Point-Counterpoint: Is Arthrodiastasis A Viable Option For Ankle Arthrosis

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.

The argument of whether to place a pin through the talus is negated with the amount of surgeon experience. The novice surgeon will reason that one must fixate the talus in order to distract the ankle. However, if the talus is fixated, the subtalar joint will not be allowed to distract. In most cases, if there is ankle arthrosis, there is subtalar joint arthrosis. Accordingly, one should distract both joints. Once the surgeon is able to recognize that he or she can achieve distraction of the ankle joint and the subtalar joint simply by placing wires through the calcaneus, he or she will increase their chances of greater success with minimal complications.

What You Should Know About Using Hinges In Ankle Distraction
Placing hinges about the ankle joint and subsequently distracting the ankle joint will shift the axis of the hinges. This results in locking of the joint. Therefore, if one places the hinges, the surgeon should do so only after achieving the distraction process. Initially, surgeons are eager to accept the theory that one can distract a joint after placing a hinge axis to obtain greater range of motion throughout the distraction process.

However, the surgeon only has to perform one procedure to realize the fact that when one places the hinge in a static position prior to lengthening, the axis shifts after lengthening and there is locking of the joint.

I do not recognize or subject myself to the theory of distraction with a hinge within the frame. Surgeons only have to perform one procedure with hinges to understand that the patient will not tolerate distraction with range of motion. In fact, this may only pave the way to possible greater joint destruction in the future.

Final Notes

The concept of gradual distraction or acute distraction is of surgeon preference. To achieve optimal results, one only needs to distract the joint three to four times the preoperative joint space measurement. To subject the patient to daily distractions is senseless and only delays the process in which fibrocartilage can be produced.

Finally, surgeons have utilized synthetic injections to promote fibrocartilage in the ankle to help promote the distraction process. Unless there is an allergy issue or if the process is cost-prohibitive, I see no drawbacks with the use of these synthetic injections. However, bear in mind that these synthetic injections are not currently indicated by the Food and Drug Administration (FDA) for ankle injections.

Dr. Vito is the Director of the Atlanta Leg Deformity Correction Center in Macon, Ga. He is a Fellow of the American College of Foot and Ankle Surgeons, and is a faculty member of the Podiatry Institute.

Reference

1. Van Valburg AA, Van Roermund PM, Lammens J, Van Melkebeek J, Verbout AJ, Lafeber FPJG, Bijlsma JWJ. Can Illizarov joint distraction delay the need for an arthrodesis of the ankle? A preliminary report. J Bone Joint Sur 77-B:720-5, 1995.

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No. By Lawrence Fallat, DPM, FACFAS. While arthrodiastasis is an intriguing procedure, the existing literature raises many questions that need to be addressed with more well designed studies.

Arthrodiastasis is a joint distraction procedure that is advocated to reduce pain and increase motion of an arthritic joint without sacrificing the joint. Although the procedure appears to be beneficial to some patients, it is controversial and surrounded by questions.

Does the procedure work well enough to justify the cost of the external fixator, an operation to apply the fixator and another procedure to remove it? Is arthrodiastasis a primary procedure or an adjunctive procedure? If one combines arthrodiastasis with an arthroplasty joint remodeling procedure, which procedure is really providing relief or are both procedures necessary?
Are there studies that compare outcomes of an arthroplasty with arthrodiastasis? Are there valid prospective studies that measure outcomes in a large number of patients over a long duration? What are the indications and limitations of arthrodiastasis? To be fair, the surgeons who perform the procedure are trying to provide pain relief in the younger patient who would otherwise have a fusion or joint implant. They are trying to delay these definitive procedures or prevent them altogether.

In the lower extremity, surgeons primarily use arthrodiastasis at the first metatarsophalangeal joint and the ankle joint. Many of the arthrodiastasis reports indicate that the surgeon leaves the external fixator in place for approximately 15 weeks. In less time, a patient with severe degenerative first metatarsophalangeal joint arthrosis could have had a cheilectomy, a shortening or plantarflexory osteotomy, or a joint implant, heal and have had physical therapy. They can accomplish this with one operation.

Although the outcomes of arthrodiastasis are not well established, the results of first metatarsophalangeal implants and fusions are well known. When it comes to a severely arthritic posttraumatic ankle in a young patient, the options are more limited.

If the surgeon does not wish to perform arthrodesis or an implant procedure, one can correct angulation deformities with osteotomies or an arthroplasty to remove spurs and repair cartilage. Continuous passive motion may also provide egeneration of cartilage and stretch periarticular soft tissue structures.

A Closer Look At The Current Literature

In 1995, Van Valburg, et al., assessed the use of arthrodiastasis on 11 patients with advanced posttraumatic ankle arthritis. They accomplished distraction with Ilizarov external fixators, which they removed at 15 weeks.1 The authors reported that at 20 months, all 11 patients had less pain and six patients had better motion.

These results are interesting but upon closer review, it is clear the study is flawed. In this retrospective study, the evaluation of pain, motion and restoration of joint surfaces with distraction was of questionable validity. The investigators felt that joint distraction could stimulate cartilage repair.

One would evaluate this by measuring the joint space on preoperative and postoperative X-rays. However, at the time of follow-up, only six patients had postoperative X-rays and only three of these patients had changes consistent with repair and regeneration of cartilage.

The theory is that distraction of a joint stretches the periarticular soft tissue structures. Offloading the joint prevents mechanical contact, which promotes pressure changes in the joint fluid that lead to proteoglycan synthesis and subsequent cartilage repair.2

In some patients who have had arthrodiastasis, when the external fixator is removed, the joint space remains widened for a period of time. Some see this as confirmation that the cartilage has returned to its pretrauma thickness.

However, not all of the patients who have had the procedure exhibit widening of the joint after one has removed the fixator. In 1999, Van Valburg, et al., published a study involving 17 patients who had distraction of the ankle joint and stated that “on average, an increase in joint space width was not observed.”3

Ploegmakers, et al., also assessed the use of arthrodiastasis in 22 patients with severe osteoarthritis of the ankle joint.4 They reported that 73 percent of the patients had significant improvement at seven years. The mean age at the time of surgery was 37 + 11 years. At the time of evaluation, the study authors considered six patients (27 percent) to be treatment failures. Three of these patients had an arthrodesis within one year and two patients had a fusion four years after treatment.

Although the study authors reported that 16 patients (73 percent) had improvement at seven years, this study was retrospective. Unfortunately, because they could not review all of the preoperative X-rays, they could not evaluate joint space and subchondral sclerosis.

Some have also advocated arthrodiastasis in the treatment of hallux limitus and rigidus. In 2005, Wilusz and Pupp presented a case in which they applied a mini external fixator to the first metatarsophalangeal joint of a 63-year-old runner.5 They removed the fixator at five weeks and noted that the patient had no pain at 18 months. However, they did not evaluate the joint space postoperatively to determine if it had increased. Prior to the application of the external fixator, the authors performed an arthroplasty/ cheilectomy procedure, which consisted of removing spurs and loose bodies, debriding the synovium and releasing the sesamoid apparatus.

Which of the two procedures resulted in improvement? How do the authors know that the joint distraction provided relief when it could have been the removal of the spurs and the joint debridement?

Another article published in 2005 would seem to answer these questions.6 Talarico, et al., treated a total of 133 patients with arthrodiastasis for Grade I,II and III hallux limitus and rigidus. The study authors followed all of the patients for at least one year and followed 44 of the patients clinically for three years.

They removed the fixators between the fifth and sixth weeks. At one year, the average American Orthopaedic Foot and Ankle Society hallux metatarsophalangeal-interphalangeal score for 133 patients was 88 and the pain score was 33. Eight-six percent of the patients demonstrated an increase in radiographic joint space.

The authors indicated that they performed a cheilectomy or remodeling of the first metatarsal head if necessary. However, they did not report how many patients had these procedures performed in conjunction with joint distraction or what the outcomes were for this group. In addition, the study authors did not report if elevatus of the first metatarsal or a long first metatarsal was present, and if they addressed this finding.
Arthrodiastasis is an intriguing procedure that does seem to delay the need for a joint implant or arthrodesis in some patients. Unfortunately, many of the studies, although well meaning, were not well designed.

Emphasizing The Need For More Studies

Many of the studies combine joint arthroplasty with arthrodiastasis and then praise the success of the joint distraction. We need a prospective study that compares arthroplasty and cheilectomy to arthrodiastasis. Another study comparing the combination of the two procedures would be invaluable. Prospective, high volume, long-term outcomes studies would also help eliminate the possibility of a placebo effect, which can be very high.

The concept that distraction eliminates the load across a joint and allows restoration of the cartilage has not been appropriately evaluated. The published studies indicate that some patients retain appropriate joint space after joint distraction. One can determine this by measuring the preoperative and postoperative joint space on X-rays. Yet several of the studies did not evaluate joint space for all of the patients.

In addition, researchers did not see increased joint space in many of the patients even though the patients were reportedly doing well. If increased joint space cannot be demonstrated on X-rays, does the cartilage regenerate at all? If the cartilage is capable of healing, are there factors that may limit repair of cartilage?

Perhaps one could better determine the status of the cartilage with MRI or postoperative arthroscopic evaluation.

In the case of hallux limitus and an elevated first metatarsal, how does joint distraction change the biomechanical pathology that caused the degenerative joint arthrosis? If joint space increases, one should measure the amount and compare it to the preoperative joint space. It would also be helpful to measure this radiographically at periodic intervals to determine if the space changes with time and activity.

We also need to evaluate range of motion more consistently. Does motion actually increase with distraction and without remodeling of an arthritic joint? Many of the patients with an arthritic ankle have anterior spurs at the distal tibia and the corresponding portion of the capsule attachment on the superior surface of the talar neck. How can dorsiflexion increase with an osseous block?

In Conclusion

In summary, the arthrodiastasis concept is interesting and it may be beneficial to some patients. However, the few existing reports are not conclusive and until better, well-designed studies are conducted, the procedure remains investigational.

Dr. Fallat is a Clinical Assistant Professor within the Department of Family Medicine at the Wayne State University School of Medicine in Detroit. He is the Director of Podiatric Surgical Residency for the Oakwood Healthcare System in Dearborn, Mich. He is board-certified by the American Board of Podiatric Surgery and is a Fellow of the American College of Foot and Ankle Surgeons.

References

1. Van Valburg AA, Van Roermund PM, Lammens J, Van Melkebeek J, Verbout AJ, Lafeber FPJG, Bijlsma JWJ. Can Illizarov joint distraction delay the need for an arthrodesis of the ankle? A preliminary report. J Bone Joint Sur 77-B:720-5, 1995.
2. Buckwalter JA: Evaluating methods of restoring cartilaginous articular surfaces. Clin Orthop 367(suppl): 224-238, 1999.
3. Van Valburg AA, van Roermund PM, Marrijnissen ACA, van Melkebeek J, et al. Joint distraction in treatment of osteoarthritis: A two year follow-up of the ankle. Osteoarthritis and Cartilage 7(5):474-479, 1999.
4. Ploegmakers JJ, van Roermund PM, van Melkebeek J. et al. Prolonged clinical benefit from joint distraction in the treatment of ankle osteoarthritis. Osteoarthritis and Cartilage. 13(7): 582-588, 2005.
5. Wilusz PM, Pupp GR. When is it appropriate for arthrodiastasis of the first MPJ? Podiatry Today 18(9): 26-30, 2005.
6. Talarico LM, Vito GR, Goldstein L, Perler AD: Management of hallux limitus with distraction of the first metatarsophlangial joint. J Am Podiatric Med Assoc 95 (2): 121-129, 2005.

For a related article, see “When Is It Appropriate For Arthrodesis Of The First MPJ?” in the September 2005 issue of Podiatry Today.

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