Fred Robbins' revelation that he had microfracture surgery on his knee explains why the New York Giants were so aggressive in the off-season with the signings of defensive tackles Chris Canty and Rocky Bernard.

Ralph Vacchiano of the New York Daily News explains.

Microfracture surgery is an increasingly common procedure used by orthopedic surgeons to repair damaged cartilage. It’s an arthroscopic procedure in which the surgeon creates tiny holes (microfractures) in the bone near the damaged cartilage, which allows the body to build new cartilage.

Typical recovery time for such a procedure is about 4-6 months, though four months is considered to be optimistic and it could be considerably longer than six months depending on a variety of factors, including weight and age. Robbins is 32 and is listed at 6-4, 317. It’s not known exactly what date he had the surgery, but it was first revealed at the scouting combine in late February.

Even if the surgery took place right after the Giants’ season ended on Jan. 11, a six-month recovery time would push him awfully close to the start of training camp on Aug. 3.

The procedure has been used for more than a decade and was controversial when it was first implemented, but it has become much more commonplace in recent years. Still, it has taken some professional athletes a full year to recover from the surgery. And many, many pro athletes - from former Giants cornerback Jason Sehorn, to former NBA stars Penny Hardaway and Allan Houston - were never the same after the surgery.