How complicated can meniscus injuries be? We asked a sports medicine doctor

This is not the start to the season the Sixers were hoping for after what was largely seen as a successful offseason.

Nobody thought Joel Embiid would miss the first nine games of the regular season. The results were predictably disastrous as the team got off to a 2-7 start. It hasn’t gotten much better as the star big man has been in and out of the lineup and the Sixers have now floundered to a 4-14 record.

What’s been going on with Embiid has been as frustrating to follow as the product on the court. The 2022-23 MVP tore his meniscus in late January of this year and had surgery to fix the issue. After playing a hard-fought playoff series and helping Team USA win gold at the Paris Olympics, Embiid missing the start of the 2024-25 regular season was surprising.

In these situations, it’s important to understand the context. Liberty Ballers spoke with Dr. Matthew Grady, a sports medicine specialist at CHOP. Grady provided insight into the meniscus, what surgery could entail, what the return-to-play process is like, and the long-term effects of removing meniscus from the knee.

Dr. Grady is not treating Embiid. His views are his alone and do not reflect the views of CHOP or Liberty Ballers.

Meniscus injuries and surgeries

Many of us have become unfortunate experts when it comes to the meniscus over the years, but let’s go over its purpose.

The meniscus is a piece of cartilage in the knee that’s generally shaped like a C. It acts as a shock absorber between the top bone (femur) and the bottom bone (tibia).

“A healthy meniscus is critical for joint function,” Grady said.

There are a plethora of variables when it comes to meniscus injuries and surgeries.

A “repair,” which Embiid reportedly had in his left knee during his rookie season, is when a surgeon goes in and sews the tear. That leads to a longer recovery time (Embiid missed the rest of the season), but the meniscus is able to fully heal which is better long-term.

Last season, Embiid had surgery on Feb. 6 and returned to play on April 2. That eight-week timeline aligns with the timetable for recovering from a “meniscectomy.” A meniscectomy is done when a small piece of the meniscus is torn and the flap irritates the knee, causing pain (think of it like the worst hangnail you’ve ever had but in your knee). A surgeon will go in and cut out the part of the meniscus which is causing the pain.

The difference is where the tear occurs. Grady said tears that take place in the “red zone” have good blood supply and therefore have the ability to heal. Tears that occur in the “white zone” have poor blood supply. Tears in the “white zone” often require removing the piece of the meniscus that’s causing the issue.

While a meniscectomy will alleviate the pain and the athlete can return to action quicker, the meniscus that was cut out doesn’t grow back. How much meniscus was cut out is also a big factor in recovery and long-term stability.

“There’s multiple ways you can injure the meniscus,” Grady said. “And so without talking about any specifics, one meniscus injury may be in a ‘white zone’ where you just trim it out, and maybe it’s only 10% and it may not be doing much of the shock absorption.”

Return-to-play process

We don’t know the severity of Embiid’s injury or exactly what was done in surgery, but generally, an athlete should do “prehab” and rehab before and after the procedure. The goal is to avoid atrophy and strengthen the muscles around the knee so they make up for any shock absorption that’s missing from the lack of meniscus.

Grady notes that non-weight-bearing activities are best when beginning the rehab process from a meniscectomy. Things like anti-gravity machines or work in a pool are common.

Given the nature of being an NBA player, there likely wasn’t much “prehab” involved for Embiid. He suffered the injury on Jan. 31 and had surgery on Feb. 6.

“If you skip that prehab process, then you’re just tapping that time on the back end,” Grady said, “and so you kind of don’t get to skip it time-wise, but from a function standpoint, it’s a little bit easier to do it that way. So the NBA athletes are always pushing the envelope, and so it may take them a little bit longer, if they’ve lost that strength, to get back up to NBA level strength, because they may not have a prehab time built in.”

As for rehab, Embiid was back at exactly eight weeks playing high-level NBA basketball. He played a physical playoff series and then played in the Olympics a couple months later, leaving little time for recovery and to gain strength in the knee.

“If you were hypothetically playing an NBA season,” Grady said, “and you injured it, and you didn’t get a chance to rest it and rehab it, and then you had the surgery, that recovery may be longer than someone who maybe had two months to do [prehab] first, get their leg really good, then have the surgery, and then come back and do a little bit more rehab.

“So I do think that in this context — playing in an NBA [playoff] series, playing in the Olympics — you’re missing some of the time that you could have done to have surgery or to do the rehab. Playing is not rehab, to be perfectly honest. So if you’re trying to push the envelope to come back, you may not really have completed your rehab, and then you may be kind of starting over.”

That could be why Embiid has been dealing with swelling in his knee on multiple occasions so early in the season. That swelling has forced him out of the lineup the last four games.

“The other portion that it’s important to remember is the meniscus is kind of like a radial tire,” Grady said. “It has this construct that’s kind of like circular, and this is the shock absorbent portion of your knee. So if you disrupt that, then you disrupt the meniscus’ ability to actually absorb force. And so your meniscus is not working as good after surgery as it did prior to surgery, prior to being injured, so it’s really not doing as good a job.

“So you’re relying on the muscles around the knee to do more shock absorption, so the meniscus doesn’t have to do quite as much. So the more meniscus you lose, the stronger you have to get the knee to be able to compensate for the lack of a fully functioning meniscus.”

Another factor is the athlete trusting the repaired meniscus which Embiid has spoken about previously.

“I think there’s both a physical component and a mental component to athlete’s recovery,” Grady said, “and we see this a lot with athletes with ACL repairs, where the knee is structurally strong, they’ve done all the strength and training, but they just have some underlying unease. And so sometimes athletes will say that they felt better in their second year back, that they learned to trust the knee more. So I think there is a physical component of trusting it, but there’s also a psychological component too.

“And the reality is, if you’ve injured it multiple times, I do think there is a human factor … ‘Is this going to get injured again?’ And that may affect how you move, or affect your confidence in which you move.”

It’s important to note that it’s been less than 10 months since Embiid had surgery.

Effects in bigger athletes

On media day Embiid mentioned that he’d lost 25-30 pounds with a goal to lose more. With the physical movements required to play the sport of basketball, being lighter should theoretically help Embiid’s knee function.

“The body weight affects the strain on the meniscus 100%,” Grady said. “So if you have a lighter athlete coming down, jumping and landing, there’s less force in the meniscus than a heavier athlete coming down, jumping and landing.”

When an athlete is bigger — say 7-foot and 280 pounds — it can put more strain on the meniscus.

“We would traditionally talk about ‘forces,’” Grady said, “and we would say just in general, like leg forces and loading, standing up is one times your body weight in force, walking is about 1.5 times your body weight and running would be about 2.5 and then jumping and landing could be three or more. So the bigger the body weight, the amplification of that body weight is not a 1-to-1. It’s probably a 2- or 3-to-1. And so the heavier the athlete, the more you’re asking the meniscus to do in terms of shock absorption.”

To his credit, Embiid does look to be the trimmest he’s been in some time — maybe even since his rookie year. Back in 2020, Embiid hired renowned sports dietitian Louise Burke to help him change some of his poor eating habits.

Long-term effects

Embiid played in just four contests before experiencing swelling which forced him to miss the last four games. We’re still awaiting word on Embiid’s status moving forward (also worth noting that “personal reasons” was recently added to his status).

At 30 years old and having dealt with so many injuries, it’s fair to wonder about Embiid’s long-term outlook. Will he be able to get through an 82-game season? Will he get better as he’s further removed from the surgery?

Without knowing the location, severity and other factors, it’s nearly impossible to say for sure.

“The location of the tear would definitely impact recovery time,” Grady said. “Even within the meniscus itself — even if you just said in generalities the location — we don’t know exactly where his tear is, but the location would affect recovery time and affect the meniscus function long-term.”

But to reiterate, the reality is when you cut out a piece of the meniscus that piece is gone. That’s going to have short- and long-term effects.

“The other piece that’s important is that modern era, we try to save as much meniscus as possible,” Grady said, “because the more we take out, the greater your long-term risk of arthritis is. There is some long-term health component to this of like, well, if I trim it out, you might be able to play faster, but if I repair it, you might have better long-term function. Not just long term like one and two years, but long term like 10 and 20 and 30 years later. So that is a consideration when we’re trying to make decisions about people’s health.”

We can lose sight of the humanity of an athlete in a time like this. Embiid did what he had to do to get back as fast as he could last season. He had the surgery done not long after suffering the tear. He returned to play after eight weeks but hasn’t taken much time off to rest and strengthen his knee since.

Every decision Embiid makes when it comes to his knee could have long-term ramifications.

“I do want to be fair with the athletes,” Grady said, “because a lot of times they are pushing the envelope on what we should be doing as opposed to what we do, and then when it doesn’t turn out as quick we’d like it to, we get mad at them, and it’s not all their fault. They were trying to push the envelope, and then … they have a setback because they’re pushing the envelope.”

If Joel Embiid’s situation seems complicated and confusing, it’s because it is. There are so many things we don’t know. It’s understandable that Embiid likes to keep as much of his health information as private as possible, but a little transparency could go a long way.

Until then, we’ll be in the dark as the team’s season continues to go off the rails.