New ACL surgery could cut rehab and recovery time in half
An engineer-turned-doctor says clinical studies show real promise
On Sunday, San Diego Chargers running back Danny Woodhead tore his ACL. Woodhead became the second offensive star for the Chargers to go down due to a torn ACL. In San Diego’s Week 1 loss to the Kansas City Chiefs, wide receiver Keenan Allen was lost for the season.
Losing the team’s two leading receivers from a year ago will certainly make the next several weeks difficult for the team. However, if quarterback Philip Rivers and the Chargers can find a way to win four of their next seven games, they will be in good shape to make a push for the playoffs after the Week 11 bye week, when Woodhead and Allen return to the field.
To most sports fans and doctors, that sentence sounds like complete fantasy. But one unlikely doctor’s breakthrough may revolutionize sports medicine in the near future.
Inevitably, some teams lose impact players for the year due to a torn ACL. This season, the big name was Minnesota Vikings quarterback Teddy Bridgewater. Last year, top receivers Kelvin Benjamin of the Carolina Panthers and Jordy Nelson of the Green Bay Packers had their seasons ended before Week 1 because of the injury. It’s an injury that doesn’t discriminate by position. It has afflicted quarterbacks Joe Flacco of the Baltimore Ravens, Carson Palmer of the Arizona Cardinals and Tom Brady of the New England Patriots.
It changes the trajectory of seasons and careers. A healthy Benjamin could have been enough to push the Panthers past the Denver Broncos in last season’s Super Bowl. And the Patriots were certainly Super Bowl contenders in 2008, before Brady tore his ACL. Who knows what type of career quarterback Robert Griffin III would be having had it not been disrupted by an ACL tear?
It’s not just a football injury. ACL tears have contributed to the shocking plummets of PGA golfer Tiger Woods and NBA guard Derrick Rose. Players, coaches and fans are familiar with the anxiety-filled hours between a player collapsing to the ground, grabbing his knee and the moments before we know MRI results. I clutched my knee and collapsed to the ground in the closing moments of the first practice of the 2010 Baltimore Ravens training camp. So, I am intimately familiar with the powerless finger-crossing people do before they learn what the MRI told the doctor.
Maybe it’s a sprain? That’ll just be a week or so. It could be a tear in the meniscus or MCL. On Sunday, Minnesota Vikings running back Adrian Peterson suffered a torn meniscus after getting tackled against the Green Bay Packers. That means surgery, but back on the field in a couple of months at the most.
Even with a grade 3 MCL tear during training camp, a player would likely be back for 10 to 12 of the regular-season games, maybe more. Players, coaches and fans are praying to hear anything other than those dreaded three letters: ACL. A tear to the ACL means that the player is out for the season and his knee may never be the same again.
Many athletes who tear their ACL go see renowned surgeon Dr. James Andrews, as I did. They opt for a reconstruction using a graft cut out of the patellar tendon. The rehabilitation takes nine months to a year because it takes that long to regain the loss of quadricep strength and knee flexibility caused by having a portion of the patella tendon removed.
Thanks to pigs, a bear, cows from New Zealand and the “Soup Lady,” the devastating ACL tear may soon be no more debilitating than an MCL tear.
In February 2015, Dr. Martha Murray and her team launched a study that was 28 years in the making. Twenty patients with recently torn ACLs volunteered to participate in the study. Dr. Lyle Micheli performed the surgeries for the study, in which 10 patients had traditional ACL reconstruction surgery, where a surgeon removes what is left of the severed ACL and replaces it with a graft. For these patients, the graft was created using two of their own hamstring tendons. Micheli performed Murray’s Bridge-Enhanced ACL Repair (BEAR) procedure on the other 10 patients. They became the first people to regrow a torn ACL, according to Murray.
An engineering mindset helped rethink ACL tears
In 1987, Murray was a material science engineering graduate student at Stanford University. She was surprised to see a friend with his knee in a brace, hobbling around on crutches. The friend, who was studying to become a doctor, was facing ACL reconstruction surgery. Murray said to him, “Reconstruction? Can’t they just repair the ligament?” Dismissively, the injured med school friend chuckled and told the engineer that ACLs can’t heal. Murray thought, “What do you mean they can’t heal? That’s what the body does so well with everything else.”
So, she went straight to the library and began reading everything she could about what was known about ACL healing. She found that during the 1970s many surgeons performed “primary repairs,” reconnecting the severed ends of the ACL with stitches. But the ligament never healed. Because of the early failures of the suture repairs, the medical profession accepted that the ACL can’t heal and abandoned that procedure in favor of the now standard graft reconstruction procedure. Murray, with no medical background but an engineering mind, thought: What if they were wrong? Could there be a way to help the ACL heal? So, she left her graduate program and decided to dedicate herself to trying to find out. She enrolled in University of Pennsylvania’s medical school. She went from there to do her residency at Harvard.
Still committed to “solving the ACL problem,” she persuaded surgeons to allow her to sit in on ACL reconstruction procedures. The nurses called her the “Soup Lady” because once she had the right approvals from the hospital, she was able to take the damaged ligaments the surgeons removed from the knee and bring them back to the lab to study. She was always collecting ACLs. The nurses joked that she must have been taking them to make soup. When she put the ACLs under her microscope, she saw that they still had active cells and blood vessels. She was right. The ACL was trying to heal.
Murray discovered that although the ligament itself was working hard to heal, the synovial fluid — the lubricating substance that exists inside of all joints — was washing away the blood clot that serves as the initial connection between torn tissue ends in other parts of the body. Finally, she knew what needed to be done. She had to find a bridge that would last in the joint long enough to allow the ACL ends to heal back together.
In 2008, Murray had developed such a bridge and was ready to run studies on pigs. She and Dr. Braden Fleming, an engineering professor at Brown University and Murray’s principal collaborator, published a study in 2013 proving that her creation worked. Called the Bridge-Enhanced ACL Repair (BEAR) scaffold, it was made of tissue from cows in New Zealand and could regrow ACLs in pigs. Interestingly, the pigs treated with the BEAR procedure also had significantly less arthritis than those treated with a standard graft reconstruction, another common problem associated with ACL injuries.
Next, Murray needed a successful study with humans. Despite very promising progress, she struggled to get funding from potential commercial partners. She was able to get initial funding from the Translational Research Program at Boston Children’s Hospital, and given this innovation’s potential impact on NFL players, she was able to continue funding the clinical studies with grants from the NFL Players Association’s (NFLPA) Football Players Health Study at Harvard. Murray estimates that without the help of the NFLPA, these studies would have been delayed at least two years.
Three months after surgery in the first human trial, MRIs, flexibility tests and strength tests were completed on all 20 patients in the study. All 10 of the BEAR recipients had healing ACLs, flexibility close to that of their healthy knee and the operated legs of the BEAR recipients had recovered strength more quickly than the graft recipients. Orthopaedic Journal of Sports Medicine will publish this study in December.
With the help of the U.S. Food and Drug Administration, Murray and her team are now performing a 100-participant trial. She hopes that the BEAR scaffold and procedure will continue to have good results and someday be approved and available to the public. But she recognizes there are challenges and likely future roadblocks to be encountered, as there are in developing any new surgical technique. She also recognizes that much more work is likely to be needed before athletes would feel comfortable using this new approach.
Yet, Murray thinks that ACL healing is just the beginning. It is a proof of concept that is hoped will create a mind shift and bring others to help with the development of orthopedic surgery techniques aimed at healing, rather than replacement of joint tissues. She believes that a BEAR gel could be used to heal deteriorating articular cartilage, which would treat arthritis and reduce pain in hundreds of millions of people. Tears in the labrum in the shoulder could be fitted with customized pieces of the spongelike BEAR material, as could rotator cuff tears. Perhaps torn ulnar collateral ligament damage, which is also currently treated with reconstruction by Tommy John surgery and sidelines baseball pitchers for a year, would have a faster recovery time if healing were possible and replacement of the ligament was no longer necessary.
The ultimate dream is to use modern biologic techniques and knowledge to stimulate better, faster and stronger healing after joint injuries. Murray dreams that someday an ACL tear in training camp will no longer mean injured reserve and the end of the season for an NFL player, but instead a brief stint on the inactive list and then the player is back in the game by midseason.
A few sports orthopedic surgeons, including Andrews, are focused on speeding ACL recovery from reconstruction through the use of stem cells and platelet-rich plasma. Andrews said, “The research should continue, but I am concerned about sensationalism.” Murray agrees.
Though she sees the BEAR as a potential future game-changer for orthopedic medicine, she knows there’s a lot more work to be done. Like an athlete who is recovering from ACL surgery, she can’t wait to get started.