Repetitive knee stress and failure to accommodate sufficient rest between periods of strenuous exercise may be key factors behind the rapid rise in anterior cruciate ligament (ACL) injuries in world sport, a new international study has found.
While it is already well recognized that a single supramaximal force can cause ACL failure, it has been assumed that sub-maximal forces could not cause ACL failure.
But this world-first research, published in the American Journal of Sports Medicine, has found that a series of submaximal forces can indeed cause damage to accrue in the ACL, in a process called low-cycle material fatigue, and that same damage is found in ACLs which have failed.
Authors of a new study say that while guidelines exist for rehabilitation after anterior cruciate ligament (ACL) reconstruction, there remains “a large degree of variation in rehabilitation progression” among physical therapists (PTs), particularly when it comes to timing of the progression, strength assessment, and use of patient-reported outcome measures
Those conclusions, published in the Journal of Orthopaedic and Sports Physical Therapy were based on results of an online survey of 1, 074 members of APTA’s Academy of Orthopaedic Physical Therapy, American Academy of Sports Physical Therapy, and Private Practice Section. Authors believe that this is the first time PTs’ private practice patterns in this area have been studied.
As for the respondent pool, the majority of PTs treated patients in a private practice or hospital-based outpatient facility. Just over half (52.5%) held American Board of Physical Therapy Specialties certifications in either orthopaedic or sports physical therapy, and 92.5% were APTA members. Authors of the study also classified respondents by the volume of post anterior cruciate ligament repair (ACLR) patients they treated annually, with 32.3% falling into the “low volume” category of 1 to 5 per year, 28.8% grouped into a “medium volume” category of 6 to 10 patients per year, and 37.9% categorized as “high volume,” with 11 or more post-ACLR patients per year. Researchers also tracked respondents by years in practice.
It’s not an uncommon scenario. An athlete is sailing through the air or making a quick turn when all of a sudden he or she hears a “pop” in the knee. An athlete who experiences this followed by sudden pain and swelling often receives the much-feared diagnosis of an anterior cruciate ligament (ACL) tear.
“Young, growing athletes are at high risk for ACL injuries, so it is important to work with coaches, trainers and medical professionals to minimize the risk of injury today, as well as the likelihood of reinjury or arthritis many years from now,” said Dr. Paul Sherbondy, an orthopedic surgeon at Penn State Health Medical Group – Park Avenue in State College.
According to Sherbondy, the ACL is one of the four major ligaments in the knee and the most commonly injured. It connects the thigh bone to the shin bone and helps stabilize the knee joint. ACL injuries range from a mild overextension to a full tear. “Anyone who has injured this ligament is at higher risk for reinjury, as well as early-onset osteoarthritis of the knee,” he said.