ABSTRACTSingle‐degree‐of‐freedom (SDOF) systems are a simple but widely used method in engineering to describe mechanical phenomena. Mathematically, a SDOF system can be described by a second‐order differential equation (Newton's second law). In general, the differential equation depends on arbitrary parameters (e.g., spring stiffness, damping, friction), which have to be estimated from measurements. Parameter estimation of such models is still a broad research field, especially for nonlinear systems. A widely used method for parameter estimation is the restoring force method. A robust and computationally effective method for the determination of unknown nonparametric restoring forces (e.g., nonlinear damping) for nonlinear SDOF systems based on measured data will be presented in this work. The parameter estimation problem is formulated as an inverse problem. Inverse problems are almost always ill‐posed. The Inverse problem is transformed into a boundary value problem using the calculus of variation. The ill‐posed problem is then solved efficiently using regularization techniques. Numerical experiments and the derivation of the method showed that a regularization term is necessary to obtain reasonable results. Furthermore, this approach does not require solving a complex and computationally intensive optimization problem. In this work, the method has been successfully demonstrated on a numerical example of a nonlinear SDOF.

Introduction & Purpose Change of direction (COD) movements are a common cause of injuries to the anterior cruciate ligament (ACL), especially in sports such as soccer, basketball, handball (Agel et al., 2016). In Mohr et al., (2024) an 8-week injury prevention training program including COD technique training was investigated. The movements during COD were recorded in an experimental setup with a marker-based system before and after the training program. While Mohr and colleagues observed training effects on the COD movement strategy, it remains unknown whether the ACL forces are actually reduced by the training program. The purpose of this project was to 1) develop a simulation-based approach to estimate ACL forces during COD movements using musculoskeletal simulations (OpenSim) and finite element (FE) knee simulations, and 2) use existing kinematics from a COD movement of one athlete before and after the 8-week injury prevention training program to investigate training effects on ACL force (Mohr et al., 2024). Methods The model OKS008 from the publicly-available collection of Open Knee(s) (OKS) FE models (2nd generation) of the Cleveland Clinic (Chokhandre et al., 2023) was implemented in the FE software Abaqus CAE. In the original OKS008 model (Chokhandre et al., 2023) material parameters and pre-strains were taken from literature. However, the pre-strain of the ligaments is very individual (Lahkar et al., 2021). Therefore, in this study, the pre-strain of the ligaments and four material parameters of the OKS008 model were fit to in vitro kinetic testing data, using an optimization algorithm (interior-point algorithm). The kinetic data from in-vitro tests is available alongside with the OKS knee models, for which all donor knees were mechanically tested during passive flexion experiments (Chokhandre et al., 2023). The optimization was solved based on about 550 FE simulations over the course of one month (AMD Ryzen threadripper 3960 x 24-core processor x 48, 35 cores were used). The effect of the knee kinematics from Mohr and colleagues (2024) on the loading of the anterior cruciate ligament (ACL) was then investigated with the optimized FE knee model in a post-processing step. Inverse kinematics in OpenSim was used to determine the 3D knee joint kinematics of one athlete during a maximum-speed 135° COD movement before and after the injury prevention training program. This athlete was selected because after the 8-week injury prevention training program, he showed a significant reduction in maximum knee adduction moment. The run-up velocity of the athlete on the COD was 3.97 m/s before the training program (baseline) and 4.09 m/s after the training program (follow-up). To simulate the COD movements in Abaqus, the FE knee model was driven by the measured knee kinematics of the COD, where the secondary kinematics (knee adduction and internal rotation) of the OpenSim model were added to the FE model’s secondary kinematics during passive flexion. The resulting force on the ACL was calculated by a free body cut in Abaqus CAE. Results The pre-strain optimized FE knee model closely reproduced the secondary kinematics (abduction, internal rotation) of the donor knee during passive flexion (mean error of 2.1687° before vs. 0.5799° after optimization). The athlete’s maximum ACL force during the COD before the training program was 457 N, while after the training program a reduction in ACL force during the COD to 246 N was observed (46% reduction). The ACL force during the COD before and after the injury prevention training program is shown in Figure 1. Discussion A publicly available FE knee model was successfully optimized based on cadaveric mechanical testing data and implemented into a simulation-based approach to estimate ACL force. The plausibility of the model was checked by a mesh study and comparison with cadaver studies done in Wascher et al. (1993) and Hosseini Nasab et al. (2016). The timing of peak ACL force during a simulated COD movement, between 50 ms and 100 ms after initial contact, is physiologically plausible given that ACL injuries during CODs typically occur around 50 ms after initial contact (Krosshaug et al., 2007). The pre-strain optimization showed that it is necessary to estimate material parameters, e.g. ligament pre-strain, individually for each model to obtain realistic mechanical behaviour. The case study demonstrated a reduction in ACL force during a COD by 46% following an injury prevention training program. The existing kinematic data from Mohr and colleagues (2024) show that the analyzed athlete performed the COD with decreased knee internal rotation and abduction after the 8-week injury prevention training. It is assumed that the ACL force was reduced due to the lower internal rotation and abduction. Figure 1 show further interesting observations that warrant investigation, e.g. the time-shifted peak ACL force following training. This will be done in future studies including more athletes. Importantly, ACL forces during change of direction (COD) were calculated by applying only rotational kinematics to the FE model. The next step will be to implement joint reaction forces (JRF) into the FE simulations because they would have an effect on the ACL force (Esrafilian et al., 2022). It is therefore advisable to include the JRF in the subsequent simulations in order to obtain more physiologically relevant results. Conclusion We developed a FE simulation model in Abaqus CAE of the OKS008 knee to estimate and compare ACL forces based on the existing kinematics of a COD movement. However, individual material parameter estimation is required for each model. The material parameter estimation increases the replicability of the specimen specific mechanical cadaver testing. This is an improvement to the original OKS008 model. For the one analyzed athlete, after the 8-week injury prevention exercise program (Mohr et al., 2024) the ACL force caused by rotational kinematics of a COD is less than before the exercise program. The maximum ACL force during COD is reduced by 46% after the exercise program. References Agel, J., Rockwood, T., & Klossner, D. (2016). Collegiate ACL injury rates across 15 sports: National collegiate athletic association injury surveillance system data update (2004-2005 through 2012-2013). Clinical Journal of Sport Medicine, 26(6), 518-523. https://doi.org/10.1097/JSM.0000000000000290 Chokhandre, S., Schwartz, A., Klonowski, E., Landis, B., & Erdemir, A. (2023). Open knee(s): A free and open source library of specimen-specific models and related digital assets for finite element analysis of the knee joint. Annals of Biomedical Engineering, 51, 10-23. https://doi.org/10.1007/s10439-022-03074-0 Esrafilian, A., Stenroth, L., Mononen, M. E., Vartiainen, P., Tanska, P., Karjalainen, P. A., Suomalainen, J.-S., Arokoski, J. P. A., Saxby, D. J., Lloyd, D. G., & Korhonen, R. K. (2022). Toward tailored rehabilitation by implementation of a novel musculoskeletal finite element analysis pipeline. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 30, 789-802. https://doi.org/10.1109/TNSRE.2022.3159685 Hosseini Nasab, S. H., List, R., Oberhofer, K., Fucentese, S. F., Snedeker, J. G., & Taylor, W. R. (2016). Loading patterns of the posterior cruciate ligament in the healthy knee: A systematic review. PLoS One, 11(11), Article e0167106. https://doi.org/10.1371/journal.pone.0167106 Krosshaug, T., Nakamae, A., Boden, B. P., Engebretsen, L., Smith, G., Slauterbeck, J. R., Hewett, T. E., & Bahr, R. (2007). Mechanisms of anterior cruciate ligament injury in basketball: Video analysis of 39 cases. The American Journal of Sports Medicine, 35(3), 359-67. https://doi.org/10.1177/0363546506293899 Lahkar, B. K., Rohan, P.-Y., Pillet, H., Thoreux, P., & Skalli, W. (2021). Development and evaluation of a new procedure for subject-specific tensioning of finite element knee ligaments. Computer Methods in Biomechanics and Biomedical Engineering, 24(11), 1195-1205. https://doi.org/10.1080/10255842.2020.1870220 Mohr, M., Federolf, P., Heinrich, D., Nitschke, M., Raschner, C., Scharbert, J., & Koelewijn, A. D. (2024). An 8-week injury prevention exercise program combined with change-of-direction technique training limits movement patterns associated with anterior cruciate ligament injury risk. Scientific Reports, 14, Article 3115. https://doi.org/10.1038/s41598-024-53640-w Wascher, D. C., Markolf, K. L., Shapiro, M. S., & Finerman, G. A. (1993). Direct in vitro measurement of forces in the cruciate ligaments. Part I: The effect of multiplane loading in the intact knee. The Journal of Bone and Joint Surgery, 75(3), 377-386. https://doi.org/10.2106/00004623-199303000-00009

Occupational shoulder exoskeletons need to provide meaningful torques to achieve the desired support, thereby high pressures can occur within the physical human–machine interface (pHMI) of exoskeletons that may lead to discomfort, pain, or soft tissue injuries. This pilot study investigates the effects of occurring circumferential pressures within the pHMI in three different shoulder exoskeletons on the tissue oxygenation underneath the interfaces in resting position and dynamic use of the exoskeletons in 12 healthy subjects using near-infrared spectroscopy. Similar to standard Vascular Occlusion Tests, the tissue oxygen decreases while wearing the exoskeletons at rest (−2.1 (1.4) %/min). Dynamic use of the exoskeleton enhances the decrease in tissue oxygen (−7.3 (4.1) %/min) significantly and leads to greater resaturation after reopening the interface compared to resting position. This can be a sign of restricted blood supply to the upper extremity while wearing the exoskeleton. The shape and width of the circular interfaces showed no effect on the tissue oxygenation during use. Tissue oxygenation can be established as an additional safety criterion of exoskeletal pHMIs. The design of pHMI of shoulder exoskeletons should be reconsidered, e.g., in terms of open structures or the elasticity of closure straps to avoid occlusion effects.

The static Euler-Bernoulli beam is a simplified model from linear elasticity theory for small deformations, with which the stresses and deflections of slender beams can be determined very well. The simplicity of Euler-Bernoulli beam theory makes it still an important tool in the sciences, particularly in construction and mechanical engineering. The behavior and the deflection of a static Euler-Bernoulli beam is completely given by the bending stiffness curve. The bending stiffness curve of a real beam structure can be determined using mea-sured data from a bending test. However, the determination of the bending stiffness curve for non-uniform beams leads to a so-called inverse problem, which is ill-posed. In this work, a robust and computationally effective method for determining the bending stiff-ness curve of a non-uniform Euler-Bernoulli beam based on measured data from a static bending test and the calculus of variations is presented. With the calculus of variations, the complex optimization problem of the inverse problem is transformed into a bound-ary value problem, which is then solved by collocation with lower computational costs. In addition, the new method does not require the second derivative of the beam deflection and the problem of determining the bending stiffness at the boundaries does not arise, as with the traditional method. The new method to determine the bending stiffness curve of non-uniform beams is demonstrated in several test examples.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Purpose Dynamic loads like traffic make bridges vibrate. Especially for bridges with a large span, vibrations have a significant impact on their structural stability and durability. Due to material defects, fatigue and other influences, a bridge typically has random structural irregularities, which affect its dynamic response. In this work, an effective mathematical approach is presented to study the dynamic response of a model single span slender beam bridge, in the presence of random structural irregularities. In addition, an approach to assess the structural degradation of a bridge is presented. Methods The slender beam bridge is modelled as an Euler-Bernoulli beam and the random structural irregularities are considered by random fields in the bending stiffness and the mass per unit length. As an illustrative example, the vibrations of a model road bridge are investigated for randomly crossing vehicles. After Monte Carlo experiments with and without random structural irregularities the vibrations and mechanical stresses of the bridge are determined and analysed. Results The study shows statistically significant variations in the most dominant frequencies with and without random structural irregularities. Conclusion The influence of the random irregularities on the structural stability status of a bridge may not be negligible. The probability of a serious structural degradation in the bridge can be assessed by means of a binomial logistic model. The developed approach enables a better understanding of the vibrations and structural status of bridges, taking into account random structural irregularities and random traffic.

Bone and ligament injuries are one of the most common serious injuries in sports. Musculoskeletal simulation models are popular to investigate injury situations on a computer. The existing musculoskeletal simulation models typically consist of a rigid multi-body model (representing the skeleton) and muscles, which actuate the movement of the skeleton. Rigid segments prevent certain mechanical behaviour of bones from being taken into account. Further, bone injuries or effects on the bone structure during the simulated movements cannot be analysed. In this study a computational approach has been developed that allows for investigation of human movements with a simulation model considering the structural behaviour of bones. The rigid bones in the multi-body model have been replaced by Euler-Bernoulli beams. The Euler-Bernoulli beams were included in the simulation model using the floating frame of reference formulation. The developed approach has been applied to simulate a fall from a height of 1.7 m, in which a person lands with the ulna on the ground.

In alpine skiing an athlete's performance or injury mechanisms are strongly influenced by ski vibrations. Ski vibrations are mainly caused by irregularities of the ski-snow interaction (e.g. ripplets and disturbances of the slope, friction between ski and snow). With respect to the ski-snow interaction ski vibrations were not yet considered in computer simulation studies. During this study a planar multibody simulation model of a mono-skier has been developed to investigate transversal vibrations of unedged skis during schussing in the fall line over rough (random) ski slopes. The skis are modelled as dynamic Euler-Bernoulli beams and are incorporated as flexible beams into a multibody skier model. The interaction between skis and snow is modelled by a Kelvin-Voigt constitutive equation for the snow penetration force. The random ripplets and disturbances of the slope are described by random fields, which are generated based on real data obtained from measuring a public ski slope surface with a high resolution laser scanner. By the Monte Carlo simulation method a sequence of runs over random slope surfaces is performed and the ski vibrations of the ski shovel are analysed. The results show that the irregularities on a ski slope contribute considerably to the vibration of a ski and the performance of a skier. Thus, they have to be considered in multibody simulation models of alpine skiing. The developed simulation model will support the understanding of ski vibrations and their causes to improve the run time and to prevent injuries in alpine skiing. The presented simulation model can also be applied to find optimal material parameters to reduce ski vibrations during schussing. This work combines a flexible multibody simulation model and random fields. The implementation of random fields in multibody simulation models admits a more realistic investigation of the mechanical behaviour of complex systems due to random spatial uncertainties in input parameters.

Introduction “Fast-Track” protocols have been introduced in TKA with the intention to increase health care savings while maintaining or improving patient outcomes. The influence of the implant design in a “Fast-Track” setting has not been described yet. The primary goal of this study was to compare a customized implant with standard off-the-shelf (OTS) devices when utilizing a “Fast-Track” protocol Methods Sixty-two (62) patients were prospectively enrolled at a single center and implanted with either a customized or a standard off-the-shelf implant resulting in thirty (30) patients being treated with an OTS design and thirty-two (32) with the customized design. The same institutional fast-track protocol was utilized on all patients and included pre-, intra-, and postoperative medical treatment. We assessed total length of stay (LOS), discharge destination and range of motion at 6-8 weeks post-op and at an average of 16 months post-op follow-up to compare the OTS implant with the customized device. Implant survivorship was assessed at a minimum of 25 months post-op. Results Using the fast track protocol we were able to decrease overall LOS to 2.1 days versus 3.6 days prior to introduction of the protocol. The use of the customized implant further reduced LOS significantly to 1.6 days. Significantly higher number of patients who got implanted with the customized device (66%) were discharged within 24 hours than in the OTS group (30%). Patients treated with the customized implant were found to be discharged home more often than patients treated with the OTS implants (97% vs. 80%) and achieved higher range of motion both at 6-8 weeks (114° vs. 101°) and at an average of 16 months (122° vs. 114°) than patients who got treated with the OTS device. At an average follow-up of 28 months, there was 1 implant revision in the customized group (due to tibial fracture resulting from patient fall). For the OTS group there was 1 implant revision (late infection) and 1 poly swap (due to instability). Discussion Based on our analysis we observed a positive influence of the customized device on patient outcomes and hospital metrics and we therefore conclude that the implant choice is an important factor for TKA in a “fast-track” setting.

AbstractIn alpine skiing the vibrations of the skis influence the performance of a skier considerably. An alpine ski can be modelled as an Euler‐Bernoulli beam with which the vibrations of the ski can be analysed mathematically. The main characterising property of a ski is its bending stiffness, which can be measured in the lab. Since a ski is a composite material the measured bending stiffness shows variations. These variations can be taken into account by adding a random field to an average bending stiffness. An experiment of a clamped ski is investigated theoretically.

INTRODUCTIONPost-operative infections following end-stage joint salvage reconstruction, tumor resection and megaprosthetic reconstruction is a major problem because of increasing infection rates in...

ACL-injuries are one of the most common knee injuries in noncontact sports. Kinematic data of injury prone situations provide important information to study the underlying ACL-injury mechanisms. However, these data are rare. In this work an approach is presented to generate injury prone situations for noncontact ACL-injuries on a computer. The injury prone situations are generated by a musculoskeletal simulation model using kinematic data of a non-injury situation and the method of Monte Carlo simulation. The approach is successfully applied to generate injury prone landings in downhill ski racing. The characteristics of the obtained injury prone landings are consistent with video recordings of injury cases.

Background: Among recreational skiers, ACL injury risk is about three times greater in females compared to males and female skiers suffering from ACL injury reported about 20

A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The purpose of this study is to investigate the effect of different SBRS on the maximal ACL tensile forces during injury prone landings considering muscle forces by a two-dimensional musculoskeletal simulation model. Injury prone situations for ACL-injuries were generated by the musculoskeletal simulation model using measured kinematics of a non-injury situation and the method of Monte Carlo simulation. Subsequently, the SBRS was varied for injury prone landings. The maximal ACL tensile forces and contributing factors to the ACL forces were compared for the different SBRS. In the injury prone landings the maximal ACL tensile forces increased with increasing SBRS. It was found that the higher maximal ACL force was caused by higher forces acting on the tibia by the boot and by higher quadriceps muscle forces both due to the higher SBRS. Practical experience suggested that the reduction of SBRS is not accepted by ski racers due to performance reasons. Thus, preventive measures may concentrate on the reduction of the quadriceps muscle force during impact.

Rasante Fortschritte bei der Entwicklung von Speichermedien ermöglichen die Erfassung riesiger Datenmengen. Diese liefern bei systematischer Auswertung neue Möglichkeiten zur Bestimmung von Ermüdungslasten für Eisenbahnbrücken. Während bisher die Bildung von Lastkollektiven über vorab definierte Regelzüge und eine darauf basierende Verkehrszusammensetzung die übliche Herangehensweise war, kann die Lastkollektivbildung jetzt deutlich genauer in Kombination mit Einwirkungsdaten über längere Zeiträume gelöst werden, wenn auch rechenintensiver. Dieser Artikel zeigt praktische Ergebnisse dieser neuen Herangehensweise zur Lastkollektivbildung anhand systematischer Berechnungen am Einfeldträger samt kurzen theoretischen Erläuterungen. Die dabei von den Österreichischen Bundesbahnen zur Verfügung gestellten Achslastmessdaten liefern teils erhebliche Unterschiede zu den normativen Werten. Zudem werden für die Konstruktion relevante Anwendungsmöglichkeiten der berechneten Ergebnisse gezeigt. Teil 1 befasst sich dabei ausschließlich mit dem Schadensäquivalenzfaktor λ 1 , während Teil 2 die Schadensäquivalenzfaktoren λ 2 und λ 3 sowie den Grenzwert λ max und ein Modell zur Berücksichtigung von Verkehrsveränderungen beinhaltet.

Dear Editor-in-chief Knee sleeves or braces represent auxiliary tools that have repeatedly been used by athletes, in an attempt to increase knee stability and, thus, reduce the risk of (recurrent) ligamentous injuries. Since ACL injuries typically occur in situations involving either torsion or hyperextension of the knee, it has been speculated that braces might protect the ACL by countering excessive anterior translation of the tibia with respect to the femur (Beynnon et al., 1997). However, the preponderance of in vivo studies to test this hypothesis was performed in cohorts of patients suffering from existent ligamentous (Branch et al., 1988; Colville et al., 1986) or other knee injury (Beynnon et al., 1997; Fleming et al., 2000). This complicates the extrapolation of results to healthy subjects. Further, the braces used in these studies were mostly rigid constructs that consisted of either uni- or bilateral hinged bars (Rishiraj et al., 2009). Such braces might hinder performance (Veldhuizen et al., 1991) and would be rejected by the vast majority of healthy athletes. For these reasons, we would like to use this letter to the editor to report the results of our experiments investigating whether a relatively light elastic knee sleeve would limit the degree of anterior tibial translation in computerized arthrometry tests as performed in a sample of non-injured subjects. We recruited ten female college students (age: 23.4 ± 3.2 yrs, height: 1.68 ± 0.05 m, mass: 59.9 ± 5.5 kg) who were free of acute or previous injury or any form of orthopaedic disease of the knee joints. The anterior displacement of the tibia was measured using the GNRB® computerized arthrometer (GeNouRob, Laval, France). With subjects lying in the supine position, the lower leg was firmly fixed with plastic caps mounted over the ankle joint and patella. An electrical pressure pad then exerted increasing pressure of up to 250 N on the calf, while a motion sensor, which was positioned on the ventral aspect of the shank, just distal of the patella, recorded the anterior displacement of the tibia. Displacements were continuously recorded but only the discrete values coinciding with 50, 100, 150, 200 and 250 N were extracted for statistical analyses. The GNRB® system features a measurement accuracy of 0.1 mm and has been shown to be a valid tool for measurements of anterior knee laxity (Jenny et al., 2013). To control inadvertent coactivation of hamstring muscles, which may bias the results of arthrometry measurements (Steele et al., 1994), the integrated electromyographic (EMG) activity of the biceps femoris and semitendinosus muscle was simultaneously recorded and normalized to additional recordings obtained during maximal voluntary contraction (MVC). These tests confirmed that, during arthrometry measurements, the EMG activities of biceps femoris and semitendinosus muscle were negligible and remained below 3% of MVC levels at all times. To assess measurement reliability, tests were repeated twice under both experimental conditions: first without and then after application of a light elastic knee sleeve (Cellacare Genu, Lohmann & Rauscher, Rengsdorf, Germany). According to the manufacturer’s information, this sleeve can be used for a variety of indications including injury prevention. Test-retest reliability of arthrometry measurements was excellent, as reflected by low typical measurement errors (0.08 mm) and high correlation coefficients (r = 0.99, p < 0.001). Analysis of results (Figure 1) by factorial ANOVA revealed that the elastic sleeve tested in this study reduced the anterior displacement of the tibia by a small (max. 0.7 mm on average) yet statistically significant amount (F(1,9) = 22.88, p = 0.001, r = 0.98). In an attempt to better understand the degree of protection provided by the sleeve, we determined its material properties by appending weight discs (2.5-15 kg, in steps of 2.5 kg) to its dorsal aspect and measuring the resulting elongation. The resulting force-elongation relationship was found to be linear (R2 = 0.99), with a slope (i.e., the stiffness of the sleeve) of 2 N·mm-1. Thus, at an elongation of 6.5 mm (roughly coinciding with the maximal anterior tibial translation observed in our study), the sleeve would provide a resistive force of ~13 N countering the shear force pushing the tibia anteriorly. However, significant “force × sleeve” interaction effects (F(0.34,0.09) = 11.53, p < 0.001) also demonstrated that the degree by which the sleeves affected measurement results was dependent on the level of force. With rising force, differences between experimental conditions increased in absolute (from 0.2 to 0.7 mm), yet decreased in relative terms (from 27 to 7%). In this regard, it is important to note that the force exerted on the tibia (max. 250 N) in this study coincides with ACL forces that are well below the range at which ligament tears typically occur. Extrapolation of our data to weight bearing situations, which are characterized by active muscle contraction and significantly greater ACL forces, is complicated so it is not currently clear whether elastic knee sleeves would provide clinically relevant protection to the ACL when subject to excessive loads. In regular movements that induce principally uncritical ACL strains, however, elastic knee sleeves might assist hamstring muscles in countering anterior tibial displacement, thus postponing the onset of muscular fatigue. This hypothesis is subject of ongoing research in our laboratory. Figure 1. Anterior tibial translation in dependency of the shear force acting on the tibia and usage of an elastic knee sleeve. Note: Displacements coinciding with 50, 100, 150, 200 and 250 N of force were extracted for statistical analysis and fitted by linear ... In conclusion, our results demonstrate that usage of an elastic knee sleeve reduces anterior tibial translation in healthy subjects by a small, yet statistically significant amount. Further, the protective effect appeared to be load-dependent, with larger effects seen at greater forces.

Since the introduction of the original cementing technique introduced by Charnley in 1960, the use of polymethylmethacrylate (PMMA) for cementing the femoral component has become one of the most frequent and successful procedures in orthopedic surgery. The early results of Charnley have become the “gold standard” by which the results of modern component designs and fixation methods are compared.