Top Knee Doctor: Warriors’ Klay Thompson Should Sit Out Two Years

Klay Thompson, Warriors

Getty Klay Thompson, Warriors

Klay Thompson of the Golden State Warriors says he would like to play for Team USA in the 2020 Olympics. One problem: Thompson should not play high-level basketball at all, not for two years.

At least that’s what the science says.

A paper presented by Dr. Tim Hewett, a consultant who spent the bulk of his career studying the biomechanics of the knee for the Mayo Clinic and as the director of Ohio State’s Sports Health and Performance Institute, and Dr. Christopher Nagelli of the Mayo Clinic, finds that athletes who suffer ACL tears should not return to action for two years.

Thompson suffered a torn ACL during the NBA Finals in June. He is likely to miss all of next season if the Warriors stick to the standard protocol on returning players to the court after ACL injuries, which is nine to 12 months. Thompson could return to the floor around midseason if the Warriors put him on an accelerated return track.

“Please do share that with Klay,” Dr. Hewett, who has consulted with NBA trainers in the past, told “This is not my opinion. People say to me, ‘Well, that is your opinion, there are other opinions.’ No, I deal in science and I deal in fact. People don’t like to hear it but it does not change the facts, and that facts are that you’re at risk for re-injury before two years and you won’t be the same player in the first year.”

Re-injury a Big Risk Factor for Thompson

Thompson has good reason to wait to return to the floor. So do the Warriors. This summer, despite the knee injury, Thompson signed a five-year contract with Golden State that will pay him $190 million. Barring a trade, he is slated to be with the Warriors through the 2023-24 season, when he is 34 years old.

Sitting out two years will mean Golden State would pay Thompson $68 million for two seasons of rehab before he plays again for the team. But since the Warriors are already committed to another three years with Thompson after that, it behooves them to reduce the risk of a Thompson re-injury as much as possible.

Re-injury is a very big concern. It happened to Jabari Parker just two years ago. It ended the career of Josh Howard and effectively ended the career of Michael Redd. That’s only three players in the past decade, but considering there were 31 ACL injuries in that span, that’s a nearly 10 percent rate.

Over the last 25 years of NBA knee injuries, there were six re-injuries out of 67 ACL tears, again nearly 10 percent.

“If you return that athlete anywhere prior to 12 months, or in that range, the risk is exponentially higher,” Dr. Hewett said. “You decrease your risk for re-injury every month you delay. If you have a $15 million or $20 million athlete, it just makes sense to wait as long as you can to normalize their biology, physiology and their performance.”

It makes even more sense, then, for a $190 million athlete like Thompson.

Thompson Won’t Be the Same In His First Year Back

What’s more, even if Thompson were to return in less than a year, he would not be the same on the floor. Anecdotally, players report that they don’t feel right in the year after an ACL surgery and, often, it is chalked up to a player needing to regain confidence in the knee—as though it were all mental.

Not so, says Dr. Hewett.

“It’s not just psychological,” he said. “It is physical, too. Your graft is still mush. You are grafting a piece of tendon onto the ACL in that surgery. It takes 18-24 months for a grafted ligament to re-ligamentize, to mature to the point where it is something close to a baseline of where it was before. If you are playing before that, you’re playing on a ligament that’s not done healing.”

Hewett points to NFL running back Dalvin Cook of the Vikings. He tore his ACL four games into his NFL career in 2017 and returned to action last year. He was decent in 11 games for Minnesota, averaging 55.9 yards rushing per game and 5.3 yards per touch. But this season, two years removed from his surgery, he leads the league in rushing (132.5 yards per game) and averages 6.8 yards per touch.

The NBA is replete with similar examples. Zach LaVine suffered an ACL tear in February 2017 and returned the following year for 24 games. He shot 38.3 percent from the field and averaged 16.7 points, with a PER of 14.6. He was a below-average offensive guard.

Last season in Chicago—two years after his ACL surgery—LaVine averaged 23.7 points on 46.7 percent shooting, with a PER of 18.7. He was back to his old self.

Forward Danilo Gallinari had a unique experience in Denver, initially attempting to resolve his ACL injury with a procedure called “healing response.” After eight months, when healing response did not work, he finally had surgery.

Gallinari told Sportando that his initial approach to fixing the knee was a, “wrong choice.” But it might have been right after all. When he did return to action, Gallinari posted numbers that were close to his stats before the injury on a per-36-miute basis. His PER was nearly unchanged, 16.7 before the surgery and 16.8 after.

“Look at the data,” Dr. Hewett said. “It’s really good data and what it says is that the reality of this is that less than half of athletes are back to their sport within a year and only about two-thirds of the athletes make it back to their sports after two years. As much as people would say, ‘You’re being unrealistic to hold athletes back for two years,’ it is the reality of the situation. This is not based on what people say or what people purport, this is the actual evidence.”

Warriors’ Worst-Case: ‘You Just Lost All That Money’

That brings us back to Thompson. Not only should he skip the Olympics, he should skip the 2020-21 season, too—or at least wait until around midseason, which will mean he’d have more than 18 months of recovery time. That’s what the data indicates.

Many players can’t afford to sit out that long, not if they’re playing for that next contract. And there are players who exceed expectations when returning from injury.

But Thompson has a long-term deal in place. Even if there was no risk of re-injury, the best the Warriors could hope for in the short term likely would be a so-so version of Thompson, a 2020-21 season in which he struggles as the graft on his ACL turns from mush into a functional ligament. He’ll deal with pain and won’t be able to produce the way he normally would—the way he will in 2021-22, when the knee is actually healed.

Add the possibility of Thompson re-injuring the ACL if he returns too quickly and it does not seem worth it for to push himself back onto the floor. Even if there is only about a nine percent chance he’ll injure the ACL again, that risk is not insignificant.

It was pointed out to Dr. Hewett that this would mean the Warriors would pay Thompson to do leg curls for two years. “Understood,” he said. “Of course, he’ll have to do a lot of leg curls and a lot more than just leg curls to rehab. It’s a lot of money to pay someone to not play but he would be working. And if you have that second injury while a guy is under contract, you just lost all the money.”

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