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The American Journal of Sports Medicine Jun 2023Overuse ligament and tendon injuries are prevalent among recreational and competitive adolescent athletes. In vitro studies of the ligament and tendon suggest that...
BACKGROUND
Overuse ligament and tendon injuries are prevalent among recreational and competitive adolescent athletes. In vitro studies of the ligament and tendon suggest that mechanical overuse musculoskeletal injuries begin with collagen triple-helix unraveling, leading to collagen laxity and matrix damage. However, there are little in vivo data concerning this mechanism or the physiomechanical response to collagen disruption, particularly regarding the anterior cruciate ligament (ACL).
PURPOSE
To develop and validate a novel in vivo animal model for investigating the physiomechanical response to ACL collagen matrix damage accumulation and propagation in the ACL midsubstance, fibrocartilaginous entheses, and subchondral bone.
STUDY DESIGN
Controlled laboratory study.
METHODS
C57BL/6J adolescent inbred mice underwent 3 moderate to strenuous ACL fatigue loading sessions with a 72-hour recovery between sessions. Before each session, randomly selected subsets of mice (n = 12) were euthanized for quantifying collagen matrix damage (percent collagen unraveling) and ACL mechanics (strength and stiffness). This enabled the quasi-longitudinal assessment of collagen matrix damage accrual and whole tissue mechanical property changes across fatigue sessions. Additionally, all cyclic loading data were quantified to evaluate changes in knee mechanics (stiffness and hysteresis) across fatigue sessions.
RESULTS
Moderate to strenuous fatigue loading across 3 sessions led to a 24% weaker ( = .07) and 35% less stiff ( < .01) ACL compared with nonloaded controls. The unraveled collagen densities within the fatigued ACL and entheseal matrices after the second and third sessions were 38% ( < .01) and 15% ( = .02) higher compared with the nonloaded controls.
CONCLUSION
This study confirmed the hypothesis that in vivo ACL collagen matrix damage increases with tissue fatigue sessions, adversely impacting ACL mechanical properties. Moreover, the in vivo ACL findings were consistent with in vitro overloading research in humans.
CLINICAL RELEVANCE
The outcomes from this study support the use of this model for investigating ACL overuse injuries.
Topics: Humans; Adolescent; Mice; Animals; Anterior Cruciate Ligament; Mice, Inbred C57BL; Anterior Cruciate Ligament Reconstruction; Knee Joint; Anterior Cruciate Ligament Injuries; Collagen; Cumulative Trauma Disorders; Biomechanical Phenomena
PubMed: 37092727
DOI: 10.1177/03635465231165753 -
Arthroscopy : the Journal of... Oct 2013To determine whether the basic science evidence supports the use of continuous passive motion (CPM) after articular cartilage injury in the knee. (Review)
Review
PURPOSE
To determine whether the basic science evidence supports the use of continuous passive motion (CPM) after articular cartilage injury in the knee.
METHODS
A systematic review was performed identifying and evaluating studies in animal models that focused on the basic science of CPM of the knee. Databases included in this review were PubMed, Biosis Previews, SPORTDiscus, PEDro, and EMBASE. All functional, gross anatomic, histologic, and histochemical outcomes were extracted and analyzed.
RESULTS
Primary outcomes of CPM analyzed in rabbit animal models (19 studies) included histologic changes in articular cartilage (13 studies), biomechanical changes and nutrition of intra-articular tissue (3 studies), and anti-inflammatory biochemical changes (3 studies). Nine studies specifically examined osteochondral defects, 6 of which used autogenous periosteal grafts. Other pathologies included were antigen-induced arthritis, septic arthritis, medial collateral ligament reconstruction, hemarthrosis, and chymopapain-induced proteoglycan destruction. In comparison to immobilized knees, CPM therapy led to decreased joint stiffness and complications related to adhesions while promoting improved neochondrogenesis with formation and preservation of normal articular cartilage. CPM was also shown to create a strong anti-inflammatory environment by effectively clearing harmful, inflammatory particles from within the knee.
CONCLUSIONS
Current basic science evidence from rabbit studies has shown that CPM for the knee significantly improves motion and biological properties of articular cartilage. This may be translated to potentially improved outcomes in the management of articular cartilage pathology of the knee.
CLINICAL RELEVANCE
If the rabbit model is relevant to humans, CPM may contribute to improved knee health by preventing joint stiffness, preserving normal articular tissue with better histologic and biologic properties, and improving range of motion as compared with joint immobilization and intermittent active motion.
Topics: Animals; Arthritis; Biomechanical Phenomena; Cartilage, Articular; Joint Diseases; Knee Joint; Models, Animal; Motion Therapy, Continuous Passive; Rabbits; Range of Motion, Articular; Recovery of Function
PubMed: 23890952
DOI: 10.1016/j.arthro.2013.05.028 -
Scientific Reports Jun 2023Inter-segmental moments come from muscles contractions, but also from passive moments, resulting from the resistance of the periarticular structures. To quantify the...
Inter-segmental moments come from muscles contractions, but also from passive moments, resulting from the resistance of the periarticular structures. To quantify the passive contribution of uni- and biarticular structures during gait, we propose an innovative procedure and model. 12 typically developed (TD) children and 17 with cerebral palsy (CP) participated in a passive testing protocol. The relaxed lower limb joints were manipulated through full ranges of motion while kinematics and applied forces were simultaneously measured. The relationships between uni-/biarticular passive moments/forces and joint angles/musculo-tendon lengths were modelled by a set of exponential functions. Then, subject specific gait joint angles/musculo-tendon lengths were input into the determined passive models to estimate joint moments and power attributable to passive structures. We found that passive mechanisms contribute substantially in both populations, mainly during push-off and swing phases for hip and knee and push-off for the ankle, with a distinction between uni- and biarticular structures. CP children showed comparable passive mechanisms but larger variability than the TD ones and higher contributions. The proposed procedure and model enable a comprehensive assessment of the passive mechanisms for a subject-specific treatment of the stiffness implying gait disorders by targeting when and how passive forces are impacting gait.
Topics: Child; Humans; Lower Extremity; Ankle Joint; Cerebral Palsy; Gait; Knee Joint
PubMed: 37386101
DOI: 10.1038/s41598-023-37357-w -
Journal of Biomechanics Apr 2017Simulating realistic musculoskeletal dynamics is critical to understanding neural control of muscle activity evoked in sensorimotor feedback responses that have inherent...
Simulating realistic musculoskeletal dynamics is critical to understanding neural control of muscle activity evoked in sensorimotor feedback responses that have inherent neural transmission delays. Thus, the initial mechanical response of muscles to perturbations in the absence of any change in muscle activity determines which corrective neural responses are required to stabilize body posture. Muscle short-range stiffness, a history-dependent property of muscle that causes a rapid and transient rise in muscle force upon stretch, likely affects musculoskeletal dynamics in the initial mechanical response to perturbations. Here we identified the contributions of short-range stiffness to joint torques and angles in the initial mechanical response to support surface translations using dynamic simulation. We developed a dynamic model of muscle short-range stiffness to augment a Hill-type muscle model. Our simulations show that short-range stiffness can provide stability against external perturbations during the neuromechanical response delay. Assuming constant muscle activation during the initial mechanical response, including muscle short-range stiffness was necessary to account for the rapid rise in experimental sagittal plane knee and hip joint torques that occurs simultaneously with very small changes in joint angles and reduced root mean square errors between simulated and experimental torques by 56% and 47%, respectively. Moreover, forward simulations lacking short-range stiffness produced unreasonably large joint angle changes during the initial response. Using muscle models accounting for short-range stiffness along with other aspects of history-dependent muscle dynamics may be important to advance our ability to simulate inherently unstable human movements based on principles of neural control and biomechanics.
Topics: Adult; Biomechanical Phenomena; Hip Joint; Humans; Kinetics; Knee Joint; Male; Mechanical Phenomena; Movement; Muscles; Postural Balance; Torque; Young Adult
PubMed: 28259465
DOI: 10.1016/j.jbiomech.2017.02.008 -
IEEE Transactions on Bio-medical... Sep 2012During natural locomotion, the stiffness of the human knee is modulated continuously and subconsciously according to the demands of activity and terrain. Given modern...
During natural locomotion, the stiffness of the human knee is modulated continuously and subconsciously according to the demands of activity and terrain. Given modern actuator technology, powered transfemoral prostheses could theoretically provide a similar degree of sophistication and function. However, experimentally quantifying knee stiffness modulation during natural gait is challenging. Alternatively, joint stiffness could be estimated in a less disruptive manner using electromyography (EMG) combined with kinetic and kinematic measurements to estimate muscle force, together with models that relate muscle force to stiffness. Here we present the first step in that process, where we develop such an approach and evaluate it in isometric conditions, where experimental measurements are more feasible. Our EMG-guided modeling approach allows us to consider conditions with antagonistic muscle activation, a phenomenon commonly observed in physiological gait. Our validation shows that model-based estimates of knee joint stiffness coincide well with experimental data obtained using conventional perturbation techniques. We conclude that knee stiffness can be accurately estimated in isometric conditions without applying perturbations, which presents an important step toward our ultimate goal of quantifying knee stiffness during gait.
Topics: Adult; Biomechanical Phenomena; Electromyography; Humans; Joint Diseases; Knee Joint; Male; Models, Biological; Muscle, Skeletal; Reproducibility of Results; Signal Processing, Computer-Assisted; Torque
PubMed: 22801482
DOI: 10.1109/TBME.2012.2207895 -
PloS One 2023The surface effects on running biomechanics have been greatly investigated. However, the effects on rearfoot strike runners remain unknown. The purpose of this study was...
The surface effects on running biomechanics have been greatly investigated. However, the effects on rearfoot strike runners remain unknown. The purpose of this study was to investigate the effects of surfaces on the running kinematics, kinetics, and lower-limb stiffness of habitual rearfoot strikers. Thirty healthy male runners were recruited to run at 3.3 ± 0.2 m/s on a customized runway covered with three different surfaces (artificial grass, synthetic rubber, or concrete), and their running kinematics, kinetics, and lower-limb stiffness were compared. Differences among the three surfaces were examined using statistical parametric mapping and one-way repeated-measure analysis of variance. There were no statistical differences in the lower-limb joint motion, vertical ground reaction force (GRF), loading rates, and lower-limb stiffness when running on the three surfaces. The braking force (17%-36% of the stance phase) and mediolateral GRF were decreased when running on concrete surface compared with running on the other two surfaces. The moments of ankle joint in all three plane movement and frontal plane hip and knee joints were increased when running on concrete surface. Therefore, habitual rearfoot strikers may expose to a higher risk of running-related overuse injuries when running on a harder surface.
Topics: Male; Humans; Biomechanical Phenomena; Foot; Lower Extremity; Ankle Joint; Knee Joint
PubMed: 36947495
DOI: 10.1371/journal.pone.0283323 -
PloS One 2022Quasi-stiffness characterizes the dynamics of a joint in specific sections of stance-phase and is used in the design of wearable devices to assist walking. We sought to...
Quasi-stiffness characterizes the dynamics of a joint in specific sections of stance-phase and is used in the design of wearable devices to assist walking. We sought to investigate the effect of simulated reduced gravity and walking speed on quasi-stiffness of the hip, knee, and ankle in overground walking. 12 participants walked at 0.4, 0.8, 1.2, and 1.6 m/s in 1, 0.76, 0.54, and 0.31 gravity. We defined 11 delimiting points in stance phase (4 each for the ankle and hip, 3 for the knee) and calculated the quasi-stiffness for 4 phases for both the hip and ankle, and 2 phases for the knee. The R2 value quantified the suitability of the quasi-stiffness models. We found gravity level had a significant effect on 6 phases of quasi-stiffness, while speed significantly affected the quasi-stiffness in 5 phases. We concluded that the intrinsic muscle-tendon unit stiffness was the biggest determinant of quasi-stiffness. Speed had a significant effect on the R2 of all phases of quasi-stiffness. Slow walking (0.4 m/s) was the least accurately modelled walking speed. Our findings showed adaptions in gait strategy when relative power and strength of the joints were increased in low gravity, which has implications for prosthesis and exoskeleton design.
Topics: Ankle; Ankle Joint; Biomechanical Phenomena; Gait; Humans; Hypogravity; Knee Joint; Walking; Walking Speed
PubMed: 35944021
DOI: 10.1371/journal.pone.0271927 -
Annals of the Rheumatic Diseases Oct 1979One hundred consecutive cases of osteoarthritis seen in a medical clinic have been reviewed and contrasted with 100 patients with rheumatoid disease. Osteoarthritis was... (Comparative Study)
Comparative Study
One hundred consecutive cases of osteoarthritis seen in a medical clinic have been reviewed and contrasted with 100 patients with rheumatoid disease. Osteoarthritis was usually a polyarticular disease and as symmetrical in distribution as rheumatoid; the knees and hands were the most commonly involved sites. Evidence of inflammation was often found in patients with osteoarthritis and included morning stiffness, redness of distal interphalangeal joints, warmth, and effusions in the knees. In many cases there was either radiological or electron microscopical evidence of deposition of calcium salts. These findings do not support the concept of osteoarthritis as a mechanical, noninflammatory 'wear and tear' condition. An active metabolic abnormality of articular cartilage resulting in cartilage destruction, calcification, and inflammation is suggested as being more compatible with the findings.
Topics: Arthritis, Rheumatoid; Calcinosis; Female; Finger Joint; Humans; Knee Joint; Male; Middle Aged; Osteoarthritis; Shoulder Joint; Synovial Fluid; Time Factors
PubMed: 518141
DOI: 10.1136/ard.38.5.423 -
Journal of Neurology, Neurosurgery, and... Sep 1995Torque-angle relations at the elbow and ankle joints of relaxed normal controls and patients with hemiparetic stroke were compared. Low velocity flexion/hold/extension...
Torque-angle relations at the elbow and ankle joints of relaxed normal controls and patients with hemiparetic stroke were compared. Low velocity flexion/hold/extension angular perturbations were applied to the joint under examination. The resulting torque-angle profiles described a hysteresis loop with similar slopes during the extension and flexion stages but separated by a vertical torque offset. Torque-angle responses obtained in the absence of significant muscle activation, as recorded by surface electromyographic activity, were designated as passive. Elbow passive stiffness estimates were calculated from the slope of the torque-angle response during the flexion stage of the perturbation. The elbow torque-angle plots exhibited linear passive stiffness with magnitude significantly lower than the passive stiffness of the ankle in both normal subjects and spastic patients. Changing ramp velocity had no significant effect on the passive torque-angle hysteresis loop at the elbow. A comparison of the torque-angle relations between hemiparetic spastic and normal control arms showed no significant differences in passive stiffness. Furthermore, no significant differences were found between paretic and contralateral upper limbs of a given hemiparetic subject. By contrast, significant differences in the torque-angle hysteresis loop were present between the paretic and contralateral ankles in all hemiparetic patients tested. These differences were more significant during dorsiflexion, and therefore seem to be related to preferential changes in mechanical properties of plantar flexor muscles. It is hypothesised that the differences in the torque-angle hysteresis loop between elbow and angle joints are related primarily to the larger amount of connective tissue in the calf muscles, as well as to a larger total physiological cross sectional area of calf muscles compared with elbow muscles. It is further hypothesized that the preferential increases in passive stiffness at the ankle in spastic legs result from immobilisation induced changes in muscle connective tissue, which are most prominent in muscles with predominantly slow-twitch fibres (such as soleus). Connective tissue surrounding such slow twitch muscle fibres have been shown to be more sensitive to immobilisation than those in fast twitch muscle. The functional, pathophysiological, and clinical implications of our findings are reviewed.
Topics: Ankle Joint; Cerebrovascular Disorders; Elbow Joint; Electromyography; Functional Laterality; Humans; Muscle Spasticity; Paresis
PubMed: 7673955
DOI: 10.1136/jnnp.59.3.271 -
Acta Reumatologica Portuguesa 2010Articular cartilage is a main component of the synovial joints that provides a low friction surface in joint motion and, during locomotion and standing distributes the... (Review)
Review
Articular cartilage is a main component of the synovial joints that provides a low friction surface in joint motion and, during locomotion and standing distributes the load applied to the joint, therefore minimizing the stresses on the subchondral bone. One of the initial sign of Osteoarthritis (OA) consists in the degeneration of the extracellular matrix of articular cartilage leading to a progressive failure in the biomechanical properties of cartilage, compromising its full functionality. Because osteoarthritis is one of the most common diseases in humans, is highly prevalent in clinical rheumatology and its pathophysiology based on changes of cartilage, it is important for rheumatologists and physicians interested in this area are updated with regard to its structure, composition and key regulatory mechanisms. Thus, this article intends to make an updated review of the structure and histochemical composition of normal cartilage, from which depends the viscoelasticity and dynamic stiffness to compression properties. Furthermore, the nonhomogeneous stratified architecture in the typical four layers, as well as the main macromolecules of the solid matrix, collagen and proteoglicans are described. Finally, a description of the chondrocytes at their ultrastructural level, variations with depth of cartilage and metabolism is done.
Topics: Cartilage, Articular; Chondrocytes; Collagen; Humans; Proteoglycans
PubMed: 21245810
DOI: No ID Found