MORTONS NEUROMA: HOW TO AVOID THE KNIFE WITH THIS DIAGNOSIS

I find little discussion on the true etiology of Mortons Neuroma.  I will propose some thoughts on the etiology of this common condition and a case study on the successful conservative treatment of this complicated case.

I find Mortons Neuromas to be related to lateral column over load of the foot structure.  This can be caused by a various problems, including tibial varum, both structural and functional (functional being related to the limb varus commonly associated with running), met adductus, structural hindfoot varus, forefoot valgus (lateral column hypermobility), and functional hallux limitus (FHL).  One of the common compensatory mechanisms to FHL is to lateralize the foot in propulsion as the first MTPJ cannot bend to allow the body to progress normally over the foot.

Of these possible etiologies, only forefoot valgus and FHL are correctable with conservative care. Functional tibial varum, or limb varus, may be correctable with proper training guidelines. I find that FHL and FF valgus are often co-morbidities.

My review of this problem shows that a full 95 % of patients will demonstrate a positive FHL test that complain of lateral forefoot overload.  Do not neglect to check for this disorder anytime you see a Mortons Neuroma.  Addressing this will have profound implications for your success rates in dealing with this population of individuals, and orthotics alone are often not sufficient.  Addressing first ray function is critical to the successful treatment of these individuals, in my opinion.

I would like to present this case for your interest and get your feedback on the biomechanics of Mortons Neuroma

At 30 years of age she had already had 3 surgeries for a mortons neuroma, on the left foot a bunion surgery on the right and removal of a cyst from the big toe left.  She walked into my office with pain on the ball of her left foot where the neuroma had been removed and heel pain on the right, seeking a solution.

The surgeon had removed a neuroma twice and shortened the fourth metatarsal in an attempt to alleviate her discomfort, without success. Custom orthotics had failed. Heel pain was now developing on the opposite foot and she was ready for a solution to her problems.  Life was not pleasant for this 30 year old with 3 active children and a husband in Iraq.

She presented with evidence of lateral forefoot overload with callouses under metatarsals 3 and 4.  A bilateral functional hallux limitus was appreciated both on clinical exam and gait analysis. Her heel on the opposite foot was tender over the abductor hallucis without evidence of tarsal tunnel syndrome or calcaneal stress fracture. She had 10 degrees of ankle dorsiflexion bilaterally with the knee extended. Symptoms in the heel were present first thing in the morning and improved to a degree with activity.  Heel resting stance position demonstrated a vertical heel position without significant tibial varum.  Radiographs showed about 1 cm. of shortening of the fourth metatarsal relative to the third. There was no evidence of a soft tissue lesion in the third interspace clinically.

What is your diagnosis?  What would you do?  There are a lot of possibilities here and I decided to take a simple approach first. Just to rule out mechanical overload laterally from a functional hallux limitus, I treated the functional hallux limitus.  A Cluffy Wedge (CW) was utilized on a Powerstep insole as the carriage for the CW. She was instructed to walk more medially, feeling like she was rolling off her big toe. She left my office feeling less pressure on the ball of her foot. Three weeks later she returned to the office.  She stated  “ I have absolutely no pain in either foot.”

What do you think, and how do you address Mortons Neuroma conservatively?  What orthotic modifications would you do to address the specific needs of this pathology?  Are you finding much success with conservative treatment of this condition?