Bunion (Hallux Valgus) Surgery
Over the last century, more than 100 different procedures have been described for correcting bunions. 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 return to normal shoewear. In Australia, there are three main approaches currently used by orthopaedic surgeons:
- 1st metatarsal and proximal phalanx bone cuts to correct the deformity
- Fusion of the 1st metatarsophalangeal (MTP) joint
- Fusion of the 1st tarsometatarsal (TMT) joint
Bunion Deformity Correction
Correcting the bunion with bone cuts (osteotomies) is the most common operation, and the majority of bunions are amenable to this procedure. Dr Zilko performs both minimally invasive (keyhole) bunion surgery as well as the traditional open bunion surgery.
With a minimally invasive (keyhole) bunion correction, several small incisions are made on the side of the big toe. Under x-ray guidance, special cutting burrs are used through these keyhole incisions to create corrective bone cuts of both the 1st metatarsal and 1st proximal phalanx bones. These bone cuts are then held in place with screws.
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 1st 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 1st 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.
Fusion of the Big Toe
Big toe (1st MTPJ) 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. Read about big toe fusion here.
1st tarsometatarsal (TMT) 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 TMTJ. An incision is made over the inside aspect of the foot, and the TMT joint is cut and prepared to allow the 1st 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.
The majority of bunion corrections Dr Zilko does are performed as day procedures, and patients walk full weightbearing in a stiff-soled surgical shoe from day 1. A local anaesthetic block is done at the time of surgery, which usually makes the foot pain-free for 6-12 hours. Strong pain killers are usually only needed for the first 5-7 days, after which paracetamol is generally all that’s required.
After discharge, the dressings and bandages must all stay intact and dry until review 2 weeks after surgery. During this time, it is particularly important to elevate the foot for most of the day, with “toes above the nose”! Strict elevation helps swelling come down faster, which means less pain and less chance of wound healing issues.
At 2 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 the surgical shoe for up to 6 weeks, and if it’s their 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 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.
If the surgery involves a big toe fusion, then heel weightbearing in a surgical shoe is required for 6 weeks. If the Lapidus midfoot fusion procedure is necessary, then patients need to be non-weightbearing in a plaster for up to 6 weeks.
What should patients know before considering bunion surgery?
There’s no such thing as risk-free surgery, so patients need to be having enough problems with their feet to warrant surgical intervention, and of course be aware of the potential risks.
Recurrence of the bunion is possible, and depends on both the severity of the patient’s pre-operative 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 (medical practitioner).
Bunion surgery is covered by both Medicare and private health funds only when performed by an orthopaedic surgeon (medical doctor).