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Anterior shear force for one representative subject (mass 48.9kg, height 1.60m) using standard and revised optimisation methods with different values of c The activation of biceps femoris long head is expressed as a c value. The arrow indicates that the peak anterior shear force was reduced to zero with c = 0.30 in the revised optimisation.
Source publication
The anterior cruciate ligament (ACL) provides resistance to tibial internal rotation torque and anterior shear at the knee. ACL deficiency results in knee instability. Optimisation of muscle contraction through functional electrical stimulation (FES) offers the prospect of mitigating the destabilising effects of ACL deficiency. The hypothesis of th...
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Introduction:
Recently, a new minimally invasive single bundle technique for anatomic ACL reconstruction has been described, called the "All-Inside graft-link technique". One of the advantages of this procedure is the reduced morbidity at the donor site as the graft choice is the quadrupled semitendinosus, thus sparing the gracilis tendon. The aim...
Citations
... (3) Stabilizers against tibial translation are divided into anterior and posterior stabilizers, and posterior stability provided by the PLC reduces the strain on the PCL and is guaranteed mostly by the popliteus complex at approximately 90 • [21] and by the AC [22,23]. PC seems to stabilize the knee at early degrees of flexion [24], while biceps femoris long-head activation offers resistance against anterior tibial translation before 40 • [25], and both layers of the ITB restrain anterior tibial translation throughout the ROM [20]. ...
One of the least understood and most elaborate and neglected knee stabilizers is the posterolateral corner (PLC) complex. PLC injury is associated with a high risk of re-injury, early athletic career termination, instability, progressive osteoarthritis, and a high risk of artificial knee replacement. The growing focus on the PLC, along with various recent anatomical and biomechanical studies, has provided further insights into the anatomy and function of posterolateral structures in knee stabilization and kinematics. The PLC should be considered as a functional unit, not only an anatomical unit. A low suspicion threshold should be maintained when considering PLC injuries, and thorough history evaluation, clinical examination, and adequate imaging should be conducted to reduce the chances of neglected PLC injuries. Various PLC repair and reconstruction techniques, ranging from non-anatomical to anatomical, have been introduced, with treatments increasingly favoring minimal incisions and arthroscopic procedures. Recent studies on the PCL have reported an increasing number of satisfactory clinical outcomes. This study aimed to provide a deeper understanding, as well as review the current and most feasible treatments for PLC injuries.
... In theory, the internal knee contact force can be manipulated to several times bodyweight without changing kinematics [22,23]. Musculoskeletal simulation provides a practical platform to identify the effect of altered muscle coordination strategies on joint loading [21][22][23][24][25][26]. This is achieved by customising a new cost function to explore other potential muscle activation patterns, considering the muscle redundancy around the knee [24,25]. ...
Purpose
People with unilateral transtibial amputation experienced a higher incidence of knee osteoarthritis due to abnormal movement patterns. This study aimed to explore alternations in muscle coordination to reduce mechanical burdens in their daily activities.
Methods
Five males with unilateral transtibial amputation were recruited. Two daily activities (level walking and standing up from a chair) were simulated using muscle-driven simulation. Two cost functions were applied: minimising the knee adduction moment and minimising both the knee adduction moment and knee flexion moment. This enabled the identification of altered muscle coordination and any possible changes in kinematic patterns.
Results
For people with unilateral transtibial amputation, reducing knee adduction angles during stance was found effective in reducing knee adduction moments. To mitigate peak contact forces at the intact knee, muscle activations of vasti and gastrocnemius should be decreased, while muscle activations of soleus should be increased during activities of level walking and standing up from a chair.
Conclusion
Our study suggested that minimising knee adduction moments was effective in reducing joint loading during level walking while minimising both knee adduction moments and knee flexion moments was effective during standing up from a chair. Therefore, the alteration of muscle coordination should be carefully designed for different daily activities.
... Xu et al. simulated the impact of increased biceps femoris activation on knee joint loading and demonstrated that an additional activation of the biceps femoris during the stance phase of gait reduced the second peak of the medial knee joint contact force by 17% [14]. Similarly, Azmi et al. reported that a 20.8% increase in biceps femoris activation could effectively reduce the anterior shear force to zero and decrease the internal rotation torque by 188% [15]. These findings highlight the promising role of FES in reducing medial compartment contact force. ...
... The demonstrated efficacy of FES in reducing pKAM is consistent with previous research that has reported lower KAM and knee compressive forces during level walking with stimulation of the long head of biceps femoris as shown by musculoskeletal modeling [14,15]. The distal attachment of the biceps femoris to the fibular head, when activated through neuromuscular electrical stimulation, may result in the shortening of the muscle-tendon unit. ...
... Conceivably, the application of neuromuscular electrical stimulation to the gastrocnemius during elliptical stepping may activate the type II muscle fibers to a greater extent than during voluntary contractions, thereby exerting a more pronounced effect on knee joint loading. In the current study, the FES was applied throughout the entire elliptical cycle, whereas in the previous studies, stimulation was limited to the stance phase of gait [14,15]. The continuous muscle stimulation may enhance its activation and further reduce medial knee compartment loading. ...
Knee osteoarthritis (KOA) is an age-dependent disease dominantly affected by mechanical loading. Balancing the forces acting on the medial knee compartment has been the focus of KOA interventions. This pilot study investigated the effects of functional electrical stimulation (FES) of the biceps femoris and lateral gastrocnemius on reducing peak knee adduction moment (pKAM) in healthy adults and individuals with medial KOA while stepping on an instrumented elliptical system. Sixteen healthy individuals and five individuals with medial KOA stepped on the robotic stepping system, which measured footplate-reaction forces/torques and ankle kinematics and calculated 3-D knee moments in real time using inverse dynamics. Participants performed four different tasks: regular stepping without FES as the baseline condition, stepping with continuous FES of the lateral gastrocnemius (FESLG), biceps femoris (FESBF), and simultaneous FES of both lateral gastrocnemius and biceps femoris (FESLGBF), throughout the elliptical cycle. The 3-D knee moments, tibia kinematics, and footplate-reaction forces were compared between the baseline and the three FES stepping conditions. Healthy participants demonstrated lower pKAM during each of the three FES conditions compared to baseline (FESLG (p = 0.041), FESBF (p = 0.049), FESLGBF (p = 0.048)). Participants with KOA showed a trend of lower pKAM during FES, which was not statistically significant given the small sample available. Incorporating elliptical + FES as a training strategy is feasible and may help to enhance selective force generation of the targeted muscles and reduce the medial knee compartment loading.
... Most studies [13,14,16,[21][22][23][24][25][27][28][29] obtained a PEDro score of 6 or higher (n = 10), i.e., a good methodological quality ( Table 2). The remaining five studies [15,22,24,26,31] scored 5, corresponding to a moderate methodological quality. The included studies are subject to common biases, especially in relation to items 6 and 7, which indicate that none of the examiners or researchers involved in these studies was blinded. ...
... The most frequently targeted muscle was the gastrocnemius [13,14,16,22,23,25,29,30], followed by the biceps femoris [13,15,16,23,25,26,30], tibialis anterior [13,16,23,25,27,30], rectus femoris [13,16,21,25,30], and soleus [13,14,22]. Additionally, isolated studies investigated the effects of FES on the gluteus medius [24], peroneus longus [31], and abductor hallucis [28]. ...
... Thirteen studies mentioned the stimulation frequency. Among these studies, nine used a stimulation frequency of 40 Hz [13][14][15][16][25][26][27]29,31]. Two studies used a stimulation frequency of 33 Hz [15,22], whereas two others employed frequencies of 45 Hz [24] and 65 Hz [23]. ...
Background: This systematic review aimed to provide a comprehensive overview of the effects of functional electrical stimulation (FES) on gait characteristics in healthy individuals. Methods: Six electronic databases (PubMed, Embase, Epistemonikos, PEDro, COCHRANE Library, and Scopus) were searched for studies evaluating the effects of FES on spatiotemporal, kinematic, and kinetic gait parameters in healthy individuals. Two examiners evaluated the eligibility and quality of the included studies using the PEDro scale. Results: A total of 15 studies met the inclusion criteria. The findings from the literature reveal that FES can be used to modify lower-limb joint kinematics, i.e., to increase or reduce the range of motion of the hip, knee, and ankle joints. In addition, FES can be used to alter kinetics parameters, including ground reaction forces, center of pressure trajectory, or knee joint reaction force. As a consequence of these kinetics and kinematics changes, FES can lead to changes in spatiotemporal gait parameters, such as gait speed, step cadence, and stance duration. Conclusions: The findings of this review improve our understanding of the effects of FES on gait biomechanics in healthy individuals and highlight the potential of this technology as a training or assistive solution for improving gait performance in this population.
... 8 To prevent injuries during sports, it is imperative to recruit dynamic muscle restraints to resist perturbation and control external loads to the lower extremity. 15 participants, 16 as well as extension and flexion tests in patients with ACL deficiency. 17 However, the studies did not validate the effect of myoelectrical stimulation on ACL injury prevention during tasks such as DVJ. ...
... The findings of this research could prevent ACL injury in active people and might pave the way for future implementation of myoelectrical stimulation to mitigate knee joint instability among patients with ACL deficiency and protect ACL reconstructions during postoperative rehabilitation. 16 [4.7] kg) were recruited for this study. Compared with untrained participants, trained and elite athletes showed more quality in intramuscular and intermuscular coordination, and they may be better able to coordinate a mechanical and electrical stimulation at the same time and thus be able to be stimulated more effectively. ...
Anterior cruciate ligament injury prevention should focus primarily on reduction of the knee abduction moment (KAM) in landing tasks. Gluteus medius and hamstring forces are considered to decrease KAM during landing. The effects of different muscle stimulations on KAM reduction were compared using 2 electrode sizes (standard 38 cm ² and half size 19 cm ² ) during a landing task. Twelve young healthy female adults (22.3 [3.6] y, 1.62 [0.02] m, 50.2 [4.7] kg) were recruited. KAM was calculated under 3 conditions of muscle stimulation (gluteus medius, biceps femoris, and both gluteus medius, and biceps femoris) using 2 electrode sizes, respectively versus no stimulation during a landing task. A repeated-measures analysis of variance determined that KAM differed significantly among stimulation conditions and post hoc analysis revealed that KAM was significantly decreased in conditions of stimulating either the gluteus medius ( P < .001) or the biceps femoris ( P < .001) with the standard electrode size, and condition of stimulating both gluteus medius and biceps femoris with half-size electrode ( P = .012) when compared with the control condition. Therefore, stimulation on the gluteus medius, the biceps femoris, or both muscles could be implemented for the examination of anterior cruciate ligament injury potential.
... FreeBody is a segment-based 3D MSK modelling software (Cleather and Bull 2015), which has been validated for the prediction of in vivo knee contact forces during different ADLs, generating encouraging results (Ding et al., 2016). The validated model has provided the means to investigate the efficacy of clinical interventions that reduced knee contact forces during gait (Rane and Bull 2016;Azmi et al., 2018;Xu et al., 2019). However, FreeBody has not been validated for the prediction of hip joint contact forces. ...
Background: Quantifying in vivo hip muscle and contact forces during activities of daily living (ADL) provides valuable information for diagnosis and treatment of hip-related disorders. The objective of this study was to utilize Freebody, a segment-based musculoskeletal model, for the prediction of hip contact forces using a novel objective function during seven common ADLs and validate its performance against the publicly available HIP98 dataset.
Methods: Marker data, ground reaction forces, and hip contact forces during slow, normal, and fast walking, stair ascent and descent, and standing up and sitting down were extracted for 3 subjects from the HIP98 dataset. A musculoskeletal anatomical dataset was scaled to match the dimensions of each subject, and muscle and hip contact forces were estimated by minimizing a novel objective function, which was the summation of the muscle stresses squared and body weight-normalised hip contact force. The accuracy of predictions were quantified using several metrics, and muscle forces were qualitatively compared to experimental EMGs in the literature.
Results: FreeBody predicted the hip contact forces during the ADLs with encouraging accuracy: The root mean squared error of predictions were 44.0 ± 8.5, 47.4 ± 6.5, and 59.8 ± 7.1% BW during slow, normal, and fast walking, 44.2 ± 16.8% and 53.3 ± 12.2% BW for stair ascent and descent, and 31.8 ± 8.2% and 17.1 ± 5.0% BW for standing up and sitting down, respectively. The error in prediction of peak hip contact forces were 14–18%, 24–28%, 17–35% for slow, normal, and fast walking, 7–25% and 15–32% in stair ascent and descent, and around 10% for standing up and sitting down. The coefficient of determination was larger than 0.90 in all activities except in standing up (0.86 ± 0.08).
Conclusion: This study has implemented a novel objective function in a segment-based musculoskeletal model, FreeBody, for the prediction of hip contact forces during a large range of ADLs. The model outputs compare favourably for all ADLs and are the best in standing up and sitting down, while muscle activation patterns are consistent with experimental EMGs from literature. This new objective function addresses one of the major limitations associated with musculoskeletal models in the literature, namely the high non-physiological predicted hip joint contact forces.
... This model enables us to assess the effect of joint instability on OA progression, which is frequently observed in knee OA patient with laxity 25e27 . Moreover, ACL suppresses the shear-stress in the knee joint 28 ; therefore, it is perhaps possible to evaluate the effects of shear-stress on OA progression. Osteoarthritis and Cartilage (A) Immunohistochemical analysis of MMP-3 in cartilage. ...
Objective
The ACL-deficient model helps to clarify the mechanism of knee OA; however, the conventional ACL injury model could have included concurrent onset factors such as direct compression stress to cartilage and subchondral bone. In this study, we established a novel Non-invasive ACL-Ruptured mouse model without concurrent injuries and elucidated the relationship between OA progression and joint instability.
Design
We induced the ACL-Rupture non-invasively in twelve-week-old C57BL/6 male mice and evaluated histological, macroscopical, and morphological analysis at 0 days. Next, we created the ACL-R, controlled abnormal tibial translation (CATT), and Sham groups. Then, the joint stability and OA pathophysiology were analyzed at 2, 4, and 8 weeks.
Results
No intra-articular injuries, except for ACL rupture, were observed in the ACL-R model. ACL-R mice increased anterior tibial displacement compared to the Sham group (p<0.001, 95% CI [-1.509 to -0.966]) and CATT group (p<0.001, 95% CI [-0.841 to -0.298]) at 8 weeks. All mice in the ACL-R group caused cartilage degeneration. The degree of cartilage degeneration in the ACL-R group was higher than in the CATT group (p=0.006) at 8 weeks. The MMP-3-positive cell rate of chondrocytes increased in the ACL-R group than CATT group from 4 weeks (p=0.043; 95% CI [-28.32 to -0.364]) while that of synovial cells increased at 8 weeks (p=0.031; 95% CI [-23.398 to -1.021]).
Conclusion
We successfully established a Non-invasive ACL-R model without intra-articular damage. Our model revealed that chondrocytes might react to abnormal mechanical stress prior to synovial cells while the knee OA onset.
... High voluntary activation of the hamstring during an eccentric exercise contraction is critical for neural adaptation, and data about the EMG activity of the involved muscles during the NHE are controversial. The lateral part of the hamstring prevents excessive tibial internal rotation and anterior shear force at the knee (Azmi et al. 2018). Some studies using surface EMG found no significant difference between the activity of the medial and lateral hamstring muscles (Iga et al. 2012;Zebis et al. 2013). ...
... As ACL injury risk starts to increase at 12-13 years of age in girls (Granan et al. 2009), and hamstring strengthening is one important part of the successful ACL prevention programs (Sugimoto et al. 2015), hamstring strengthening might be advisable in young females before the adolescent growth spurt. Efficient activation of the lateral hamstring has been suggested to reduce the tibial internal rotation torque and the anterior shear force at the knee (Azmi et al. 2018). Our data suggest that the NHE preferentially activated the lateral part of the hamstring (129% and 118% in left and right, respectively), providing important training stimulus to target ACL protection. ...
Purpose
The multidimensional role of hamstring muscle group strength in athletic performance and injury prevention is well documented, and nordic hamstring exercise (NHE) is a popular method for the development of hamstring strength. Our aim was to examine the EMG characteristics of the eccentric NHE as well as the effects of long-term eccentric NHE training on muscle strength and vertical jump performance in 10- to 11-year-old female handball players.
Methods
Players from the same handball team were randomly assigned to an eccentric NHE training (13 players) or a control group (10 players). Both groups continued their regular handball training routine, but the NHE group performed additional eccentric NHE exercises once or twice a week, with progressively increasing volume, over 20 weeks. To test training effects, countermovement jump (CMJ) height, eccentric hamstring impulse, peak torque, and angle of peak torque were evaluated before, during and after the training period. In the pre-exercise test, EMG activity of the medial and lateral hamstring muscle was also assessed during NHE.
Results
Hamstring activities ranged between 98 and 129%. Lateral hamstring activity was greater than medial only in the right leg during NHE. Eccentric hamstring impulse improved in both legs at 10 weeks in both groups. Then, at 20 weeks, it remained unchanged in the NHE but decreased in controls. A similar adaptation was seen in eccentric hamstring torque, without change in the optimum knee angle. CMJ height improved only in the NHE.
Conclusion
It is concluded that NHE activates the hamstring musculature effectively, and a favourable mechanical adaptation to long-term NHE exercise in girls can be triggered as early as 11 years of age.
... 55 56 Increased co-contraction of the hamstring muscles is considered protective, as the hamstrings have a posterior line of pull in a flexed knee and might thus act as an ACL agonist, counteracting high anterior tibial shear forces. 57 A neuromuscular modelling approach indicated that during single leg drop landing, the muscles that generated the greatest ACL-protective posterior shear force, were the soleus, medial hamstrings and biceps femoris. 58 In our cohort of ACLR patients although, the contribution of the medial and lateral hamstrings in the involved limb was greater than the uninvolved, but soleus contribution was less than controls bilaterally. ...
Objectives: Vertical jump performance (height) is a more representative metric for knee function than horizontal hop performance (distance) in healthy individuals. It is not known what the biomechanical status of athletes after anterior cruciate ligament (ACL) reconstruction (ACLR) is at the time they are cleared to return to sport (RTS) or whether vertical performance metrics better evaluate knee function.
Methods: Standard marker-based motion capture and electromyography (EMG) were collected from 26 male athletes cleared to RTS after ACLR and 22 control healthy subjects during single leg vertical jumps (SLJ) and single leg drop jumps (SLDJ). Performance outcomes, jump height and the Reactive Strength Index, were calculated. Sagittal plane kinematics, joint moments and joint work were obtained using inverse dynamics and lower limb muscle forces were computed using an EMG-constrained musculoskeletal model. Muscle contribution was calculated as a percentage of the impulse of all muscle forces in the model. Between-limb and between-group differences were explored using mixed models analyses.
Results: Jump performance, assessed by jump height and Reactive Strength Index, was significantly lower in the involved than the uninvolved limb and controls, with large effect sizes. For the ACLR group, jump height limb symmetry index was 83% and 77% during the SLJ and SLDJ, respectively. Work generation was significantly less in the involved knee compared to uninvolved limb and controls during the SLJ (p<0.001; d=1.19; p=0.003, d=0.91, respectively) and during the SLDJ (p<0.001; d=1.54; p=0.002, d=1.05, respectively). Hamstrings muscle contribution was greater in the involved compared to the uninvolved limb and controls, whereas soleus contribution was lower in the involved limb compared to controls.
Conclusions: During vertical jumps, male athletes after ACLR at RTS still exhibit knee biomechanical deficits, despite symmetry in horizontal functional performance and strength tests. Vertical performance metrics like jump height and RSI can better identify interlimb asymmetries than the more commonly used hop distance and should be included in the testing battery for the RTS.
... Hence, pathomechanics might involve the posterior proximal tibiofibular ligament (PPTFL) [26], located inferior to the lateral joint space of the fibular head. When patients perform forceful knee flexion, the PPTFL serves as an important accommodator which, in conjunction with the biceps femoris, pulls the fibula head posteriorly [9,10,17,22]. An atypical increase in RTFD during forceful knee flexion in some patients in this study was attributable to impairment of the PPTFL and the tendon of the biceps femoris. ...
Background
Proximal tibiofibular joint (PTFJ) instability is uncommon, resulting from violent twisting motions of the flexed knee during sport activities. No known image variables functionally relate the degrees of PTFJ instability.
Objective
This study used ultrasound imaging to quantify the discrimination threshold for PTFJ instability and relevant functional significances.
Methods
Twenty patients (mean age: 42.7 (21–59) years) with chronic PTFJ instability participated in this study. Along with the Knee Injury and Osteoarthritis Outcome Score (KOOS), the tibiofibular distances of the affected and unaffected knees were estimated with ultrasonography in the four standardized conditions at 90° of flexion of the hip and knee, including neutrally relaxed position, passive internal rotation, passive external rotation, and forceful flexion of the knee joint.
Results
During forceful knee flexion, the absolute tibiofibular distance in the affected leg (28.1 ± 4.0 mm) was greater than the unaffected leg (25.1 ± 3.7 mm). Relative changes in tibiofibular distance (RTFD) were different for both legs (affected leg: 3.9 ± 2.7 mm; unaffected leg: 1.0 ± 1.4 mm) (P < 0.001). The area under the receiver operator characteristic curve for the RTFD was a potent predictor of PTFJ instability (84.5%) with specificity of 95% and sensitivity of 65%. Patients with RTFD greater than 2.95 mm exhibited higher scores on the KOOS subscales of pain (P = 0.043) and quality of life (P = 0.009).
Conclusion
Ultrasonic measurement of the tibiofibular distance under forceful knee flexion is clinically valuable for diagnosing PTFJ instability with functional significance.
