HSS Researchers Launch Study to Look for Clues to Meniscal Healing After Surgery
Researchers at Hospital for Special Surgery in New York City are launching a new study to identify inflammatory molecules that might help improve treatment of people with certain knee injuries.
The goals of the study, which is now enrolling patients, is to find biomarkers correlated with the development of osteoarthritis of the joint after surgery to fix traumatic tears of the meniscus. This horseshoe-shaped layer of cartilage cushions the bones of the knee during weight-bearing activities like running and jumping.
More than one million Americans annually undergo meniscal surgery, making it among the most common orthopedic procedures performed in the United States. The injuries generally occur in young athletes who experience violent trauma to the knee, although older people can suffer them without such trauma, as well. However, patients who undergo the procedure often develop osteoarthritis of the joint—a painful, degenerative condition that to date has no cure or particularly effective treatment.
"The bottom line is, this is a very common orthopedic surgery and the results are not very good," said David W. Altchek, MD, sports medicine surgeon and co-chief emeritus of HSS Sports Medicine, and medical director for the New York Mets. "It seems like the surgery makes a small number of people better, some have an indifferent response and, unfortunately, a significant number of people get worse."
"We don’t really know much about the biology of how the meniscus heals. We kind of let pain be the guide," added Christopher Mendias, PhD, ATC, associate scientist at HSS, who is helping conduct the study. "We want to be able to say, 'Is it healing well, and is there a correlation between doing poorly clinically and elevated levels of pro-inflammatory biomarkers or that we can detect with advanced imaging?'"
The HSS study will have several components. Drs. Altchek, Mendias and their colleagues will take samples of synovial fluid--a viscous substance that lubricates joints--from 28 patients (14 men and 14 women) aged 18 to 45 undergoing a procedure called partial meniscectomy in which surgeons shave away frayed pieces of the cartilage. Those samples will be screened for the presence of proteins associated with inflammation, molecules such as interleukin 1 beta, which is known to play a role in osteoarthritis, as well as other previously unidentified substances.
The researchers also will use an advanced form of magnetic resonance imaging to track meniscal healing over time, and will match that information with the biomarker activity to look for patterns of protein activity that predict either successful healing or poor outcomes.
"This whole idea of precision medicine is just kind of catching on in orthopedics now," Dr. Mendias said. Ideally, a biomarker panel could help surgeons determine which patients will be most likely to benefit from particular meniscal procedures, and what kind of rehabilitation--and even prehabilitation--routine they should undergo. "It could also help us identify therapies to block those inflammatory molecules and reduce the risks of osteoarthritis later in life," he said.
"The hypothesis is that there is a degenerative effect afterward, as a result of the injury or the surgery, or both—and that biologic therapy might slow that down," Dr. Altchek said. He added that there is "a tremendous amount of excitement" in the field of orthopedics about new biologic therapies, including platelet rich plasma and stem cells, that are now being used to treat tendon injuries and certain other ailments. Whether they might work to treat or even prevent the development of osteoarthritis after knee surgery is unclear. "This project is an important step in the direction" of answering that question, he said.
Scott A. Rodeo, MD, sports medicine surgeon, co-chief emeritus of HSS Sports Medicine, and co-director of the Tissue Engineering, Regeneration, and Repair Program, will be contributing patients to the study.
"A common clinical observation is that there is tremendous variability in the rate and risk of progressive degenerative changes in patients undergoing surgery for meniscus injury," said Dr. Rodeo, who also is head team physician for the New York Giants. "Some patients will do well for decades with no further problems, while there is a subset of patients who develop relatively rapid progression of degenerative changes. In addition to biomechanical factors, it is likely that the ‘biologic milieu’ in the joint is a major factor accounting for these discrepant outcomes. In this study we will characterize inflammatory mediators, matrix degrading enzymes, and a host of other cytokines that likely play an important role in joint homeostasis. Such information will not only help us gain a better understanding of the underlying mechanism of joint degeneration in patients with meniscus injury, but, importantly, may suggest therapeutic targets to allow development of innovative treatments."
If you have a meniscus tear and are interested in the study, or would like to serve as a healthy control subject, please contact Daniel Edon (firstname.lastname@example.org).