Bunion (hallux valgus) surgery

A bunion is a bony bump that forms on the joint at the base of the big toe. It forms when the big toe pushes against the next toe, forcing the joint of the big toe to get bigger and stick out.

The skin over the bunion might be red and sore. Wearing tight, narrow shoes might cause bunions or make them worse.
Hallux valgus, bunion in womans foot
Typical bunion (hallux valgus).
Healthy foot and foot with Bunio
Left: Healthy foot, Right: bunion (hallux valgus).

The best approach

The ultimate goal of any bunion surgery is to restore the normal shape and biomechanics of the foot in order to reduce pain and allow the patient to return to wearing normal shoes.

In Australia, there are three main approaches currently used by orthopaedic surgeons:
  • First metatarsal and proximal phalanx bone cuts to correct the deformity.
  • Fusion of the first metatarsophalangeal (MTP) joint.
  • Fusion of the first tarsometatarsal (TMT) joint.
Bones of foot diagram

The surgery

Correcting the bunion with bone cuts (osteotomies) is the most common operation, and the majority of bunions are amenable to this procedure.

With an open bunion correction, an incision is made on the inside of the foot over the bunion, and a special z-shaped cut of the first metatarsal bone is made – this is called a Scarf osteotomy and it's actually a carpentry principle. This osteotomy allows the surgeon to rotate and translate the distal part of the bone (i.e. the part with the metatarsal head and MTP joint) into a corrected position, which is then held with small compression screws.

If necessary, a small wedge of bone can also be taken from the first proximal phalanx in order to pull the toe even straighter. This bone cut is usually held with a small staple.

In addition to the bone cuts, the tight soft tissues on the lateral side of the big toe joint are lengthened, and the loose soft tissues over the bunion prominence are tightened up.
X-ray of foot with deformed toes
X-ray before the surgery.
after the bunion operation
After the surgery.
Fusion of the big toe
Big toe (first MTP joint) fusion is mainly considered when there is arthritis present in the joint along with a bunion deformity. Fusing the joint allows for both correction of the hallux valgus deformity as well as alleviating the arthritis pain.
Lapidus procedure
First tarsometatarsal (TMTI) joint fusion for bunions is also called the Lapidus procedure, and this is reserved for patients with very severe hallux valgus deformities, or significant hypermobility or midfoot arthritis at the TMT joint.

An incision is made over the inside aspect of the foot. and the TMT joint is cut and prepared to allow the first metatarsal to be rotated back into the correct position. A special Lapidus plate is then inserted to hold the joint in the new position. A second cut is usually needed around the MTP joint in order to shave the bunion prominence and tighten the stretched medial capsule.

Care after surgery

After discharge, the dressings and bandages must all stay intact and dry until the patient is reviewed one week after surgery. During this time, it is particularly important to elevate the foot for most of the day, keeping the toes above the nose. Strict elevation helps reduce swelling faster, which means less pain and less chance of wound healing issues.

Two weeks after surgery, the wounds are checked. Range of motion exercises and rehabilitation are started once the wound has healed. A simple exercise of gently manually moving the great toe up and down is important to prevent stiffness.

Patients need to wear a surgical shoe for up to 6 weeks. If it is the right foot they won't be able to drive for this period. Office and desk-job workers can go back to work after 2 weeks, but those doing manual jobs on their feet often need a full 6 weeks off. Most patients can wear supportive sneakers from 6 weeks post-op, and after this time they can usually swim and use an exercise bike or an elliptical trainer.

The bone cuts take 8–12 weeks to fully heal, and most of the swelling diminishes by 3 months. By 6 months most patients have returned to their normal activities without pain or discomfort.
Fusion of the big toe
If the surgery involves a big toe fusion, then heel weightbearing in a surgical shoe is required for 6 weeks.
Lapidus procedure
If the Lapidus midfoot fusion procedure is done, then patients cannot put weight on the foot and are typically in a plaster for up to 6 weeks.

What should patients know before considering bunion surgery?

Surgery has its risks, so patients need to be having enough problems with their feet to warrant surgical intervention – and be aware of the potential risks.

Recurrence of the bunion is possible and depends on both the severity of the patient's pre­operative deformity, the surgical technique employed, as well as their age. Infection rates are generally very low, as are the risks of nerve damage, stiffness. or problems with bone healing.

Conditions like diabetes, peripheral vascular disease or long-term use of immunosuppressant drugs are possible contraindications to surgery, and patients with these conditions require careful evaluation by an orthopaedic surgeon.

Bunion surgery is covered by both Medicare and private health funds only when performed by an orthopaedic surgeon.

You may also like to view the most frequently asked questions about feet and ankles.
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