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Dr. Chadwick Prodromos

Dr. Chadwick Prodromos: A Pioneer in the Field of Knee and Shoulder Repair

November 03, 2003

Dr. Prodromos is currently the President of the Illinois Sportsmedicine and Orthopaedic Center, and an assistant professor at Rush Medical School. Among his many significant accomplishments, he has devised a new minimally invasive technique for ACL reconstruction including a safer approach for harvesting the hamstring graft.

He has also revolutionized our understanding of the factors leading to success in knee realignment procedures. Dr. Prodromos has won numerous awards for his research in knee repair and reconstruction.

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Audio Resources:
Dr. Prodromos shares his thoughts on important aspects of knee care:
High Tibial Osteotomy
Innovations in Osteotomy
Stability Rates of Hamstring Grafts
Advances in Joint Deficiency Treatments
Tissue Engineering/Microfracture

Knee1: At what point in your life did you know you wanted to be a doctor?

Dr. Prodromos: I was interested in medicine and science from grade school. I used to read about it whenever I could and decided early on that I would like to enter the field. I decided to go into orthopedic surgery because it seemed to me in medical school that it was a growing and interesting field, which it has certainly turned out to be.

Knee1: In 1986, not long after you finished your residency and fellowship, you published a very influential paper that ended up winning several research awards. We’ll quote from your own summary of your findings: "I found a low pre-operative adduction moment to be highly predictive of post-operative success. This was the first evidence, and is still the best evidence, that dynamic loading, rather than just static alignment, is a key factor in the success of realignment procedures." Can you tell us a little more about what this discovery means, in layman’s terms?

Dr. Prodromos: The procedure that we were studying is called high tibial osteotomy: cutting the bone and changing the angle of the tibia. People with arthritis who were a little bowlegged had their alignment changed, so that they were not bowlegged but had a straight-legged or even, slightly knock-kneed stance. This was a very popular operation until the late 1980s, and then it became largely supplanted by knee replacements. Its popularity did not dim nearly as much in Europe, and has greatly increased lately in the USA because it has turned out to be a very important accompanying procedure to various knee restorative procedures, such as articular cartilage implantation. It had been noted for decades that some people did very well, some people did somewhat well, and some people didn’t do as well after this procedure. The obvious question is "why does this variability exist?" Using infrared-reflecting diodes, cameras, and a force plate in a sophisticated motion analysis laboratory, we could analyze the forces on the knee during gait, before and after surgery. In analyzing this, I found that the force people exert on the knee is dependent in part on the static alignment of their leg, but also heavily dependent on how their body moves when they walk, how they turn, and many other dynamic factors. Two people with identical static alignment could have different compressive loads on the inner part of the knee (that is, the medial part of the knee). I found that you can alter the force on the medial part of the knee, depending on how you walk; and the people who walked in such a way that the force on the inner part of the knee was reduced to a certain level, all had good clinical results afterwards. So this was very interesting. This one factor was an extremely powerful predictor of how people would do afterward. At the same time, the procedure began to be used somewhat less, because knee replacement procedures, which had previously been unreliable, had advanced to the point that their use became widespread. So the findings, while highly significant within the field of osteotomies, became less significant in medicine as a whole, because osteotomy was a less significant option. But particularly in the last five years, there have been dramatic increases in the ability to improve and restore some knees rather than replace them and a corresponding increase in the importance and volume of osteotomies. Osteotomies have thus had a renaissance. We have now begun new biomechanical and clinical investigations on osteotomies used in conjunction with procedures that restore cartilage within the knee. The goal will be to impact the dynamic factors, how people move, to produce a reliably good result in all surgical patients.

Knee1: Tell us more about your work with hamstring ACL reconstruction. You mentioned that you recently documented the safety of the procedure, and that you have several studies going on. How will these studies impact patient care?

Dr. Prodromos: ACL reconstructions are primarily done using one of two grafts that come from the patient’s own body: part of the patellar tendon in the front of the knee, or hamstring tendons from the back of the thigh. Both procedures are done on a large scale worldwide; both yield excellent results. I was trained initially in hamstring ACL replacements and have done them throughout my career; and the procedure, as with all ACL procedures, has developed during that time. Currently, I use a procedure, as do most surgeons using the hamstring graft, with what we call a quadruple strength graft, a very strong graft. I recently finished two studies in regard to our ACLs. One of them looked at our results over a long period of time, up to eight or nine years after we had done them, in a large number of patients—about 150—the largest group that has been studied with at least two-year follow up—and what we found was that the stability results were very good. There had been some thought, particularly early on, that the hamstring grafts did not produce stability at as high a level as the patellar tendon graft, although it appeared to have a lower complication rate. What the study showed—mine is not the only study showing it, although there are not many of them and mine is the largest of the studies—is that the hamstring graft produces stability rates at least as high as those produced with patellar tendon or bone grafts. If you were a surgeon interested in doing this graft because of its low complication rate, but were worried that the stability might not be as high, it’s now well demonstrated that, when properly done, stability rates are as high as with the other methods. I don’t wish to suggest that one study in and of itself will conclusively establish this in the medical literature, but it is a strong piece of evidence in that direction. Another of out studies involved how we harvest the graft used for the reconstruction; a technical matter. I was trained to, and for six years did, take this graft from an incision on the front of the tibia, just below the knee. This works satisfactorily, but some of the dissection has to be done in the back of the knee, and can be a little tricky to do from the front. It is possible that the graft that is obtained may be a little shorter than one might like, if the surgeon isn’t very careful. Ten years ago, I thought, "If much of the dissection done to obtain the harvest is done in the back of the knee, why not make a small incision in the back of the knee to make it easier to do the dissection?" I began harvesting the graft in this manner and found that it greatly facilitated this part of the procedure. Hamstring tendon grafts have been growing steadily in popularity in recent years. It had been brought to my attention from a number of sources that some surgeons who want to use hamstring grafts were reluctant to do so, because the harvest of the graft was seen as being difficult. However, taking the graft with this small incision on the back of the knee makes the graft harvest significantly easier. Most importantly, in the occasional difficult case, this procedure allows the surgeon greater visibility in the problematic area, so that he can more easily and safely perform it. Another side benefit of this technique is that by putting part of the incision in the back of the knee, within the skin crease, that part of the incision becomes inconspicuous. This incision is about an inch in length, and allows the incision in the front to also be quite small. I did not devise it for cosmetic reasons, but a pleasant byproduct is that an excellent cosmetic result occurs. It doesn’t matter to some patients, but other people who would like to have a relatively inconspicuous incision appreciate it. It is also possible to do it the traditional way and make the incision relatively small, but it’s harder. With the traditional technique I was never able to comfortably make the incision even close to being as small as I do now. As hamstring reconstruction becomes more and more popular, I think that this technique is probably most useful to surgeons who have not done the procedure before and would like to start doing it, to provide them with a level of comfort and safety for what many surgeons have told me is the most difficult part of the procedure. And again, as a pleasant byproduct, the cosmesis is also very good.

Knee1: If you could change anything about the field of orthopedics, what would it be?
Dr. Prodromos: The one thing that I would have liked to see evolve, or change, is already happening. In the field of sports medicine, we are generally interested in restoring joints that have a deficiency, with the most obvious being the ACL. The thing that has been the most bothersome to me over the years is seeing knees with deficiencies that we couldn’t address, and feeling fairly helpless, talking to patients about just living with it until it got bad enough to replace the entire knee with a metal and plastic knee. We’ve recently seen great advances in being able to restore other aspects of joints: to slow down degeneration and possibly stop it altogether; basically to attempt to restore the joint rather than just wait to replace it. We’re in the infancy of doing this now, but I think that in the future we’re only going to have more success. My practice, for example, has evolved from just sports medicine to a special interest in what some people are calling cartilage restoration. So, for example, I had a patient recently who had degeneration in one compartment in the knee and a deficient ACL, and was a young working person, a carpenter, and we were able to do a procedure to restore the cartilage and the meniscus as well as the ACL. Even a few years ago, I would have had to tell him there wasn’t anything I could do except give him pills and wait till his knee got bad enough to replace. What was always a rewarding field has thus gotten to be much more rewarding, because our tools have increased. I expect, because of the field of tissue engineering, we’ll be able to do much more in the future.

Knee1: What kind of an impact will genetic engineering have on orthopedics?
Dr. Prodromos: It will impact it enormously. For example, we now have some success with a procedure called microfracture, using a patient’s own marrow cells to regenerate cartilage. But the cartilage is not normal, and the results are usually not thought to be permanent. I think over time we will figure out what signals we will have to send to those cells, whether mechanical or biological, that will cause these cells to form more normal, more permanent cartilage. In transplantation procedures we have good results, but our results tend to be better in younger people who have problems but not globally arthritic knees. I think in time we’re going to get better and better at being able to treat and restore, rather than replace. We now know that there are cells in a person’s own body that have the potential to become different kinds of cells to repair damaged joints. That was not known a few years ago. We just haven’t figured out well enough how to make them do it. Joint repair will always be very useful, but there are many people who we will be able to treat, to restore their joints, rather than replace them, in the future. There are really five separate parameters to restoring a knee or any joint: the stability of the knee, the articular cartilage, the meniscal cartilage, the bone, and then there’s alignment . We now have tools to address all of these: ACL reconstruction; articular cartilage implantation/microfracture, osteochondral allograft implantation; meniscal transplants; bone grafts; and osteotomies, respectively. When I see a patient now with a degenerated knee I look at him in terms of all five areas. How can we address them? What are the chances of success? At least, we can look at it rationally. We don’t have the answers for every person yet. But now the future can be seen as just a process of getting and improving treatments in all five areas. Just a few years ago, we didn’t have reliable treatments in any of those areas.

Knee1: For our readers who may be looking for an orthopedist, how would you recommend they find a good one?

Dr. Prodromos: I think it’s generally useful to talk to their primary care doctor; I think hospitals can often give them indications. Many physicians now, including me, have websites that indicate what that surgeon does. The field of orthopedics has become very specialized, so it’s often useful to find out exactly what that particular doctor is interested in and comfortable doing. And of course, always talk to other people in the community. There are two organizations: one is the American Orthopedic Society for Sports Medicine, and the other is the Arthroscopy Association of North America. The members of both of those organizations, which are in many ways similar, are doctors with a special interest in sports medicine and arthroscopic procedures, and they can help find surgeons in the area.

Last updated: 03-Nov-03

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