McGowan Institute for Regenerative Medicine faculty member Freddie Fu, MD, is the David Silver Professor of Orthopaedic Surgery and Chairman of the Department of Orthopaedic Surgery at the University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center. He is known worldwide for his pioneering surgical techniques to treat sports-related injuries to the knee and shoulder and his extensive scientific and clinical research in the biomechanics of such injuries. Nowadays, patients seeing Dr. Fu are getting younger and younger…a surprising change.
As reported in the New York Times, children today are getting an injury that doctors used to think they almost never got—a torn anterior cruciate ligament, or ACL, the main ligament that stabilizes the joint. Although there are no complete or official numbers, orthopedists at leading medical centers estimate that several thousand children and young adolescents are getting ACL tears each year, with the number being diagnosed soaring recently. Some centers that used to see only a few such cases a year are now seeing several each week. And contrary to the old belief that boys are more prone to the injury than girls, as many as eight times more girls than boys are suffering the tears, doctors report.
It is not an overuse injury from playing one sport too intensively, like shoulder injuries in young pitchers. Instead, doctors say, the injury occurs simply from twisting the knee, and diagnoses are on the rise partly because it can now be easily detected and partly because the very nature of youth sports has changed. Now that almost every child with a hurt knee gets a magnetic resonance imaging, doctors are finding the ligament tears on a regular basis. The other reason for the reported surge in ACL tears, doctors speculate, is that the best athletes are more or less constantly at risk. They play year-round and on multiple teams with frequent games, in which the risk of injury is higher than in practice because of the intensity of play.
It is only with the new increase in diagnosed ACL tears in children, orthopedists say, that they discovered how mistaken they once were about this injury. Doctors used to think the tears did not occur or were extremely rare in children because children’s ligaments were stronger than their bones. They thought an injury that would rip an adult’s ACL would, in children, result in a broken bone. Doctors often suggest putting a brace on the injured knee and limiting a child’s activities, delaying surgery until the child finishes growing. But the children who tear ACL’s tend to be highly competitive athletes who chafe under the restrictions.
Whatever the reason, the increase in diagnoses has created a new problem: what to do about the injury.
The standard and effective treatment for such an injury in adults is surgery. But the operation poses a greater risk for children and adolescents who have not finished growing because it involves drilling into a growth plate, an area of still-developing tissue at the end of the leg bone.
But the standard ACL repair operation, with its drilling into the growth plate, may cause permanent damage to the still-growing bones of young children. After drilling, surgeons replace the torn ligament with a tendon taken from elsewhere in the body, like the hamstring, or from a cadaver. But if the drilling damages a child’s growth plate, the leg bone will not develop normally.
That happened recently to a 14-year-old boy who was referred to Dr. Fu. A year after the operation, Dr. Fu said, the leg with the repair was bowed 20 degrees on one side and was shorter than the other leg.
“I had to go in on the other side and stop the growth,” Dr. Fu said. “Now, about six months later, the leg is still crooked. There still is a two-inch difference in length which I have to fix.” The boy, he said, “will be a little bit shorter” as a result, although both legs will be the same length.
Some surgeons are developing new and technically demanding methods to repair ACL tears in children, drilling holes to create little tunnels in bone that is already finished growing and threading tendons around the growth plate. But the tendons are not anchored where they would normally be and the long-term effects of the operation are not known.
Doctors have also learned that contact injuries are not the most common cause of ACL injuries. It turns out that tears occur more often from twisting and jumping. A child can be running and step in a hole, twisting a leg. Or they can fall off a bike. Other times, a young athlete can tear an ACL by coming down from a rebound in basketball or by accelerating and decelerating.
Illustration: Microsoft Clipart.
The New York Times (02/18/08)
The Seattle Times (02/18/08)