Effect of Ligament Properties on Nonlinear Dynamics and Wear Prediction of Knee Prostheses

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Ehsan Askari ◽  
Michael S. Andersen
Keyword(s):  
Nonlinear Dynamics ◽  
Soft Tissues ◽  
Cruciate Ligament ◽  
Knee Laxity ◽  
Linear Wear ◽  
Elastic Model ◽  
Knee Prostheses ◽  
Medial Condyle ◽  
Wear Rates ◽  
Stiffness Reduction

Abstract Although wear is known as the primary cause of long-time failure of total knee arthroplasty (TKA), it can be vital in short- and midterm TKA failure due to laxity. One of the reasons leading to joint laxity and instability is ligamentous insufficiency. This study, therefore, aims to investigate the effects of insufficient ligaments-related knee laxity on both nonlinear dynamics and wear of TKA. The study hypothesizes (a) ligamentous insufficiency can increase TKA damage; (b) stiffness reduction of each of the posterior cruciate ligament (PCL) and medial–lateral collateral ligaments (MCL-LCL) can differently contribute to TKA damage. A forward dynamics methodology is developed and the ligament behavior is simulated employing an asymmetric nonlinear elastic model. External loads and moment, due to the presence of all soft tissues, e.g., muscles and hip joint reaction forces, applied to the femoral bone are determined using a musculoskeletal approach linked to the developed model. A mesh density analysis is performed and comparing outcomes with that available in the literature allows for the assessment of our approach. From the results acquired, reduced PCL stiffness leads to an increase in linear wear rates and results in the maximum damage in TKAs. However, the maximum linear wear rates on both condyles occur once the stiffness of all ligaments is reduced. Moreover, the worn area of the tibia surface increases with the reduction in MCL-LCL stiffness on the medial condyle. The joint with insufficient PCL also shows a considerable increase in ligament forces right after toe-off.

scholarly journals On the Effect of Friction on Tibiofemoral Joint Kinematics

2021 ◽  
Vol 11 (16) ◽  
pp. 7516
Author(s):  
Ehsan Askari ◽  
Michael S. Andersen
Keyword(s):  
Nonlinear Dynamics ◽  
Knee Joint ◽  
Soft Tissues ◽  
Research Work ◽  
Computational Time ◽  
Elastic Model ◽  
Friction Forces ◽  
Normal Contact ◽  
Mesh Density ◽  
Friction Induced Vibration

The effect of friction on nonlinear dynamics and vibration of total knee arthroplasties is yet to be investigated and understood. This research work aims at studying the influence of friction on nonlinear dynamics, friction-induced vibration, and damage of tibiofemoral joints. For this purpose, a spatial dynamic knee model is developed using an asymmetric nonlinear elastic model accounting for knee joint ligaments and a penalty contact model to compute normal contact stresses in the joint while contact detection is treated such that the associated computational time is reduced. Several friction models are considered and embedded in the dynamic model to estimate tangential friction forces in the knee joint. External loads and moments, due to the presence of all soft tissues, e.g., muscles and hip-joint reaction forces, applied to the femoral bone are determined using a musculoskeletal approach. In the post-processing stage, damage, i.e., wear and creep, are estimated using three wear models and an empirical creep formulation, respectively. In addition, a FFT analysis is performed to evaluate likely friction-induced vibration of tibiofemoral joints. Mesh density analysis is performed and the methodology is assessed against outcomes available in the literature. It can be concluded that friction influences not only the tribology, but also dynamics of the knee joint, and friction-induced vibration is likely to take place when the friction coefficient increases.

Altered Knee Laxity and Stiffness in Response to a Soccer Match Simulation in Players Returning to Sport Within 12 Months After Anterior Cruciate Ligament Reconstruction

2021 ◽  
pp. 036354652110130
Author(s):  
Stefano Nuccio ◽  
Luciana Labanca ◽  
Jacopo Emanuele Rocchi ◽  
Pier Paolo Mariani ◽  
Paola Sbriccoli ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Cruciate Ligament ◽  
Return To Sport ◽  
Knee Laxity ◽  
Activity Level ◽  
Soccer Players ◽  
Control Group ◽  
Soccer Match ◽  
Anterior Cruciate ◽  
Anterior Knee

Background: The acute effects of exercise on anterior knee laxity (AKL) and anterior knee stiffness (AKS) have been documented in healthy participants, but only limited evidence has been provided for athletes cleared to return to sports after anterior cruciate ligament (ACL) reconstruction (ACLR). Purpose/Hypothesis: The purpose was to determine if 45 minutes of a soccer match simulation lead to acute changes in AKL and AKS in soccer players returning to sport within 12 months after ACLR. We hypothesized that the reconstructed knee of the ACLR group would exhibit an altered response to sport-specific exercise. Study Design: Controlled laboratory study. Methods: A total of 13 soccer players cleared to return to sport after ACLR and 13 healthy control soccer players matched for age, physical activity level, limb dominance, and anthropometric characteristics were recruited. To assess the effects of a standardized soccer match simulation (Soccer Aerobic Field Test [SAFT45]) on AKL and AKS, an arthrometric evaluation was carried out bilaterally before and immediately after SAFT45. To conduct a comprehensive examination of the force-displacement curve, the absolute and side-to-side difference (SSD) values of both AKL and AKS were extracted at 67, 134, and 200 N. Results: The ACLR and control groups showed similar AKL and AKS at baseline ( P > .05). In response to SAFT45, laxity increased bilaterally at all force levels by 14% to 17% only in the control group ( P < .025). Similarly, AKS at 134 and 200 N decreased in response to SAFT45 only in the control group (10.5% and 20.5%, respectively; P < .025). After SAFT45, the ACLR group had 1.9 and 2.5 times higher SSDs of AKS at 67 and 134 N compared with the control group, respectively ( P < .025), as well as a 1.9 times higher SSD of AKS at 134 N compared with baseline ( P = .014). Conclusion: Soccer players at the time of return to sport after ACLR showed an altered mechanical response to a sport-specific match simulation consisting of bilaterally unchanged AKL and AKS. Clinical Relevance: Soccer players showing altered AKL and AKS in response to exercise after ACLR may not be ready to sustain their preinjury levels of sport, thus potentially increasing the risk of second ACL injuries.

Effect of Tibial Tunnel Placement Using the Lateral Meniscus as a Landmark on Clinical Outcomes of Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

2021 ◽  
pp. 036354652199967
Author(s):  
Kadir Büyükdoğan ◽  
Michael S. Laidlaw ◽  
Michael A. Fox ◽  
Michelle E. Kew ◽  
Mark D. Miller
Keyword(s):  
Tibial Plateau ◽  
Cruciate Ligament ◽  
Tibial Tunnel ◽  
Lateral Meniscus ◽  
Knee Laxity ◽  
Pivot Shift Test ◽  
Anterior Knee Laxity ◽  
Posterior Group ◽  
Kt 1000 ◽  
Anterior Knee

Background: It remains unclear if use of the lateral meniscus anterior horn (LMAH) as a landmark will produce consistent tunnel positions in the anteroposterior (AP) distance across the tibial plateau. Purpose: To evaluate the AP location of anterior cruciate ligament (ACL) reconstruction tibial tunnels utilizing the LMAH as an intra-articular landmark and to examine how tunnel placement affects knee stability and clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective review was conducted of 98 patients who underwent primary ACL reconstruction with quadrupled hamstring tendon autografts between March 2013 and June 2017. Patients with unilateral ACL injuries and a minimum follow-up of 2 years were included in the study. All guide pins for the tibial tunnel were placed using the posterior border of the LMAH as an intra-articular landmark. Guide pins were evaluated with the Bernard-Hertel grid in the femur and the Stäubli-Rauschning method in the tibia. Patients were divided by the radiographic location of the articular entry point of the guide pin with relation to the anterior 40% of the tibial plateau. Outcomes were evaluated by the Marx Activity Scale and International Knee Documentation Committee (IKDC) form. Anterior knee laxity was evaluated using a KT-1000 arthrometer and graded with the objective portion of the IKDC form. Rotational stability was evaluated using the pivot-shift test. Results: A total of 60 patients were available for follow-up at a mean 28.6 months. The overall percentage of AP placement of the tibial tunnel was 39.3% ± 3.8% (mean ± SD; range, 31%-47%). Side-to-side difference of anterior knee laxity was significantly lower in the anterior group than the posterior group (1.2 ± 1.1 mm vs 2.5 ± 1.3 mm; P < .001; r = 0.51). The percentage of AP placement of the tibial tunnel demonstrated a positive medium correlation with side-to-side difference of anterior knee laxity as measured by a KT-1000 arthrometer ( r = 0.430; P < .001). The anterior group reported significantly better distribution of IKDC grading as compared with the posterior group (26 grade A and 6 grade B vs 15 grade A and 13 grade B; P = .043; V = 0.297). The pivot-shift test results and outcome scores showed no significant differences between the groups. Conclusion: Using the posterior border of the LMAH as an intraoperative landmark yields a wide range of tibial tunnel locations along the tibial plateau, with anterior placement of the tibial tunnel leading toward improved anterior knee stability.

Static rotational knee laxity in anterior cruciate ligament injuries

2012 ◽  
Vol 20 (4) ◽  
pp. 652-662 ◽  
Author(s):  
Caroline Mouton ◽  
Daniel Theisen ◽  
Dietrich Pape ◽  
Christian Nührenbörger ◽  
Romain Seil
Keyword(s):  
Anterior Cruciate Ligament ◽  
Cruciate Ligament ◽  
Knee Laxity ◽  
Ligament Injuries ◽  
Anterior Cruciate Ligament Injuries ◽  
Anterior Cruciate ◽  
Rotational Knee Laxity

Wear Characteristics of Conventional and Squeeze-Film Artificial Hip Joints

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
S. Boedo ◽  
S. A. Coots
Keyword(s):  
Implant Design ◽  
Squeeze Film ◽  
Linear Wear ◽  
Wear Depth ◽  
Element Analysis ◽  
Wear Characteristics ◽  
Wear Rates ◽  
Cycle Loading ◽  
Artificial Hip Joints ◽  
Elastic Elements

This paper investigates the wear characteristics of a novel squeeze-film hip implant design. Key features of the design are elastic elements attached to the cup which provide a mechanical means for ball separation during the swing phase of the gait loading cycle. An Archard-based wear formulation was implemented utilizing the ansys finite element analysis program which relates contact pressure and sliding distance to linear wear depth. It is found that low-modulus elastic elements with bonded high-modulus metal coatings offer significant predicted improvement in linear and volumetric wear rates when compared with conventional implant geometries for gait cycle loading and kinematic conditions found in practice.

Adjusting Insert Thickness and Tibial Slope Do Not Correct Internal Tibial Rotation Loss Caused by PCL Resection: In Vitro Study of a Medial Constraint TKA Implanted with Unrestricted Calipered Kinematic Alignment

2021 ◽  
Author(s):  
Alexander J. Nedopil ◽  
Peter J. Thadani ◽  
Thomas H. McCoy ◽  
Stephen M. Howell ◽  
Maury L. Hull
Keyword(s):  
Internal Rotation ◽  
Cruciate Ligament ◽  
Tibial Slope ◽  
Kinematic Alignment ◽  
Tibial Rotation ◽  
Medial Condyle ◽  
Maximum Extension ◽  
Posterior Tibial ◽  
Internal Tibial Rotation ◽  
Lift Off

AbstractMost medial stabilized (MS) total knee arthroplasty (TKA) implants recommend excision of the posterior cruciate ligament (PCL), which eliminates the ligament's tension effect on the tibia that drives tibial rotation and compromises passive internal tibial rotation in flexion. Whether increasing the insert thickness and reducing the posterior tibial slope corrects the loss of rotation without extension loss and undesirable anterior lift-off of the insert is unknown. In 10 fresh-frozen cadaveric knees, an MS design with a medial ball-in-socket (i.e., spherical joint) and lateral flat insert was implanted with unrestricted calipered kinematic alignment (KA) and PCL retention. Trial inserts with goniometric markings measured the internal–external orientation relative to the femoral component's medial condyle at maximum extension and 90 degrees of flexion. After PCL excision, these measurements were repeated with the same insert, a 1 mm thicker insert, and a 2- and 4-mm shim under the posterior tibial baseplate to reduce the tibial slope. Internal tibial rotation from maximum extension and 90 degrees of flexion was 15 degrees with PCL retention and 7 degrees with PCL excision (p < 0.000). With a 1 mm thicker insert, internal rotation was 8 degrees (p < 0.000), and four TKAs lost extension. With a 2 mm shim, internal rotation was 9 degrees (p = 0.001) and two TKAs lost extension. With a 4 mm shim, internal rotation was 10 degrees (p = 0.002) and five TKAs lost extension and three had anterior lift-off. The methods of inserting a 1 mm thicker insert and reducing the posterior slope did not correct the loss of internal tibial rotation after PCL excision and caused extension loss and anterior lift-off in several knees. PCL retention should be considered when using unrestricted calipered KA and implanting a medial ball-in-socket and lateral flat insert TKA design, so the progression of internal tibial rotation and coupled reduction in Q-angle throughout flexion matches the native knee, optimizing the retinacular ligaments' tension and patellofemoral tracking.

scholarly journals Collagen-Platelet Composites Improve the Biomechanical Properties of Healing Anterior Cruciate Ligament Grafts in a Porcine Model

2009 ◽  
Vol 37 (8) ◽  
pp. 1554-1563 ◽  
Author(s):  
Braden C. Fleming ◽  
Kurt P. Spindler ◽  
Matthew P. Palmer ◽  
Elise M. Magarian ◽  
Martha M. Murray
Keyword(s):  
Anterior Cruciate Ligament ◽  
Structural Properties ◽  
Acl Reconstruction ◽  
Porcine Model ◽  
Cruciate Ligament ◽  
Bone Allograft ◽  
Knee Laxity ◽  
Biomechanical Properties ◽  
Anterior Cruciate ◽  
Vessel Infiltration

Background The outcome of anterior cruciate ligament (ACL) reconstruction is variable, and many patients have increased joint laxity postoperatively. Hypothesis Placement of a collagen-platelet composite (CPC) around the graft at the time of ACL reconstruction decreases postoperative knee laxity and improves the structural properties of the graft compared with standard ACL reconstruction. Study Design Controlled laboratory study. Methods Thirteen immature pigs underwent unilateral ACL reconstruction with a bone–patellar tendon–bone allograft. In 6 pigs, a standard allograft was used to reconstruct the ACL. In 7 pigs, a CPC was placed around the allograft. After 15 weeks of healing, the animals were euthanized, and the anterior-posterior (AP) knee laxity and structural properties of the graft were measured. Qualitative histology of the grafts was also performed. Results The AP laxity values of the reconstructed knees, normalized to the contralateral control, were significantly reduced by 28% and 57% at 60° and 90° of knee flexion, respectively, with the addition of CPC (P <. 001). Significant improvements in the graft structural properties were also found; the normalized yield (P =. 044) and maximum failure loads (P =. 025) of the CPC group were 60% higher than the standard ACL-reconstructed group. Although cellular and vessel infiltration were observed in the grafts of both groups, regions of necrosis were present only in the standard ACL-reconstructed group. Conclusion These data demonstrate that the application of CPC at the time of ACL reconstruction improves the structural properties of the graft and reduces early AP knee laxity in the porcine model after 15 weeks of healing. Clinical Relevance Application of a CPC to an ACL graft at the time of surgery decreased knee laxity and increased the structural properties of the graft after 15 weeks of healing.

Assessment of Knee Laxity Following Anterior Cruciate Ligament Reconstruction

1993 ◽  
Vol 2 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Kelly R. Holcomb ◽  
Cheryl A. Skaggs ◽  
Teddy W. Worrell ◽  
Mark DeCarlo ◽  
K. Donald Shelbourne
Keyword(s):  
Anterior Cruciate Ligament ◽  
Standard Error ◽  
Cruciate Ligament ◽  
Intraclass Correlation ◽  
Knee Laxity ◽  
Testing Procedures ◽  
Kt 1000 ◽  
Anterior Cruciate ◽  
Standard Error Of Measurement ◽  
Error Of Measurement

A paucity of information exists concerning reliability of the KT-1000 knee arthrometer (MEDmetric Corp., San Diego, CA) when used by different clinicians to assess the same anterior cruciate ligament-deficient patient. The purpose of this study was to determine the reliability and standard error of measurement of four clinicians who routinely report KT-1000 arthrometer values to referring orthopedic surgeons. Two physical therapists and two athletic trainers performed anterior laxity tests using the KT-1000 on 19 subjects. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to determine reliability. Intratester ICC ranged from .98 to 1.0 and intratesterSEMranged from 0.0 to .28 mm. Intertester ICC andSEMfor all four testers were .53 and 1.2 mm, respectively. A 95% confidence interval (M ± 1.96 ×SEM) of the intertester variability ranged from −0.18 to 4.52 mm. Therefore, large intertester variation existed in KT-1000 values. Each facility should standardize testing procedures and establish intratester and intertester reliability for all clinicians reporting KT-1000 values.

scholarly journals Preliminary Results in Anatomic All-inside Anterior Cruciate Ligament Reconstruction

2016 ◽  
Vol 1 (s2) ◽  
pp. 23-26
Author(s):  
Octav Russu ◽  
Tiberiu Bățagă ◽  
Andrei-Marian Feier ◽  
Radu Prejbeanu ◽  
Radu Fleaca ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Knee Laxity ◽  
Clinical Results ◽  
Lysholm Score ◽  
X Rays ◽  
The Mean ◽  
Anterior Cruciate

Abstract Introduction: Anterior cruciate ligament (ACL) rupture is one of the most common lesions in knee traumatology; therefore the number of ACL reconstructions is increasing worldwide. Usually, an anteromedial (AM) accessory portal is required in anatomical positioning of the femoral tunnel, which is not absolutely necessary in this technique. Aim: Assessment of all-inside ACL reconstruction preliminary clinical results with adjustable loops and buttons on both femoral and tibial surfaces. Method: Our prospective study included 28 subjects (19 male, 9 female) with chronic ACL ruptures. The mean age of the study population was 27.72 ± 8.23 years. In all cases ACL reconstruction was carried out with the use of quadrupled semitendinosus auto-grafts with adjustable loops and buttons on the femoral and tibial surfaces and anatomic placement of both tunnels, using an outside-in technique, with flipcutters (Arthrex®). Clinical and radiological evaluations were carried out before surgery and at 3 and 6 months postoperatively, with the Lysholm scoring system, the Tegner activity scale and anterior-posterior and latero-lateral X-rays. Anterior knee laxity was measured in 25° of flexion using a portable arthrometer (RolimeterTM, Aircast®) and maximum manual force. Results: During the final follow-up, the Lysholm score was good and excellent in 27 cases, with a mean Lysholm score of 95.55 ± 4.63; all results were classified as good. The mean preoperative Tegner activity score was 3.46 ± 1.71 (range: 1-7), and the post-operative mean score was 5.75 ± 2.24 (range: 2-10). We found no graft ruptures. Preoperative knee laxity measurements showed a mean displacement of 11.5 ± 3.1 mm and side-to-side differences of 5.6 ± 3.5 mm, while the postoperative measurements at the last follow-up were 6.3 ± 1.54 mm and 2.65 ± 1.86 mm, respectively. Conclusion: Short-term clinical outcomes of all-inside ACL restoration with anatomic placement femoral and tibial tunnels seem to recommend this surgical option, with good subjective and objective results. Additional research will have to prove the long-term success.

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