It seemed like just an ordinary play, but a Bruce Ellington run in the fourth quarter Saturday might define the entire season for the University of South Carolina football team. Marcus Lattimore was blocking for his fellow running back when a Mississippi State defender rolled into the side of his left knee. While the Gamecocks ultimately triumphed over the Bulldogs, the victory was overshadowed by the news that the sophomore sensation suffered a torn ligament and cartilage damage in his knee and will miss the rest of the season.

"Our worst fears were realized," Gamecocks coach Steve Spurrier said Sunday. He told reporters that Lattimore would need surgery in a few weeks. ESPN.com's Chris Low wrote Sunday that doctors wanted to brace the knee and stabilize it for several weeks prior to surgery.

Dr. Jeffrey Guy, USC athletics medical director, discussed these types of injuries with a Columbia website. While he declined to comment on Lattimore's injury specifically, the writer quotes Guy as noting that with these injuries, "athletes can be running again after about three or four months, and returning to their sports after about six."

While it is difficult to know exactly the extent of Lattimore's injury, those statements seem to indicate that the star running back suffered at least a tear of his anterior cruciate ligament (ACL). The cartilage damage Spurrier mentions likely refers to the meniscus, a C-shaped piece of shock-absorbing cartilage. Both are injuries that would necessitate surgical treatment.

The ACL is critically important to the knee for providing stability, both front-to-back stability and rotational stability. Athletes with these injuries can regain motion and strength of the knee without surgery. But without a functioning ACL, athletes usually lack the ability

to push off and change directions effectively because the knee gives way. This instability not only affects confidence in the knee but can also lead to further damage. Therefore, high-level athletes usually require surgery to reconstruct the ACL.

As sports fans have observed with all of the athletes who have suffered these injuries, the road back to sports is a long one. While the surgery is an outpatient procedure, it takes most athletes about six months before they are cleared to return to sports. And cleared usually just means the surgeon allows the athlete to play. Many sports medicine surgeons see overall recovery, meaning the athlete finally gets back to the same level at which he played before the injury, as taking up to 12 months or longer.

The rehabilitation is lengthy, as the physical therapist will work aggressively to restore motion and strength while protecting the healing ligament. The athlete will ride a stationary bike and use weights and machines to regain leg strength, and after about three months he will start jogging. Balance, plyometrics, agility and other functional training comprise the last few months of rehab as the surgeon determines when it is safe to allow him to return to the field.

Some studies recently have questioned the overall success of ACL reconstruction, including one from Australia where less than 50 percent of the athletes surveyed two to seven years after surgery had returned to preinjury level or to competitive sports. Most of us in the United States contend that ACL reconstruction is a successful procedure, and we have seen countless elite athletes in many sports return successfully from ACL surgery. There is no reason to expect otherwise with Lattimore, if in fact he undergoes ACL surgery.

But there is no question that the recovery process will be a long and difficult one.

Dr. Geier is Director of MUSC Sports Medicine and an orthopaedic surgeon. For more information about football injuries and other sports medicine topics, please go to Dr. Geier's blog at drdavidgeier.com.