Shohei Ohtani, plagued by irritation in his left knee, produced optimism this week.
The two-way superstar with the Los Angeles Dodgers on Wednesday, July 22 threw his first bullpen session in two weeks. Afterward, Dodgers manager Dave Roberts called it a “big sign."
"The arm's fine,’’ Roberts told reporters. “It's kind of just going down the slope, getting over your front side. That's the big test."
Yet the same day, Ohtani missed his second straight start because of the knee discomfort the Dodgers have attributed to cartilage and joint issues. He has not pitched since July 3 and it's unclear when he will.
Concern lingers.
Ohtani, 32, had a 1.06 ERA in what was shaping up as his finest season on the mound – before his left knee emerged as a problem six weeks ago. In the three starts he’s made since then, Ohtani surrendered nine earned runs in 18 innings and lost his aura of dominance.
USA TODAY Sports interviewed two orthopedic surgeons and an expert in pitching mechanics to better understand the problem with Ohtani’s left knee and how worried the Dodgers should be.
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Shohei Ohtani faces 'delicate balance'
Glenn Fleisig is the Director of Biomechanics Research at American Sports Medicine Institute. He has written more than 300 scholarly articles.
Ohtani has suggested his knee issues could be related to poor pitching mechanics. And when told that Ohtani said he is adjusting his mechanics as a result, Fleisig said the approach can have unintended consequences.
“Making adjustments for the knee for the sake of the safety of the knee or the health of the knee is one thing," Fleisig told USA TODAY Sports. “But for such an elite athlete, these professional athletes, it's a very delicate balance to try not to change the stress on the elbow or shoulder."
This is where the biomechanists come into play, according to Fleisig. He said pitchers' mechanics will be analyzed to ensure the whole body is used in coordination -- "the kinetic chain," Fleisig called it -- to prevent too much stress being placed on the elbow and shoulder.
“I can't just broadly say that changing mechanics is good or bad,'' he said. "Sometimes it can make a (pitcher) better, sometimes worse, and sometimes, which is what they're going for in this case (with Ohtani), it can make it no better, no worse, just different.
"So it really depends what mechanical change (is made) and if it messes up the whole chain of events or if it keeps the chain working right."
Ohtani had surgery on the elbow in his throwing arm in 2018 and surgery in 2023 when the problem reoccurred.
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What torque reveals about Ohtani's knee issues
Matthew Matava is an orthopedic surgeon, a team physician for the St. Louis Blues and the president of the National Football League Physician Society.
With the adjustment in his mechanics, ESPN reported, Ohtani is trying to reduce the torque on the left knee. Matava addressed torque and what it reflects about Ohtani's issues.
Because Ohtani is a right-handed pitcher, he pushes off with his right leg and lands on his left leg with the balky knee.
"A right-hand pitcher, his follow-through comes across his left knee," said Matava, who is not involved in the treatment of Ohtani. "So that causes a twisting sensation or a twisting motion. A torque, call it, between the tibia and the femur. That's a knee joint. And so any sort of condition that may irritate the kneecap, for example, is a very common one because the kneecap can move side to side.
"That kind of motion will cause discomfort and can cause further pain.''
A favorable sign, Matava said, is that the torque-related discomfort in Ohtani's left knee has not kept him out of the Dodgers lineup. Ohtani, the team's designated hitter, leads the Dodgers with 22 home runs and a .525 slugging percentage.
“He's swinging the bat at high speed,’’ Matava said. “There is some torque there. Second of all, he has to push off that left knee to go to first base and then run the bases, potentially slide.
“You know what I'm saying? There's still a lot of stress on that joint that they still think he could handle or else they would've shut him down from hitting, too.’’
The history of Shohei Ohtani's problematic left knee
Timothy Gibson is an orthopedic surgeon who specializes in sports medicine and treats a wide variety of orthopedic conditions. Ohtani is not immune to those.
In 2019, he was diagnosed with bipartite patella, a congenital condition where the two bones of his kneecap fail to fuse.
Gibson, who is not involved in the treatment of Ohtani, estimated that less than 2% of the population has bipartite patella and less than 5% of those people who have it never get symptoms. But Ohtani experienced discomfort in his left knee during bullpen sessions and had surgery in 2019.
“I'm sure they've looked at that to minimize the strain,’’ Gibson said. “I mean, to require surgery for that condition is not very common.’’
Now, according to Gibson, Ohtani may be suffering from chondromalacia, which is the softening or deterioration of the cartilage under the kneecap. Ohtani has cited “wear and tear" as a source of the inflammation and that’s consistent with descriptions of chondromalacia.
Gibson said cartilage issues pose different problems than bipartite patella does -- primarily excessive fluid buildup around the joint. “So that would be more concerning if his knee swells up,’’ he said.
Treatment options for Shohei Ohtani
Over the All-Star break, Ohtani was injected with Orthovisc, which is used to relieve pain due to osteoarthritis and degenerative joint disease.
“I don't think anybody really knows how it works," said Gibson, the orthopedic surgeon. “Some people just think it's like a lubricant. Others probably think that it brings down inflammation or tries to modulate the local environment so your body produces a better quality of fluid. I would say it's really not known exactly the mechanism."
What is known, Gibson said, is that only about 50% of people have a positive response.
A week after Ohtani got the injection, he was scratched from his next scheduled start, July 22. The Dodgers also have treated the knee with rest by keeping Ohtani off the mound.
Other than hyaluronic acid injections like Orthvisc, Gibson said other common treatment options include: 1) platelet-rich plasma injections, a process where blood is drawn, put it in a centrifuge to create a smaller volume of highly concentrated platelets and then reinjected, and 2) stem cell therapy, which uses the body’s cells to promote repair of tissue; and draining fluid from the knee.
Of the Dodgers' approach, Gibson said, “What they're doing I think sounds conservative and reasonable, very reasonable."
Shohei Ohtani knee issues: Now what?
Ohtani was climbing over the dugout wall Wednesday on his way to celebrate the Dodgers’ 9-5 victory over the Phillies when he got accidentally kicked in the right arm by teammate Alex Call.
Ohtani winced. He shook his pitching arm off and on for about 45 seconds. Reportedly, he got the arm checked out later, and it’s fine.
The mishap momentarily diverted attention from the much bigger issue: the left knee. So how concerning should it be for the Dodgers?
Matava said it’s difficult to know because the Dodgers might not disclose all of the pertinent information.
“I'm not saying they're being at all deceitful," he said. “But it's their prerogative to release whatever information they want to release. And you don't always know exactly why the player's being kept out."
Gibson said fluid in the knee would be more concerning. So far the Dodgers have said only that they did not drain fluid from Ohtani’s knee.
Instead of quantifying the level of concern, Fleisig, the biomechanist, talked about an imperative.
“So when they make the adjustment for leg motions, they have to make sure that it did not throw off the mechanics of the trunk,’’ he said.
The consensus: Wait and see.
This article originally appeared on USA TODAY: Should Dodgers be worried about Shohei Ohtani's knee? Experts weigh in