Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement

Abstract

The incidence of anterior cruciate ligament (ACL) injury remains high in young athletes. Because female athletes have a much higher incidence of ACL injuries in sports such as basketball and team handball than male athletes, the IOC Medical Commission invited a multidisciplinary group of ACL expert clinicians and scientists to (1) review current evidence including data from the new Scandinavian ACL registries; (2) critically evaluate high-quality studies of injury mechanics; (3) consider the key elements of successful prevention programmes; (4) summarise clinical management including surgery and conservative management; and (5) identify areas for further research. Risk factors for female athletes suffering ACL injury include: (1) being in the preovulatory phase of the menstrual cycle compared with the postovulatory phase; (2) having decreased intercondylar notch width on plain radiography; and (3) developing increased knee abduction moment (a valgus intersegmental torque) during impact on landing. Well-designed injury prevention programmes reduce the risk of ACL for athletes, particularly women. These programmes attempt to alter dynamic loading of the tibiofemoral joint through neuromuscular and proprioceptive training. They emphasise proper landing and cutting techniques. This includes landing softly on the forefoot and rolling back to the rearfoot, engaging knee and hip flexion and, where possible, landing on two feet. Players are trained to avoid excessive dynamic valgus of the knee and to focus on the "knee over toe position" when cutting.

Figure 1

Distribution of patients in the Norwegian National Knee Ligament Registry by age and sex.

Figure 2

Occurrence of anterior cruciate ligament (ACL) injury expressed as (A) a percentage of all injuries and (B) the rate per 1000 exposures (games and practices combined, 1988–9 through 2003–4).

Figure 3

Single leg squat. The athlete should maintain a straight line through the hip, knee and toe. She should keep a horizontal orientation of the hips and avoid a pelvic tilt during one-legged squat balance exercises. The athlete should be encouraged to reach deep knee flexion when performing this drill.

Figure 4

Drop vertical jump test. To identify athletes at risk of severe knee injuries, the drop vertical jump test as described by Hewett et al¹⁴⁸ should be used. The athlete is instructed to “drop off the box and immediately jump as high as you possibly can”. Athletes who land with good valgus knee motion should perform neuromuscular training before sports participation. Training which emphasises the “hip-knee-toe line” position when landing (avoid “kissing knees”) could prevent future ACL injuries. Reproduced with permission from Hewett et al.