Computer Graphics Based Analysis of Loading Patterns in the Anterior Cruciate Ligament of the Human Knee
16 Jul 2019-pp 1175-1180
TL;DR: A computer-based model of the knee with intact ligaments and anatomical articular surfaces was used to visualize contributions of different fiber bundles in the ligament with distinct areas of attachment on the femoral bone that are searched for appropriate positions of femoral tunnel during single or double bundle ligament reconstruction.
Abstract: Injuries of anterior cruciate ligament of the knee are common, particularly in young athletes. Though surgical reconstruction of the ligament attempts to restore the joint function, a significant percentage of the patients report unsatisfactory outcome and joint complications that may require repeated surgery. The present study used a computer-based model of the knee with intact ligaments and anatomical articular surfaces to visualize contributions of different fiber bundles in the ligament with distinct areas of attachment on the femoral bone that are searched for appropriate positions of femoral tunnel during single or double bundle ligament reconstruction. Knee motion during flexion and an anterior drawer test at different joint positions were simulated in the sagittal plane. The model analysis showed that the ligament fibers attached anteriorly on the femoral bone contributed significantly throughout the knee motion and resisted anterior loads on the tibia at all flexion positions, while the fibers attached posteriorly on the femoral bone contributed during 0–45° and above 90° flexion. The results agreed with experimental observations and have clinical relevance.
Citations
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01 Jan 2021
TL;DR: In this paper, a model of the knee is used to simulate a knee laxity test used to judge ligament integrity and the analysis suggests that knee ligaments may be predisposed to injury during specific situations like playing football.
Abstract: Human joints are complex in structure and function that allow us a variety of activities with safe mobility and stability. However, the joints are prone to injuries that can affect life severely. Computer-based methods can be useful tools to understand the behaviour of the joints. Computational complexities in modelling and simulation can be overcome, to some extent, using input from related experimental work. Computational approach of modelling and simulation is useful in many areas including analysis of various activities, mechanisms of injuries during specific sports, designing of safe exercises, understanding effects of surgical procedures, etc. In the present study, a model of the knee is used to simulate a knee laxity test used to judge ligament integrity. Results of simulation are comparable to that of similar experiments on cadaver knees. For example, lower bone of the model knee moved 3.4, 6.1 and 5.3 mm anterior to the upper bone, respectively, at 0°, 45° and 90° flexion of the joint resulting from an external 150 N force on the lower bone. These movements were similar to those from experiment. Further, the model calculations suggest that effectiveness of the external force in translating the bone diminished with increasing force magnitude. The analysis suggests that knee ligaments may be predisposed to injury during specific situations like playing football. The results have clinical relevance.
2 citations
16 Jul 2020
TL;DR: Artificial human knee with partial prosthetic replacement was modelled in the sagittal plane in order to analyze the role of anterior cruciate ligament in an unconstrained artificial knee and helped in visual analysis and in gaining insight into the joint behavior with clinical relevance.
Abstract: Artificial human knee with partial prosthetic replacement was modelled in the sagittal plane in order to analyze the role of anterior cruciate ligament in an unconstrained artificial knee. The cruciate and collateral ligaments were modelled as non-linear elastic fibers that stretched and resisted relative movements of the bone. Role of fibers in the anterior and posterior fibers of the anterior cruciate ligament was analyzed during simulated tests similar to those used in clinical practice. Anterior half of the ligament was found to resist forces for all simulated flexion positions of the joint. The posterior half resisted forces in low and in high flexion positions and remained unstitched during for nearly 30–90° flexion. The model calculations agreed with experimental observations on cadaver knees reported in the literature. A graphical interface facilitated visual analysis of the joint while the ligament fibers stretched sequentially developing forces and unstretched becoming slack as the joint flexed or the femoral and tibial bones with prosthetic parts moved relative to each other. The cruciate ligaments controlled the joint kinematics after replacement. The model analysis helps in visual analysis and in gaining insight into the joint behavior with clinical relevance.
09 Sep 2022
TL;DR: In this article , a mathematical model is used to simulate such laxity tests and estimate cruciate ligament forces when the lower leg at the knee is translated anterior to thigh, thus, stretching the anterior cruciato ligament.
Abstract: Cruciate ligaments are main stabilizers of the joint in the sagittal plane. Anterior cruciate ligament is one of the most injured ligaments, particularly during strenuous activities. Integrity of these ligaments is examined clinically by estimating appropriate relative movements of the connected bones. Experiments on cadaver knees provide laxity measurements. However, determination of corresponding ligament forces is either difficult or not possible due to several challenges. In the present study, a mathematical model is used to simulate such laxity tests and estimate cruciate ligament forces when the lower leg at the knee is translated anterior to thigh, thus, stretching the anterior cruciate ligament. The simulation is repeated at several joint positions and with different forces that cause translation. The model calculations showed general agreement with experimental measurements in the literature. For example, the lower leg translated 6, 6.1, and 5.9 mm, respectively, at 30, 45, and 60° flexion with 150 N anterior translating load on the tibia. This is similar to the patterns reported in the literature from in vitro studies. The model helped in gaining further insight in the joint behavior with estimation of corresponding forces developed in the ligament for each simulation. The analysis suggests that 30–60° flexion may be appropriate range for clinical estimation of the ligament integrity as at these joint positions, the laxity is higher, while the ligament forces are not highest in comparison to other flexion angles.KeywordsAnterior drawer testCruciate ligamentsAnterior tibial translation (ATT)Knee laxityModeling and simulation of human knee
01 Jan 2021
TL;DR: In this article, the authors used mathematical modeling to simulate the knee function in the sagittal plane when the ligaments are intact, which could be used to investigate effects of different tunnel positions during the ligament reconstruction.
Abstract: Anterior Cruciate Ligament of the knee is injured quite often while performing strenuous activities like in sports. Due to poor healing characteristics, surgical reconstruction of the ligament is used to restore the joint function. However, many significant percentage of the patients are unable to return to their pre-injury levels of activity. In addition, more complications of the joint can result in repeated surgeries. Several clinical and experimental reports suggest the need for further investigations in order to gain insight in the behavior of the reconstructed ligament and related outcome. The present study used mathematical modelling to simulate the knee function in the sagittal plane when the ligaments are intact. The ligaments were separated into fiber bundles similar to those reported in the literature. Such simulations could be used to investigate effects of different tunnel positions during the ligament reconstruction. Knee motion during 0°–120° flexion and an anterior laxity test at different joint positions were simulated. The outcome of the model simulations suggest that anterior fibers of the ligament contribute significantly throughout the knee flexion in resisting anterior forces on the tibia. In comparison, the posterior fibers contribute in near extremes of motion only. The results of model simulations corroborated with experimental observations from literature and have clinical relevance.
References
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TL;DR: The fibre length changes suggested that the 'isometric point' aimed at by some ligament replacements lay anterior and superior to the femoral origin of the intermediate fibre bundle and towards the roof of the intercondylar notch.
Abstract: This work studied the fibre bundle anatomy of the anterior cruciate ligament. Three functional bundles--anteromedial, intermediate, and posterolateral--were identified in cadaver knees. Their contributions to resisting anterior subluxation in flexion and extension were found by repeated tests after sequential bundle transection. Changes of length in flexion and extension and in tibial rotation were measured. None of the fibres were isometric. The posterolateral bundle was stretched in extension and the anteromedial in flexion, which correlated with increased contributions to knee stability and the likelihood of partial ruptures in these positions. Tibial rotation had no significant effect. The fibre length changes suggested that the 'isometric point' aimed at by some ligament replacements lay anterior and superior to the femoral origin of the intermediate fibre bundle and towards the roof of the intercondylar notch.
716 citations
TL;DR: The fascicle material properties in bone-fascicle-bone units were determined for the anterior and posterior cruciate ligaments, the lateral collateral ligament and the patellar tendon from three young human donor knees and no significant differences were present in the maximum strains for any of the four tissue types examined.
489 citations
TL;DR: Return to the preinjury level of sport at 12 months after surgery was not predictive of participation at the pre injury level in the medium term, which suggests that people who return to sport within 12 months may not maintain their sports participation.
Abstract: Background: Most people have not returned to their preinjury level of sports participation at 12 months after anterior cruciate ligament (ACL) reconstruction surgery. Twelve months’ follow-up may be too early to assess return-to-sport outcomes accurately.Purpose: This study was undertaken to evaluate the medium-term return-to-sport outcomes after ACL reconstruction surgery.Study Design: Case series; Level of evidence, 3.Methods: A self-report questionnaire was used to collect data at 2 to 7 years after ACL reconstruction surgery regarding preinjury sports participation, postoperative sports participation, and subjective knee function. The main inclusion criteria were participation in regular sports activity before injury and the attendance at routine surgical follow-up appointments.Results: A total of 314 participants (mean age, 32.5 ± 10.2 years) were included at a mean 39.6 ± 13.8 months after ACL reconstruction surgery. At follow-up, 45% were playing sport at their preinjury level and 29% were playing ...
351 citations
TL;DR: After rupture, the human anterior cruciate ligament undergoes four histological phases, consisting of inflammation, epiligamentous regeneration, proliferation, and remodeling, which is similar to that reported in other dense connective tissues.
Abstract: Background:Four phases in the response to injury of the ruptured human anterior cruciate ligament are observed histologically; these include an inflammatory phase, an epiligamentous repair phase, a proliferative phase, and a remodeling phase. One objective of this study was to describe the h
338 citations
01 Dec 1989
TL;DR: A geometric simulation of the tibio-femoral joint in the sagittal plane is developed which illustrates the central role played by the cruciate ligaments in the kinematics of the knee and which can be used for the analysis of ligament and contact forces.
Abstract: A geometric model of the tibio-femoral joint in the sagittal plane has been developed which demonstrates the relationship between the geometry of the cruciate ligaments and the geometry of the articular surfaces The cruciate ligaments are represented as two inextensible fibres which, with the femur and the tibia, are analysed as a crossed four-bar linkage The directions of the ligaments at each position of flexion are calculated The instant centre, where the flexion axis crosses the parasagittal plane through the joint, lies at the intersection of the cruciates It moves relative to each of the bones during flexion and extension The successive positions of the flexion axis relative to a fixed femur and to a fixed tibia are deduced The shapes of articular surfaces which would allow the bones to flex and extend while maintaining the ligaments each at constant length are calculated and are found to agree closely with the shapes of the natural articular surfaces The calculated movements of the contact point between the femur and the tibia during flexion also agree well with measurements made on cadaver specimens The outcome is a geometric simulation of the tibio-femoral joint in the sagittal plane which illustrates the central role played by the cruciate ligaments in the kinematics of the knee and which can be used for the analysis of ligament and contact forces
161 citations