What Is Morton's Neuroma?
Morton’s neuroma is an inflammation of nerve tissue and it occurs in the foot, most often in the third or fourth toe. This is a benign, non-cancerous condition that’s often known in the medical setting as an intermetatarsal neuroma. It isn’t a malignant tumor, but a thickening of the tissue that surrounds the nerve.
As experts point out, Morton’s neuroma is more common in women, by a ratio of 5:1 compared to men. Its prevalence in the population is unknown, although evidence indicates that up to 33% of patients don’t develop symptoms. It’s for this reason that it may be more common than previously thought, as the signs are restricted to the level of inflammation in the nervous tissue.
Morton’s neuroma symptoms
Most neuromas of this type develop between the third and fourth toes. This is due to the fact that the space between the tissues in this area is narrower in relation to the others. At first, it may not manifest any symptoms, and these usually appear gradually. Here are the typical symptoms of Morton’s neuroma:
- Tingling or numbness in the foot (paresthesia)
- The sensation that there’s something on the bottom of the foot
- Pain in the heel
- Discomfort in the third or fourth toe
Symptoms usually worsen when people wear tight-fitting shoes or when they’re physically active. On the contrary, they reduce when the person removes the shoe and rests the feet from some type of activity. Sometimes, the inflammatory process is postponed for days or weeks, regardless of the factors mentioned.
Most of the episodes develop with a mild or moderate intensity, although, over the years, they can become more serious or intense. Everything is conditioned by the level of activity, and its early detection can help control its evolution. It’s important to note that the patient can’t see or feel the neuroma, as it isn’t a tumor (it’s just tissue inflammation).
Many patients describe Morton’s neuroma as feeling like a stone is in their shoe or sock. In fact, many people search in vain for an object inside their shoe, or think that there’s something wrong with the shoe. This sensation should be taken as a starting point to detect it in its initial state.
Causes of Morton’s neuroma
The causes of Morton’s neuroma aren’t fully understood. As we’ve already mentioned, physiologically the area is predisposed to inflammation compared to other surrounding areas, although there must be a trigger for the inflammatory process. Here are some of the main causes of this type of foot neuroma:
- Uneven weight distribution: This can occur from, among many other things, high arches, flat feet, or hammer toes. These alterations in the anatomy of the foot prevent the weight from being distributed evenly when walking, which can mediate inflammation of the tissue due to excess pressure.
- The use of certain types of shoes such as heeled shoes. These shift most of the weight to the toes and the front part of the foot, and not on the entire base of the foot. Shoes that are too tight or that don’t fit the shape of the foot can also have the same effect.
- High-impact activities: These include jogging, playing tennis or soccer, and other activities that cause a high impact on the feet. Climbing and hiking can also lead to these inflammatory processes, partly due to the type of footwear required to develop them and the terrain.
- Trauma: Another possible trigger is trauma to the forefoot area. Bumps and falls can cause the tissue to crack, which can evolve over time into temporary and then permanent inflammation.
Almost all cases can be explained by these triggers, although of course some episodes are a consequence of an underlying problem. For example, Morton’s neuroma is relatively common in people with Haglund’s deformity, synovial sarcoma, plantar cysts, bursitis, plantar warts, plantar fibromas, and dyshidrotic eczema.
Diagnosis of Morton’s neuroma
The diagnosis of Morton’s neuroma is relatively simple. First, the specialist will try to rule out other possible explanations for the symptoms, all of these based on the initial appointment. Imaging tests are then done, initially X-rays, ultrasounds, and MRIs.
Although all three are useful for detecting neuroma, experts consider MRI to be the gold standard (the most appropriate method).
This condition has many differential diagnoses. Foot fractures, muscle exhaustion, calluses, tendinitis, synovitis, tarsal tunnel syndrome, localized vasculitis, Freiberg’s disease, peripheral neuritis, bunions, and rheumatoid arthritis (among many others) must be ruled out. It’s important to consider all of these, as forefoot pain is often diagnosed as Morton’s neuroma.
Treatment options
The first option to treat Morton’s neuroma consists of conservative therapies. By this, we’re talking about resting, the application of cold or hot compresses, the use of special insoles and shoes, physiotherapy, weight loss (to reduce pressure on the sole) and the intake of over-the-counter pain relievers to alleviate pain (such as ibuprofen).
If these strategies don’t work, the patient can opt for injection therapy. This consists of the local administration of cortisone, anesthetics and other agents to eliminate the complications associated with the neuroma. In certain contexts, the specialist may suggest surgical intervention, although this is considered the last resort if previous therapies haven’t been effective.
The patient should know that a significant percentage of surgical interventions are not entirely successful. Among other things, this is due to misdiagnosis, incomplete extraction, complex regional pain syndrome, and recurrence episodes. For this reason, you should try the least invasive treatments, although you must also be open to the specialist’s suggestions.
- Bencardino, J., Rosenberg, Z. S., Beltran, J., Liu, X., & Marty-Delfaut, E. Morton’s neuroma: is it always symptomatic? American journal of roentgenology. 2000; 175(3): 649-653.
- Bhatia M, Thomson L. Morton’s neuroma – Current concepts review. J Clin Orthop Trauma. 2020;11(3):406-409.
- Munir, U., Tafti, D., & Morgan, S. Morton neuroma. 2017.
