The Kansas Jayhawks open up the Big 12 Tournament today against Oklahoma State, and they'll be without freshman center Joel Embiid. Embiid, who's spent much of this season somehow keeping pace with comparisons to Hakeem Olajuwon, has reportedly been diagnosed with a spinal stress fracture. The implications for NCAA Tournament are obvious, and how the injury will affect Selection Sunday remains less than clear. But more importantly, just how is this going to affect the career of a young center with as much promise as Embiid?
To understand how likely Embiid's return may be—and to appreciate just how risky it might be for him to play in the NCAA Tournament—it's important to know what kind of injury he's dealing with. A stress fracture occurs when a bone breaks after being subjected to repeated compressive or tensile stresses, none of which would be large enough individually to cause the bone to break on its own. The overriding symptom is pain, and patients classically report the insidious onset of a sharp, burning sensation at the site of the injury. The pain is initially related to activity and increases in severity with increased activity. Eventually the pain is present during less strenuous activity and ultimately during rest. Basketball players soon find themselves with decreased range of motion and impaired agility. They might be able to jog up and down the court, but they don't have the explosiveness to grab a rebound or block a shot.
We typically associate stress fractures with long-distance runners, who often develop them in their feet and shins from the repeated pounding of jogging. But stress fractures can also occur through a different mechanism. They can be the result of a small number of repetitions with a relatively large load (e.g. a military recruit marching for several miles with a heavy backpack) and that's probably what happened with Joel Embiid. Like Olajuwon, he only began playing in high school and it's now clear that his body hasn't adjusted to rigors of dragging a 250-pound frame up and down the court night after night. If he'd been playing basketball his entire life, this might not have happened.
To that point, it's important to know that our bones are in a constant state of rebuilding themselves—undergoing the simultaneous, competing processes of degradation and regeneration—in response to a variety of factors, including the mechanical stress of playing basketball. The rate and amount of remodeling depends upon something called Wolff's Law, which says that as the load on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading. Like muscle, bone responds to microscopic injury by repairing itself.
But an abrupt increase in the duration, intensity, or frequency of physical activity without enough time to rest can lead to pathologic changes in bone. These changes result from an imbalance between bone resorption—a process where cells called osteoclasts break down bone—and bone formation. During periods of intense exercise, bone formation lags behind bone resorption, and this renders the bone susceptible to stress fractures. In short, Joel Embiid required more rest than he was able to get.
What's unusual about Embiid's case is that basketball-related stress fractures usually occur in the player's tibia or the 5th metatarsal in the foot, not the spine. And he will potentially be at risk for these, too. (Spinal stress fractures more commonly occur in gymnasts, which appears to result from a combination of perilous movements and disordered eating.)
Embiid's injury presumably occurred because of the torque placed on his lumbar spine when his enormous frame lunges for a rebound or bends over for a loose ball. Being seven feet tall means that every time he twists or turns, he's subjected to greater torque than the rest of us. Imagine holding a pencil by its very tip and wobbling it back and forth. Now imagine the pencil is seven feet long—more pressure on the end you're holding it by, right? That's what Embiid's skeleton has been going through, as it's been subjected to forces that are simply beyond what the bones can, or have been asked to until now, handle.
Whether this injury will linger and whether it will affect the presumptive number one pick's draft status remains unclear for now. But a history of stress fractures is a strong predictor of future stress fractures, and any fan of basketball can rattle off a list of big men plagued by back problems. Bill Walton, Brad Daugherty and Ralph Sampson were all taken No. 1 overall in the NBA Draft and were all hampered by nagging back injuries. But that doesn't mean Embiid will be. In fact, Pistons center Andre Drummond suffered the same spinal injury last year and has shown no ill effects this season.
Like Jadeveon Clowney, Joel Embiid will have to weigh his own health and draft status against the need to carry his college team. Returning too quickly puts the Kansas star at risk for displacement of the vertebrae and improper healing, or simply the extension of the current fracture. As a physician, I'd tell him to proceed cautiously. While a number of treatment options are available—pain medications, therapeutic ultrasound, electrical stimulation, shock wave therapy, surgery—what Joel Embiid really needs is time away from the basketball court. Otherwise this injury will continue to follow him. Of course, that's a bit of a catch 22, because even though beginning to play basketball relatively recently is likely what has him injured, it also dictates that he probably needs more hours on the practice court than most.
The Big 12 defensive player of the year saw a back specialist in LA earlier this week who presumably performed a battery of imaging studies (Bone scan, CT scan, MRI) and we should soon know how long he will ultimately be sidelined. Generally, a period of 6 to 8 weeks is needed for healing, but Joel Embiid will be under pressure to come back much sooner than that. It's important to realize that in contrast to the run-of-the-mill stress fracture of the foot or shin, the location of his injury places him at high risk for serious complications. Without sufficient rest, the current fracture could increase in size or heal improperly. And if the bones did heal improperly, he might not know about it for some time, perhaps not until he's wearing an NBA jersey. He might not experience searing pain, but he may find himself with less flexibility, unable to tolerate the violent movements associated with playing basketball. The decision to return in time for March Madness may pay dividends for Kansas now, but it could cost Joel Embiid in the NBA.
Matt McCarthy is board-certified in internal medicine. You can follow him on Twitter here.