Background When assessing non-contact anterior cruciate ligament (ACL) injury risk, prospective measures of high valgus knee angle (>8°) and high knee abduction moment (>25 Nm) measured during landings have been shown to predict ACL injury in female athletes.

Objective The purpose of this study was to determine the relationships between these ‘high risk’ landing variables and anterior tibial translation (ATT) and lateral tibial translations (LTT). We hypothesised individuals exhibiting high knee valgus angles and/or knee abductor moments will also experience larger ATT and/or LTT during a landing.

Design Descriptive laboratory study.

Setting Controlled laboratory setting; highly active recreational, high school and college athletes.

Participants 15 healthy female athletes (26.1 ± 6.3 years; 167.9 cm ± 6.3, 58.2 ± 5.2 Kg).

Assessment of risk factors The subjects performed a drop-landing motion by stepping off a 40 cm platform onto a force plate and then immediately performed a maximum effort vertical jump.

Main outcome measurements Knee abductor moment and valgus angle were measured using motion capture and inverse dynamic analyses. ATT and LTT were measured concurrently using high-speed biplane fluoroscopy with sub-millimeter accuracy.

Results No significant relationship was noted between peak knee valgus angle (range: −2.9° to 20.8°) and peak ATT or LTT (r=−0.17, r=-0.42, respectively); nor, between peak knee abductor moment (range: 2.5–37.2 N*m) and peak ATT or LTT (r=-0.23, r=-0.09, respectively)(p>0.05).

Conclusion The results did not support the hypothesis that high knee valgus angles or abductor moment values will lead to larger ATT or LTT during landing. Although compelling evidence has identified high knee valgus angle and high knee abductor moment as predictive of ACL injury, these parameters did not result in greater knee translations during landing.