Dr. Peter Fowler

Dr. Peter Fowler: Beyond the Ligament in ACL Injury

June 26, 2000

By Neal Patel, Knee1/Body1 Staff

ACL tears are often accompanied by certain associated injuries that, if not given enough time to heal, can lead to degenerative disorders. In today’s haste to get patients back to their normal lives, the danger exists that these associated injuries are overlooked and therefore do not heal completely before patients resume impact activities. Dr. Peter Fowler advises, “the ligament is just one component of the injury and [physicians] must be ever mindful of the other associated injuries.” According to Dr. Fowler, although a surgeon needs to focus on properly reconstructing the ligament, it is just as important for a surgeon to have an overall philosophy for knee care that emphasizes the total present and future well-being of the patient.

Dr. Peter Fowler received his medical degree from the University of Western Ontario in London, Ontario in 1964. Currently he practices at the Fowler • Kennedy Sport Medicine Clinic, which is named in his honor, and is a professor of orthopedic surgery at the University of Western Ontario, where he is enthusiastic about passing on his orthopedic philosophy to his students. In addition, Dr. Fowler has been appointed several times to serve as Chief Medical Officer/Orthopedic Consultant to Canadian National Teams participating in various international events. Recently, Dr. Fowler was named as the senior orthopedic surgeon to travel to Europe with three young North American surgeons as members of the American Orthopedic Society for Sports Medicine Traveling Fellowship, to participate in an exchange of knowledge between the two continents.

Knee1: Of all the medical specialties, why did you select orthopedics and specifically knee care?

Dr. Fowler: Two factors led me into orthopedic knee care. First, there was Dr. Jack Kennedy. In 1970, I was appointed to the faculty at the University of Western Ontario, where I worked with Dr. Kennedy. He was one of the leaders in developing the sub-specialty of sport medicine and his enthusiasm for knee injuries fueled my interest in that area. Second, there was my exposure to arthroscopy. Dr. Bob Jackson, who used to practice in Toronto and now is in Dallas, brought arthroscopy to North America in the mid-to-late 60s. I went down to Dr. Jackson’s clinic in 1971, and he taught me about arthroscopy. In 1972, we started doing arthroscopy at our center. Early on, the arthroscope was used only as a diagnostic tool; however, because I was the only one practicing this procedure at our center, it began to take more and more of my time. As a result, I went from being a general orthopedic surgeon to a surgeon who specializes in sport medicine and knee problems exclusively.

Knee1: What effect do you feel arthroscopy has had on orthopedic knee care?

Dr. Fowler: Arthroscopy has changed everything. Being able to do procedures assisted by arthroscopy has shortened much of the rehabilitation time in many procedures. However, one of the biggest challenges created by arthroscopy has been to keep people aware of the fact that even though a surgical procedure is assisted by arthroscopy, the injury is still severe and the surgery is still major. Since arthroscopy allows procedures to be minimally invasive, patients feel relatively good after the surgery and so the trend today is towards accelerated rehabilitation. We started off by keeping patients out of their normal activities for over a year and then this time was reduced to nine months. Recovery time now is six months and some talk about reducing it to four months. We may get away with accelerated rehabilitation in some low-impact sports, such as ice hockey, but if it’s a high-impact sport, such as basketball or volleyball, we may be doing patients a lot more harm in the long run. It takes time for the body to recover and it is the associated injuries that need the extra time to heal.

Knee1: Beyond the actual tearing of the ligament, what are the associated injuries involved in an anterior cruciate ligament injury?

Dr. Fowler: What many people don’t appreciate is that the so-called “isolated” tear of the anterior cruciate ligament comes with a significant partial dislocation of the knee occurring with all of the patient’s weight on the knee. When magnetic resonance imaging (MRI) came into use, we started noticing that in as much as 90 percent of our ACL injury patients, extremely significant bone bruises occurred in a characteristic pattern at the impact point between the dislocated tibia and the femur. These bruises are significant because it is at this specific point of impact on the femur that we see the start of many of the degenerative changes associated with ACL injuries. Thus, it is not failure of stability in the knee that plagues patients many years down the road, but rather, it is the degenerative wear and tear changes that occur in the knee that cause discomfort in the future. I think for years, we have been given the information that the degenerative conditions associated with ACL injury occur because of multiple episodes of instability prior to a reconstruction, when in fact, the impact from the first injury is more than enough to start the degenerative process.

In addition, besides the impact injuries to the cartilage and bone, it has been observed that with the reduction of the dislocation accompanying ACL tears, shear forces are generated that cause tearing or the beginning of a degenerative process in the menisci.

Moreover, with the loss of the mechanical function of the ACL, we also lose the neuromuscular function of the ACL as well. Many people feel the ACL, like other ligaments, is just a piece of rope that provides mechanical stability when in fact the ACL is rich in small neuromechanical receptors that provide position sense and other information for the knee.

Knee1: Do you feel that the associated injuries have been overlooked in treatment of ACL injuries?

Dr. Fowler: Yes. It is a fact that the impact injuries need a chance to heal. The factors that we often use as a guide to return a patient to a sport or other impact activity are whether the patient has regained strength and motion in the knee, and whether the knee is quiet and stable. These are all important aspects, however, we forget that what troubles patients in the end is the degenerative arthritis. Although many patients are stable and have full motion, they get out there and they hurt because something is still wrong. Often, the sub-chondral bone, where we see these bruises, has not had a chance to heal and is not thought about in rehabilitation. We are always saying that we must reconstruct a ligament to try and prevent arthritis; however, reconstruction alone does not prevent arthritis. Degenerative changes are progressive. If there are some degenerative changes that go along with the initial injury, then we must try and keep them to a minimum to prevent future problems.

Knee1: How do you detect associated injuries and track the progress of these injuries?

Dr. Fowler: Many people have an MRI after the initial ACL injury and that will show the extent of the overall injury. A bone scan, however, is a simpler way to follow the activity of the bone injuries. The reason we see the images on the bone scan is because there has been micro fracturing with bleeding at the points of impact. The bone scan picks up the increases in metabolic activity in the bone caused by the injury and the healing of the injury. Decreased activity on the bone scan should indicate completion or near completion of healing of these injuries. I’m not recommending that patients have a bone scan every week; however, maybe at six months the bone scan should be done to see if this activity has increased or decreased. If significant decrease in activity is not seen, maybe the patient should be held off of impact activity further. Moreover, in two- thirds of the people who have a geographic bone bruise, articular cartilage degeneration occurs right at the site of the bone bruise. However, this articular cartilage degeneration does not show up until after six months. If we do a repeat MRI or arthroscopy for other reasons six months later, we may be able to pick up on these cartilage changes and take steps to minimize further damage. What we are trying to figure out is how we can alter these degenerative changes in the articular cartilage occurring in the area of this impact. Maybe with less impact during rehabilitation and a longer time before returning to sport, there will be less degenerative damage.

Knee1: So, you are opposed to today’s movement towards accelerated rehabilitation and getting patients back to full activity as quickly as possible?

Dr. Fowler: I can see problems with accelerated rehabilitation. It is always our goal to get patients back to normal activity quickly, but we want to be mindful of these problems. I am not opposed to accelerating the return of full range of motion, strength or endurance in the knee. But I am opposed to decreasing the time before the knee is subjected to impact. We have to figure out what this critical time is so that the knee can sagely withstand high impact activities.

Currently, we are trying to understand the effect of impact on rehabilitation. We are conducting a prospective, randomized study in which one group of patients who have had ACL reconstruction undergo our standard ACL rehabilitation program and a second group undertakes a non-impact rehabilitation regimen in which mainly water and stationary bicycle exercises are employed as opposed to running and jumping. At six months and one year, we are doing bone scans to see if the lower impact rehabilitation has been more effective in decreasing activity on the bone scans. As of now, we have all our bone scans and we are waiting for the nuclear radiologist to analyze them. It is my hope that soon we will be able to alter this process by some means.


To contact Dr. Folwer, send e-mails to [email protected]

Last updated: 26-Jun-00

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