The treatment of rheumatoid arthritis is two fold:
- Keep the foot as stable as possible and prevent further deterioration of the joints and increasing deformity of the foot
- Obtain relief in walking and make it easier to wear shoes
Unfortunately, as the deformity (particularly of the toes) worsens, it becomes very difficult to proceed without surgery. Surgery on the toes, particularly the knuckle joints of the toes (metatarso-phalangeal joints), needs to be performed as soon as possible. This will prevent some of the destructive changes of the joints from occurring. Although it is possible to treat even the most severe deformities of the toes, it is always preferable to try to maintain the toe function and the toe movement.
Surgery of the toes is divided into those of the big toe (the hallux) and those of the little toes and their joints (the lesser metatarso-phalangeal joints). As the deformity of the big toe worsens, the most reliable procedure for correction is to fuse the joint. This straightens the toe, provides a permanent correction to the deformity and prevents any recurrent deformity or pain from arthritis. It is however, possible to correct the big toe joint without a fusion, particularly if the deformity can be addressed earlier on in the course of events.
The same applies to the lesser metatarsal phalangeal joints. If the joints are severely dislocated and bone changes are present, the most reliable procedure is to remove all of the metatarsals (the knuckles of the front of the foot). This straightens the toes, relieves the curling or clawing of the toes and relieves all of the terrible pressure under the ball of front of the foot. It is preferable to try to maintain the joints without removing the knuckles. This can be done with bone cuts (called osteotomies) of the metatarsals. These osteotomies need to be performed early on in the disease process.
Rheumatoid arthritis also affects the back of the foot and the ankle joint. Arthritis of these joints is often associated with flattening of the arch of the foot. The ideal treatment would be to prevent these severe deformities from occurring by performing surgery in the early stages of rheumatoid arthritis. As the deformity worsens, it becomes increasingly difficult to obtain a normally aligned foot. Even with severe deformities, surgery can still be performed. The foot is straightened with fusion of the joints of the back of the foot.
When rheumatoid arthritis involves the ankle joint, the ideal surgical treatment is total ankle replacement. Although a fusion of the ankle joint is possible and sometimes necessary, the majority of patients with rheumatoid arthritis that involves the ankle joint do better with a total ankle replacement then with a fusion. This is because the ankle joint is not the only joint involved. Other joints of the back of the foot are also involved. For this reason, it is preferable to maintain movement of the foot and ankle whenever possible and avoid fusion (arthrodesis).