Bunions (Hallux Valgus)
A bunion is a painful swelling at the base of the big toe. It occurs in people who have a wide forefoot. The big toe becomes angulated and points across the foot. The medical name for this is hallux valgus.
The prominent bone rubs on the inside of shoes, which is painful. In more severe cases, the big toe may cause overcrowding of the smaller toes, resulting in hammer-toe deformity, painful corns or pain underneath the ball of the foot.
What causes bunions?
The exact cause is unknown, but bunions often run in families. They are more common in women, especially in very flexible people, who may have been told they have flat feet. Wearing tight or high-heeled shoes makes bunions more painful, but may not be the cause of the problem. In some cases bunions are caused by arthritis.
Wide fitting flat shoes will reduce the pain associated with a bunion. There are various splints, straps and pads available which may help reduce symptoms but they do not correct the problem.
If a bunion is not painful, it is best to try and avoid surgery. Doing an operation for purely cosmetic reasons is not recommended.
The Scarf Akin osteotomy
There are lots of different operations for bunions, but the most commonly used is known as the Scarf Akin osteotomy.
The surgery is in two parts. First is the Scarf osteotomy: The first metatarsal bone is cut along its length in order to correct the angle and reduce the width of the foot. The bone is held with screws. The bunion is trimmed and the ligaments around the toe adjusted to prevent recurrence.
In most cases, some angulation of the big toe remains, and the second part of the operation, known as the Akin osteotomy is required to correct this. A small wedge of bone is removed from the base of the toe to straighten it out.
If a hammer toe has developed, this can be corrected at the same time, by straightening the toe and holding it with a wire. The wire is removed in clinic after six weeks.
It is important to appreciate that the Scarf Akin operation is a fairly major procedure. The two main weight bearing bones in the forefoot are cut and will have to heal. Just like healing a broken bone, this normally takes six to eight weeks. During this time your foot will be sore and swollen, especially if it is not properly elevated. Until the bones are healed you must not bear weight through the front of your foot. The soft tissues take a further six weeks to fully heal. Most people have some swelling and aching for up to six months after the operation. This is a long time, and can be frustrating.
Do I have to stay in hospital?
In most cases, no. Bunion surgery is usually done under a general anaesthetic (you will be asleep), as a day case. When you wake up you will be seen by a physiotherapist who will help you mobilise in the special sandal. You will be given a supply of painkillers to go home with. If you have pre-existing medical or mobility problems we may keep you in hospital overnight, but we will discuss this with you before surgery.
Can I walk after surgery?
After the operation you will be sent home with a special sandal. Although you can walk short distances to and from the bathroom for example, for the first two weeks, the swelling and aching will be considerable and it is advisable to keep your foot elevated at home.
When will I be seen in clinic?
After two weeks, we will check the wound in clinic. The stitches are dissolvable. If it is healing well, you can gradually increase your activity, but it is important to remain wearing the sandal. Most of the time your foot should be elevated.
After six weeks the position and healing of the bone is checked with an x-ray. If it is healing well, then you can walk in a normal shoe at this stage. The foot will be swollen though, so a wide fitting shoe is best. You will need to elevate the foot for several hours a day to reduce swelling. Swelling may continue for up to six months.
When can I go back to work?
This depends on the type of work you do. The majority of people need six weeks off work. After two weeks, if you have an office job and can be seated with the foot elevated you may feel able to return for short days. For jobs which require standing for long periods or wearing work boots it can take up to three months.
When can I drive?
You cannot drive for six weeks. When you return to driving you must let your insurance company know that you have had an operation.
What can go wrong?
The majority of patients undergo bunion surgery without problems. However, complications may occur in some cases and it is important to understand this before deciding to proceed with surgery.
Complications of anaesthetic – the anaesthetic is brief, so complications are unusual. If you have concerns regarding the anaesthetic you should discuss them with the anaesthetist on the day of surgery.
Infection and wound healing problems – superficial infections may occur in up to 10% of cases. It is more common in diabetics or smokers. The best way to avoid infection is to keep the foot elevated and keep the wound clean and dry until it has healed (around 10-14 days). You must stop smoking before surgery.
Nerve damage – a small nerve which gives sensation to the big toe runs over the bunion. It may have already been stretched or damaged. Around 5% of patients have a patch of numbness after surgery. This usually resolves with time.
Blood clots – Deep venous thrombosis (DVT) or pulmonary embolism (PE) is very rare after bunion surgery. All patients are assessed for risk of blood clots and if necessary blood thinning medication can be given. Let us know if you have previously had a blood clot or take the contraceptive pill or HRT. If you develop a swollen calf, difficulty breathing or chest pain after surgery, contact your GP or attend A&E.
Pain and swelling – this is the commonest problem after surgery. Swelling and pain occur in everyone and may last for up to six months. The foot should be elevated to reduce swelling. This is most important in the first six weeks after the operation. In a 1-2% of patients chronic regional pain (CRPS) syndrome may develop. It generally improves with time but sometimes medications may be needed.
Stiffness – after surgery the big toe joint will be stiff. After six weeks you can stretch joint to get it moving. In a few cases physiotherapy is needed.
Non-union – the operation involves cutting the bones. Healing usually occurs within six to eight weeks, but sometimes this can be longer. Smokers and diabetics are most at risk. In 1-2% of cases the bone fails to heal and further surgery may be needed.
Malunion – sometimes the bone may heal in the wrong position. The risk is increased if you do not wear the protective sandal for the first six weeks. Malunion can result in persistent pain beneath the ball of the foot. This can usually be treated with an insole. Sometimes further surgery may be needed.
Recurrence – Rarely the bunion may recur. This is more common in very young people, men or in very severe cases.