Cath Lab Digest

Yes. By George Vito, DPM FACFAS. With appropriate experience, surgeons can help relieve symptoms of severe osteoarthritis of the ankle with this procedure and delay the need for a joint destructive procedure.

There are basically two major forms of osteoarthritis, both of which can be severely disabling. In primary osteoarthritis, the cause is generally unknown. In secondary osteoarthritis, the cause is generally traumatic in origin. Both forms present with similar clinical symptoms, which include pain, decreased range of motion and swelling.

Radiologically, there is a decrease in the joint space and the presence of osteophytes and subchondral cysts with sclerosis of subchondral bone. On an extracellular level, articular cartilage has two principal components: collagen and proteoglycans. Collagen gives the articular cartilage its shape and tensile strength. Proteoglycans give articular cartilage its compressive properties.

In osteoarthritis, there is an imbalance between the synthesis and the release of these two components. This leads to both a disruption of the collagen network and a loss of proteoglycans. These biochemical changes that occur appear to have no diagnostic clinical correlation, especially in the early states of the disease process.

The goal of ankle arthrodiastasis is to eliminate mechanical stress on the ankle joint and prevent contact between the tibia and the talus. Due to the intermittent hydrostatic pressure changes with distraction and weightbearing, the result is a significant increase in the synthesis of proteoglycans, which provide the articular cartilage with its compressive properties.
Therefore, a twofold argument suggests that when intermittent intraarticular hydrostatic pressure is applied to the human articular cartilage in the absence of mechanical stress, the result is a reparative activity by the chondrocytes in the osteoarthritic cartilage. The second reason for making the choice to perform an ankle arthrodiastasis is that the procedure is not joint destructive.

I have performed well over 200 ankle arthrodiastasis procedures with very promising results. The clinical benefit of joint distraction with ring fixation in the treatment of severe osteoarthritis opens the door for the treatment of severe degenerative joint disease. Considering the high prevalence of osteoarthritis, arthrodiastasis provides relief of symptoms and, at the very least, may delay the need for arthrodesis or joint implantation, both of which are joint destructive procedures.
It is my opinion that prior to performing any type of joint implant or joint destructive procedure, one should attempt an ankle arthrodiastasis.

The procedure itself is not technically demanding with most procedures being performed in a surgical center outpatient setting. The cost for an ankle arthrodiastasis procedure is drastically reduced in comparison to joint implants and ankle fusion procedures with overnight hospitalization.

Addressing Key Issues With Ankle Arthrodiastasis

There are five controversies that one must address when contemplating ankle arthrodiastasis. These controversies include:

• the length of time in which the fixator is placed;
• whether to place a pin through the talus;
• the use of hinges within the frame;
• whether to distract acutely or chronically; and
• the use of postoperative injections to increase the production of fibrocartilage.

In regard to the length of time for fixator placement, this varies drastically when one reviews the literature. European authors suggest a period of three months.1 However, it has been my experience that a period of five to six weeks is sufficient to obtain maximal results. The longer the patient is in the frame, the greater the chance of frame complications and failure. The goal of the surgery is not to distract the soft tissues but to stimulate the growth of fibrocartilage. The stimulation has been well documented and observed within a five- to six-week period. The longer one keeps the frame on the patient, the greater the chance for ankle stiffness upon removal of the frame.