Braden C. Fleming, Ph.D. Wins OREF Clinical Research Award

Braden C. Fleming, Ph.D., the Lucy Lippitt Professor of Orthopaedics at Brown University, has been honored with the Orthopaedic Research and Education Foundation (OREF) Clinical Research Award. The American Academy of Orthopaedic Surgeons (AAOS) announced Dr. Fleming as the recipient of this award as part of its virtual annual meeting experience. The award recognizes outstanding clinical research related to musculoskeletal disease or injury. This award is in honor of his for research into the long-term outcomes of anterior cruciate ligament (ACL) reconstruction with a focus on post-traumatic osteoarthritis (PTOA).

Dr. Fleming and his co-authors Gary Badger, M.S., Paul D. Fadale, M.D., Michael J. Hulstyn, M.D., Robert M. Shalvoy, M.D., and Glenn Tung, M.D., spent more than 15 years looking at various mechanical, psychological and biological factors that may result in the onset and progression of PTOA after anterior cruciate ligament reconstruction (ACLR).

According to OREF, “Their work primarily studied the tension applied to a graft (a replacement ligament to assume the role of the damaged ACL) used to reconstruct the ACL. The team wanted to determine if the tension difference was a primary factor for developing PTOA since it dictates joint contact conditions…”

“As a bioengineer, I wanted to explore the mechanical functions of the knee and the way the joint distributes its force or load during activity to determine if joint stability is related to PTOA risk,” said Dr. Fleming. “We studied graft tension to evaluate and explore two schools of thought. One was to apply a tight graft at the time of surgery with the idea that it will stretch over time, and it will basically return to normal. The other was to put the graft in at a low tension and restore normal at the time of surgery, so ideally it won’t stretch out.”

We asked Dr. Fleming about the origins of this study and he told OTW, “It was a debate that was going on between the surgeons I worked with at the University of Vermont. Both tensioning approaches were used clinically. There are surgeons who thought it was best to restore the normal laxity of the knee. Under this tension condition, the graft should not stretch out and hence the joint contact mechanics would be normal. However, if it were to stretch out, then there would be too much motion in the joint and this could be a reason why the ACL reconstructed knee was at higher risk for osteoarthritis.”

“The other school of thought was that the graft would stretch out so it would be better to implant it using a tension condition that would over-constrain knee laxity. Thus, with time, it would become normal. The potential risk is that the joint compressive loads would be greater than normal if the graft did not stretch out and hence this could be a reason why the ACL reconstructed knee would be at higher risk for osteoarthritis. We set out to answer this question.”

The team enrolled 90 patients in the study and matched them with an uninjured control group of 60 patients of similar age, race, sex and activity level.

Fleming’s primary hypothesis was that the high-tension group would have better outcomes when compared to the low-tension group after about seven years. His other hypothesis was that the outcomes for the high-tension group would be equivalent to the control group.

When the results of the study came in, the researchers found no significant differences in the clinical, functional and patient-reported outcomes between the two graft tensioning techniques. Particularly interesting are the psychological factors associated with the onset and progression of PTOA after anterior ACLR.

Dr. Fleming told OTW, “The psychological factors associated with ACL reconstruction outcomes has become a hot topic. There are now a number of instruments to evaluate psychological factors. However, these were not available at the time the study was designed. In our study we utilized the SF-36v2 questionnaire.”

“Several domains of this patient reported outcome instrument evaluate psychological factors, including general mental health (psychological distress and well-being), role limitations due to emotional problems, vitality and general health perceptions. It is interesting to note that the pre-operative general mental health score was predictive of who would have a painful knee seven years after surgery. There was also a trend indicating that the general mental health score was lower (worse) in the low-tension group. The long-term implications of this remain to be seen.”

Furthermore, said Dr. Fleming, “All grafts stretch out during the healing process regardless of the initial graft tension utilized at the time of surgery. Setting the graft tension within the brackets studied here will produce similar outcomes.

“There is evidence of mild arthritis in the ACL reconstructed knee following an isolated ACL injury at seven-year follow-up in many patients.”

“Outcomes studies of ACL reconstruction should include an age, sex, race, and activity matched control group to directly compare the surgical outcomes to those of the normal population. Most ACL reconstruction outcome studies do not include a control group.”