Introduction

Hallux rigidus is a degenerative arthritis that affects the large joint at the base of the big toe (Fig.1). Degenerative arthritis results from wear and tear on the joint surface over time. The condition may also follow an injury to the joint.

Anatomy

The joint at the base of the big toe is called the metatarsophalangeal (MTP) joint (Figs. 2,3). Like any other joint in the body, this big toe joint is covered with articular cartilage, a slick, shiny covering on the end of the bone. If this material is injured, it begins a slow wearing out process, or degeneration. The articular surface can wear away until bone rubs against bone.

Bone spurs can form around the joint as part of the degenerative process (Fig. 4). The spurs may restrict the joint and keep the toe from bending upward when the foot moves forward.

Causes

Doctors remain uncertain about the true cause of hallux rigidus. In many cases, the condition begins with an injury to the articular cartilage lining the joint. The injury sets in motion a degenerative process that may last for years before symptoms occur. Other cases of hallux rigidus seem to arise without any type of serious injury. Minor differences in foot anatomy may make it more likely that certain individuals develop hallux rigidus. These minor abnormalities may increase the stress placed on the big toe joint while walking. Over many years, this may add up to degenerative arthritis of the joint.

Symptoms

The degeneration of hallux rigidus causes pain and loss of motion in the MTP joint. Walking is painful and difficult if the MTP joint is not able to move enough to allow the foot to roll through a full step.

Diagnosis

Diagnosis is usually made through physical examination. However, x-rays may be required to determine the extent of the degeneration and bone spur formation.

Treatment

Conservative Treatment

Conservative treatment begins with anti-inflammatory medications to control the pain, swelling, heat, and redness of the degenerative arthritis. Special shoes that restrict movement of the toe while walking may also help. A "rocker" type of sole allowing the shoe to take some of the bending force may be used with a metal brace in the sole to limit the flexibility of the sole of the shoe (Fig. 5). This reduces the motion needed in the MTP joint.

An injection of cortisone into the joint may give temporary relief of symptoms. Your doctor may suggest an injection in conjunction with special shoes to control your pain while walking. As with any injection into a joint, a risk of infection exists with this procedure.

Surgery

Surgery may be suggested if conservative treatment is not successful. Several types of procedures can be useful in treating this condition.

Cheilectomy

Bone spurs that form on the top of the joint can bump together when the big toe bends upward, or extends. The constant irritation from bone spurs bumping together leads to pain and difficulty walking.

A cheilectomy is a procedure to remove the bone spurs at the top of the big toe joint (Fig. 6). This allows the toe to bend better and reduces the amount of pain while walking. To perform a cheilectomy, an incision is made along the top of the joint. The bone spurs that are blocking the joint from extending are identified and removed from both bones that make up the joint. Extra bone may be taken off to ensure that nothing rubs when the hallux is raised. The skin is closed and allowed to heal.

Joint Fusion

Many surgeons favor arthrodesis, or joint fusion, of the big toe joint to relieve the pain (Fig. 7). The joint between the two bones is removed and the two bones are allowed to fuse. This results in a big toe joint that no longer moves. Wearing a rocker-soled shoe is usually necessary following a fusion to improve your manner of walking, or gait.

To perform a fusion, an incision is made into the MTP joint. The joint surfaces are removed. The two surfaces are then fixed with either a metal pin or screw, with the toe turned slightly upward to allow for walking. The bones are then allowed to fuse. The fusion usually takes about three months to become solid.

Artificial Joint Replacement

Artificial joint replacement of the MTP is another treatment option for hallux rigidus. In this procedure, one of the joint surfaces is removed and replaced with a plastic or metal surface (Fig.8). This procedure may relieve the pain and preserve the joint motion. However, the artificial toe joint probably will not last a lifetime and more operations will be required later if it begins to fail.

To perform an artificial joint replacement, an incision is first made on the top of the big toe over the MTP joint. The arthritic joint surface of the proximal phalanx (the first bone of the big toe) is removed and the bone is prepared with special instruments so that the artificial joint surface will fit snugly into it.

When the surgeon is satisfied that everything fits, the artificial joint surface is implanted and the joint capsule and skin incision are closed with small stitches.

Rehabilitation

For non-surgical treatments, improvements of symptoms are usually noticeable within a few days. Anti-inflammatory medications may take up to seven to ten days to become effective. A cortisone shot usually works within twenty-four hours. Alterations to shoe wear may take several weeks to have an effect.

Recovery from toe joint replacement surgery may take about eight weeks before the bones and soft tissues are well healed. Patients may be placed in a wooden soled shoe, or a cast, while the bones heal. Crutches may be needed briefly and a physical therapist may be consulted to teach their proper uses.

A bandage or dressing will probably be worn for about a week following the toe joint replacement. The stitches will be removed in ten to fourteen days. If dissolvable stitches are used, they will not need to be removed.

During follow-up visits, x-rays will probably be taken so that the surgeon can follow the healing of the bones if a fusion was performed. X-rays are also important if an artificial toe joint was used to ensure the implant is properly aligned and positioned.