Dr. John Fulkerson: The Search for a Better ACL Graft
By Tom Keppeler, Knee 1 Staff
Rupture of the anterior cruciate ligament is a common and potentially very debilitating problem, particularly in an athlete. Although many techniques have evolved to reconstruct the ACL, nearly all involve pain during recovery and some loss of motion can occur at times. Traditionally, doctors who use autografts (that is, tissue from the patient’s own body) have borrowed tendons from the patient’s medial hamstring or patellar tendon. Dr. John Fulkerson suggests a new approach: taking a free tendon graft from the quadriceps tendon just above the kneecap. Using this quadriceps free tendon graft may help patients rehabilitate faster and feel better than with hamstring or patellar tendon grafts.
Dr. Fulkerson is a partner at Orthopedic Associates of Hartford, as well as Fellowship Director of Sports Medicine and Director of Orthopedic Resident Selection at the University of Connecticut’s School of Medicine. He graduated from Williams College and Yale Medical School, and served as team physician for the National Hockey League Hartford Whalers hockey team from 1989 to 1996. He has authored over 70 scientific articles, and still finds enough free time to pursue interests in tennis, skiing, organic gardening and raising grapes at his vineyard.
Knee1: Let’s first talk a little about one of your long-term interests, the patellofemoral joint. How did you become interested in this area of the knee?
Dr. Fulkerson: When I first went into practice in 1978, it was considered a problem area. The treatments for people with anterior knee pain were more empirical than I thought they should be, and so I thought it would be a fruitful area to look into.
Knee1: Who is at the greatest risk of patellofemoral pain?
Dr. Fulkerson: Women are more prone to anterior knee pain, partly because of the mechanical alignment factors that are more prominent in women than in men. It has to do with the woman's relatively wider pelvis. Therefore, the hips are set further away from the central axis of the lower extremities. Consequently, the lower leg is put into an orientation that makes the kneecap more prone to slip to the outside. As a result, women may develop stability and pain problems around the front of the knee. If I had to pick a group at the highest risk, I would say young, very active women are the most prone to develop anterior knee pain when they have a predisposing anatomical malalignment.
Knee1: What have you done to help the diagnosis and treatment of patellofemoral pain in particular?
Dr. Fulkerson: My main area of interest has been the soft tissue structures around the front of the knee, not just the kneecap and the joint itself. The investing soft tissue around the knee can become painful as a result of overuse. Chronic imbalance of the kneecap can cause stretching and pain in the support structure around the front of the knee. We have studied the use of computerized tomography and tomographic imaging to better delineate the alignment of the kneecap and the proper mechanical function of the kneecap. I developed a technique for antero-medial-tibial-tubercle transfer to better realign the kneecap extension mechanism onto healthier cartilage and place the kneecap into a more-normal alignment pattern. This osteotomy achieves both diminished pressure on the kneecap as well as realignment of the knee’s extension mechanism.
Knee1: Can you perform the procedure arthroscopically?
Dr. Fulkerson: No. It is an open-knee procedure.
Knee1: You have also made advances in anterior cruciate ligament (ACL) reconstruction by using the central quadriceps tendon. What attracted you to that specific tendon versus any other?
Dr. Fulkerson: In the early 1990s, I was struck that the traditional graft of the time, the bone-tendon-bone graft, which involves removing a piece of bone from the knee cap, seemed to cause anterior knee pain in some patients while kneeling. Using this graft seems to cause anterior knee pain in some people after their surgery. I decided I would look for a better alternative. One other graft that was being used at that time was the medial hamstring tendons. These are still used frequently for ACL reconstruction. Using the hamstring tendons did not really appeal to me, since the hamstrings are important stabilizing structures for the knee. They help support the inside, back portion of the knee. It just seemed like it would be better to leave those tendons alone, particularly in athletes. Some say these tendons come back, but I am not convinced. I was also concerned about using allograft, which is cadaver tendon, because some studies by Frank Noyes suggested that the longer-term results of using cadaver tendons were not quite as good as reconstructions that use a person’s own tendon.
All of the grafts work, but I was looking for something better. Because of my interest in the anterior knee, I had looked at that anatomy extensively, and I noticed that the tendon above the kneecap, the quadriceps tendon, is actually a bigger tendon with more connective tissue than the tendon below the kneecap, the patellar tendon, which was frequently being used for ACL reconstruction. It seemed logical that one could use the tendon above the knee for the reconstruction, with no real downside, that is, long-term loss of strength or function. I looked into it, and found that a Swiss surgeon named [Dr. Hans-Ulrich] Staubli had been using the quadriceps tendon with a piece of bone for reconstructing the cruciate ligament since the 1980s. I soon adopted his technique and found that it worked very well. The patients had less pain, and, in fact, I had better success with it than with the bone-tendon-bone graft. We used that for three years, and then it occurred to me that the techniques for fixation of tendon grafts were improving. There were a number of different techniques that used pure tendon graft without any bone—mainly the hamstring tendons. I felt I could adapt the same techniques for using the quadriceps tendon graft without bone. That’s turned out to be wonderful, because now we can take a graft out of the tendon above the knee without any bone, so there is no violation of the kneecap whatsoever. It really is a benign graft, and a smoother post-operative course. I actually feel it is a better autograft reconstruction graft. Fixing it properly is very important.
Knee1: Have you noticed any effect on the patients’ recovery time?
Dr. Fulkerson: It seems to diminish recovery time. Patients feel better quicker. Our main concern with that, however, is that recipients also feel better so much quicker that they become active quicker. We worry about them doing too much too soon. One focus in rehabilitation program is preventing them from returning to activity until they have strength return and healing of the graft. That’s easier when they’re having discomfort and swelling, but with this graft, there is less of that, so we have to pay more attention to educating people about the importance of going through a controlled rehabilitation program that gives them adequate time to healing of the tendon graft to bone.
Knee1: Is the quadriceps graft procedure the only one you use to fix torn ACLs?
Dr. Fulkerson: Yes, I use the central quadriceps tendon for everybody. The only time I would not use it is if someone has already had that tendon taken. However, we’ve actually used the quadriceps tendon from the other knee in preference to other autograft alternatives, because we feel confident about its success. We have two national champions now who have had reconstruction with the central quadriceps free tendon and we feel confident that we can use that graft in anyone, no matter how great their level of activity. We also feel it’s better for women, because they are more likely to tear their ACL. Some recent research at the University of Michigan has suggested that and taking the hamstring tendon in a woman may be particularly risky. We feel confident that leaving them intact and using the quadriceps free tendon increases overall stability around the knee. I think this technique works for any level of athlete, male or female, large or small, contact or non-contact.
Knee1: Who would be the best candidate for ACL reconstruction?
Dr. Fulkerson: Any patient who is involved in high-demand activities, anyone who needs greater knee stability after an ACL rupture, or anyone who has recurrent instability after having torn the ACL.
Knee1: Tell me about the procedure itself. What differentiates it from, say, a hamstring tendon or patellar tendon graft reconstruction?
Dr. Fulkerson: About the only thing that is different is the harvesting of the tendon, because it is in a different location. The only other thing that we do that is a little different is that we take a small disc of cortical bone graft from the tibia, below the knee and attach that to the end of the quadriceps free tendon. That is just an extra little buttress or anchor that helps make the fixation more secure and helps with the incorporation of the bone inside the tunnel after the graft is placed there.
Knee1: There have been a number of great gains in treating knee problems over the last few years. Where do you see gains in the next few years in knee surgery?
Dr. Fulkerson: I think bioengineering is interesting. I am still pretty sold on the idea of autografts, however, particularly since we have a relatively benign autograft alternative for ACLs, and it’s going to be hard to beat someone’s own tissue for a reconstruction unless a graft can eventually be synthesized from a patient's own cells. However, I think there will be a future with bioengineered synthetic tendons, and they may some day approach the quality of the patients’ own tendons. I also think we need a lot of education with patellofemoral problems, where there is a big gap in knowledge. I think we need to educate orthopedic surgeons better about how to take care of patellofemoral problems, to develop logical approaches to treating patients. Additionally, resurfacing procedures—specifically patellofemoral resurfacing—is something that is still in its infancy and needs to be looked into further. Meniscus transplantation is an area that needs a lot of research. Dr. Richard Steadman is one of the innovators in that area. Autologous Cartilage Implantation, or ACI, is something that needs some work—we need to see what the long-term effects of that type of procedure are. There is a lot of interest in that, so I think we’ll see some gains in that area. Robotics may also have a place in surgery of the future.
Knee1: You have also looked into better bracing procedures for knee injuries. Could you tell me more about that?
Dr. Fulkerson: I’ve been very interested in that. I have a patented brace that is sold by DonJoy Ortho for support of the patella. It’s a different kind of support than other braces offer. I think there’s a lot of room for innovation in bracing, and there are some new braces for patients with arthritic knees that are adjustable by the individual patient. Cruciate braces could certainly be better, as well as ones that are designed for rehabilitation and ligament pain. It’s an area that has not received a lot of attention, but I think there’s a lot of potential there.
Knee1: How do you see diagnosis of knee pain improving over the years?
Dr. Fulkerson: I think the best area for improvement is physical examination. Going back to what I mentioned earlier, I think it is very important to educate orthopedic surgeons and other healthcare professionals about the intricacies of good physical examinations.
Knee1: How has your relationship with the University of Connecticut helped your research?
Dr. Fulkerson: I spent 17 years there as a full-time faculty member, and became a full professor in 1989. That tie-in has always been very valuable. There are a lot of creative people at U.Conn. with great resources who are always very willing to collaborate, so that’s been a very fruitful relationship for any research I’ve needed to do—anything from electron microscopy on the tissues of the front of the knee to mechanical studies on fixation of the quadriceps tendon. We've been able to get some really good, objective data over the years by working with experts in each field.