ACL Tears On the Rise. NewsWire

NewsWire: 7/21/21

• ACL injuries are a growing issue among young athletes, especially young female athletes. One possible cause: the rise of single-sport specialization, which may be putting more repetitive stress on young athletes’ joints. (The Economist)
• NH: In the US alone, there are over 100,000 ACL tears every year. The most common causes of ACL tears are quick awkward movements under acceleration and pressure. Tears are most prevalent in sports that require fast pivots at high speed. Think soccer, basketball, and downhill skiing.
• What happens when an athlete gets an ACL tear? Most often, the injury is treated by surgery and rehab, after which he or she may not be able to continue competing. After repair, the re-tear rate is estimated to be around 20%. And even if there is no re-tear, the vast majority of these injuries are expected to trigger post-traumatic osteoarthritis in that joint long before arthritis affects other joints. Some doctors estimate that an ACL tear "ages" a joint by 30 years.
• So ACL tears are traumatic, they are expensive, they may end an athletic career, and they often lead to permanent joint damage.
• But there's worse. The number of tears has been rapidly rising among young athletes in recent years. According to the American Academy of Pediatricians, pediatric tears increased +2.3% annually from 1994 to 2013--that's nearly +60% overall. Researchers believe this is due to sport specialization among the young. Overuse of the same muscles significantly strains the ACL. And when kids play the same club sport all year long, the ACL can come under significant stress. 
• Female athletes are especially at risk. Women may be 8X more likely (or more) than men to experience an ACL tear in the same sport. Growing female participation in high-speed "action" sports may therefore be one reason for the overall rise in injuries.
• Why are women at much greater risk? One theory suggests tears are correlated with the menstrual cycle. Research indicates ACL injuries are most common right before ovulation when estrogen levels spike. The ACL does have estrogen receptors, but so do other ligaments. Doctors are still unclear why the link exists. It has also been theorized that the greater injury rate could be due to anatomical differences between men and women. Women are more likely to have “wider hips, more-inverted knees, and over-dominant quad muscles.” All of these factors result in more pressure on the knee.
• So can anything be done to stop these injuries?
• There is some research that training can help. One study found that balance and agility drills can decrease the chance of a tear by almost 50%.
• This type of training would be advisable for young athletes. Parents and clubs could also help kids diversify their practice regimens and do more off-season cross-training. We have written about kids relentlessly specializing in sports with the hope of scholarships and going professional. But watch out! Those dreams can disappear with just one wrong pivot. (See "Kids Sports Are a Ticking Time Bomb.")