What is a Morton’s Neuroma?
A Morton’s Neuroma is a swelling of a nerve that runs between the bones of the foot. There is pain on standing, which gets worse with time, especially when wearing closed leather shoes. The pain is usually, but not always, better in sandals, trainers and bare feet. The nerve entrapment leads to pins and needles in adjacent toes, or shooting pains. Sometimes the toes become splayed apart over time.
The symptoms of a Morton’s Neuroma can arise because the nerve is entrapped and has become swollen on one side – this makes the entrapment worse. Sometimes the symptoms are caused by a bag of fluid which forms as a lubricant between two bones. This bag can contain inflammatory chemicals that irritate the nerve.
The problem usually arises between the third and fourth toes, and the second and third toes. Between the third and fourth toes, lots of nerves come together.
If you have similar symptoms, it is best to see an orthopaedic surgeon who specialises in foot and ankle surgery. You should have x-rays taken in a standing position – this will allow other conditions of the forefoot to be excluded. There are lots of causes for pain in the forefoot, and Morton’s Neuroma is only one of them. If there is any doubt, then an MRI scan or an ultrasound scan may demonstrate a neuroma, but often they are not sensitive enough to pick them up. A full clinical examination and an injection is the best way to properly identify the neuroma.
How is the Surgery Performed?
The traditional approach to surgery for Morton’s Neuroma is to remove the nerve. The nerve is normally swollen as a result of pressure from adjacent bones or from inflammation around the nerve.
A cut is made on the top of the foot. The ligament between the bones is cut and the nerve is identified. The nerve is separated from the branches going into the toes and cut much higher up the foot.
The nerve is allowed to fall back so that it cannot be irritated.
As the nerve has been cut, there is a numb patch in between the two toes and under the foot itself. This is permanent.
One risk of surgery is that the raw end of the cut nerve can be very sensitive. Most patients are better and have a lot less pain after surgery. Some patients find that the pain is just as bad as it was prior to the operation and in a very few, it is worse. This occurs especially in the space between the third and fourth toe, where there are lots of nerve branches. If there is recurrence, then a second operation may be performed to cut the nerve back further.
One way to try to avoid cutting the nerve is by performing bony surgery around the nerve. This aims to relieve pressure on the nerve by decreasing the amount of load on the surrounding metatarsal bones. If this is unsuccessful, then the nerve may still need to be removed.
Surgery is carried out under general anaesthetic, but can be carried out with local anaesthetic injections behind the knee or around the ankle. The injections are normally given while you are asleep for your comfort. They can give good pain relief for the first day after the operation. You can go home the same day in the evening.
Risks of Surgery
Bleeding, infection, poor bone healing, poor skin healing, injury to tendons, injury to nerves, recurrence, and a need for further surgery.
There is a small risk of blood clots in the legs or lungs (DVT and PE), and there are also risks from anaesthesia – the process of being put to sleep for your operation.
Risks of Anaesthesia
The injection behind your knee is given using an ultrasound machine to guide the needle. There is a less than 1% chance of injury to the nerve. General anaesthetic also carries risks. These risks are proportional to your general health. You will need to be assessed for your fitness for surgery and an Anaesthetist will be able to advise you on your individual risk.
What Happens After Surgery?
You will have had injections to numb your foot so that you are not in pain after the operation. This injection will wear off after 18-24 hours, so you must take regular painkillers so that you are not in severe pain when the injection wears off. Ibuprofen and Diclofenac should not be used for more than a few days after the operation as they can interfere with bone healing.
The pain will settle over a few weeks. You may see blood stains on the dressings. This is normal and not a cause for alarm. If blood is dripping from the dressings however, return to hospital.
The foot will be swollen as well as sore. You should keep the foot elevated as much as possible for the first two weeks. Keep walking down to a minimum – going to the toilet or for meals. Letting the leg hang down will cause the foot to become more swollen. Most of the swelling will settle within the first few months, but swelling can continue for up to one year.
If you are resting on your sofa, keep your foot elevated on the back rest or arm rest. If you are resting in bed, then place a few pillows under the foot to keep it elevated.
If you have had bony surgery, you have been given a special shoe that does not allow you to put weight on the front of the foot. This is because the re-set bones are held together by screws, and putting weight on it can dislodge the screws holding the bone. You should wear this continuously for the first two weeks, including in bed. After that, you should wear it whenever you are walking, even at home. Crutches are for balance only.
If you have had nerve only surgery, then you will be given a flat shoe. This is for your comfort when walking, as the foot will not fit into a normal shoe with heavy dressings applied.
If you have had bony surgery, you should not perform exercises for the toes, but you can draw the alphabet in the air with your foot to keep the ankle and other joints mobile.
If you have had nerve only surgery, then you can bend the toes up and down ten times, four times a day to prevent any stiffness and to stop scarring tethering the remainder of the nerve.
RETURNING TO WORK
If you have had bony surgery, you will be wearing the special shoe for six weeks, and we will then take an xray. I advise that you do not return to work before this, especially if you are on your feet all day at work. Most people can drive after 8 weeks.
If you had nerve only surgery, then you can return to work and driving at four weeks. Remember that not everyone is the same, and some people take a longer time to recover from their surgery. Please request a sick note before you leave hospital, if you need one.