A few hours later, Ed Bouchette of the Pittsburgh Post-Gazette broke the news everyone feared: Pouncey sustained tears to his ACL and MCL, costing him the season:
While the devastating development came as bit of a shock, the circumstances of the play during which Pouncey went down hinted at what an MRI would eventually show.
To understand why, let's take a look at the anatomy of the knee and how it relates to the perfect storm of poor timing and bad luck that ended the standout lineman's 2013 campaign.
The Anterior Cruciate Ligament (ACL) and Medial Collateral Ligament (MCL)
The knee is the joint at which the tibia—the shin bone—meets the femur, or thigh bone.
Four ligaments help keep the tibia and femur in alignment. They are the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), lateral collateral ligament (LCL) and medial collateral ligament (MCL).
Like all ligaments, the ACL and its counterparts are bands of tissue that connect one bone to another, thereby helping stabilize and coordinate motion at a joint.
Generally speaking, the ACL prevents the tibia from moving forward in relation to the femur, and the PCL prevents it from moving backward. Somewhat similarly, the MCL keeps the knee from collapsing in—toward the center of the body—while the LCL keeps it from buckling out.
The ACL also helps prevent the tibia from twisting inward.
When one or more of the four ligaments ruptures, the knee becomes unstable in the direction of the missing ligament. For example, without an intact MCL, the stress of running and cutting can cause the knee to give way inward.
Maurkice Pouncey's Injury Mechanism
A GIF of Pouncey's injury is below, courtesy of SB Nation.
As shown, when Steelers guard David DeCastro went low and presumably inadvertently hit Pouncey, his weight forced Pouncey's knee to twist inward.
The inward movement overwhelmed the two ligaments whose job it is to deter such motion—the ACL and MCL—causing them to tear simultaneously. The hit spared the LCL and PCL because—as previously mentioned—they limit outward and backward motion, respectively.
A freeze frame shows the exact moment the injury occurred.
In many ways, Pouncey's injury mechanism is very similar to that of Adrian Peterson's in 2011.
In the above play, Peterson planted his left leg just as a defender landed a hit to the outside of his knee. The knee, unable to give way, twisted inwards. As a result, doctors later diagnosed Peterson with the same combination of injuries as Pouncey suffered on Sunday.
What's Next for Pouncey?
Doctors usually employ reconstructive knee surgery to repair a torn ACL.
The operation involves replacing the ruptured ligament with a piece of muscle tendon from elsewhere in the body, such as the patellar tendon—the part of the knee a doctor hits with a reflex hammer.
During the post-operative and rehabilitation phases, the body cements the tendon into place to serve as a new ACL.
Over the next months and years, a fascinating process called ligamentization takes place.
During ligamentization, the body transforms the tendon into tissue more closely resembling the native ligament.
As for the MCL, following many injuries—even complete MCL tears—surgery is not necessarily required. However, since doctors will need to work inside Pouncey's knee anyway to reconstruct his ACL, they may decide to work on the MCL at the same time.
That said, whether or not surgeons decide to repair a ruptured MCL depends on the specific athlete and injury, as no two are exactly alike.
When Will Pouncey Return?
Rehab time following reconstructive knee surgery is incredibly variable. Some athletes can return in about nine months, and others can need well over a year.
Additionally, many athletes return triumphantly, but a significant fraction never again function at the same level.
Nevertheless, one thing is all but certain: Pouncey will not play again this year.
Though advancing rehab science is providing for continually improving outcomes—not to mention better and better physical therapists—many would likely consider Pouncey returning for the start of the 2014 season a bona fide success.
The rehab process for an ACL tear is immensely complicated.
Following surgery, athletes start down a long road of regaining range of motion, strength and agility—not to mention the mental fortitude to come back from such an injury.
Add in the fact that Pouncey also tore his MCL—complicating his recovery though not necessarily lengthening it—and that road becomes even tougher.
What's the Bottom Line?
There's no reason to think Pouncey can't return from his injury. He will work with some of the best physical therapists and medical personnel on this planet, and eventually—just like countless athletes before him—he'll take the field once again.
Yet for the time being, the already-troubled Steelers offensive line will certainly feel the loss.
After also losing linebacker Larry Foote to a ruptured biceps tendon—according to NFL.com's Chris Wesseling—running back LaRod Stephens-Howling to a torn ACL—according to Fox Sports 1's Mike Garafolo—and their Week 1 contest against the Tennessee Titans...well, let's just say the Steelers' 2013 season didn't exactly start off according to plan.
Dr. Dave Siebert is a medical analyst at Bleacher Report and a resident physician at the University of Washington. He plans to pursue fellowship training in Primary Care (non-operative) Sports Medicine, and information discussed above is based on his own knowledge and clinical experience.