Application of a clinic-based algorithm as a tool to identify female athletes at risk for anterior cruciate ligament injury: a prospective cohort study with a nested, matched case-control analysis

Abstract

Background: When landing from a jump, the production of increased intersegmental knee abduction moments and coupled valgus motions has been associated with an increased risk of suffering a noncontact anterior cruciate ligament (ACL) injury in one study. This research has led to the development of a clinic-based algorithm that utilizes measures of knee valgus motion, knee flexion range of motion, body mass, tibial length, and quadriceps-to-hamstring strength ratio data to predict the probability of a high knee abduction moment (pKAM) when landing from a jump in female athletes. The ability of this algorithm to identify athletes at increased risk of suffering ACL injury has not been assessed.

Hypothesis: The pKAM is associated with ACL injury in female athletes.

Study design: Case-control study; Level of evidence, 3.

Methods: This study was based on secondary analysis of data obtained from a previous investigation that focused on the use of the drop vertical jump (DVJ) test to assess the risk of ACL injury in female athletes. The DVJ screenings were performed on 1855 female high school and college athletes over 3 years. Knee valgus motion, knee flexion range of motion, and tibial length were measured from videos of the DVJ obtained during preseason screenings. Mass was measured using a physician's scale, and quadriceps-to-hamstring strength ratio was included using a surrogate value. These data were entered into the clinic-based algorithm that determined the pKAM. The association of pKAM with ACL injury was assessed using conditional logistic regression.

Results: A total of 20 athletes sustained ACL injury and were matched with 45 uninjured control athletes who were recruited from the same teams. There was no relationship between the risk of suffering ACL injury and pKAM, as determined by the clinic-based algorithm.

Conclusion: The pKAM was not associated with noncontact ACL injury in our group of injured athletes and matched controls.

Figure 1

Knee joint center at initial contact with the ground during the landing phase of the drop vertical jump. The + represents the location of the knee joint center at initial contact of the foot with the ground.

Figure 2

Knee joint center at maximum medial position during the landing phase of the drop vertical jump. The top + represents the location of the knee joint center at initial contact with the ground, and the bottom + is the knee joint center at its maximum medial position during landing.

Figure 3

Knee valgus motion during the landing phase of the drop vertical jump (DVJ). The line between the top and bottom + is a measurement of knee motion from initial contact with the ground to the maximum medial position of the knee during the landing portion of the DVJ.

Figure 4

Knee flexion angle at initial contact with the ground produced during the landing phase of the drop vertical jump.

Figure 5

Knee flexion angle at maximum flexion during the landing phase of the drop vertical jump.