The ankle contains two joints. The ankle joint connects the shinbone (tibia) and the lower leg (fibula) to the anklebone (talus). This joint works like a hinge, allowing the foot to move up and down. The anklebone also connects to the heel bone (calcaneus), forming another joint, called the subtalar joint. That joint allows the foot to rock form side to side. Ligaments (strong bands of fibrous tissue) on each side of the ankle hold the bones together and provide stability.
The foot and ankle take a pounding during motion and activity and are susceptible to injury. The most common type of ankle injury is a sprain. It's usually caused when the foot turns inward during a jump or fall, causing the ligaments to stretch or tear. According to the American Academy of Orthopaedic Surgeons, Americans make 1.6 million visits to physician's offices every year for treatment of ankle sprains. About 950,000 visits are for treatment of ankle fractures or broken ankle bones.
Treating Ankle Arthritis
Ankle arthritis is often caused by an earlier injury to the joint, leading to inflammation and significant pain and disability. Initially, doctors may recommend limitations in activity, weight reduction, medications, shoe modifications, and/or braces. If conservative treatments don't provide relief or disability, the patient may be referred for surgery.
In ankle fusion (arthrodesis), doctors make a cut into the shinbone and anklebone of the affected joint. Then, the two ends of the bones are brought together and held in place with screws. As the bones heal, they fuse, or grow together. Fusion is about 95 percent successful and leads to a very stable and durable joint. However, there are some downsides to the procedure. Range of motion is somewhat limited because patients lose the up and down motion of the joint. The procedure also puts extra stress on other joints around the ankle, and can eventually lead to arthritis in those joints.
Another option for severe ankle arthritis is ankle replacement. Ankle replacements were done years ago, but fell out of favor because they were associated with serious complications, such as delayed wound healing, infection, and loosening of parts of the artificial joint. Today, surgeons have a better understanding about how the natural ankle works. Researchers have engineered an ankle prosthesis, called the Agility™ Total Ankle Replacement System, that mimics the natural structure and motion of the ankle. The Agility replaces a part of the tibia with a polyethylene and titanium base plate. The end of the talus is made of cobalt and chromium alloy. The device comes in six sizes, so surgeons can get a proper fit for the patient.
Unlike ankle fusion, the Agility system allows more natural movement of the ankle. Once implanted, the joint should last about 15 years. The system is recommended for mature patients (late middle age and older) who fail to respond to conservative treatments. Doctors discourage any activity that puts significant stress on the ankle joint, such as running. As with other types of joint replacement, there is a slight risk of infection, nerve injury, or loosening of the joint components.
For information on the Agility™ Total Ankle System, or referral to a physician, visit the company's website at www.agilityankle.com
For general information about ankle arthritis: The American Academy of Orthopaedic Surgeons, www.orthoinfo.aaos.org
The American College of Foot and Ankle Surgeons, 515 Busse Highway, Park Ridge, IL 60068, www.acfas.org