Mica Technique - Dr Tim O'Carrigan, Orthopaedic Surgeon
A bunion, also known as hallux valgus, is bony prominence at the base of the big toe, which often results in pain, redness and rubbing in footwear. The 1st metatarsal bone abnormally angles outward towards the other foot from its joint in the midfoot. A bunion can change the shape of your foot, make it difficult for you to find shoes that fit correctly and worsen the symptoms if left untreated.
Although it is not clearly understood why bunions occur, possible causes include:
- Family history and genetics
- Arthritis (inflammation of the joints) including rheumatoid arthritis, psoriatic arthritis and gout
- Neuromuscular conditions such as cerebral palsy (affects movement and co-ordination)
- Connective tissue disorders such as Marfan’s syndrome (affects the connective tissues)
- Tight fitting shoes that are too tight, narrow or high heeled.
Signs and symptoms
The main indication of a bunion is the pointing of the big toe towards the other toes of the foot. Other signs and symptoms include:
- Pain and swelling over the big toe that increases while wearing shoes
- Swelling with red, sore and calloused skin at the base of the big toe
- Inward turning of the big toe pushes the second toe out of place
- Bony bump at the base of the big toe
- Sore skin over the bony bump
- Difficulty walking and wearing shoes
The diagnosis of a bunion by an orthopedic surgeon includes taking a medical history, and performing a physical examination to assess the extent of misalignment and damage to the soft tissues. Your surgeon will usually order weight bearing X-rays (i.e. taken while standing) to access the severity of the bunion and deformity of the toe joints.
Your GP may have already initially recommended conservative treatment measures with the goal of reducing or eliminating your foot pain.
Such measures can include:
- Medications for relieving pain and inflammation
- Wearing surgical shoes with a wide and high toe box, avoiding tight, pointed or high-heeled shoes.
- Use of orthotics to realign the bones of your foot and ease pain.
- Padding of bunions
- Ice applications several times a day
Conservative treatment measures can help relieve the discomfort of a bunion, however these measures will not prevent the bunion from becoming worse.
Surgery is the only means of correcting a bunion. Surgery is also recommended when conservative measures fail to treat the symptoms of bunion.
There are many surgical options to treat a bunion. The common goal is to realign the bones in the foot, correct the deformity, and relieve pain and discomfort. The surgery is performed as a day procedure, under the effect of a light general anesthetic and a regional nerve block. When you wake up, you will not be in pain and will be able to walk on your foot straight away.
Osteotomy is a common type of bunion surgery that involves the surgical cutting and realignment of the bones around your big toe. Your surgeon selects the appropriate surgical procedure based on the type of bunion and its severity.
There are 3 main types of osteotomies used by foot and ankle surgeons; namely akin osteotomy, chevron osteotomy, and scarf osteotomy.
Akin osteotomy corrects the sideways deviation of the big toe. In this procedure, your surgeon makes a small cut in the proximal phalanx (base of the big toe) and removes a wedge of bone to straighten the big toe. The bony fragments are then stabilized using a screw or staples. This procedure is often used in conjunction with the other procedures below.
A chevron osteotomy is usually recommended for mild to moderate bunion deformities. During this procedure, your surgeon will make an incision over your big toe. The joint capsule is opened and the bunion is removed using a surgical saw. A
V-shaped cut is made on your big toe and the metatarsal bones are shifted to bring your toe into its normal anatomical position. The bunion is then shaved and the soft tissues are realigned to correct the position. Akin osteotomy may be performed if necessary. The mobility of your big toe is examined, and the capsule and wound are re-approximated with sutures. Screws or pins are used to hold the bones in their new position until healing.
This procedure can also be performed minimally invasively with keyhole style incisions.
Arthrodesis: Involves fusing the two bones that form the big toe joint. This procedure is used for severe bunions and when arthritis has set in. The movement of your big toe is reduced following this procedure but pain and deformity are very well controlled.
Scarf osteotomy is usually recommended for moderate to severe bunion deformities.
Your surgeon will make an incision along your big toe and open the joint capsule to expose the bump. The bump on your big toe is then removed using a bone saw. Your first metatarsal bone is then cut in a Z shape and realigned to correct the deformity. Your surgeon will fix the cut bone with pins or screws. The joint capsule and surgical wounds are then re-approximated using dissolvable sutures keeping your toe in a straight position. This is a very powerful corrective procedure with excellent long-term results.
Risks and complications
As with any surgery, bunion surgery involves certain risks and complications. They include:
- Recurrence of the bunion
- Nerve damage
- Unresolved pain and swelling
- Joint stiffness or restricted movement
- Delayed healing or healing in the wrong position
In rare cases, a second surgery may be necessary to correct the problems.
Patients should follow all instructions given by the surgeon following the surgery. These include:
- Keep your dressings dry and leave them in place until your next outpatient appointment.
- Minimize walking where possible.
- Elevate the foot to minimize swelling as much as possible for the first 6 weeks.
- You will have to wear specially designed post-operative shoes to protect the wounds and assist in walking
- You may not be able to wear regular shoes for 6 weeks