Hallux Valgus ( Bunion)

What is it?

Hallux valgus is a deformity of the big toe and forefoot.  There is splaying of the first and second metatarsal bones which makes the forefoot wide. The soft tissue attachments to the big toe then pull the big toe towards the smallest toes. As the foot becomes broad the skin rubs on shoes and this skin can become inflamed. This is a bunion.

hallux valgus

What problems does it cause?

The main problem with this condition is pressure over this bony prominence from shoe wear.  The skin can sometimes become red and blistered.  If the foot is very broad then it may be difficult to get wide enough fitting shoes. 

As the big toe moves sideways it can touch the second toe. If the big toe moves further it can lie under the second toe pushing it upwards. The second toe can hence rub on shoes.

In a normal foot the weight is taken under the first metatarsal. In hallux valgus this mechanism may not work as efficiently and the other metatarsals may have take more weight.  This can cause pain under the ball of the foot. This is called at metatarsalgia.

Sometimes the joint can wear out; this is called osteoarthritis. This can be painful.

Are bunions hereditary?

Bunions do tend to run in families.  However if you have a bunion your children will not necessarily have one too.  Bunions are more common in females rather than males.

Are shoes to blame?

Bunions can occur in populations in which shoes are not worn. However, shoes which squeeze the big toe or that do not fit properly may exacerbate the deformity in a patient with a broad forefoot.

What can be done about a bunion?

Most of the difficulty with bunions arises from shoe wear.  Many people are comfortable if they wear wide, well fitting shoes. Sometimes the leather needs to stretch and so it is important to allow time for the feet to adapt to new shoes.
Sometimes a small pad over the bony prominence can take pressure off the bunion. 
High heeled shoes tend to squeeze the foot at the front  where the foot is broadest. This can make pressure problems worse.
Some shoe shops can stretch your new shoes with special moulds to make the shoes wider. It is worth asking at the shoe shop or a cobbler.

Can an operation cure a bunion?

If simple measures do not make you comfortable then an operation may improve the situation.  The operation will not make your foot normal but who will correct some of the deformity of your big toe and narrow your foot back towards what it should be. There are many operations to correct bunions depending on the severity of the deformity and the shape of your foot.  However the operation will not make your foot narrow enough to wear tight shoes nor can it restore the strength of your big toe. 

The scarf osteotomy

This operation involves several procedures to narrow the foot and straighten the big toe. This is the most common operation used at by me to deal with this problem.  This "scarf" term used refers to cut in the first metatarsal bone. This "scarf" is a Z shaped type of carpentry joint.

SCARF osteotomy

The operation is performed usually under a general anaesthetic.  If one foot is being operated on then the procedure may be performed as a day case. If both feet are being  operated on simultaneously then a short in patients stay may be necessary.

The first stage of the operation is to release the soft tissues pulling at the big toe sideways.  This involves an incision on the top of your foot.

Stage 1 Scarf Osteotomy           Stage 2 Scarf Osteotomy

stage 1 scarf osteotomystage 2 scafr osteotomy

The second stage of the operation involves removing the bump from the inside of the foot and then carefully dividing the first metatarsal bone to narrow your foot.  This involves a long incision on the inside of your foot. Once the bones have been moved they are fixed with two screws.

Stage three of the operation involves tightening of the soft tissues on the inside of the foot to further straighten the toe. At this point a decision is made as to whether stage four of the operation is necessary.  If necessary then small wedge of bone is taken out of the big toe bone and fixed with a staple.

Stage 3 Scarf Osteotomy              Stage 4 Scarf Osteotomy

stage 3 scarf osteotomy stage 4 scarf osteotomy

The diagram below shows the finished result.

post op scarf osteotomy x-ray

This is a skilled operation requiring in the region of 60 to 90 minutes of operating time.

The scarf osteotomy : post operative course

A large woolly dressing is usually applied to your foot postoperatively. You will then mobilise as best you can in a special shoe.  This special shoe is designed to take pressure from the operative site and allow you some mobility.  You will have to wear the shoe for 6 weeks in total.

You will be seen at two weeks for a  wound inspection.  You will then continue in your shoe until six weeks. You will usually be seen in clinic at weeks six and have a check X-ray taken.  At this point you will hopefully mobilise in normal shoes. However your foot will remain swollen and sore for some months after the operation and it will take some time for the foot to settle down.

post op shoe

The scarf osteotomy : risks and complications

Overall 85% of patients after this type of surgery are satisfied with the results. However, the scarf operation is major surgery for your foot involving several procedures. Complications do arise and you need to understand these before you make your decision.

Infection and wound healing problems

After any surgery infection and wound healing problems can occur. Usually these are treated quickly without lasting complications.

Pain and Swelling

It is not surprising that it may take several weeks or months for your foot to settle down after this extensive surgery. Many patients experience pain and swelling especially in the first few weeks. Rest and high elevation are required to keep these at a minimum.

Nerve Injury

A small nerve about 1mm in diameter lies just beneath the skin on the inside of the foot. This nerve is vulnerable during the operation but we are trained to find and protect the nerve. Despite these measures the nerve can be injured resulting in numbness along the side of the big toe or a painful nodule on the nerve. Further surgery may be needed.


The big toe joint may lose some of its flexibility after this operation. Sometimes the stiffness can be profound and may cause problems with walking; this is a rare occurrence. If there is pre-existing arthritis then this can be accelerated after this procedure leading to pain in addition to stiffness.


The operation involves dividing the metatarsal bone. These bones are small and technical errors can occur resulting in inadvertent fracture. This is unusual and can easily be remedied during the operation. If this occurs then it may prolong the rehabilitation. Fracture can occur post- operatively. If this occurs then further surgery may be necessary.

Metatarsalgia – Pain under the ball of your foot

The scarf osteotomy changes the mechanics of your foot. After the operation excessive pressure may be taken under the ball of your foot. This may cause pain. If this happens then a special insole can be made to relieve the pain. If this does not help the further surgery may be necessary.

Recurrence of the deformity

Despite an initial good result from surgery the big toe can drift back to the original position. This may occur if tight shoes are worn. Some times if the deformity is bad enough repeat surgery is required.

Deep vein thrombosis and pulmonary embolus

A deep vein thrombosis is a clot in the deep veins of the leg. If this clot breaks off it can travel to the lungs. This is a pulmonary embolus. These complications can be serious.
A risk assessment will be performed preoperatively. The majority of people undergoing this surgery are at a low risk and do not require any prophylactic treatment. If your risk is moderate or high prophylactic treatment may be necessary.

Other osteotomies performed for hallux valgus

If the deformity is very large then the scarf osteotomy may not correct all the deformity. In this situation then a Basal osteotomy may be required. This an operation at the base of the 1st metatarsal. The overall effect is the same as the scarf osteotomy and the risks and complications are the same. The only difference is that the foot may need to be protected in a below the knee plaster of Paris cast for 4 – 6 weeks depending on the exact technique used and the stability of the fixation at the time of surgery.

Final Word

The above information is my view on hallux valgus and my approach on how to solve these problems. There are many operations available and different surgeons may have different views regarding the treatment of this condition. If any questions arise I would be most happy to answer them at your next consultation.