Ankle Arthritis and Cartilage Damage

What is arthritis?

The bone ends of 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 requires an MRI scan.

Treatment

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. 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. You might benefit from a course of physical therapy 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 sometimes they do not provide any 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.

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 residual functional loss following a joint fusion. Also, 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 metatarsophalangeal joint, the mid-tarsal or tarsometatarsal joints, the hindfoot joints (known as a triple arthrodesis), and the ankle joint. Dr. Roger Mann has published his results with one of the largest series of patients who have undergone an ankle joint fusion.

Ankle joint replacement

In the past 5 years, ankle joint replacements have become a good treatment option for advanced ankle arthritis in many patients. New joint replacements (prostheses) have become available that last longer and provide good pain relief. Dr. Roger Mann and Dr. Jeffrey Mann represent one of ten centers in the country participating in an FDA study with the Scandinavian Total Ankle Replacement or STAR prosthesis. The STAR prosthesis has been used in Europe for 20 years, and is widely recognized as the most successful ankle joint replacement that has been developed to date.

An ankle joint replacement has the advantage 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. However, most joint replacements have a finite life span. Therefore a young or active individual may require a revision of their joint replacement or changing the replacement to a fusion after a certain amount of time. From European studies, it appears that most STAR procedures will last 12-15 years.

We have presented our results with the STAR prosthesis at meetings all over the country.

90% of our patients report good or excellent results with their ankle replacements over the 8 years that we have been performing this procedure. We feel that an ankle replacement with the STAR prosthesis provides an excellent alternative to an ankle fusion for most patients. However, some patients are not candidates for the procedure, due to excessive bone loss around the ankle joint, or if they have a severely deformed ankle. We anticipate that the FDA will grant approval for wide-spread use of the STAR prosthesis early in 2007.

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 drilled into the surface of the bone to provide channels to healthier bone. 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 people who don’t benefit from this operation tend to have larger areas of damaged cartilage, and ones that involve damage to the bone as well. This procedure is known as drilling, microfracture or chondroplasty.

In the 25% of people who don’t get pain relief from the arthroscopic surgery, there are other, more advanced treatment options available. The most common advanced procedure involves transferring cartilage and bone from your own knee joint, or a cadaver joint, to the damaged area of the talus. This procedure is known as an osteochondral autograft transfer, or OATS procedure. The OATS procedure is an extensive operation, and often requires cutting through a part of the tibia bone to gain access to the ankle joint. Dr. Jeffrey Mann has co-authored a paper reporting results of 95% success rate with the OATS procedure.