In Vivo Knee Kinematics in Patients With Arthrofibrosis After Anterior Cruciate Ligament Reconstruction

Context: Arthrofibrosis after anterior cruciate ligament (ACL) reconstruction can be detrimental to the knee joint function and patient outcomes. However, the effects of arthrofibrosis on the in vivo tibiofemoral and patellofemoral joint kinematics after ACL reconstruction remain unclear. Objective: The objective of this study was to quantify the in vivo knee kinematics during a dynamic lunge task in the knee with arthrofibrosis after ACL reconstruction. Methods: Eleven patients with arthrofibrosis in one knee after ACL reconstruction participated in this study. Computed tomography and dual fluoroscopic imaging were used to evaluate in vivo kinematics of affected and contralateral knees during a lunge task. Differences in 6 degrees of freedom tibiofemoral kinematics and patellar tracking between limbs were assessed via repeated-measures analysis of variance. Results: Internal tibial rotation (5.2° vs 7.5°, respectively; P P P = .009) throughout the measured ROM and less laterally tilted by 3° (P = .017) compared with the contralateral knee from 30° to 75° of knee flexion. Conclusions: A significant superior shift and medial tilt of the patella were found in the affected knee compared with those in the contralateral knee during the dynamic lunge. Decreased internal tibial rotation and patellar flexion were found in knees with arthrofibrosis following ACL reconstruction; whether these kinematic changes are caused by arthrofibrosis need further investigation.