Mechanisms of non-contact ACL injuries

Abstract

In soccer one of the most common knee injuries is the anterior cruciate ligament (ACL) tear, which usually occurs through non-contact mechanisms. Female soccer players are at higher risk of sustaining non-contact ACL injuries than male soccer players. A good understanding of ACL loading mechanisms is the basis for a good understanding of the mechanisms of non-contact ACL injuries, which in turn is essential for identifying risk factors and developing prevention strategies. Current literature demonstrates that sagittal plane biomechanical factors, such as small knee flexion angle, great posterior ground reaction force and great quadriceps muscle force, are the major ACL loading mechanisms. A great posterior ground reaction force may be associated with a great quadriceps muscle force, which would cause great anterior draw force at the knee. A small knee flexion is associated with a large patella tendon-tibia shaft angle and ACL elevation angle, which would result in great ACL loading. Current literature also demonstrates that the ACL is not the major structure of bearing knee valgus-varus moment and internal-external rotation loadings. Knee valgus-varus moment and internal-external rotation moment alone are not likely to result in isolated ACL injuries without injuring other knee structures.A nterior cruciate ligament (ACL) injury is one of the most commonly seen injuries in sport and has a devastating influence on patients' activity levels and quality of life. Gottlob et al 21 estimated that approximately 175 000 primary ACL reconstruction surgeries were performed annually in the USA with an estimated cost of over US$2 billion. Complete ACL rupture can induce other pathological knee conditions including knee instability, damage to menisci and the chondral surface, and osteoarthritis. Studies have repeatedly shown that patients with complete ACL rupture have chronic knee instability and secondary damage to menisci and chondral surfaces.19 28 30 ACL injuries that occur without physical contact between athletes are referred to as non-contact ACL injuries 8 17 18 and most occur through a non-contact mechanism of injury in sports in which sudden deceleration, landing and pivoting manoeuvres are repeatedly performed.8 Female athletes had a higher incidence of ACL injuries compared with their male counterparts.2 18 Studies have shown that the incidence in female athletes is two to eight times higher than in males in soccer, basketball and volleyball. As with other sports injuries, understanding injury mechanisms is a key component of preventing non-contact ACL injuries. 36a The research effort to determine the risk factors for sustaining non-contact ACL injuries is increasing as concerns grow about the larger number of incidents, the greater treatment costs and the serious consequences of non-contact ACL injuries. Prospective cohort studies commonly use epidemiological research designs for determining injury and disease risk factors, 48 and are being used for determining the risk factors for sustaining non-contact ACL ...

ECSS Position Statement 2009: Prevention of acute sports injuries

“…The two most discussed theories involve the quadriceps drawer mechanism and valgus loading. Proponents of the first theory argue that ACL injuries result from loading in the sagittal plane only, primarily as a result of anterior shear forces caused by forceful quadriceps contraction when landing or cutting (Yu & Garrett, 2007). This mechanism was demonstrated in a cadaver study (DeMorat, Weinhold, Blackburn, Chudik, & Garrett, 2004), but was criticized for not taking ground reaction forces into consideration.…”

The Effect of Fatigue on Lower-Limb Biomechanics During Single-Limb Landings: A Systematic Review

“…This interest is in part due to the role biomechanical factors are thought to play in the noncontact ACL injury mechanism. 33 Biomechanical risk factors have also been a research focus due to their potential for modification. 21 The majority of studies included in this review were conducted within the last 4 years and demonstrate that this is indeed a growing research area.…”

Biomechanics of Musculoskeletal Injury

“…Despite intense study of the ACL injury during the past three decades, the exact mechanism of injury is not known (Boden et al, 2009). ACL injury occurs when an excessive tension force is applied to the ACL (Yu & Garrett, 2007). It has also been noted that in 96% of ACL tears, an opposing player is within close proximity, which could cause an alteration in the players' coordination leading to dangerous leg positions (Boden et al, 2009).…”

“…Additionally, higher hip flexion angle at landing places the torso farther posterior to the knee, requiring that the quadriceps muscle must be activating during landing. The quadriceps muscle force provides anterior shear force on the proximal tibia which increases ACL strain (Boden et al, 2009;Yu & Garrett, 2007). Knee abduction (or knee valgus) also may play a role, particularly in female athletes, by potentially reducing the compression force threshold needed to produce ACL injury (Boden et al, 2010).…”