Hallux Valgus – Bunions

Bunions are caused by instability of the joint at the base of the big toe and by miss shaped bone here.   If there is instability, deformity will progress with time.   Often bunions cause pain for a variety of reasons including the prominence rubbing on shoes; degenerative change (arthritis) and inflammation as joint structures are stretched.   Decreased function of the big toe puts more stress on the remainder of the forefoot resulting in lesser toe problems including corns, claw toes and occasionally ulceration or infection.

Usually surgery is not essential

Not all bunions are problematic - in most surgical treatment is optional.   Non surgical treatment involves the modification of shoes so that there is enough room to fit the foot in the shoe without tightness.   Typically a shoe with a fairly solid sole is needed.   Insoles may lessen pain in outer aspect of the foot but rarely slow the progression of bunion deformity.   Sometimes anti-inflammatory drugs help.

The aims of surgery are to relieve pain, to realign the toe, to decrease its’ bulk and to maintain or improve function.

The primary aim of surgery is to relieve pain & improve function - appearance is not a reason to operate.

Scarf osteotomy

The Scarf osteotomy consists of a horizontal cut and two transversal cuts of the first metatarsal, allowing for a broad range of angular corrections.

The procedure aims to realign, rebalance and stabilise the 1MTP joint. It involves a z cut  osteotomy of the metatarsal, which is then realigned, rebalanced and position is fixed with screws. It is unusual for the metalware to be removed.

Akin osteotomy

This procedure involves re-shaping the big toe’s proximal phalanx.  Its’ prime place is when this bone is deformed and this is the cause of the problem. It has a very limited place for use in isolation. Its most frequent place is as an adjunct with one of the other surgeries.

It involves taking a wedge of bone from the medial (inside) of the base of the great toe and hence straightening it.  It may be fixed with permanent screws, staples, sutures or temporarily with wires which are removed at two or three weeks (a procedure which is similar to removal of sutures in its’ level of discomfort)

Distal Chevron Osteotomy

This procedure is best used for lesser degrees of deformity.   It is essentially reliable; recovery is relatively rapid.   In more severe cases results are less assured.   In essence the great toe is re-aligned using a short cut in the distal end of the metatarsal (the bone at the base of the toe).

A short incision is made along the medial (inside) aspect of the big toe M.T.P. joint.   The joint capsule is opened and the joint is exposed then the prominence is resected.   A “Chevron” or “V” cut is then made in the metatarsal, and the head of the bone is translated towards the outer border of the foot.   The toe is then straightened and after resecting both excess capsule and any residual bony prominence the capsule is tightened and repaired.

Adductor Hallucis Transfer

The operation involves transferring the adductor hallucis muscle (which normally pulls the toe into valgus) and using it to pull the metatarsal into improved alignment.   Realigning the first metatarsal further reduces the first - second metatarsals gap.   This allows the toe to be brought into a corrected position.

Initially an incision is made on the dorsum (top) of the foot between the first and second toes.   The outer aspect of the great toe M.T.P. joint is released and the Adductor Hallucis muscle moved from the base of the lateral sesamoid and big toe then transferred to the first metatarsal head.