Morton’s Neuroma Revisited

Thank you all so much for your comments and support. I have received a lot of feedback and fantastic questions about the Morton’s neuromas (MN) post and your problems with diagnosis and treatment of such. This area of the foot can indeed be terribly confounding and difficult to diagnose. I want to help you all as much as I can with this conundrum, and I would love to answer each and every one of you individually, but I just can’t and shouldn’t in this setting.

If you have been labeled with the diagnosis of a Morton’s neuroma and various treatments are not working so well, maybe you don’t have a Morton’s neuroma.

The MN diagnosis is made way too often. Why? Here are some misconceptions that surround the dreaded Morton’s neuroma that can lead us astray:

• MN’s are really common. Actually, they are not common, especially a 2nd web space MN (15%, my opinion, almost ZERO percent). Even the 3rd web space MN is not common. If your doc is indicating a 2nd web space MN, question it and consider the much more common 2nd MTP synovitis (inflammation of the central ball joint). If they are thinking 1st or 4th web space, RUN.

• MN diagnosis is SEXY. We docs just got to make that diagnosis. “You have a Morton’s neuroma”. It has teeth. It sounds so definitive and sure. It is like a golf ball set up on a tee just waiting to be shanked.

• MN’s are easy to diagnose. Actually, they are not easy to diagnose. I have done this for 27 years, and now more than ever, I am even more cautious, and I respect making this diagnosis more than ever. It is actually a diagnosis of exclusion. This means that I rule out the other possibilities to the best of my ability before making the call of a MN. Too many good docs jump right to this diagnosis. It has to be the last diagnosis, and even then, I am often not as sure as I would typically like to be.

• “You have a Mulder’s click”. This is a physical finding that is rarely helpful, but boy, do we love it.

• The MRI and more recently, ultrasound have not helped matters either. In fact, those who rely on these tests are increasingly trying to make a claim regarding their diagnostic prowess, which is not true. Stick to old-fashioned history and exam.

• MN may be all your doctor knows. What I mean is, if there is forefoot pain, MN seems to be the go-to diagnosis. Remember, it is sexy.

Basically, central forefoot (2nd, 3rd, 4th metatarsal head region, not 1st or 5th) pain that starts in an otherwise normal foot can be divvied up into four basic diagnoses the great majority of the time. There are several more possible diagnoses that are uncommon and frankly, outliers that are not discussed here, such as Freiberg’s infraction, inflammatory arthritis (rheumatoid), etc. Here are the names and the diagnostic criteria, according to the AO. Keep in mind that the majority of these can be diagnosed by history alone and an MRI or an ultra sound is generally not needed in any of these. In fact, they are a waste of time and money. If your doc is quick to say they need an MRI  to make the diagnosis consider another route. I’m not sayin’, I’m just sayin’. Exam is important, but only to support and confirm the history. By the way, no matter what you think or hear, none of these ever have a history of actual causative acute trauma. If you have a history of trauma and you have one of these, I would say True-True-Unrelated. Finally, I am not discussing treatment. The treatment of each of these is clear-cut as long as one is confident in the diagnosis, which is what this is about. Intractable plantar keratosis (IPK) or plantar corn or callus

• Generally older, 50 yo plus, but can be any adult

• Pain is on the bottom

• Insidious slow onset, present for some time

• Visible seed, small tight callus that is exquisitely tender to touch.

• No swelling

• You would have to be brain dead to miss this one.

• Pain only with weight bearing

• Worse on barefoot, especially on a hard floor, better in shoes, carpet

• When it comes to trauma, this one could be the exception. If there is bonafide past or remote trauma to your foot/metatarsal or previous surgery that leads you to have a residual unevenness to the weight bearing surface of your metatarsals, then you could develop an IPK form that.

• X-rays negative

• Can be confused with a plantar wart.

  
  

  Metatarsal neck stress fracture

  
  

• Ages 20's on up

• Military recruits, boot camp, “march fracture”

• Distance runners, any age, training error

• 50+ female>>male

• Recent rapid onset

• Recent rise in activity level, especially number of steps! Normal activity (fewer steps per day) with a change to many more steps per day, vacation, new exercise program, etc. Or lower activity, as in being down from prolonged inactivity, i.e., illness, heading back to your normal activity level. Jumping out of the back of a pickup truck and breaking your metatarsal is an acute fracture, not a stress fracture, and is different.

• Pain on top of foot

• Swelling top of foot

• Usually 2nd metatarsal, next to big toe metatarsal

• Pain with weight bearing, with or with out shoes

• X-rays negative in first 21 days, then new reparative bone formation is seen and sometimes the fracture is seen.

• MRI, again, is a waste of time unless your doc owns the MRI, then at least one of you benefits.

  
  

  Morton’s neuroma

• Adults, peak age 40’s thru 50’s.

• Insidious onset, often years.

• Unlike all the others, at first and often even later, the location of the pain can be vague; it can’t be pinpointed. It can be frustrating for both the patient and the doctor.

• Pain is mostly in the bottom.

• Can take a while to get started with standing/walking.

• Worse in confining shoes, better in sandals or barefoot.

• NO SWELLING..............EVER. Whoops, caps lock and BOLD on again.

• Can feel swollen, however. Numbness can feel like swelling. Remember the last time you got home from the dentist and you looked in the mirror because you were sure that your tongue was hanging out of your mouth only to find out all was well. I rest my case.

• There can be a sensation of actual, perceptible numbness between the two affected toes that border the neuroma. This sensation or finding by your doc is extremely variable and unreliable. Its presence or absence really means nothing. I basically ignore it, except to support my other findings.

• Mulder’s click is a useless finding. It’s absence means nothing. While I do dismiss it, a Mulder’s click may be supportive if, when performed, it pretty much recreates your pain exactly.

• 3rd web...85-90%, 2nd web 10-15%, 1st or 4th web.......not.

• These are two experiences that get my attention and often have meaning, but only supportive with other findings and history:

  • feeling of folded sock bottom of foot

  • urge to take off shoes and rub foot. Does not matter whether you actually ever do it, it is just the urge part.

Second MTP synovitis (AKA, capsulitis, pre-dislocation syndrome)

• Majority in specific demographic,  55 +/- yo female

• Not mentioned as a differential diagnosis on Mayo or WebMD sites, but capsulitis is right there on Wikipedia.

• By and far the most common of these four diagnoses

• Primarily 2nd metatarsal. Infrequently, the 3rd.

• Insidious onset, few days to weeks.

• Swelling top and bottom often, but not always.

• Painful “lump” or “rock” under the ball of the foot. Pain is perceived at the bottom of the foot.

• Worse on a hard floor barefoot, better on carpet or cushioned shoes.

• Sometimes there is the perception of some form of trauma, but any trauma is just the “straw that broke the camel's back” phenomenon, or the patient's "theory" of causation. For instance, dancing in heels at a wedding could get it started. But here is something you MUST know; it was going to start eventually anyway because it is a result of:

  • Mostly, these occur as a result of calves that are too tight, which places more pressure on the forefoot/metatarsal heads. This represents a more recent change, and why this is happening now and not before.

  • It occurs at the 2nd metatarsal due to basic human anatomy; the 2nd metatarsal is the most prominent in almost all of us. This has been your anatomy forever. Your doctor might refer to your 2nd metatarsal as “too long,” but let this point sink in: it has been that length all your life. Seriously, it isn’t as if your metatarsal suddenly (and magically) grew longer. Now, refer back to calves. This is what changed!.

  • Transfer metatarsalgia secondary to a bunion. Often blamed, but the calves that are too tight are the larger reason this is going on at this point in your life.

• When this problem is left untreated, eventually a hammertoe will develop if the swelling is allowed to persist. Hey, here is a novel idea, if this is going on, start stretching your calves. The great majority of isolated 2nd and/or 3rd hammertoes result from MTP synovitis, which comes from calves that are too tight, which is almost entirely preventable as long as you stretch your calves.

• Often, the inflammation from the 2nd MTP synovitis can irritate the adjacent 2nd web space nerve, causing neuritis, which is a secondary thing and not a Morton’s neuroma. If you are reading this, you likely fit into one of these four groups. Certainly, you’ve gotten loads of information from the stranger on the bus next to you, or your nosey neighbor (everybody is an expert), or from the internet, or even your doctor. Again, the mere fact that you are reading this means things probably aren’t going so well. No matter what you have heard from these random sources, statistically, your problem is second MTP synovitis, and not a Morton’s neuroma.

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