Background Lower extremity alignment (LEA) measures have been linked to non-contact anterior cruciate ligament (ACL) injuries. High deceleration movements have been implicated in non-contact ACL injury mechanisms; and, evidence suggests that greater anterior tibial translation (ATT) may occur in healthy knees that demonstrate greater laxity compared to a stiff knee.
Objective To determine the relationship between LEA measures, KT1000 anterior laxity values and ATT during landings using biplane fluoroscopy.
Design Descriptive laboratory study.
Setting Controlled laboratory setting. Subjects had a sport participation history at the high school or college level.
Participants 16 healthy adults (10 females; 6 males).
Assessment of risk factors KT1000 values and seven measures of LEA (pelvic angle, hip anteversion, Q-angle, genu recurvatum, tibial torsion, navicular drop and rear foot angle) were measured.
Main outcome measurements Subjects performed a drop-landing (40 cm) while being filmed using a high speed, biplane fluoroscopy system. Initial, peak and excursions for ATT were calculated and regression analysis used to determine the relationships.
Results KT1000 values were positively correlated with peak ATT values for group (r=0.89) and both genders (males, r=0.97; females, r=0.93) (p=<0.0001). Navicular drop was also significantly correlated to maximal ATT (r=0.56) (p<0.05). No other LEA was significantly correlated with initial, peak or range of ATT (all p>0.05).
Conclusion A strong relationship was observed between passive anterior knee laxity measured via KT1000 and ATT experienced during a landing activity in otherwise healthy persons. Navicular drop was significantly correlated with ATT during landing and is a relationship that warrants further investigation as it relates to ACL injury. Anterior knee laxity measured via the KT1000 should be considered in non-contact ACL injury risk assessment for all athletes.