The Vertical Drop Jump Is a Poor Screening Test for ACL Injuries in Female Elite Soccer and Handball Players
Background: The evidence linking knee kinematics and kinetics during a vertical drop jump (VDJ) to anterior cruciate ligament (ACL) injury risk is restricted to a single small sample. Still, the VDJ test continues to be advocated for clinical screening purposes. Purpose: To test whether 5 selected kinematic and kinetic variables were associated with future ACL injuries in a large cohort of Norwegian female elite soccer and handball players. Furthermore, we wanted to assess whether the VDJ test can be recommended as a screening test to identify players with increased risk. Study Design: Cohort study; Level of evidence, 2. Methods: Elite female soccer and handball players participated in preseason screening tests from 2007 through 2014. The tests included marker based 3 dimensional motion analysis of a drop jump landing. We followed a predefined statistical protocol in which we included the following candidate risk factors in 5 separate logistic regression analyses, with new ACL injury as the outcome: (1) knee valgus angle at initial contact, (2) peak knee abduction moment, (3) peak knee flexion angle, (4) peak vertical ground reaction force, and (5) medial knee displacement. Results: A total of 782 players were tested (age, 21 4 years; height, 170 7 cm; body mass, 67 8 kg) of which 710 were included in the analyses. We registered 42 new noncontact ACL injuries, including 12 in previously ACL injured players. Previous ACL injury (relative risk, 3.8; 95% CI, 2.1 7.1) and medial knee displacement (odds ratio, 1.40; 95% CI, 1.12 1.74 per 1 SD change) were associated with increased risk for injury. However, among the 643 players without previous injury, we found no association with medial knee displacement. A receiver operating characteristic curve analysis of medial knee displacement showed an area under the curve of 0.6, indicating a poor to failed combined sensitivity and specificity of the test, even when including previously injured players. Conclusion: Of the 5 risk factors considered, medial knee displacement was the only factor associated with increased risk for ACL. However, receiver operating characteristic curve analysis indicated a poor combined sensitivity and specificity when medial knee displacement was used as a screening test for predicting ACL injury. For players with no previous injury, none of the VDJ variables were associated with increased injury risk. Clinical Relevance: VDJ tests cannot predict ACL injuries in female elite soccer and handball players.
The American journal of sports medicine