported pain scores increased again by 6 months.
- Regarding multiple steroid injections, three or four injections over 6 months seem to be safe and avoid unwanted complications, although there was a lack of good quality studies about multiple injections. Skin depigmentation and skin or fat pat atrophy were reported as minor complications.
A June 2020 study in the journal Pain and Therapy (7) explored different injection techniques for Morton’s Neuroma. In the discussion about cortisone, the researchers, led by Harvard Medical School, noted:
“Steroid treatment is commonly used to alleviate symptoms (of Morton’s Neuroma) along with changes in footwear and stretching. Principal findings (in a previous study) showed that corticosteroid injections with local anesthetics did improve symptoms temporarily between the experimental and control groups. However, the beneficial effects diminished over a short period of time. In addition to the short-term effects, (research) also noted diminished short-term pain after injection in 73% of their patients. However, there were side effects that resulted in pain in the injection site, skin lesions, tissue alterations consist with “steroid flare,” tissue atrophy, and pigment alterations.”
Medium-term results of corticosteroid injections for Morton’s neuroma
An April 2021 study in the journal Foot and Ankle International (8) evaluated the medium-term results of corticosteroid injections for Morton’s neuroma. In this study, forty-five neuromas in 36 patients were injected with a single corticosteroid injection either with or without ultrasound guidance.
- At an average follow-up of 4.8 years, the original corticosteroid injection remained effective in 36% of the patients.
- 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% of the initial group underwent surgical excision by the medium-term follow-up.
Conclusion: “Corticosteroid injections for Morton’s neuroma remained effective in over a third of cases for up to almost 5 years.”
“Corticosteroid injections showed a satisfactory clinical outcome . . . in spite of almost 30% of included subjects eventually underwent operative treatment.”
A January 2022 study in the journal Foot and ankle orthopaedics (14) suggested “Corticosteroid injections showed a satisfactory clinical outcome in patients with Morton’s interdigital neuroma in spite of almost 30% of included subjects eventually underwent operative treatment.” The researchers also made a recommendation that future studies about the safety and effectiveness of multiple injections at the same site are highly necessary.
Is cortisone the best we can do? How about burning out the nerves?
In February 2019 researchers wrote in the Journal of Foot and Ankle Research (9) “Corticosteroid injections and manipulation/mobilization are the two interventions with the strongest evidence for pain reduction, however high-quality evidence for a gold standard intervention was not found.” This was also a comparison against extracorporeal shockwave therapy, Sclerosing (alcohol injections), Botox injections, radiofrequency ablation, and cryoneurolysis. The alcohol injections that burn out the nerve were found more effective in another study published in the journal Foot and Ankle Surgery, April 2019 (10). Here the researchers noted “Needle-electrode guided percutaneous alcoholization is an outpatient, minimally invasive procedure with a low rate of complications. Better results of those obtained with traditional conservative treatments and comparable with those reported with other alcohol injections or surgical nerve excision were observed.”
Surgical treatment for Morton’s Neuroma has been problematic with poor results and complications
Doctors at the Royal Infirmary of Edinburgh (11) wrote in the Bone and Joint Journal of examined patients who had excision of Morton’s neuroma. (The removal of the Neuroma and the nerve it was attached to – neurectomy).
- 49.5% of patients reported their overall satisfaction as excellent
- 29.3% of patients reported their overall satisfaction as good
- 8.1% of patients reported their overall satisfaction as poor
- 2% of patients reported their overall satisfaction as very poor
- Only 63 patients (63%) were pain-free at follow-up:
- in eight patients (8.1%), the score worsened.
There was no statistically significant difference in outcome between surgery on single or multiple sites. However, pain scores were significantly worse after repair or revision surgery
“The patient-reported outcomes after resection of 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.”
Doctors at the University of Tennessee suggest that approximately 80% of patients require surgical excision of neuromas for symptom relief. Although 50% to 85% of patients obtain relief after primary excision, symptoms may recur because of an incorrect diagnosis, inadequate resection, or adherence of pressure on a nerve stump neuroma. They suggest counseling patients on the increased possibility of more than one surgery. (12) It should be pointed out that the title of this research paper is “The recurrent Morton neuroma: what now?”
In October 2021, doctors writing in the journal Foot and ankle surgery (x) examined the effectiveness of operative treatments other than neurectomy for Morton’s neuroma as these other surgical incursions success remains debatable despite several reported studies. The researchers noted that although a number of studies with high level of evidence are limited, they could still divide them into four surgical-type categories:
- Neurolysis with or without nerve transposition (moving the nerve to an area where it is less likely to be compressed),
- minimally invasive nerve decompression, (releasing the transverse intermetatarsal ligament)
- metatarsal osteotomy, (cutting the metatarsal bone) and,
- additional procedures after nerve transection or neurectomy.
All categories showed reliable outcomes except minimally invasive nerve decompression. The proportion of postoperative neurogenic symptoms was lower with neurolysis than with neurectomy.
The researchers concluded: “Whether the alternative procedures were superior to neurectomy remains unclear as the number of good quality studies was limited. The proportion of postoperative neurogenic symptoms was lower with neurolysis (burning the nerve) than with neurectomy. Furthermore, performing simultaneous dorsal transposition (moving) of the nerve along with neurolysis is more recommended than neurolysis alone. Surgeons should be more careful with minimally invasive deep transverse intermetatarsal ligament release and metatarsal shortening osteotomy as their effectiveness remains inconclusive. Finally, we strongly recommend performing intramuscular embedding or intermuscular transposition of the nerve cutting end if neurectomy or nerve transection is inevitable. (Put the nerve is a place that is more accessible for the next surgery.)”
Our Research on Prolotherapy for Morton’s Neuroma
This is a summary of research from Caring Medical investigators published in the medical journal the Foot and Ankle Online Journal. (13)
This study investigates the effectiveness of Dextrose Prolotherapy injections on a group of patients with “Morton’s neuroma.”
The patients in the study had reported other previous treatments prior to beginning the Prolotherapy treatments.
Some patients had tried:
- wide-toed shoes,
- and steroid injections.
Some patients had had MRI and radiographic diagnoses. One of seventeen had seen a podiatrist. A physician told three patients that surgery was required, but only one had surgery to remedy the pain on the other foot.
The average length of time patients experienced the pain of Morton’s neuroma was 20 months before entering the clinic.
- Patients received an average of 3.7 Prolotherapy treatments.
Before treatment patients were asked to rate their pain levels on a scale of 0 to 10—with 0 being no pain and 10 being severe crippling pain (this scale is referred to as VAS).
All 17 patients reported pain as a symptom. Thus, patients were asked to report pain levels before and after Prolotherapy in these four categories:
1) pain at rest;
2) pain with normal activities;
3) pain with exercise, and
4) pain while walking barefoot.
Concerning 1) pain at rest:
Prior to Prolotherapy treatment, pain levels averaged VAS 4.68. None of the patients had a starting pain of less than three.
- After Prolotherapy treatment, VAS pain levels averaged 0.95 (less than 1 out of 10).
- Significant improvement was recorded.
Concerning 2) pain with normal activity and mobility:
Prior to Prolotherapy treatment, 15 of the 17 participants reported walking with some degree of pain, and a VAS pain level of 6.89.
- Eleven of 17 patients were unable to walk fifty feet without pain;
- 14 of 17 could not walk a half-mile without pain.
- Four of 17 patients reported an inability to walk barefoot.
- After Prolotherapy, all patients reported improvements in walking without pain, and a VAS pain level of 1.89.
- Fourteen of the 17 participants walked normally again and rated their pain relief at greater than 74%.
- Sixteen of the 17 could walk one block or more.
Concerning 3) pain with exercise:
Prior to Prolotherapy, 15 of the 17 patients reported decreased ability to exercise, and a VAS pain level of 7.27.
- Of those 15, eight were totally compromised and unable to exercise;
- five were moderately (only 30 to 60 minutes possible) to severely compromised (only 0 to 30 minutes possible).
Nearly half of the patients were totally compromised in their athletic abilities prior to treatment.
- After Prolotherapy, 5 of the 17 patients reported being able to exercise as much as they wanted without impediments and with satisfaction, with a VAS pain level of 1.73.
Other physical improvements occurred, notably, decreases in stiffness and numbness (burning). Thirteen to 14 patients reported a 100% improvement in the activities of daily living that continued to the end of the study. None reported an inability to exercise.
Concerning 4) pain while walking in bare feet:
- Prior to Prolotherapy treatment, 10 of 17 patients could not walk barefooted without severe pain at levels eight, nine, or ten, and an average VAS pain level of 6.47.
Furthermore, 12 of 17 patients could walk less than 50 feet before they experienced noticeable pain, with or without shoes. Only 3 of the 17 patients could walk more than a half-mile without pain.
- After Prolotherapy, all patients had a pain level of four or less walking barefooted, and a VAS pain level of 1.65. As for walking distances without pain, all patients could walk at least one block or more. One patient was restricted to walking between 50 feet and one block. Among the 19 treated feet of the 17 patients in the study, eighteen feet could manage walking a half-mile or more, eight of the treated feet reported no walking restrictions.
When comparing the four previous categories before and after Prolotherapy, all reached a statistically significant outcome.
This study justifies the desirability and use of Prolotherapy for Morton’s neuroma pain. Future studies need to further substantiate these findings, especially if Prolotherapy enables Morton’s neuroma sufferers to avoid surgery and its possible adverse effects.
Although a study with more patients in a controlled empirical setting is needed to document the efficacy of Dextrose Prolotherapy, this treatment should be considered, based on the substantial advantages and minimal drawbacks (e.g., aversion to needles), as well as the reduced risks and increased rewards of Prolotherapy over conventional treatments.
Demonstration of Prolotherapy treatment for Morton’s Neuroma
In this video, Danielle Matias, MMS, PA-C demonstrates and explains the Prolotherapy treatment for Morton’s Neuroma
Summary highlights of the video are below:
- Typically patients with Morton’s Neuroma get pain right in the ball of their feet. They may even have pain or numbness that radiates into their toes.
- Many patients we see have had cortisone shots or surgery and nothing has made their situation better and in fact, their situation is getting worse.
- In the treatment, injections are given at the ligament attachments at the top and bottom of the ball of the foot. The Prolotherapy injections help restore stability in the foot and prevent hypermobility and the pressure the foot bones are exerting on the nerves. Removing this pressure by getting the bones back where they belong will give the nerves a better chance of healing and restore natural foot stability.
- The patient in this video tolerates the treatments very well, typically 3 – 6 treatments are needed with more treatments that may be necessary for patients who have cortisone or surgical history.
Summary and contact us. Can we help you?
Most chronic foot pain and numbness are not primarily due to a nerve being pinched but due to weakness in the ligaments and soft tissue structures that support the ball of the foot and the arch. Prolotherapy injections start these areas to grow new and stronger tissue. Once this tissue gains normal strength the pain, numbness, and disability normally stop. If it does not, the nerve entrapment can be “unpinched” quickly and nonsurgically with Nerve Release Injection Therapy (NRIT). (Please see our article on Nerve Release Injection Therapy). In our office, we frequently combine dextrose Prolotherapy with Nerve Release Injection Therapy (NRIT) and/or Lyftogt Perineural Injection Therapy for nerve-related pain. This combined approach works well to correct the underlying joint instability, as well as free up and nourish the entrapped nerve.
While the exact cause of Morton’s neuroma (MN) is still debated, our research confirms Prolotherapy not only reduces levels of pain for patients with Morton’s Neuroma, but also enhances other quality of life concerns.
In our study as discussed above, we found that dextrose Prolotherapy was extremely effective at improving a number of pain factors: pain at rest; pain with normal activities; pain with exercise; pain while walking barefoot. Patients’ subjective experience of pain offers the best measure for statistical accuracy, and all patients in our study reported pain as a symptom. Patients were additionally asked about numbness levels and stiffness.
This prospective, non-controlled study demonstrated that Prolotherapy decreases pain and improves the quality of life for patients with Morton’s neuroma, which was unresolved by previous therapies, medications, and interventions. Prolotherapy provided relief of at least 74% for 14 out of 17 of the patients at least six months after their last treatment. Two out of three patients who were told they needed surgery prior to Prolotherapy, felt sufficient pain relief with Prolotherapy and were able to avoid surgery. After the study period, patients experienced overall improvement in range of motion, ability to walk and exercise, as well as relief of stiffness and numbness/burning.
We hope you found this article informative and it helped answer many of the questions you may have surrounding your foot problems. If you would like to get more information specific to your challenges of peroneal tendon injury and ankle instability, please email us: Get help and information from our Caring Medical staff
Brian Hutcheson, DC | Ross Hauser, MD | Danielle Steilen-Matias, PA-C
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This article was updated June 21, 2021