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Tibiofemoral joint contact model Tibio-femoral joint contact model (right leg) used to estimate medial compartment loads (FMC). The patella is not shown. Net moments about the lateral tibial contact point (MMTULC+MextLC) were divided by the intercondylar distance (dIC).
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Background
The muscle-tendon properties of the semitendinosus (ST) and gracilis (GR) are substantially altered following tendon harvest for the purpose of anterior cruciate ligament reconstruction (ACLR). This study adopted a musculoskeletal modelling approach to determine how the changes to the ST and GR muscle-tendon properties alter their contri...
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Background:
Musculoskeletal models do not include patient-specific muscle forces but rely on a scaled generic model, with muscle forces left unscaled in most cases. However, to use musculoskeletal simulations to inform clinical decision-making in children with cerebral palsy (CP), inclusion of subject-specific muscle forces is of utmost importance...
Citations
... The activations of GMIN, GMAX, PEC, and SAR are to ensure the stability of the hip joint and pelvis during walking 25 , so that the trunk and lower limbs are firmly associated with each other during gait. Furthermore, GRA activation can stabilize the external moment to maintain body stability during walk 26 . The greater activations of pelvic and thigh muscles following Δ2℃ of T oral during obstacle crossing at 20% and 30% of obstacle heights could be due to the fact that greater lower limb simulated muscle activation are necessary to compensate the reduction of ankle proprioception due to hyperthermia 5 . ...
It is well known that hyperthermia greatly impairs neuromuscular function and dynamic balance. However, whether a greater level of hyperthermia could potentially alter the lower limb simulated muscle activation when crossing an obstacle in female participants remains unknown. Therefore we examined the effect of a systematic increase in oral temperature on lower limb simulated muscle activation when crossing an obstacle in female participants. Eighteen female participants were recruited where they underwent a control trial (Con) and two progressive passive heating trials with Δ 1°C and Δ 2°C increase of oral temperature (Toral) using a 45°C water bath. In each trial, we assessed lower limb simulated muscle activation when crossing an obstacle height of 10%, 20%, and 30% of the participant’s leg length and toe-off, toe-above-obstacle and heel-strike events were identified and analyzed. In all events, the lower limb simulated muscle activation were greater in Δ2°C than Δ1°C and Con when both leading and trailing limbs crossed the obstacle height of 20% and 30% leg length (all p < 0.001). However, the lower limb simulated muscle activation were not different between Δ1°C and Con across all obstacle heights (p > 0.05). This study concluded that a greater level of hyperthermia resulted in a greater lower limb simulated muscle activation to ensure safety and stability when females cross an obstacle height of 20% leg length or higher.
... For instance, Tampere et al. (Tampere et al., 2021) demonstrated reduced muscle activation in the semitendinosus and increased muscle activation of BFlh among patients who underwent ACL-R with HT autograft, as compared to healthy individuals, implying a compensatory mechanism. Furthermore, Konrath et al. (Konrath et al., 2017) proposed based on an electromyography-driven musculoskeletal model, that changes in morphological properties of semitendinosus muscle and tendon resulted in a decreased contribution to medial knee stability during running and cutting. However, this reduction was effectively compensated by the semimembranosus muscle (Konrath et al., 2017). ...
... Furthermore, Konrath et al. (Konrath et al., 2017) proposed based on an electromyography-driven musculoskeletal model, that changes in morphological properties of semitendinosus muscle and tendon resulted in a decreased contribution to medial knee stability during running and cutting. However, this reduction was effectively compensated by the semimembranosus muscle (Konrath et al., 2017). ...
... This decrease in activation was associated with an increase in semimembranous activation of 22%. They hypothesized that these reductions in activation are compensated by an increase in that of the gastrocnemius and semimembranosus (14). In addition, Rhim et al. showed the role of the triceps surae in ACLR patients 1 year postoperatively, as a compensatory mechanism. ...
Introduction: The main objective of this study was to evaluate whether running after anterior cruciate ligament reconstruction (ACLR) resulted in increased muscular activity of the gastrocnemius medialis and gastrocnemius lateralis compared to running in healthy participants. The secondary objective was to assess whether these changes in muscular activity correspond to changes in cadence, vertical stiffness, flight time and ground contact time while running.
Methods: This pilot case-control study included 7 patients with hamstring graft at 6 postoperative months (208.7 days ± 34.6) and 8 healthy athletes with no knee injury history. Two groups were formed, an ACLR group (n=7) and a control group (n=8). After maximal voluntary isometric contraction (MVIC) assessment, both groups performed treadmill running assessment with Optogait®. After a 6 minutes warm up on a treadmill at 10 km.h-1, (1) 30 sec were recorded to measure the surface electromyographical activity (EMG) of the GM and GL. (2,3) After root mean square (RMS) treatment of the raw signal, RMS EMG results were normalized by MVIC activity to allow inter-subject comparability.
Results: Between-group analyses showed a significant increase in RMS EMG for the ACLR group compared to the control group for the GM (34.7%MVIC ± 11.0 vs 25.5%MVIC ± 13.0, p = 0.05, Effect Size = 0.52) and the GL (32.8%MVIC ± 10.6 vs 17.2%MVIC ± 6.30, p < 0.01, Effect Size = 0.78). Significant correlation was observed in the ACLR group with GL RMS EMG for ground contact time (r = 0.84; p = 0.02). However, there were no significant correlations with cadence (r = 0.50; p = 0.27), vertical stiffness (r = 0.50; p = 0.27) and flight time (r = 0.02; p = 0.97). No significant correlations were observed in the ACLR group with GM RMS EMG.
Conclusion: These findings indicate that ACLR subjects presented with higher GM and GL activity while running compared to the control group. The overuse of these muscles may play a role in the alteration of spatiotemporal parameters of running after ACLR.
... 2 3 The semitendinosus and/or gracilis tendons do not regenerate in ~30% of ACLR patients. 4 Moreover, ACLR patients often have long-term deficits in knee flexor and internal rotator strength, [5][6][7] as well as altered knee biomechanics, [8][9][10] muscle activation patterns [11][12][13] and knee function (patient-reported outcomes measure, PROM). 14 15 These chronic deficits in knee function are thought due, in part, to ...
Introduction
Anterior cruciate ligament (ACL) rupture is debilitating, often requiring surgical reconstruction. An ACL reconstruction (ACLR) using a tendon autograft harvested from the semitendinosus results in substantial injury to the donor muscle. Following ACLR, patients rarely return to their preinjury level of physical activity, are at elevated risk of secondary lower limb injuries and early onset knee osteoarthritis. To date, no randomised controlled trial has evaluated the efficacy of platelet-rich plasma (PRP) in aiding knee function and semitendinosus morphology of following ALCR.
Methods and analysis
This is a multicentre double-blind randomised placebo-controlled trial. Fifty-four ACLR patients aged 18–50 years will be randomised to receive either a single application of PRP (ACLR+) or placebo saline (ACLR) into the semitendinosus harvest zone at the time of surgery. All patients will undergo normal postoperative rehabilitation recommended by the attending orthopaedic surgeon or physiotherapist. The primary outcome measure is between-limb difference (ACLR compared with intact contralateral) in isometric knee flexor strength at 60 o knee flexion, collected 10–12 months postsurgery. This primary outcome measure will be statistically compared between groups (ACLR+ and standard ACLR). Secondary outcome measures include bilateral assessments of hamstring muscle morphology via MRI, biomechanical and electromyographic parameters during an anticipated 45° running side-step cut and multidirectional hopping task and patient-reported outcomes questionaries. Additionally, patient-reported outcomes questionaries will be collected before (baseline) as well as immediately after surgery, and at 2–6 weeks, 3–4 months, 10–12 months and 22–24 months postsurgery 10–12 months following surgery.
Ethics and dissemination
Ethics approval has been granted by Griffith University Human Research Ethics Committee, Greenslopes Research and Ethics Committee, and Royal Brisbane & Women’s Hospital Human Research Ethics Committee. Results will be submitted for publication in a peer-reviewed medical journal.
Trial registration number
ACTRN12618000762257p.
... Moreover, the anabolic effects of moderate cyclic loading can be enhanced with growth factor supplementation (such as IGF-1) [180]. In contrast, a high loading frequency [181][182][183][184] or static loading, underloading (e.g., after ACL reconstruction [185,186]), or a lack of movement are suggested to be disadvantageous for cartilage function [103,184,187]. Finally, supra-physiological injurious loading (such as 50% strain with 100%/s strain rate [46,168,188]) and excessive cyclic loading (>30% axial strain [46,143]) are detrimental and may cause inflammation-like cell responses (such as the release of MMPs [158] and biomechanical strain threshold-dependent TNF-α expression [143]), trigger morphological changes in near-lesion cells [189], and even cause cell death [188,190,191]. ...
Osteoarthritis is a debilitating musculoskeletal whole-joint disease affecting the quality of life of over 340 million people globally. One of the most common disease sites is the knee joint. The disease is characterized by degradation of the articular cartilage covering the ends of bones. Degraded cartilage exhibits detrimental changes in its structure and composition, such as loss of proteoglycans (PG). The changes compromise the functioning of the cartilage. Ultimately, articular cartilage degradation leads to pain, joint space narrowing, joint stiffness, and a restricted range of motion, rendering the disease as a leading cause of disability. The disease phenotype initiated by traumatic injuries, i.e. post-traumatic osteoarthritis (PTOA), has been suggested to be triggered by two intertwined mechanisms: (1) biomechanics-related degradation resulting from impact damage, injuries, joint overloading, as well as mechanical shearing and wearing of cartilage, and (2) inflammation-related changes in cellular behavior and subsequent biochemical degradation.
These two fundamental mechanisms of cartilage degradation and their dynamics are not fully understood. As a result, the current clinical treatment options are limited, diagnosis is delayed to the late phases of the disease where extensive and irreparable degradation has already occurred, and there are no known ways to restore cartilage back to its healthy state. The endeavors to treat symptoms, but not the causes, are also expensive. Therefore, the best and most cost-effective cure would be prevention. In order to achieve this goal, there is a need for a novel computational framework capable of predicting the progression of PTOA.
Computational models incorporating biomechanical cartilage degradation mechanisms have recently been a focus of interest. However, there is a myriad of evidence underlining the importance of biochemical mechanisms. Thus, biomechanics-only models are likely to be incomplete in providing a comprehensive picture of the disease progression, and should be enriched with biochemical factors. When validated with experiments where both mechanisms are examined at several time points, such comprehensive models would represent promising tools for predicting PTOA progression and designing personalized intervention strategies.
The first aim of this thesis was to develop tissue-level finite element models to predict PG matrix damage of injured knee cartilage explants incorporating both biomechanical and biochemical degradation mechanisms based on previous in vitro findings. With respect to biomechanical degradation, several mechanical strain measures and one stress measure were investigated; for biochemical degradation, the net catabolic effect of inflammation was modeled with the diffusion of pro-inflammatory messenger proteins into cartilage (interleukin-1 cytokines) followed by cell-level perturbations in the biosynthesis levels of enzymatic proteins (aggrecanases) and PGs (aggrecan). These two approaches were combined, i.e. excessive levels of maximum shear strain were used in tandem with assessments of cytokine diffusion. The second aim was to study in more detail the biomechanical and biochemical degradation mechanisms by conducting a new set of in vitro experiments in a bovine cartilage PTOA model. We investigated these mechanisms at several early time points up until 12 days of explant culture incorporating a combination of injurious loading, cytokine challenge, and a cyclic loading protocol that was considered healthy and mimicking daily activities. The experiments provided important information about the early-stage disease progression in terms of changes in tissue glycosaminoglycan content (GAG, a building block of PGs), aggrecan biosynthesis, and cell viability. The final aim was to generate, for the first time, a subject-specific knee joint-level computational model with both biomechanical (chondral injury, gait information) and biochemical (synovial fluid cytokine concentrations) aspects in a patient who had undergone an anterior cruciate ligament reconstruction surgery. These results were compared to quantitative magnetic resonance imaging (MRI) findings at the 3-year follow-up.
The results of this thesis confirm that inflammation plays a crucial role alongside biomechanical factors in early PTOA progression. Thus, including both degradation mechanisms into adaptive models of cartilage allows a more comprehensive prediction of disease progression than is possible with biomechanics-only models. Specifically, injury-related PG loss and cell death localized near to lesions, cytokine-induced PG loss occurred also near to explant edges, and the combination of injurious loading and the presence of excess cytokine levels caused more PG matrix damage than either of these conditions alone. All of these findings were captured by the tissue-level computational models with elevated maximum shear strain as a biomechanical damage biomarker. Shear strain-driven PG loss was also prominent near a lesion in the joint-level model, corresponding with MRI findings which detected a localized substantial increase of T1rho relaxation time. Relaxation times were also increased in areas away from the lesions, possibly affected by the presence of pro-inflammatory cytokines as suggested in the new model.
Interestingly, in the new experiments, the chosen cyclic loading regime (15% strain amplitude, 1 Hz frequency) was beneficial for GAG retention in inflamed cartilage within the first four days of loading, but became deleterious after 12 days despite the increasing aggrecan biosynthesis rate. The early-stage (1--4 days) protecting effect of cyclic loading is suggested to be prominent in the lower transitional and deep cartilage zones.
In conclusion, the novel biomechanical and inflammation models of cartilage degradation presented in this thesis could be used to predict PTOA progression. In the future, such deterministic, physics-based models could help clinicians to assess either patient-specific or even population-specific risks of PTOA progression based on non-invasively imaged cartilage geometries, gait patterns if available, and synovial fluid biomarker profiles. The effects of different interventions could also be evaluated with the predictive model. Moreover, the new experimental findings provide a foundation for further in vivo studies where anti-catabolic drug treatment could be combined with early well-timed rehabilitation, but physical rehabilitation would not be continued if there were signs of chronic inflammation. The effectiveness of disease-modifying drug interventions could also be investigated with the proposed modeling platform. However, rigorous validation with large patient populations will be needed before this enters clinical use.
... The maximum isometric force of each muscle was tripled to allow the generation of high forces required to perform the dynamic movements. 30,39 The foot was modeled as 1 rigid segment. First, the generic model was scaled to the participants' anthropometric data. ...
Background
Current return-to-sport (RTS) criteria after anterior cruciate ligament (ACL) reconstruction (ACLR) include demonstrating symmetry in functional and strength tests. It remains unknown if at the time that athletes are cleared to RTS, they exhibit between-limb symmetry in ACL and tibiofemoral contact forces or if these forces are comparable with those in uninjured athletes.
Purposes
To (1) examine ACL and tibiofemoral contact forces in athletes who underwent ACLR and were cleared to RTS and (2) compare the involved leg to the healthy contralateral leg and healthy controls during functional tasks.
Study Design
Cross-sectional study; Level of evidence, 3.
Methods
A total of 26 male athletes who underwent ACLR were tested at the time of RTS during tasks that included single-leg vertical, horizontal, and side jumps; cutting maneuvers; and high-intensity running. We used an electromyography-constrained musculoskeletal modeling workflow to estimate ACL and tibiofemoral contact forces and compared the results with those of 23 healthy male participants.
Results
The ACLR group presented no differences in peak tibiofemoral contact forces in the involved limb compared with the control group. However, there were significant between-limb differences mainly due to higher contact forces in the uninvolved (healthy) limb of the ACLR group compared with the control group. In the ACLR group, ACL forces were significantly higher in the uninvolved limb compared with the involved limb during cutting and running. Lateral contact forces were lower in the involved compared with the uninvolved limb, with large effect sizes during cutting ( d = 1.14; P < .001) and running ( d = 1.10; P < .001).
Conclusion
Current discharge criteria for clearance to RTS after ACLR did not ensure the restoration of symmetric loading in our cohort of male athletes. ACL force asymmetry was observed during cutting and running, in addition to knee loading asymmetries on several tasks tested.
... Gait biomechanics and processed EMGs were then used to calibrate and execute an EMG-driven model, for each subject, to estimate muscle forces by using CEINMS [51]. CEINMS has already been mentioned in depth [51,52], so it will only be addressed briefly here. The musculo-tendon unit parameters of each individual were adjusted, which is part of the CEINMS framework, i.e., optimizing the musculo-tendon unit parameters to minimize the least square differences between the expected joint moments of the model and the experimentally measured joint moments. ...
The primary role of muscles is to move, and control joints. It is therefore important to understand how degenerative joint disease changes this role with the resulting effect on mechanical joint loading. Muscular control strategies can vary depending on strength and coordination which in turn influences joint control and loading. The purpose of this study was to investigate the variation in neuromuscular control mechanisms and joint biomechanics for three subject groups including those with: uni-compartmental knee osteoarthritis (OA), listed for high tibial osteotomy surgery (pre-HTO, n = 10); multi-compartmental knee OA listed for total knee replacement (pre-TKR, n = 9), and non-pathological knees (NP, n = 11). Lower limb kinematics and electromyography (EMG) data for subjects walking at self-selected speed, were input to an EMG-driven musculoskeletal knee model which was scaled and calibrated to each individual to estimate muscle forces. Compared to NP, the peak gastrocnemius muscle force reduced by 30% and 18% for pre-HTO and pre-TKR respectively, and the peak force estimated for hamstring muscle increased by 25% for pre-HTO. Higher quadriceps and hamstring forces suggest that co-contraction with the gastrocnemius could lead to higher joint contact forces. Combined with the excessive loading due to a high external knee adduction moment this may exacerbate joint destruction. An increased lateral muscle co-contraction reflects the progression from NP to uni-compartmental OA (pre-HTO). Pre-TKR patients adopt a different gait pattern to pre-HTO patients. Increased medial muscle co-activation could potentially differentiate between uni- or multi-compartmental OA.
... 9,10 A possible mechanism that may lead to OA in patients with ACLR is altered knee joint biomechanics, leading to abnormal stresses or strains experienced by articular cartilage. 11,12 These abnormal stresses and strains have been evaluated experimentally 13,14 and computationally 13,14 ex vivo, and by finite element (FE) modeling of human joints. 15,16 In a clinical setting, the FE model generation and computational solution should be as fast as possible. ...
The aims of this case‐control study were to: (1) Identify cartilage locations and volumes at risk of osteoarthritis (OA) using subject‐specific finite element (FE) models; (2) Quantify the relationships between the simulated biomechanical parameters and T2 and T1ρ relaxation times of magnetic resonance imaging (MRI). We created subject‐specific FE models for seven patients with anterior cruciate ligament (ACL) reconstruction and six controls based on a previous proof‐of‐concept study. We identified locations and cartilage volumes susceptible to OA, based on maximum principal stresses and absolute maximum shear strains in cartilage exceeding thresholds of 7 MPa and 32%, respectively. The locations and volumes susceptible to OA were compared qualitatively and quantitatively against 2‐year longitudinal changes in T2 and T1ρ relaxation times. The degeneration volumes predicted by the FE models, based on excessive maximum principal stresses, were significantly correlated (r = 0.711, p < 0.001) with the degeneration volumes determined from T2 relaxation times. There was also a significant correlation between the predicted stress values and changes in T2 relaxation time (r = 0.649, p < 0.001). Absolute maximum shear strains and changes in T1ρ relaxation time were not significantly correlated. Five out of seven patients with ACL reconstruction showed excessive maximum principal stresses in either one or both tibial cartilage compartments, in agreement with follow‐up information from MRI. Expectedly, for controls, the FE models and follow‐up information showed no degenerative signs. Our results suggest that the presented modelling methodology could be applied to prospectively identify ACL reconstructed patients at risk of biomechanically driven OA, particularly by the analysis of maximum principal stresses of cartilage.
... These earlier results may shed light on the association between knee cartilage degeneration and the decrease in the joint loading observed after ACL deficiency or ACL-R. 17,22,64 In this study, our sensitivity analysis indicated that changes in the cross-terms (second orders indices) are more dominant than those in the first-order indices (►Figs. 7-10). ...
In this study, we aimed to develop an in-silico synthesis of the effect of critical surgical design parameters on articular contact behavior for a bone-patellar-tendon-bone anterior cruciate ligament reconstruction (ACL-R) surgery. A previously developed finite element model of the knee joint consisting of all relevant soft tissues was employed. The knee model was further updated with additional features to develop the parametric FE model of the biomechanical experiments that depicted the ACL-R surgery. The parametricity was created involving femoral tunnel architecture (orientations and locations) and graft fixation characteristics (pretension and angle of fixation). A global sensitivity analysis based on variance decomposition was used to investigate the contribution of the surgical parameters to the uncertainty in response to the ACL-R joint. Our examinations indicated that the total contact force was primarily influenced by either combined or individual action of the graft pretension and fixation angle, with a modest contribution of the graft insertion sites. The joint contact center and area were affected mainly by the angle of fixation and the tunnel placements. Graft pretension played the dominant role in the maximum contact pressure variability, an observation that has been well-documented in the literature. Interestingly, the joint contact behavior was almost insensitive to the tunnel's coronal and sagittal orientations. Our data provide an evaluation of how the surgical parameters affect the knee joint's contact behavior after ACL-R and may provide additional information to better explain the occurrence of osteoarthritis as an aftermath of such surgery.
... However, the ST tendon autograft procedure leads to significant neuromuscular deficits, such as reduced ST muscle cross-sectional area, volume and length (Konrath et al. 2017;Nishino et al. 2006), decreased knee flexor strength at large knee joint angles (Makihara et al. 2005;Nomura et al. 2014), and altered hamstring muscle activation (Messer et al. 2019) which can persist for years, even after return to sport. Further, despite possible regeneration of a tendon-like tissue, the mechanical properties of the neo-tendon remain altered beyond 12 months (Suydam et al. 2017). ...
PurposeKnee flexor electromechanical delay (EMD) has been proposed as a contributing factor to non-contact anterior cruciate ligament (ACL) injury risk and the semitendinosus (ST) autograft technique has been shown to impair knee flexor torque at large angles of knee flexion. The purpose of this study was to analyse the effects of ACL reconstruction (ACLR) using the ST tendon autograft technique on knee flexor EMD across the knee flexion range of motion, in athletes who had returned to competition.Methods
Athletes with ACLR (n = 8 females, n = 3 males, 1.7 ± 0.5 years post-surgery) and non-injured control athletes (n = 6 females, n = 4 males) performed rapid maximal voluntary contractions of isometric knee flexion and extension at 30°, 50°, 70°, 90°,and 105° of knee flexion. Electrical activity of the ST, biceps femoris (BF), vastus lateralis, and vastus medialis was recorded using surface electromyography.ResultsNo change in EMD for the knee flexors or extensors was observed across joint angles. Greater EMD was found only for the BF in the ACLR limb of injured athletes compared to the contralateral limb (P < 0.05). In post-hoc analysis, evidence of ST tendon regrowth was noted for only 2/11 athletes.Conclusion
While the EMD-joint angle relationship appeared to be unaffected by ST tendon harvest for ACLR, the absence of ST tendon regrowth should be considered. Despite return to competition, greater BF EMD was found, which may impair knee joint stabilization capacity by delaying the transfer time of muscle tension to the tibia after ST autograft.
