Whole new game plan

An ingenious injectable gel reinvents surgery for an injury that vexes young athletes.

Each year more than 175,000 Americans tear their anterior cruciate ligament, or ACL, the major stabilizing tissue in the knee. About 38 percent of those are high schoolers, a number that keeps rising as more kids get involved in sports; the injury is especially prevalent in girls, who are five times more likely to suffer a knee rupture. “In a traditional ACL reconstruction, you drill holes into the bones,” says Martha Murray, an orthopedic surgeon at Children’s Hospital. “With adolescents, those bones are still growing. But you can’t tell a 10-year-old ‘no cutting’ or ‘no pivoting.’ They try, but they just can’t remember.”

So Murray, a mother of three, looked for an alternative to old-school reconstruction, in which doctors replace the ACL entirely with a tendon, usually taken from the patient’s patella or hamstring—a painful surgery that requires a long rehab and leaves as many as 78 percent of patients to later develop arthritis in the compromised joint. She’s developed a new procedure—after much testing on pigs—that’s yielding encouraging early results, particularly for young knees. It’s based on a collagen gel mixed with the patient’s blood to form what Murray calls, less than scientifically, a “sticky Jell-O.” Murray sews together as much of the ruptured ligament as she can, and the Jell-O does the rest, serving as a kind of bridge that also stimulates tissue regeneration. (Her test pigs regained 40 to 50 percent of their original knee strength within four weeks.) “It’s definitely better than reconstruction,” says Murray, who in July received a $1.1 million grant from the National Institutes of Health to study how her new method might work for different age groups. Her hope is that, like bones, younger ligaments heal faster than older ones.