Dataset Information

The Influence of Anterior Cruciate Ligament Matrix Mechanical Properties on Simulated Whole-Knee Biomechanics.

ABSTRACT: Knee finite element (FE) models are used to study tissue deformation in response to complex loads. Typically, ligaments are modeled using transversely isotropic, hyperelastic material models fitted to tension data along the predominant fiber direction (longitudinal) and, less commonly, to tension data orthogonal to the fiber direction (transverse). Currently, the shear and bulk responses of the anterior cruciate ligament (ACL) are not fitted to experimental data. In this study, a newly proposed material model was fitted to longitudinal tension, transverse tension, and shear experimental data. The matrix transverse tensile, shear, and bulk stiffnesses were then varied independently to determine the impact of each property on knee kinematics and tissue deformation in a whole-knee FE model. The range of values for each parameter was chosen based on published FE studies of the knee. For a knee at full extension under 134 N anterior tibial force (ATF), increasing matrix transverse tensile stiffness, shear stiffness, or bulk stiffness decreased anterior tibial translation (ATT), ACL longitudinal strain, and ACL shear strain. For a knee under 134 N ATF and 1600 N compression, changing the ACL matrix mechanical properties caused variations in ATT and thus changed cartilage deformation contours by changing the point of contact between the femoral and the tibial cartilage. These findings indicate that material models for the ACL must describe matrix material properties to best predict the in vivo response to applied loads.

SUBMITTER: Rosario R

PROVIDER: S-EPMC7580848 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundKnee joint kinematics and kinetics during running recover at 12 months, not 6 months, following anterior cruciate ligament (ACL) reconstruction surgery. Knee muscle strength is a criterion used to assess an individual's readiness to return-to-sports (RTS); however, the relationship between knee muscle strength and knee biomechanics is unclear. This study investigated the relationship between knee muscle strength and dynamic knee biomechanics during running at 6 and 12 months after ACL reconstruction surgery.MethodsKnee joint kinematics and kinetics during running were analyzed in 21 patients (10 males, 11 females) who underwent ACL reconstruction for a unilateral ACL deficiency. Kinematics and Kinetics were measured by three-dimensional motion analysis system, and Knee flexion angle was calculated using Point cluster technique and internal extension moment was calculated by the inverse dynamics method. Patients were compared to a control group matched by age, height and weight. Isokinetic knee extension and flexion strength in ACL-reconstructed patients were measured at 6 and 12 months postsurgery, by separated gender.ResultsKnee flexion angle was significantly lower in ACL patients at 6 months postsurgery compared to the control group (F (2, 62)=5.78, P=0.014). There were significant lower peak knee flexion angles in male groups than female (F (1, 62)=6.33, P<0.01). Knee extension moments were significantly lower in both male and female ACL patients compared to the control group at 6 and 12 months postsurgery (F (2, 62)=12.05, P<0.01(6 months), P=0.034(12 months)), and there were significant correlations with knee extension moments and maximum torque of knee extension/flexion (P<0.05). At 12 months after surgery, knee joint kinematics in ACL patients were restored. Both peak knee angle and knee extension moment were significantly associated with maximum knee extension/flexion torque values in female patients at 12 months postsurgery.ConclusionsDynamic knee biomechanics during running were not restored 6 and 12 months after ACL reconstruction both male and female. It is necessary to strengthen knee extension and flexion muscles to restore knee kinetics during running, especially female patients.

Project description:BackgroundWe aimed to evaluate clinical and radiological results after simultaneous open-wedge high tibial osteotomy (HTO) and anterior cruciate ligament (ACL) reconstruction in patients with ACL deficiency combined with medial uni-compartmental osteoarthritis (OA) and varus deformity.MethodsThis retrospective study was performed using data collected from 2005 to 2011 on a total of 24 patients who were diagnosed with ACL injury and medial unicompartmental OA with varus deformity, and who subsequently underwent simultaneous open-wedge HTO and arthroscopic ACL reconstruction. The mean follow-up duration was 5.2 years. For clinical outcomes, we evaluated Lysholm score, Tegner activity score, range of motion, Lachmann test, and pivot-shift test, and for radiological outcomes, we evaluated the degree of varus deformity, progression of medial OA, tibial posterior slope, anterior instability, and postoperative complication.ResultsThere were no limitations in range of motion found in any cases. Three patients showed progressive osteoarthritis on the medial compartment. The mechanical femorotibial angle was significantly corrected from varus 7.0 degrees to valgus 1.2 degrees, and the tibial posterior slope was not significantly changed. The Lysholm and Tegner activity scores were significantly improved after surgery (from 58 to 94 points on the Lysholm scale and from 4.0 to 5.3 points on the Tegner activity scale). Although the Lachman test and the pivot-shift test showed significant improvements after surgery, instability greater than Gr II was observed in three patients on the Lachman test and in four patients on the pivot-shift test. The side-to-side difference improved from 9.6 mm to 4.2 mm postoperatively as assessed using a Telos® arthrometer. There were no cases of nonunion or fixation loss.ConclusionsSimultaneous open-wedge HTO and ACL reconstruction in patients with ACL injury with medial compartmental OA showed satisfactory functional outcomes and postoperative activity level scores. However, some patients showed residual instability and progression of OA.

Project description:Anterior cruciate ligament (ACL) deficiency alters 6 degrees of freedom knee kinematics, yet only anterior translation and internal rotation have been the primary measures in previous studies.To compare the 6 degrees of freedom knee kinematics and the graft forces after single- and double-bundle ACL reconstructions under various external loading conditions.Controlled laboratory study.Ten human cadaveric knees were tested with a robotic testing system under 4 conditions: intact, ACL deficient, single-bundle reconstructed with a quadrupled hamstring tendon graft, and double-bundle reconstructed with 2 looped hamstring tendon grafts. Knee kinematics and forces of the ACL or ACL graft in each knee were measured under 3 loading conditions: an anterior tibial load of 134 N, a simulated quadriceps muscle load of 400 N, and combined tibial torques (10 N.m valgus and 5 N.m internal tibial torques) at 0 degrees , 15 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion.The double-bundle reconstruction restored the anterior and medial laxities closer to the intact knee than the single-bundle reconstruction. However, the internal rotation of the tibia under the simulated quadriceps muscle load was significantly decreased when compared with the intact knee after both reconstructions, more so after double-bundle reconstruction (P < .05). The entire graft force of the double-bundle reconstruction was more similar to that of the intact ACL than that of the single-bundle reconstruction. However, the posterolateral bundle graft in the double-bundle reconstructed knee was overloaded as compared with the intact posterolateral bundle.The double-bundle reconstruction can better restore the normal anterior-posterior and medial-lateral laxities than the single-bundle reconstruction can, but an overloading of the posterolateral bundle graft can occur in a double-bundle reconstructed knee.Both single-bundle and double-bundle techniques cannot restore the rotational laxities and the ACL force distributions of the intact knee.

Dataset Information

The Influence of Anterior Cruciate Ligament Matrix Mechanical Properties on Simulated Whole-Knee Biomechanics.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets