Does One Sports Injury Lead to Another?

Noting that soccer rocker David Beckham sprained his ankle, then his knee, the L.A. Times wonders if it's true, as is often said, that one one sports injury leads to another.  The Times turns to UCLA orthopedic surgeon Dr. David McAllister, who informs us that "the data are scant."
What data we do have deals mainly with recurring injuries.  The Times cites a 1998 study of 714 athletes who'd had surgery to repair the anterior cruciate ligament (ACL) of one knee tallied how many tore their previously injured ACL again or hurt their healthy ACL instead. The half who had thinner ligaments were far more likely to damage the ACL in the healthy leg than the half who had thicker ligaments, and most of the thin ACLs belonged to women.  But in a 2007 study of 235 patients, risk of injuring either knee was the same, about 3%, two years after ACL repair.
The best data, the Times reports, come from baseball, which is an easier sport than most to study because pitchers tend to injure the same kinds of joints. Players who hurt their elbows are more likely to have shoulder injuries, says orthopedic researcher Brady Tripp of Florida International University in Miami. A 2007 study by Dr. William Grana and colleagues at the University of Arizona Health Sciences Center in Tucson found that of 84 Chicago White Sox pitchers, 27 had elbow ligament injuries, and 60% of the pitchers later had shoulder injuries.
In any case, most experts advise waiting for one injury to heal before pushing the body in any direction, and that means more than waiting for the pain to subside. The rule, experts say, is make sure recovering joints have the same range of motion as the healthy joints, and that limbs regain full strength before taking them out to the field of glory.
Read more in the L.A. Times.