Morton neuromas are focal areas of symptomatic perineural fibrosis around a plantar digital nerve of the foot. The abnormality is non-neoplastic and does not represent a true neuroma. It may more correctly be known as Morton?s metatarsalgia. The condition is thought to be due to chronic entrapment of the nerve by the intermetatarsal ligament. It most often occurs in middle-aged individuals and is many times more common in women than men. Approximately 30% of asymptomatic middle-aged persons have the radiological pathologic findings of a Morton?s neuroma.
The exact cause of Morton’s neuroma is not known. However, it is thought to develop as a result of long-standing (chronic) stress and irritation of a plantar digital nerve. There are a number of things that are thought to contribute to this. Some thickening (fibrosis) and swelling may then develop around a part of the nerve. This can look like a neuroma and can lead to compression of the nerve. Sometimes, other problems can contribute to the compression of the nerve. These include the growth of a fatty lump (called a lipoma) and also the formation of a fluid-filled sac that can form around a joint (a bursa). Also, inflammation in the joints in the foot next to one of the digital nerves can sometimes cause irritation of the nerve and lead to the symptoms of Morton’s neuroma.
Typically, there’s no outward sign of this condition, such as a lump. Instead, you may experience the following symptoms. A feeling as if you’re standing on a pebble in your shoe. A burning pain in the ball of your foot that may radiate into your toes. Tingling or numbness in your toes. It’s best not to ignore any foot pain that lasts longer than a few days. See your doctor if you experience a burning pain in the ball of your foot that’s not improving, despite changing your footwear and modifying activities that may cause stress to your foot.
In some cases your doctor will be able to feel the Morton’s as a swelling in the middle of your foot. However they may also suggest an X-ray or a blood test – this is normally to rule our other causes of the pain such as arthritis. The most accurate way to diagnose Morton?s itself is with magnetic resonance imaging (MRI) or ultrasound.
Non Surgical Treatment
Conservative treatment involves a reduction in the inflammation and removing the impingement factor. Reduction in inflammation is achieved via rest, elevation, ice, and massage with anti-inflammatory gels. Removing foot wear and and/r wearing broad type footwear would also help. Injection therapy is useful in reducing symptoms but not very successful in providing long term relief. The only time when it is most appropriate is when the cause of the space occupying object is not a neuroma but an inflamed bursa. Injection would help to relieve symptoms, and often cortisone is not even necessary.
Operative treatment of Morton?s neuroma should be entertained only after failure of non-operative management. Standard operative treatment involves identifying the nerve and cutting (resecting) it proximal to the point where it is irritated/injured. This is usually done through an incision on the top (dorsal) aspect of the foot, although an incision on the sole (plantar) aspect of the foot can be used. Some physicians will attempt to treat Morton?s neuroma by releasing the intermetatarsal ligament, and freeing the nerve of local scar tissue. This may also be beneficial.