I had a ProLab client call who had a patient developing neuritic pain in her toes. Several weeks ago he dispensed a hallux limitus pathology specific orthosis to treat pain in the great toe joint. Six weeks later she has had a complete resolution of her first MPJ pain but now has pain and numbness in digits 2, 3, and 4.
What likely occured is that the reverse Morton’s extension that is included in this orthotic prescription increased pressure under the metatarsal heads enough to cause a neuritis.
A reverse Morton’s extension is one of the most effective orthotic modifications in cases of hallux limitus and plantar fasciitis. The reverse Morton’s extension is a piece of 1/8” Korex placed under metatarsal heads 2 – 5. This allows the first ray to plantarflex and thus decreases compression forces within the first metatarsal phalangeal joint and reduces tensile forces on the plantar fascia.
We advocate the use of the reverse Morton’s extension to enhance orthotic therapy in the pathologies of hallux limitus and plantar fascitits. It is very effective and is the most common extension that we add to orthoses.
Be aware, however, that a reverse Morton’s extension increases force under metartarsal heads 2 – 5. This increased force will occasionally cause neuritic symptoms to occur in the ball of the foot or in the digits. Symptoms can be similar to a neuroma.
If your patient complains of neuritic symptoms after the application of a reverse Morton’s extension, simply remove or thin the extension. I have found that symptoms go away almost immediately. Our client used their grinder to thin the extension and will see the patient in a couple weeks. If she still has symptoms, he will remove it completely.
It’s a good idea to warn the patient this may happen. In my office we include this information in our dispense forms.
ProLab clients have access to our Medical Consultants to help troubleshoot all orthotic issues. Information on becoming a ProLab client is available here.