Breaking Down Vince Wilfork's Torn Achilles Tendon and Road to Recovery

The New England Patriots defense took a huge hit Sunday night when defensive captain and standout lineman Vince Wilfork went down with a torn Achilles tendon.

Shalise Manza Young of the Boston Globe had the news on Wilfork early Tuesday morning. According to ESPNBoston.com, he underwent surgery to repair the injury later that day.

Both reports claim the star lineman will likely miss the remainder of the 2013 season—a very common outcome of midseason Achilles injuries. In order to understand why ruptures are so troublesome, it helps to break down the anatomy of the injury itself.

The strongest tendon in the human body, the Achilles serves to connect the muscle bodies of the calf—the gastrocnemius and soleus—to the calcaneus, or heel bone.

When an athlete contracts the calf, the gastrocnemius and soleus pull on the Achilles tendon. In turn, the tendon yanks on the base of the heel, thereby pointing the toes—a motion also known as plantarflexion.

In conjunction with the quadriceps, strong calf muscles allow an athlete to push off the ground with his or her toes.

Plantarflexion also provides defensive linemen with the leverage they need to forcefully rise out of the three-point stance in order to go up against offensive tackles and guards.

Unfortunately, if a particular motion or step causes sharp dorsiflexion—or curling of the toes upward toward the head—the Achilles can tear. Forced dorsiflexion, occurring while an athlete is actively plantarflexing, can also cause the injury.

In other words, when two opposing forces meet, sometimes, one has to give.

That is exactly what happened to Wilfork.

The very beginning of the video below shows the moment the injury took place:

As seen, Wilfork steps too far backward onto his right foot while simultaneously pushing off the ground with his toes.

As a result, he effectively placed 100 percent of his weight—that's 325 pounds, according to Rotoworld—onto his contracted Achilles.

That weight proved too much for the tendon to bear, so it tore.

Without an intact tendon, athletes can only minimally point their toes—if at all. Needless to say, jumping and running are out of the question and even mere walking becomes extremely difficult.

To return to NFL-level activity, fully torn Achilles tendons usually require surgery for a complete repair. A ruptured tendon retracts upward into the leg and will not come back down on its own.

Other options include foregoing surgery and casting the foot in progressively decreasing amounts of plantarflexion. Doing so brings the pieces back together before slowly stretching out the tendon over time as it heals.

Nevertheless, non-surgical options historically carry a higher risk of re-rupture—though new evidence is emerging that may suggest otherwise—so it is not surprising Wilfork elected to go under the knife.

Conceptually, surgically repairing the tendon is simple: expose it, re-attach it and secure it.

Technically, though, it's an entirely different ballgame.

During the operation, surgeons must set Wilfork's tendon in place with just the right amount of tension.

A tendon that is too loose cannot provide adequate strength to perform the necessary functions of an NFL lineman.

On the other hand, one that is too tight is prone to repeated injury.

Assuming an uncomplicated surgery, Wilfork will likely require somewhere in the neighborhood of six months or so to return to the field.

His rehab will involve slowly working to increase his range of motion, strength and mobility while his repaired tendon cements itself back into place.

That said, the recovery time for an Achilles repair is extremely variable, running anywhere from four months to over a year. Predetermined factors such as a patient's age and innate healing ability play huge roles.

Whether or not Wilfork's above-average weight will further complicate matters is not exactly clear.

What is clear, however, is his will to return—one of the most important assets to any successful rehab program. He himself posted the following message on his Twitter account:

Such a mentality will serve him well over the coming months, but make no mistake—Wilfork's road ahead is certainly not easy.

Yet, nor is it impossible.

After all, his track record speaks for itself.

According to Chris Burke of SI.com, Wilfork has missed just six games in 10 years. With that in mind—despite the small-but-not-insignificant chance the injury could plague him for a prolonged period of time—no one will be surprised if Wilfork triumphantly retakes the field at the start of the 2014 NFL season.

That's just who he is.

Dr. Dave Siebert is a resident physician at the University of Washington and medical analyst for Bleacher Report. Find more of his work at the Under the Knife blog.

Follow @DaveMSiebert