What is arthritis?
The bone ends that comprise a joint are covered with a smooth material called cartilage. The cartilage cushions the bone and allows the joint to move smoothly without pain. Arthritis occurs when there is deterioration or wearing away of joint cartilage. The normal smooth lining of a joint surface becomes rough and irregular, which causes pain. Unfortunately, the body cannot repair the damaged cartilage. Arthritis can occur at any joint in the foot and ankle region, although the ankle joint itself is most commonly affected.
There are different types of arthritis, including osteoarthritis, rheumatoid arthritis, and post-injury (or post-traumatic) arthritis. Osteoarthritis (OA) is partly due to a familial tendency, and partly an inherent consequence of aging. People usually begin feeling the effects of osteoarthritis in their 60’s. Rheumatoid arthritis is characterized by joint inflammation affecting numerous joints, and often begins at a young age. As the name implies, post-injury arthritis occurs as a result of a single or recurrent injuries to a joint surface. In the ankle, this is usually the result of an ankle fracture.
Arthritis in the ankle joint can be generalized, affecting the entire joint surface evenly, or it can be more localized, where only a part of the joint surface is damaged. More localized joint damage usually occurs to the talus bone, the lower bone of the ankle joint. This condition is often referred to as an osteochondral lesion of the talus (OLT), or osteochondritis dissecans (OCD). This type of problem is quite common, and has different treatment methods available. Diagnosis of an osteochondral lesion usually requires an advanced imaging technique such as a CT or MRI scan.
As previously mentioned, arthritis can occur in every joint in the foot and ankle, but there are several typical patterns of arthritis in joints other than the ankle. The joint between the talus bone and the heel (calcaneus) bone is known as the subtalar joint. Arthritis in this joint is almost always a result of a prior fracture of the heel bone. Arthritis commonly affects the joints in the middle of the foot (tarsometatarsal joints), leading to flattening of the arch and bone spurs in the middle part of the foot. Another very common site for arthritis is in the big toe (metatarsophalangeal joint), leading to large bone spurs that makes shoe wear painful, and greatly limiting the motion in the first toe.
Nonoperative treatment of arthritis
Milder cases of arthritis can be treated with oral medications, such as anti-inflammatory medications. Ankle braces or shoe inserts (orthotics) may also help to stabilize and support the affected joint(s). An exercise program can also be helpful. This should focus on non-impact exercises (bicycling, swimming) to strengthen the muscles around the foot and ankle and to maintain motion in the joints. A course of physical therapy may be beneficial to teach appropriate exercises that will not exacerbate the arthritis pain. Finally, avoiding painful activities (running, vigorous hiking) is important, as pain may be an indication that you are causing additional damage to your joint.
In more severe and painful cases of arthritis, a cortisone injection may be offered to calm the pain and swelling. Cortisone shots may last for a few weeks to several months, although in some people they do not provide much pain relief. Complete immobilization of the foot and ankle in a brace or cast is also very effective for relieving pain, although it is often difficult to use such a device for more than a few weeks.
Treatment of localized ankle arthritis (OLT or OCD lesions)
Localized damage to the talus bone in the ankle joint may involve just the cartilage surface or the underlying bone as well. Treatment for this common condition may begin with a course of immobilization in a cast for 4 to 6 weeks, especially if the condition has recently occurred. If pain persists despite casting, surgical treatment is recommended. In most cases, this surgery can be done arthroscopically. The damaged bone and cartilage is removed from the surface of the talus bone, as this tissue is what causes the pain in the joint. Small holes are placed into the surface of the bone to provide channels to healthier bone, a procedure called “micro-fracture”. Blood cells flow through these channels to the surface of the bone where they can produce new cartilage-like material. In approximately 75% of cases, this new scar-tissue cartilage (known as fibrocartilage) is protective enough to eliminate the pain from the ankle joint.
The 25% of people who don’t benefit from arthroscopic surgery tend to have larger areas of damaged cartilage, and ones that involve extensive damage to the bone as well. In these cases, there are other, more advanced treatment options available. One procedure involves transferring dowel-shaped cartilage and bone to the damaged area of the talus (from either a cadaver joint, or from one’s own knee joint). This procedure is known as an osteochondral autograft transfer, or OATS procedure. Another operation involves implanting small pieces of cadaver cartilage into the area of cartilage damage, a procedure known as “DeNovo”.
Surgical treatment of arthritis: removal of bone spurs
Surgery is indicated when the above non-operative measures do not relieve the pain or allow return to a reasonable level of function. The procedure that is offered to the patient depends on where the arthritis is located and what is causing the symptoms. In many cases, arthritis causes bone spurs to develop on the edges of the joints. If the spurs are the major cause of the symptoms, then surgical removal of the bone spurs may be all that is necessary to relieve pain and joint stiffness. This is especially true in the big toe joint (the metatarsophalangeal joint) and in the ankle joint. In the big toe, the bone spurs can be removed using a small incision, which often greatly improves the range of motion in the big toe, and relieves pain from pressure on the top of the toe. This procedure can often be used in the big toe even when the arthritis is fairly advanced.
In the ankle joint, bone spurs can be removed arthroscopically. Arthroscopic surgery involves 2 or 3 small incisions (1/4 inch in size) and the use of a small camera to perform the operation. Removing the bone spurs decreases pain and may improve motion in the ankle. However, this procedure is not as effective if there are generalized arthritic changes present in the joint.
Surgical treatment of arthritis: joint fusion
In cases of advanced arthritis, simple removal of bone spurs will not adequately relieve pain. In those cases, a joint fusion, also known as joint arthrodesis may be offered. A fusion surgery freezes the joint in place, eliminating all the motion at the affected joint. However, the motion is maintained at the adjacent joints, and often there is little noticeable loss of motion following a joint fusion. This is because by the time a joint fusion is offered, most of the motion at the joint has already been lost due to the arthritis. Joint fusion is an extremely effective method for relieving pain in an arthritic joint. Common areas that are fused include the first toe (metatarsophalangeal joint), the midfoot (tarsometatarsal joints), the subtalar joint, and the ankle joint.
Surgical treatment of arthritis: Ankle joint replacement
Total ankle replacement (or arthroplasty) is a treatment option for painful ankle arthritis where the surfaces of the ankle joint are replaced by a prosthetic device consisting of metal and specialized orthopedic plastic (known as polyethylene). It is a similar procedure to joint replacements of the hip and knee, which have been helping to relieve pain and suffering for over 50 years. An ankle joint replacement has the advantage over ankle fusion in that it cures the problem of arthritis in the ankle but does not sacrifice motion. Maintaining ankle motion helps make a more normal walking pattern, and also prevents the wearing out of other joints in the foot that can occur after an ankle joint fusion.
From our experience and other published studies, it appears that most ankle replacement procedures will last 12-15 years. Depending on why the ankle replacement is no longer working, some individuals will benefit from a new ankle joint replacement, and some will require changing the replacement to an ankle fusion.
Following an ankle replacement, there are some conditions that can occur that may require additional surgical procedures. The most common problem is an eating away of the bone adjacent to the ankle replacement, a condition known as “osteolysis.” This appears to be a reaction of the body to small particles from the plastic portion of the replacement. Osteolysis can be easily treated at an early stage by replacing the lost bone, a procedure known as bone grafting. Much rarer conditions that require additional surgery include loosening of one of the metal components, breakage of the plastic component, or bone spurs that develop on one of the ankle bones.
Not everyone is a candidate for ankle replacement surgery. A severely deformed ankle from a prior injury, a previous infection in the ankle joint, or other conditions may prevent a successful ankle replacement. Also, a young or extremely active individual may not be a suitable candidate for joint replacement.
Dr. Jeffrey Mann has used the Scandinavian Total Ankle Replacement or STAR prosthesis for 20 years for his ankle replacement procedures. He and his father, Dr. Roger Mann, helped to pioneer the use of ankle replacements in the United States. The 2 have published many articles about the experience with the STAR prosthesis.
Additional information on ankle replacements is available at:
www.aofas.org, click the “FootCareMD” section, then type in “ankle replacement”