Subtalar arthritis is a condition where the subtalar joint in the ankle becomes inflamed and painful. The subtalar joint is where the talus bone of the ankle joins the heel bone, or calcaneus. Arthritis can occur there as the result of wear on the bones in the subtalar joint occurring over time, or following a fracture of the talus. Subtalar arthritis is generally associated with pain, experienced when the ankle is turned inward or outward. Treatment commonly involves surgery to fuse the joint and relieve the pain, although this has the disadvantage that the foot becomes less mobile.
Foot anatomy is complex, with 28 bones forming more than 30 different joints to make up a structure that not only bears the body's whole weight but also allows a person to leap into the air and land, normally without damage. The foot bones are held together by strong bands of tissue called ligaments and are shaped to form two arches, one running the length of the foot and one across. As the foot is subjected to repeated impacts over time, the damage and wear that lead to arthritis occur quite frequently, especially where extra force is placed on the joints in obese or athletic people, for example. At the ankle, the talus bone is important, as it connects the bones of the leg with those of the foot, allowing the ankle to move up, down, in and out. The in and out motions made possible by the subtalar joint are critical for walking over uneven ground.
Probably the most common cause of subtalar arthritis is a fracture of the heelbone, although a broken talus can also lead to arthritis, especially if the blood supply to part of the bone is lost, causing it to die off. The disease known as rheumatoid arthritis, where joints are attacked by the immune system and become inflamed, may also affect the subtalar joint. Having deformed feet can make a person more likely to develop subtalar arthritis, as stress may be distributed through the foot abnormally, placing extra force on the subtalar joint.
Ankle symptoms of pain, stiffness, and sometimes swelling, may be experienced by a person with subtalar arthritis. X-rays are often used to diagnose the condition, and treatment usually begins with non-surgical methods. Non-surgical techniques, which may help protect the joint and relieve pain, include losing weight, swimming and cycling rather than walking, and wearing comfortable footwear. Sometimes the ankle is strapped or braced, and ice might be applied. Painkilling drugs are typically prescribed.
When non-surgical treatment fails, the pain of subtalar arthritis can be treated with an operation to fuse the subtalar joint. Metal screws and pieces of bone graft material are used to fix the joint and help the bones heal together. The result is an ankle joint which is stiff but relatively free from pain.