Knee ACL Injuries: Can we prevent them in our athletes? Part 1

Knee ACL injuries: Can we prevent them in our athletes? Part 1

By Dr. John Mishock, PT, DPT, DC 


Knee injuries account for up to 40% of all sports injuries, commonly occurring in soccer, basketball, lacrosse, skiing, football, and gymnastics (Nessier et al. 2017). Knee injuries are the most common cause of surgery in high school and college athletes, accounting for 60% of sports injury operative procedures. (Myers et al. 2015) Each year in the US, 250,000 to 300,000 knee injuries are tears of the ACL (anterior cruciate ligament). Most of these ACL injuries require reconstruction surgery to stabilize the knee. (Sanders et al. 2016) The ACL is one of 4 ligaments that hold the knee together, stabilizing the knee during dynamic movements such as running, cutting, pivoting, and jumping. Seventy percent of ACL injuries are noncontact with artificial turf or indoor non-wood floors, increasing the risk by up to 30% (silvers et al. 2007, Sugimoto et al. 2015) Most injuries of the ACL occur during the deceleration phase of the cutting maneuver, sudden stop while running, landing from a jump with extended knees, fatigue, or a direct blow to the knee.


Who is at risk for an ACL injury?

The greatest incidence of ACL injury is among female athletes aged 12-25, with up to a ten times higher incidence than males. (Thompson et al. 2017) The increased risk of injury is due to hormones (estrogen and relaxin hormone), being more knocked kneed (knee valgus), flat feet (subtalar foot joint pronation, reduced strength (quad-ham-ration <60%), and altered motor control (proprioception) of the (ankle, knee, hips, and core). (Bisciotti et al. 2016)


What is the cost to repair and ACL injury?

Following an ACL injury, the knee instability is often corrected by ACL surgery, which costs over $17,000. (Nessler et al. 2017) In the NFL from 2013-2017, there were 202 ACL injuries at the cost of $1,000,000 per player (medical cost, workers comp, lost playing time), with 73% being noncontact. In most cases following surgery it takes 9-12 months to return to play.


What is the recovery time for an ACL surgery patient?

Following surgery and rehabilitation, many patients may still exhibit strength deficits (quads, hamstring, hips) at 24 months. (Ardern et al. 2011) Even after a physical therapy rehabilitation program many athletes are not fully recovered with only 35%-50% of athletes at their preinjury level in speed, first-step-quickness, agility, cutting, and jumping at 12 months. Most athletes do not return to their prior level of function for 18-24 months (Ardern et al., 2011). One study showed that only 63% successfully returned to sports at their previous level of competition. (Paterno et al. 2018) More than 25% of ACL injury patients do not return to sports, representing their athletic career’s end. (Sanders et al. 20016, Morgan et al. 2015) Of those who return to sport, 37% will sustain a 2nd ACL injury in the first two years of return to play. (Ithurburn et al. 2017) Long-term, there is an increased risk of osteoarthritis (OA) of the knee, with 50% of patients having radiographic signs of OA at ten years following the ACL tear. (Ithurbun et al 2017)

In Knee ACL injuries: Can we prevent them in our athletes? Part II, I will review how injury prevention programs can eliminate up to 50% of ACL injuries through exercise training using strength, motor control, and plyometric training.

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Dr. Mishock is one of only a few clinicians with doctorate-level degrees in both physical therapy and chiropractic in the state of Pennsylvania. He has authored two books; “Fundamental Training Principles: Essential Knowledge for Building the Elite Athlete”, and “The Rubber Arm; Using Science to Increase Pitch Control, Improve Velocity, and Prevent Elbow and Shoulder Injury” both can be bought on Amazon and

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