Big Toe Arthritis (Hallux Rigidus)

Arthritis of the big toe joint — hallux rigidus — is the commonest arthritis in the foot. The joint at the base of the toe stiffens, a bony bump forms on top of it, and pushing off becomes painful, so that walking distances shorten and shoes stop fitting. It is often mistaken for a bunion, but it is a different problem with different treatment. Many people manage for years with the right shoes and an insole; for those who do not, the operations are reliable, and the choice between keeping the joint and fusing it depends on how worn it is.

What big toe arthritis is

The big toe joint takes the full weight of the body every time you push off, and it needs to bend upwards by around sixty degrees to do so comfortably. In hallux rigidus the cartilage on the joint surface wears away, beginning on the top of the joint, and bone spurs form around the edges. The spur on top of the joint is what makes the bump, and it is what jams against the bone opposite when the toe tries to bend. The name means "stiff big toe", and stiffness is the first sign.

It progresses through stages, from a joint that is stiff with a bump on top but still has most of its cartilage, to a joint that is worn out. Which stage you are at is what decides the treatment.

Bunion or arthritis?

A bunion is a toe that has drifted across towards the second toe, with a bump on the inner side of the foot. Hallux rigidus is a toe that points straight ahead but will not bend, with a bump on top. They can occur together, and the two are often confused because both cause a painful lump and trouble with shoes. The treatment is different, and an X-ray settles it.

Symptoms

• pain in the big toe joint on pushing off, going up on tiptoe, squatting or wearing heels

• stiffness, particularly bending the toe upwards

• a hard bump on top of the joint that rubs on the shoe

• swelling, and sometimes numbness on the top of the toe where the bump presses on a nerve

• pain that shortens your walking distance, and a tendency to walk on the outer border of the foot to avoid the toe

• in advanced cases, pain at rest and a grinding feeling in the joint

Why it happens

Often no single cause is found. Contributors include an old injury to the toe — a stub or a fracture years earlier; a family tendency; the shape of the foot, particularly a long or raised first metatarsal; and inflammatory conditions. Gout also attacks the big toe joint and can leave arthritis behind, though an acute gout attack — a red, hot, exquisitely tender toe that comes on overnight — is a different problem needing different treatment.

How it is assessed

The examination looks at how far the toe bends, where it hurts through the range, the size of the bump, and how you walk. Weightbearing X-rays show the narrowing of the joint, the spurs and the alignment of the toe, and are usually all that is needed; they grade the arthritis, which guides the choice of operation. An MRI is rarely required. Blood tests are added where gout or inflammatory arthritis is suspected.

Non-surgical treatment

The aim is to reduce how far the toe has to bend and how hard the joint is loaded. Many people are controlled for years with:

• Shoes — a stiff sole, or a rocker sole that rolls you forward without bending the toe, and a wide, deep toe box that does not press on the bump

• A stiff insole — a carbon-fibre plate, or an insole with a rigid extension under the big toe, which stops the joint bending

• Activity changes — avoiding the movements that jam the joint, such as deep squats and toe-off in heels

• Pain relief — simple analgesics and short courses of anti-inflammatories for flare-ups

• Weight management where it is relevant

• A corticosteroid injection into the joint — useful for a flare or for buying time, but the relief is temporary and repeated injections are avoided because they accelerate wear.

Surgery that keeps the joint: cheilectomy

For the earlier stages, where the pain comes mainly from the bump and the spurs catching, a cheilectomy removes them. The spurs on top of the joint and the worn upper part of the joint surface are cut away so that the toe can bend again without jamming. It is done through a short incision on top of the toe, or through keyhole incisions with a burr, which leaves smaller scars and lets you into a shoe sooner.

Cheilectomy relieves pain in most people with early to moderate arthritis and does not burn any bridges: if the joint wears further in later years, it can still be fused. It is the wrong operation for a joint that is already worn through, because the pain there comes from the joint surface itself, not the bump.

Surgery for the worn-out joint: fusion

Where the cartilage is gone, fusing the joint is the reliable option. The worn surfaces are removed and the two bones are fixed together with a plate and screws, in a position that lets the toe sit slightly raised so it clears the ground. Over the following weeks the bones knit into one, and the pain from the joint goes with the joint. It sounds drastic, and people are often surprised by how normally they walk afterwards: the big toe joint does not need to bend much for everyday walking, and the fused toe is strong and stable for pushing off. Running, hiking and most sport are possible. What you lose is the ability to wear a heel of more than about three centimetres and to go up on the toes.

Joint replacements and implants

Artificial joints and synthetic cartilage implants for the big toe exist, but they are not available routinely in Australia. Their results have not matched fusion for pain relief or durability, and when they fail the salvage is a much more difficult fusion with bone graft. For these reason they are currently not offered.

Recovery

Both operations are done as day surgery or with an overnight stay, depending on the time of the list. You walk from the first day in a firm post-operative shoe that puts your weight through the heel rather than the toe, with the foot elevated as much as possible for the first week or two.

• After a cheilectomy — the post-operative shoe for about two weeks until the wound is checked, then a comfortable wide shoe; toe-bending exercises start early; driving at two to three weeks and most activities by six weeks

• After a fusion — the post-operative shoe for about six weeks while the bones knit intially, with an X-ray to confirm it; then a stiff-soled shoe; driving at six to eight weeks for a right foot; no heavy lifting or strenuous activity for six weeks, then a gradual return to full duties but avoiding of standing on tippy toes for 6 months.

Swelling in the toe takes months to settle after either operation and is normal.

Risks

Every operation carries risk. For cheilectomy the specific ones are numbness on top of the toe, stiffness returning, and arthritis that progresses and later needs a fusion. For fusion they are the bones failing to knit (non-union), which may need a second operation; the toe fusing at an angle that does not suit your shoes; irritation from the plate; and, over many years, arthritis in the small joint further along the toe. Both share infection, wound problems, blood clots and ongoing pain. These are discussed with you against what the toe is doing now.

Dr Janan's approach

Dr Janan Chandrananth is a foot and ankle orthopaedic surgeon who completed fellowship training in Bristol and in Tokyo, the latter under a past president of the Japanese Society for Surgery of the Foot, where joint-preserving surgery is a particular focus. Big toe arthritis is among the commonest conditions he treats surgically.

His approach is to match the operation to the joint: keep it where there is cartilage worth keeping, fuse it where there is not, and be plain about which is which on the X-ray. The choice of shoes and insole is taken as seriously as the operation, because it is what keeps many people out of surgery altogether.