USA Today Sports—February 15, 2013
"Adrian Peterson came back so well that in some ways it gives people somewhat unrealistic expectations," says Andrew Pearle, orthopedic surgeon at Hospital for Special Surgery in New York.
The Minnesota Vikings running back returned less than nine months after surgery ACL and MCL surgery to rush for 2,097 yards, 13 shy of the single-season record, and lead his team the playoffs for which he was named the league's MVP.
"For every Adrian Peterson who comes back like he has, there are lots of athletes who struggle the first year," Pearle says. "It doesn't mean they're not working hard. But that's an example of somebody who came back in a very, very remarkable way. We hope for recoveries like that. We don't always get it."
Multiple variables play roles. If the injured athlete has had the inner-knee ligament known as the ACL replaced by a graft, what other knee damage did they have? How well and how quickly do the important muscles of the thigh regain their strength?
But their first question is always how soon will they be back? Now, it's can they come back as Peterson did?
"Every ACL injury is different. It takes some people longer. … (Rose) is clearly not ready, and they're not going to rush him back," says Pearle.
Severely torn ACLs are replaced by grafts, which can be patellar or hamstring tendons from the athlete's own body or tissue from a cadaver.
"I think the most important variable is what other injuries you have in addition to the ACL injury?" says Pearle.
"For example, somebody who tears up or loses a large portion of their meniscus (cartilage) can have a much more difficult time coming back. … There have been studies in the NFL that show that only 60%-70% of players actually make it back to the NFL after ACL reconstruction. … With some ACL injuries, there is such profound damage to the meniscus that we can't save it or we can't save a large portion of it.''
During the rehabilitation, the strength of the quadriceps muscles in the thigh is closely monitored. How that goes varies by athlete.
"Some of that is effort, and some of it is luck, and some of it is genetics," says Pearle.
"Some people after the surgery lose a lot of muscle tone and function. Even with amazing effort, they have a tough time getting their muscles rebuilt. Some people can build up their quadriceps very quickly. There are some people who are neuro-muscular kinds of geniuses."
Pearle adds, "Adrian Peterson had to be a guy like that."