Training for Prevention of ACL Injury : Incorporation of Progressive Landing Skill Challenges Into a Program

Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes. Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading, predicting anterior cruciate ligament injury risk. Cohort study; Level of evidence, 2. There were 205 female athletes in the high-risk sports of soccer, basketball, and volleyball prospectively measured for neuromuscular control using 3-dimensional kinematics (joint angles) and joint loads using kinetics (joint moments) during a jump-landing task. Analysis of variance as well as linear and logistic regression were used to isolate predictors of risk in athletes who subsequently ruptured the anterior cruciate ligament. Nine athletes had a confirmed anterior cruciate ligament rupture; these 9 had significantly different knee posture and loading compared to the 196 who did not have anterior cruciate ligament rupture. Knee abduction angle (P<.05) at landing was 8 degrees greater in anterior cruciate ligament-injured than in uninjured athletes. Anterior cruciate ligament-injured athletes had a 2.5 times greater knee abduction moment (P<.001) and 20% higher ground reaction force (P<.05), whereas stance time was 16% shorter; hence, increased motion, force, and moments occurred more quickly. Knee abduction moment predicted anterior cruciate ligament injury status with 73% specificity and 78% sensitivity; dynamic valgus measures showed a predictive r2 of 0.88. Knee motion and knee loading during a landing task are predictors of anterior cruciate ligament injury risk in female athletes. Female athletes with increased dynamic valgus and high abduction loads are at increased risk of anterior cruciate ligament injury. The methods developed may be used to monitor neuromuscular control of the knee joint and may help develop simpler measures of neuromuscular control that can be used to direct female athletes to more effective, targeted interventions.

The literature has shown that anterior cruciate ligament (ACL) tear rates vary by gender, by sport, and in response to injury-reduction training programs. However, there is no consensus as to the magnitudes of these tear rates or their variations as a function of these variables. For example, the female-male ACL tear ratio has been reported to be as high as 9:1. Our purpose was to apply meta-analysis to the entire applicable literature to generate accurate estimates of the true incidences of ACL tear as a function of gender, sport, and injury-reduction training. A PubMed literature search was done to identify all studies dealing with ACL tear incidence. Bibliographic cross-referencing was done to identify additional articles. Meta-analytic principles were applied to generate ACL incidences as a function of gender, sport, and prior injury-reduction training. Female-male ACL tear incidences ratios were as follows: basketball, 3.5; soccer, 2.67; lacrosse, 1.18; and Alpine skiing, 1.0. The collegiate soccer tear rate was 0.32 for female subjects and 0.12 for male subjects. For basketball, the rates were 0.29 and 0.08, respectively. The rate for recreational Alpine skiers was 0.63, and that for experts was 0.03, with no gender variance. The two volleyball studies had no ACL tears. Training reduced the ACL tear incidence in soccer by 0.24 but did not reduce it at all in basketball. Female subjects had a roughly 3 times greater incidence of ACL tears in soccer and basketball versus male subjects. Injury-reduction programs were effective for soccer but not basketball. Recreational Alpine skiers had the highest incidences of ACL tear, whereas expert Alpine skiers had the lowest incidences. Volleyball may in fact be a low-risk sport rather than a high-risk sport. Alpine skiers and lacrosse players had no gender difference for ACL tear rate. Year-round female athletes who play soccer and basketball have an ACL tear rate of approximately 5%. Level IV, therapeutic case series.

An athlete's desire to return to sport after anterior cruciate ligament (ACL) injury is a major indication for ACL reconstruction surgery. Typical clearance to return is 6 to 12 months postoperatively. To investigate the return-to-sport rate and participation level of a large cohort at 12 months after ACL reconstruction surgery. Case series; Level of evidence, 4. Data were analyzed for 503 patients who participated in competitive-level Australian football, basketball, netball, or soccer after ACL reconstruction surgery using a quadruple-strand hamstring autograft. Inclusion criteria included participation in competitive sport before the ACL injury and clearance from the orthopaedic surgeon to return to sport postoperatively. Patients completed a self-report questionnaire regarding preoperative and postoperative sports participation and the Cincinnati Sports Activity Scale. The International Knee Documentation Committee (IKDC) knee evaluation form and hop tests were used to evaluate knee function. Sixty-seven percent of patients attempted some form of sports activity by 12 months postoperatively; 33% attempted competitive sport. Of those who did not attempt any sports activity by 12 months, 47% indicated that they were planning to return. Men were significantly more likely than women to return. Patients who played sports with a seasonal competition, versus a year-round competition, were significantly more likely to return by 12 months. Patients with normal postoperative knee function (IKDC category A), versus those with nearly normal function (IKDC category B), were no more likely to return, but patients with good hop test results (≥85% limb symmetry index) were more likely to return than patients with poor results (<85%). People may require a longer postoperative rehabilitation period than that typically advocated to facilitate a successful return to competitive sport after ACL reconstruction surgery. The relationship between postoperative knee function and return-to-sport outcomes at 12 months after surgery was inconclusive.