Anterior cruciate ligament deficiency: Rotational instability in the transverse plane. A preliminary laboratory in vivo study

Abstract

Background. Rotational instability is a major feature of anterior cruciate ligament (ACL) deficiency. Few biomechanical studies have focused on the transverse plane when assessing the function of the ACL. Objective. To analyse the biomechanics of ACL deficient knees in the transverse plane under torsional conditions to detect rotational instability. Methods. Seven subjects (eight ACL deficiency) (ACLd group) and nine recreational athletes (controls) were recruited. Each performed two tasks: crossover and pivoting-jump. Biomechanical data were collected in a movement analysis laboratory. Comparisons were made for torque, rotation and torque curves in transverse plane between ACLd, contralateral knees and controls. Results. Torque curves showed and initial avoidance pattern followed by increased values in crossover task, and lesser values for ACLd group compared to controls in pivoting-jump task. Internal rotation in crossover was 19.8°, 13.7° and 19.1° for ACLd, contralateral and controls respectively (p = 0. 176). In pivoting-jump these values were 18.6°, 13.8° and 18.1° (p = 0.297). Crossover peak torque were 257, 178.4 and 184.8 Nmm for ACLd, contralateral and controls (p = 0.5), while pivoting-jump values were 238.4, 152.2 and 218 Nmm for ACLd, contralateral and controls (p = 0.288). Conclusion. Torque curve analysis identified a distinctive pattern differentiating ACLd and control group. However, no statistically significant differences were found in peak transverse plane parameters between groups.