What is it?
Morton’s neuroma is a benign growth on the nerve that runs between the metatarsal bones and supply sensation to the toes. Most commonly, Morton’s neuroma develops between the 3rd and 4th metatarsal heads. When the growth gets compressed, between the metatarsal bones, it causes pain. Typically, the pain is on the ball of the foot and may radiate to the ends of the toes. “Nervy” symptoms such as shooting, tingling, burning, or zapping are common.
This condition usually develops because of microtrauma to the nerve. This microtrauma happens because there is not much space for the nerve to pass between two metatarsal bones (on either side of the nerve), the ground (underneath the nerve), and the deep transverse ligament (on top of the nerve). Add compression and pressure to an already small space and you have a recipe for Morton’s neuroma. Compression is added by tight or pointed footwear, heeled footwear, overpronation, generally wide feet, hammer toes and bunions (makes shoes tighter).
Diagnosis can be made clinically based on history, symptoms and in-clinic testing. Findings can be confirmed via imaging such as ultrasound or MRI.
So how do you treat it?
Firstly, it is best to talk to a foot specialist such as a chiropodist about your condition. You will be guided through treatment using conservative treatments first, then progressing based on how the foot responds. The goal is 80-100% resolution
Conservative treatments include general rest, activity modification to avoid aggravating activities, footwear changes to wider fitting shoes, and custom foot orthotics with metatarsal pads.
If conservative measures fail, there are injection therapies which are quite effective. Typically, cortisone injections are used first. Cortisone is a potent anti-inflammatory that can be injected into the area 1-3 times based on how symptoms react to the first injection.
If cortisone does not help, denatured alcohol injections are a logical next step. These injections are performed weekly for 4-7 weeks. Alcohol concentrations vary from practitioner to practitioner between 4-20%. The lower concentrations minimize risk of post-injection pain, so many practitioners opt to use 4% concentration. The goal of the alcohol injections is to gradually desensitize the nerve and reduce the size of the neuroma. These weekly injections are continued until complete resolution or until they are no longer making improvement.
If all treatments up to this point have failed, then surgery should be considered. There are two commonly performed surgeries. 1 – a neurectomy. A neurectomy is the surgical excision of the neuroma. Lasting side effects include numbness to the toes the nerve supplies (usually 3rd and 4th). The other surgery performed is a deep transverse ligament transection. In this surgery, the nerve and neuroma are left in tact. Instead, the deep transverse ligament is cut, which gives the nerve more space so it is no longer irritated. As with any injury, surgery should be considered last resort as there is higher chance of post-op complications such as infection and prolonged healing.
I hope this was an informative review of current practice guidelines on treating morton’s neuroma. If you have any pain on the ball of the foot, be sure to contact a chiropodist for an assessment and treatment.
This blog was written by Jake Cahoon and is not necessarily the opinion of The Footcare Centre.