Closer Look at Louis Nix III's Knee Injury, Surgery Heading into the NFL Draft

Dave Siebert, M.D.@DaveMSiebertFeatured ColumnistFebruary 11, 2014

SOUTH BEND, IN - OCTOBER 19: Louis Nix III #1 of the Notre Dame Fighting Irish celebrates near the end of the game against the University of Southern California Trojans at Notre Dame Stadium on October 19, 2013 in South Bend, Indiana. Notre Dame defeated USC 14-10. (Photo by Jonathan Daniel/Getty Images)
Jonathan Daniel/Getty Images

University of Notre Dame NFL draft prospect Louis Nix III missed the end of the 2013 college season with a torn meniscus, and he underwent surgery to repair the knee injury in November. Shortly thereafter, the defensive tackle officially declared for the draft, closing the book on his college career.

Coming in at 6'2.5", 342 pounds according to Notre Dame's athletics website, the massive lineman will draw much attention on draft weekend.

Yet with his knee injury history, will any of said attention be negative? Let's take a closer look.

What Is a Meniscus?

This diagram shows the location of the menisci within the knee.
This diagram shows the location of the menisci within the knee.Credit: Wikimedia Commons

Generally speaking, the knee marks the point where the femur—or thigh bone—meets the tibia or shin bone. Two crescent-shaped, cartilage menisci sit between them—one on the inside of the knee and one on the outside—acting as cushioning shock absorbers.

Just like any soft tissue in the body, menisci can tear. Tears can stem from an acute injury or chronic wear-and-tear overuse.

Similar to other cartilage in the body, menisci have relatively low blood supplies compared to tissues such as skin and muscle bodies. Therefore, since blood is responsible for carrying the body's healing and repair cells to sites of injury and inflammation, meniscus injuries usually do not heal well on their own.

Platelet-Rich Plasma (PRP) Injections

According to ESPN's Matt Fortuna, Nix battled knee problems throughout much of his 2013 college football season:

Nix said the knee first bothered him during the national championship game against Alabama last January. He played in the Irish's last game, a Nov. 9 loss at Pittsburgh, after missing the previous two games with knee tendinitis and the meniscus tear. He said he felt a sharp pain during that game and that the pain became worse during the off week as he walked around campus. He had a hard time sitting in classes and sleeping because of the pain.

Nix's story of lingering pain that acutely worsened is not uncommon. It seems he played through tendinitis-related pain for much of the season—as well as a seemingly minor meniscus tear that refused to heal—until something exacerbated his injury against Pittsburgh, finally necessitating surgery. For instance, sharp twisting or knee hyperflexion can cause or worsen a meniscus tear.

Fortuna also writes that Nix underwent platelet-rich plasma (PRP) therapy in an attempt to assist his body's natural healing process. He did so at least twice—once earlier in 2013 and again in November:

Nix had undergone platelet rich plasma therapy, but a second surgery was still needed. Kelly said doctors also performed platelet rich plasma therapy on the knee Thursday to try to help with the healing.

Whether Nix used his first PRP injection to help with his tendinitis or the underlying meniscus tear is unclear. However, the medical concepts remain the same.

Similar to meniscal cartilage, a muscle tendon—the injured and inflamed area in a case of tendinitis—does not carry a large blood supply.

PRP injections attempt to circumvent that obstacle.

First, doctors remove a sample of an athlete's blood. Then, they use an instrument known as a centrifuge to separate out the athlete's platelets—the blood cells that form clots and stop bleeding—before injecting them back into the injured area.

Platelets, highlighted here by blue arrows and sitting amongst many red blood cells, carry many different types of healing proteins.
Platelets, highlighted here by blue arrows and sitting amongst many red blood cells, carry many different types of healing proteins.Credit: Wikimedia Commons

Platelets carry many different types of healing proteins that cannot ordinarily reach cartilage or tendons due to their aforementioned low blood flow. By injecting large amounts into the injured tissue, the healing process receives a kick-start.

At least, that's the hope. PRP science is still in its infancy.

Meniscal-Repair Surgery

The exact nature of meniscal-tear surgery depends on the location and shape of the tear, surgeon preference and the athlete's long-term goals.

For example, a surgeon can simply trim away damaged tissue that is causing pain or other symptoms within the knee. The partial removal of the meniscus is also an option, improving symptoms in the short term at the expense of a higher risk of long-term problems such as arthritis.

In Nix's case, however, he and his medical team elected to proceed with a meniscal repair.

While it usually requires a longer recovery, a repair offers the chance for the restoration of normal anatomy within the joint—and thus good long-term function and prognosis. The repeat PRP injection Fortuna mentions certainly can't hurt, either.

Rehabilitation timelines following a repair vary and depend on the extent of damage within the knee. Recovery timetables thus range from several weeks to several months.

Knee Exams and Draft Stock

Over the next weeks and months, NFL teams will examine Nix's knee very closely.

For instance, certain physical-exam maneuvers can reproduce persistent meniscal pain. Swelling or pain with activity, range-of-motion limitation and catching or locking of the joint also may raise red flags.

That said, given the caliber of Nix's physicians—including Notre Dame team orthopedic surgeon Dr. Brian Ratigan and the world-renowned Dr. James Andrews who, according to Fortuna, provided a second opinion—there is no reason to expect anything less than an optimal recovery. Additionally, the former Fighting Irish lineman is surely working with some of the best physical therapists practicing today.

Yet what does all of this mean for his draft stock? Matt Miller—Bleacher Report's NFL draft lead writer—weighed in.

"Last year, Nix looked like a potential top-15 player, but his heavier frame and the knee injury make him a second rounder," Miller explained. "If he can show better burst, he has a chance to improve his stock."

Regrettably, Nix's rehabilitation may prevent him from doing so for the time being, though he is reportedly preparing for the NFL combine.

All told, given his pre-existing draft hype, his excellent medical team and the fact that he elected to go under the knife in order to preserve his knee's long-term function, it seems likely Nix will be called to the podium earlier on draft weekend rather than later.

Dr. Dave Siebert is a resident physician at the University of Washington. He plans to pursue fellowship training in Primary Care (non-operative) Sports Medicine. Quotes were obtained firsthand unless otherwise noted.

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