If you didn't see it live, I'm sure you've seen the video of New York Giants' Victor Cruz's knee injury. He wasn't tackled. His knee didn't twist in some abnormal way. How did he tear his tendon on such a routine play?

Patellar tendon ruptures are a rare injury. A 2011 study in the American Journal of Sports Medicine showed that there were only 21 isolated patellar tendon ruptures over a ten year period from 1994-2004. This study showed an 80% return to play in the NFL following surgery. The big question is even with a return to football, will he be the same player he was before surgery?

The mechanism of injury is still debatable. Research shows that it takes a force of approximately 17 times body weight to tear the patellar tendon which is why this is such an uncommon injury. In sports, it appears to be the result of an eccentric flexion load followed by forceful knee extension. If you watch Cruz's injury closely, it appears that his knee is flexing under his body weight as he forcefully tries to push off to catch the pass. The eccentric loading combined with the concentric push off likely created an extreme amount of strain on the tendon resulting in rupture. (Get a rehash of injury here)

Patellar tendon rupture requires an immediate repair of the torn tendon. The type of surgery performed is dictated by where the tendon tore and if the tendon tissue is healthy. If the tendon tore on the middle, the two ends are sewn back together. If the tendon tore closer to the bone, it can be sutured back down. If the tissue is not healthy, i.e. chronic patellar tendonitis, the repair can be augmented with a cadaver graft.

Rehab involves a period of immobilization followed by rehabilitation to regain range of motion and strength. Players are usually braced for approximately 6 weeks following surgery. During this time there is a gradual progression of knee flexion range of motion to allow the tendon to heal while trying to limit the amount of post-operative stiffness that will occur. Over the next 4-5 months rehab focuses on regaining full flexibility and strength with gradual progression to sports activities such as running, agility exercises, and plyometrics. Return to sports usually takes a minimum of 6 months.

As the NFL study showed, 80 percent of players return to football, but their definition of return to play was participating in one regular season NFL game. There is a big difference between playing in one NFL game and returning to pro bowl level of play. Only time will tell if Cruz will be celebrating touchdown receptions with his salsa dance next season.

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