Bunion Information & Types

What is a bunion?

A bunion is a prominent lump on the side of the big toe / foot. The bunion bump is caused by a prominent bone (the metatarsal head) along with thickened skin and soft tissues overlying this. There is often some deformity of the big toe (Hallux), where the toe bends / leans outwards (Hallux Valgus).

What is a bunion

Why does it happen?

The main causes of bunions are genetics - they run in families and often a parent or grandparent will have suffered with them. This tendency to develop bunions gets passed on and they can develop through any age of life. The other common cause is tight, narrow or high-heeled shoes that squash the toes together. Over time this causes the ligaments to stretch and the toe to deform. Bunions are more common in women and in people with flat feet.

Hallux Valgus and bunions are common with a prevalence of 23% in adults aged 18-65 years and 35.7% in patients aged over 65 years. Prevalence increases with age and is higher in females.

What is a bunion

How do I prevent it?

Shoeware
The best way to prevent a bunion forming is to wear shoes that fit the natural shape of the forefoot, and do not squash the toes together. There is no other reliable treatment as it is an inherited problem, but arch supports can make the foot more comfortable and may be of benefit, particularly in people with flat feet.

Toe spacers and braces
There are many makes of bunion straps and night splints available commercially. These may make the toe more comfortable while worn, but do not reverse it or prevent them getting worse.

Are they all the same?

The term “Bunion” covers many different types of problem and there is a range of deformities and treatments.

Simple bunion

Due purely to a bony prominence on the side of the metatarsal head - there is no deformity in the toe or the metatarsal. If wider shoes don’t work, they can be treated with Minimally Invasive Surgery (MI) - this is the least invasive surgery and has the quickest recovery. (For further information see the surgery section).

What is a bunion

Hallux valgus

The most common type, where the metatarsal bone deviates outwards and the toe deviates inwards. As the bones become angled, the ligaments on the inside of the joint stretch (medial capsule) and the muscles on the other side contract, pulling the toe over (adductor hallucis muscle).

The surgery to correct this is more involved and requires careful appreciation of all the contributing factors. The metatarsal is cut and realigned, the tight muscles and tendons are released and cut and the stretched ligaments reconstructed and tightened. This can be done with MI surgery or open surgery depending on the exact type of problem. (For further information see the surgery section on hallux valgus corrections).

Hallux valgus bunion

Severe Hallux valgus with lesser toe deformities

In more severe cases, the Hallux Valgus causes deformity in the lesser toes too. These become clawed and painful underneath (“Metatarsalgia”) and eventually crossover the hallux.

These require the most complex surgery, with realignment of the hallux / metatarsal and correction of the clawed toes. This involves realignment of the Hallux metatarsal as above and shortening of the lesser metatarsals (DMMO), with fusions of the small joints of the toes (interphalangeal joint fusions). This may be combined with ligament reconstruction of lesser toes (plantar plate reconstruction) and tendon lengthening or reconstruction. The surgery is complex, uses a combination of open and MI techniques and can take 2 hours or more.

Severe Hallux valgus with lesser toe deformities

Do bunions get worse?

Bunions usually get worse, slowly, over many years. There is a gradual increase in the deformity and usually with pain. This can be interspersed with long periods when the toes and foot are ‘quiet’, with the deformity and pain resting.

Over time, there is a slow migration of the big toe inwards. As it does so, it takes less and less body weight (biomechanical underload) and the lesser toes take more weight (biomechanical overload). This causes “metatarsalgia” - pain underneath the ‘ball’ of the foot, which feels like there is a “pebble in the shoe”.

As this overload continues, the toes become clawed - bending at the IP joints (interphalangeal joints) and becoming lax and unstable at the MTP joints (metatarsophalangeal joints). This is due to stretching of the ligament that supports the joint (plantar plate).

Rarely, this process can suddenly accelerate, with a rapid change in the deformity and symptoms.

Do bunions get worse

When is surgery indicated?

In early or mild cases, surgery can usually be avoided. In general, the majority of symptoms from a minor deformity can be controlled by correctly fitting shoes or insoles.

If the correct shoes / insoles do not control the pain, then surgery is indicated. There is normally no need to rush ahead with surgery and it can be organised to fit in with your schedules and timetables.

If the hallux valgus becomes unstable, with a sudden increase in the deformity or there are signs of clawing of the toes, then earlier surgery is usually needed. The progression in the deformity will continue, requiring more complex surgery and the worse it is, the harder it is to get right.

In more severe cases, shoes and insoles will still help with the pain, but surgery is usually necessary to achieve maximal relief.

When is Bunion surgery indicated

Do Bunion braces work?

There are many braces on the market - none of which work in the long term, as the forces on the bunion are too great. Occasionally, a simple toe spacer can help with pain temporarily.

Bunion Surgery - what does it involve?

The principles behind the surgery are to realign the bones (osteotomy) and to correct the ligaments and stretched tissues.

Prior to surgery, the foot deformities and xrays need precise assessment. No bunion is the same, and there is a complex interplay between the bone deformities and soft tissue contractures.

This needs careful assessment to decide upon the correct operation and to achieve the goal of a comfortable straight foot. No single operation caters for all bunions and the results will be below standard if the wrong procedure is used.

Are there any risks of surgery?

Of course there are risks with any operation. The more frequent risks and complications are of bunion surgery are discussed in the operative section under Scarf osteotomy.

When should I have surgery?

Surgery is rarely essential and more accommodative shoeware should be tried first. Unfortunately, toe-spacers, braces and orthotics do not help in the long term. Custom made shoes can be very good for severe cases where surgery is contra-indicated.

The timing of surgery and when to recommend it is a common quandary. In a stable situation, when there has been no change in deformity or symptoms, wider more accommodative shoes can help. In an unstable situation, when the pain or deformity is increasing or there are changes to the lesser toes (clawing or metatarsalgia), surgery should be considered. If left, the deformities will get worse, making surgery more complex and more extensive and previous studies have shown that surgery in these cases do less well, with higher complications and recurrence rates.

The results of modern surgery are substantially better, with published satisfaction rates of 94% (Adam 2011). This improvement is due to advances in surgical techniques, with the modern types of osteotomy and screw fixation providing a more stable construct. This reduces the surgical pain and allows immediate weightbearing. New techniques provide more precise bony realignment and balancing of the soft-tissues, with greatly improved immediate and long-term corrections. The latest advances in minimally invasive surgery further reduce surgical trauma, infection rates and recovery times.

The surgery is performed routinely as a daycase, under anaesthesia with a regional anaesthetic (ankle block) for pain relief. The patients are discharged the same day, fully weightbearing in a protective shoe. No plastercast is necessary. They have improved recovery, reduced pain, immediate weightbearing and early return to work.

The recovery from bunion surgery is more prolongued than one might expect. This is due to the swelling which takes months to dissipate. Often the foot remains too swollen to fit into normal shoes for 9-12 weeks. It will be 4-6 months before you are walking long distances in comfort. Therefore, it is sensible to leave 4-5 months before any special or major occasions.

Bunion Surgery Risks

Bunion Surgery Risks

Conventional Hallux Valgus surgery. Severe bunion pre-op on left and post-op result on right.

Bunion Surgery Risks

Minimally Invasive Surgery for less severe bunion at 2 weeks post-op.