Rheumatoid Arthritis can have significant effects on the feet and the ankle. These range from swelling of the toe joints to severe destruction of the joints of the foot and the ankle. The process of joint inflammation begins with an inflammation of the lining of the joints called the capsule. As the capsule becomes inflamed, the joint fills with fluid and becomes painful. The cartilage lining of the joint may wear out.
The joint space becomes narrow and bone begins to rub on bone, leading to painful arthritis. In addition, deformities may occur as a result of loosening of the ligaments and capsule lining of the joint. If the housing of the joint (the capsule) loosens up significantly, the joints (particularly in front of the foot) may dislocate. This can cause painful swelling on the bottom of the ball of the foot that can make walking terribly uncomfortable. In addition to the dislocation of the joints, the big toe begins to deviate and bunions may form on the inside of the big toe.
The treatment of this condition is two fold. The first goal is to keep the foot as stable as possible and prevent further deterioration of the joints and increasing deformity of the foot. The second goal is to 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 we are able 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 the condition. As the deformity worsens, it becomes increasingly difficult to obtain a normally aligned foot. Even with severe deformities, however, 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 arthrodesis.