Effect of Loading on In Vivo Tibiofemoral and Patellofemoral Kinematics of Healthy and ACL-Reconstructed Knees

Abstract

Background Although knees that have undergone anterior cruciate ligament reconstruction (ACLR) often exhibit normal laxity on clinical examination, abnormal kinematic patterns have been observed when the joint is dynamically loaded during whole body activity. This study investigated whether abnormal knee kinematics arise with loading under isolated dynamic movements. Hypothesis Tibiofemoral and patellofemoral kinematics of ACLR knees will be similar to those of the contralateral uninjured control knee during passive flexion-extension, with bilateral differences emerging when an inertial load is applied. Study Design Controlled laboratory study. Methods The bilateral knees of 18 subjects who had undergone unilateral ACLR within the past 4 years were imaged by use of magnetic resonance imaging (MRI). Their knees were cyclically (0.5 Hz) flexed passively. Subjects then actively flexed and extended their knees against an inertial load that induced stretch-shortening quadriceps contractions, as seen during the load acceptance phase of gait. A dynamic, volumetric, MRI sequence was used to track tibiofemoral and patellofemoral kinematics through 6 degrees of freedom. A repeated-measures analysis of variance was used to compare secondary tibiofemoral and patellofemoral kinematics between ACLR and healthy contralateral knees during the passive and active extension phases of the cyclic motion. Results Relative to the passive motion, inertial loading induced significant shifts in anterior and superior tibial translation, internal tibial rotation, and all patellofemoral degrees of freedom. As hypothesized, tibiofemoral and patellofemoral kinematics were bilaterally symmetric during the passive condition. However, inertial loading induced bilateral differences, with the ACLR knees exhibiting a significant shift toward external tibial rotation. A trend toward greater medial and anterior tibial translation was seen in the ACLR knees. Conclusion This study demonstrates that abnormal knee kinematic patterns in ACLR knees emerge during a simple, active knee flexion-extension task that can be performed in an MRI scanner. Clinical Relevance It is hypothesized that abnormal knee kinematics may alter cartilage loading patterns and thereby contribute to increased risk for osteoarthritis. Recent advances in quantitative MRI can be used to detect early cartilage degeneration in ACLR knees. This study demonstrates the feasibility of identifying abnormal ACLR kinematics by use of dynamic MRI, supporting the combined use of dynamic and quantitative MRI to investigate the proposed link between knee motion, cartilage contact, and early biomarkers of cartilage degeneration.

American Society of Biomechanics Clinical Biomechanics Award 2017: Non-anatomic graft geometry is linked with asymmetric tibiofemoral kinematics and cartilage contact following anterior cruciate ligament reconstruction

“…First, knee mechanics were studied during an open-chain task, in contrast to the closed-chain loading that occurs during locomotion. However, in our previous work, we found that small, subtle shifts in tibiofemoral kinematics detected during this open-chain task are similar to those observed during downhill running (Kaiser et al, 2017). Additionally, strain in the ACL is similar between open-chain and closed-chain knee flexion (Beynnon et al, 1997), which suggests the experimentally measured relationships in this study may extend to locomotion.…”

“…It is theorized that osteoarthritis in ACLR patients may arise, in part, from abnormal cartilage tissue loading after surgery (Chaudhari et al, 2008; Stergiou et al, 2007). Indeed, prior studies have identified asymmetries in ACLR knee kinematics that would affect the location of cartilage contact (Decker et al, 2011; Hofbauer et al, 2014; Kaiser et al, 2017; Scanlan et al, 2010; Tashman et al, 2006). Additionally, in vitro studies have shown that cartilage damage can be initiated by altering the load on cartilage tissue from its homeostatic condition (Griffin and Guilak, 2005).…”

Patellar Malalignment Is Associated With Patellofemoral Lesions and Cartilage Relaxation Times After Hamstring Autograft Anterior Cruciate Ligament Reconstruction

“…The PFJ is not an isolated joint; instead, kinematic coupling exists between the PFJ and tibiofemoral joint articulations, connected via the patellar tendon. 17 With an ACL injury, even after reconstruction, increased tibial anterior translation persists and moves the tibial attachment of the patellar tendon forward, 7,13 thereby increasing patellar anterior displacement and decreasing flexion angle. However, increased tibial internal rotation observed after ACLR 7,13,37 could pull the patellar apex medially through the patellar tendon, thereby limiting patellar lateral spin.…”

The effect of articular geometry features identified using statistical shape modelling on knee biomechanics

“…The participants used to develop the statistical shape model all performed an active knee flexion-extension task with resistance provided by an inertial load [37]. A dynamic, volumetric MRI sequence was used to track tibiofemoral and patellofemoral degrees of freedom during this task (for details, refer to [38,39]). PC scores were computed for each participant's segmented bone and cartilage geometry.…”