Patellofemoral kinematic characteristics in anterior cruciate ligament deficiency and reconstruction

Abstract

Background It is very important to dynamically evaluate the functional outcome in the knee after anterior cruciate ligament (ACL) reconstruction under physiological weight bearing. The objective of the current study is that we would like to compare the patellofemoral joint kinematics in three ACL status: ACL intact, ACL deficiency, ACL reconstruction. Methods Twenty patients with unilateral ACL deficient knees were recruited as preoperative group. Six months after ACL reconstruction, these ten subjects were included as postoperative subjects. Ten normal subjects with healthy knees as the control group. Each subject was asked to walk up a custom set of stairs and a single-plane fluoroscopic imaging system was used to determine the 6DOF kinematics of the injured knees, ACL reconstructed knees, and intact knees. Results ACL deficient knees showed reduced patellar flexion angle and reduced distal patellar translation during knee flexion. ACL reconstructed knees showed abnormal patellofemoral joint kinematics compared to ACL intact and ACL deficient knees, exhibiting increased patellar external rotation, lateral tilt, lateral translation during knee flexion. Conclusion These findings imply that some alterations persist after ACL deficiency and ACL reconstruction. These abnormal changes will be the onset of degeneration in patellofemoral joint even if the ACL is reconstructed in a way that restores the clinical anteroposterior stability of the knee. Some biomechanical changes should be made to improve the outcome of intervention especially in surgical treatment like ACL reconstruction.

An Anatomical-Based Subject-Specific Model of In-Vivo Knee Joint 3D Kinematics From Medical Imaging

“…For instance, fiducial points were used in this study for MRI-CT registration, since they are standard, simple, and applied in many clinical procedures, in particular when aligning bony landmarks. However, many other techniques have been proposed, like mutual information and iterative-closest-point techniques [31,33]. The use of fiducial points for MRI-CT registration showed a good accuracy in a previous investigation [31], with a mean distance between corresponding surfaces lower than 2 mm, consistent with the accuracy of the medical imaging techniques used in the present study.…”

“…Previous validation works showed an accuracy in knee kinematic reconstruction within 0.5 mm and 1 deg in the sagittal plane [30,32]. In this way, the experimental natural motion of the TF (i.e., the tibia-femur motion) and PF (i.e., the patella-femur motion) joints were obtained [33]. Registration was performed for both the flexion and extension movements, obtaining two motion curves: the volunteer unloaded motion was determined as the mean between the two.…”

Longitudinal Changes of Patellar Alignment Before and After Anterior Cruciate Ligament Reconstruction With Hamstring Autograft

“…Several studies have reported excessive patellar lateral displacement and lateral tilt at 6 months after ACLR in either static or dynamic tasks. 16,17,33 One study reported increased patellar lateral rotation (valgus rotation) during a static lunge, 33 whereas others reported decreased patellar lateral rotation. 16,17 From a biomechanical standpoint, altered patellar kinematics may lead to decreased PFJ contact area and elevated contact forces, 28 suggesting detrimental effects on the articular cartilage of the patella and trochlea.…”

“…Several studies have reported excessive patellar lateral displacement and lateral tilt at 6 months after ACLR in either static or dynamic tasks. 16,17,33 One study reported increased patellar lateral…”

“…16,17,33 One study reported increased patellar lateral rotation (valgus rotation) during a static lunge, 33 whereas others reported decreased patellar lateral rotation. 16,17 From a biomechanical standpoint, altered patellar kinematics may lead to decreased PFJ contact area and elevated contact forces, 28 suggesting detrimental effects on the articular cartilage of the patella and trochlea. Indeed, studies have demonstrated associations between patellar malalignment and worsening of PFJ cartilage lesions as well as changes in cartilage composition, 16,18,19 both of which are features of early OA degeneration.…”