Used to be, orthopedic specialists would rarely see an octogenarian with a sports injury, let alone one who was hankering to get fixed and back to his or her game. But that scenario is becoming more commonplace among older athletes, inspiring specialists and society as a whole to rethink aging, athletics, and the realm of the possible. Between 2001 and 2008, the largest increase in the number of rotator cuff and knee surgeries was among patients over 61, according to the most recent national data compiled by the federal Agency for Healthcare Research and Quality. The steepest increase, jumping from 21 to 28 percent of all such surgeries during that time period, occurred among patients ages 61 to 70 who underwent arthroplasty to repair or replace ailing knees. During the same time, the percentage of patients under 40 receiving knee or rotator cuff surgeries declined.