scholarly journals Optimized Thickness of Meniscal Component in Partial Knee Replacement Analysed with Computer Simulation

2021 ◽  
Vol 2071 (1) ◽  
pp. 012017
Author(s):  
Ahmed Imran
Keyword(s):  
Computer Simulation ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Joint Stiffness ◽  
Elastic Behaviour ◽  
Anatomical Studies ◽  
Component Selection ◽  
Surgical Errors ◽  
Anterior Cruciate ◽  
Linear Elastic Behaviour

Abstract Computer simulation with programming and Matlab graphics was used to analyse effects of meniscal component thickness on lengths of ligament fibres in partially replaced human knee with uni-compartmental arthroplasty. A circular femoral, a flat tibial and a matching meniscal component were modelled in the sagittal plane with four intact ligaments represented as fibres that showed non-linear elastic behaviour. Shapes of the prosthetic components, attachments of the ligament fibres and their material properties were from anatomical studies in the literature. The components when placed on respective bones with surgical guidelines and an optimized thickness of the meniscal insert achieved nearly fixed lengths of ligament fibres during motion. Changes in thickness of the insert either stretched or slackened the fibres with variable effects during flexion of the joint. For example, a 2 mm thicker insert stretched a fibre of anterior cruciate ligament by 4.7% at 30° and 3.2% at 120° flexion. Such variations in component selection are probable due to surgical judgments. Stretched ligaments could increase joint stiffness, while slack ligaments could increase joint laxity – either of these effects has potential for affecting the joint kinematics. Computer models of the replaced knee validated with anatomical studies allow insight in the mechanics of the replaced knee and effects of surgical errors.

scholarly journals Single-Leg Landings Following a Volleyball Spike May Increase the Risk of Anterior Cruciate Ligament Injury More Than Landing on Both-Legs

2020 ◽  
Vol 11 (1) ◽  
pp. 130
Author(s):  
Datao Xu ◽  
Xinyan Jiang ◽  
Xuanzhen Cen ◽  
Julien S. Baker ◽  
Yaodong Gu
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Flexion Angle ◽  
Ligament Injury ◽  
Time Range ◽  
Acl Injuries ◽  
Volleyball Players ◽  
Anterior Cruciate

Volleyball players often land on a single leg following a spike shot due to a shift in the center of gravity and loss of balance. Landing on a single leg following a spike may increase the probability of non-contact anterior cruciate ligament (ACL) injuries. The purpose of this study was to compare and analyze the kinematics and kinetics differences during the landing phase of volleyball players using a single leg (SL) and double-leg landing (DL) following a spike shot. The data for vertical ground reaction forces (VGRF) and sagittal plane were collected. SPM analysis revealed that SL depicted a smaller knee flexion angle (about 13.8°) and hip flexion angle (about 10.8°) during the whole landing phase, a greater knee and hip power during the 16.83–20.45% (p = 0.006) and 13.01–16.26% (p = 0.008) landing phase, a greater ankle plantarflexion angle and moment during the 0–41.07% (p < 0.001) and 2.76–79.45% (p < 0.001) landing phase, a greater VGRF during the 5.87–8.25% (p = 0.029), 19.75–24.14% (p = 0.003) landing phase when compared to DL. Most of these differences fall within the time range of ACL injury (30–50 milliseconds after landing). To reduce non-contact ACL injuries, a landing strategy of consciously increasing the hip and knee flexion, and plantarflexion of the ankle should be considered by volleyball players.

scholarly journals Mechanism of anterior cruciate ligament loading during dynamic motor tasks

2020 ◽  
Author(s):  
Azadeh Nasseri ◽  
David G Lloyd ◽  
Adam L Bryant ◽  
Jonathon Headrick ◽  
Timothy Sayer ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Lower Limb ◽  
Muscle Activation ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Whole Body ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Anterior Cruciate

AbstractThis study determined anterior cruciate ligament (ACL) force and its contributors during a standardized drop-land-lateral jump task using a validated computational model. Healthy females (n=24) who were recreationally active performed drop-land-lateral jump and straight run tasks. Three-dimensional whole-body kinematics, ground reaction forces, and muscle activation patterns from eight lower limb muscles were collected concurrently during both tasks, but only the jump was analyzed computationally, with the run included for model calibration. External biomechanics, muscle-tendon unit kinematics, and muscle activation patterns were used to model lower limb muscle and ACL forces. Peak ACL force (2.3±0.5 BW) was observed at 13% of the stance phase during the drop-land-lateral jump task. The ACL force was primarily developed through the sagittal plane, and muscle was the dominant source of ACL loading. The gastrocnemii and quadriceps were main ACL antagonists (i.e., loaders), while hamstrings were the main ACL agonists (i.e., supporters).

scholarly journals A Nonproprietary Movement Analysis System (MoJoXlab) Based on Wearable Inertial Measurement Units Applicable to Healthy Participants and Those With Anterior Cruciate Ligament Reconstruction Across a Range of Complex Tasks: Validation Study (Preprint)

2020 ◽  
Author(s):  
Riasat Islam ◽  
Mohamed Bennasar ◽  
Kevin Nicholas ◽  
Kate Button ◽  
Simon Holland ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Joint Angle ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Movement Analysis ◽  
Joint Angles ◽  
Measurement Units ◽  
Anterior Cruciate ◽  
P Movement ◽  
Healthy Participants

BACKGROUND Movement analysis in a clinical setting is frequently restricted to observational methods to inform clinical decision making, which has limited accuracy. Fixed-site, optical, expensive movement analysis laboratories provide <i>gold standard</i> kinematic measurements; however, they are rarely accessed for routine clinical use. Wearable inertial measurement units (IMUs) have been demonstrated as comparable, inexpensive, and portable movement analysis toolkits. MoJoXlab has therefore been developed to work with generic wearable IMUs. However, before using MoJoXlab in clinical practice, there is a need to establish its validity in participants with and without knee conditions across a range of tasks with varying complexity. OBJECTIVE This paper aimed to present the validation of MoJoXlab software for using generic wearable IMUs for calculating hip, knee, and ankle joint angle measurements in the sagittal, frontal, and transverse planes for walking, squatting, and jumping in healthy participants and those with anterior cruciate ligament (ACL) reconstruction. METHODS Movement data were collected from 27 healthy participants and 20 participants with ACL reconstruction. In each case, the participants wore seven MTw2 IMUs (Xsens Technologies) to monitor their movement in walking, jumping, and squatting tasks. The hip, knee, and ankle joint angles were calculated in the sagittal, frontal, and transverse planes using two different software packages: Xsens’ validated proprietary MVN Analyze and MoJoXlab. The results were validated by comparing the generated waveforms, cross-correlation (CC), and normalized root mean square error (NRMSE) values. RESULTS Across all joints and activities, for data of both healthy and ACL reconstruction participants, the CC and NRMSE values for the sagittal plane are 0.99 (SD 0.01) and 0.042 (SD 0.025); 0.88 (SD 0.048) and 0.18 (SD 0.078) for the frontal plane; and 0.85 (SD 0.027) and 0.23 (SD 0.065) for the transverse plane (hip and knee joints only). On comparing the results from the two different software systems, the sagittal plane was very highly correlated, with frontal and transverse planes showing strong correlation. CONCLUSIONS This study demonstrates that nonproprietary software such as MoJoXlab can accurately calculate joint angles for movement analysis applications comparable with proprietary software for walking, squatting, and jumping in healthy individuals and those following ACL reconstruction. MoJoXlab can be used with generic wearable IMUs that can provide clinicians accurate objective data when assessing patients’ movement, even when changes are too small to be observed visually. The availability of easy-to-setup, nonproprietary software for calibration, data collection, and joint angle calculation has the potential to increase the adoption of wearable IMU sensors in clinical practice, as well as in free living conditions, and may provide wider access to accurate, objective assessment of patients’ progress over time.

Tibial Slope and Its Effect on Force in Anterior Cruciate Ligament Grafts: Anterior Cruciate Ligament Force Increases Linearly as Posterior Tibial Slope Increases

2019 ◽  
Vol 47 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Andrew S. Bernhardson ◽  
Zachary S. Aman ◽  
Grant J. Dornan ◽  
Bryson R. Kemler ◽  
Hunter W. Storaci ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Linear Relationship ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Tibial Slope ◽  
Tibial Osteotomy ◽  
Acl Graft ◽  
Posterior Tibial ◽  
Axially Loaded ◽  
Anterior Cruciate

Background: Previous work has reported that increased tibial slope is directly correlated with increased anterior tibial translation, possibly predisposing patients to higher rates of anterior cruciate ligament (ACL) tears and causing higher rates of ACL graft failures over the long term. However, the effect of changes in sagittal plane tibial slope on ACL reconstruction (ACLR) graft force has not been well defined. Purpose/Hypothesis: The purpose of this study was to quantify the effect of changes in sagittal plane tibial slope on ACLR graft force at varying knee flexion angles. Our null hypothesis was that changing the sagittal plane tibial slope would not affect force on the ACL graft. Study Design: Controlled laboratory study. Methods: Ten male fresh-frozen cadaveric knees had a posterior tibial osteotomy performed and an external fixator placed for testing and accurate slope adjustment. Following ACLR, specimens were compressed with a 200-N axial load at flexion angles of 0°, 15°, 30°, 45°, and 60°, and the graft loads were recorded through a force transducer clamped to the graft. Tibial slope was varied between −2° and 20° of posterior slope at 2° increments under these test conditions. Results: ACL graft force in the loaded testing state increased linearly as slope increased. This effect was independent of flexion angle. The final model utilized a 2-factor linear mixed-effects regression model and noted a significant, highly positive, and linear relationship between tibial slope and ACL graft force in axially loaded knees at all flexion angles tested (slope coefficient = 0.92, SE = 0.08, P < .001). Significantly higher graft force was also observed at 0° of flexion as compared with all other flexion angles for the loaded condition (all P < .001). Conclusion: The authors found that tibial slope had a strong linear relationship to the amount of graft force experienced by an ACL graft in axially loaded knees. Thus, a flatter tibial slope had significantly less loading of ACL grafts, while steeper slopes increased ACL graft loading. Our biomechanical findings support recent clinical evidence of increased ACL graft failure with steeper tibial slope secondary to increased graft loading. Clinical Relevance: Evaluation of the effect of increasing tibial slope on ACL graft force can guide surgeons when deciding if a slope-decreasing proximal tibial osteotomy should be performed before a revision ACLR. Overall, as slope increases, ACL graft force increases, and in our study, flatter slopes had lower ACL graft forces and were protective of the ACLR graft.

scholarly journals Continued Improvements in Quadriceps Strength and Biomechanical Symmetry of the Knee After Postoperative Anterior Cruciate Ligament Reconstruction Rehabilitation: Is It Time to Reconsider the 6-Month Return-to-Activity Criteria?

2018 ◽  
Vol 53 (6) ◽  
pp. 535-544 ◽  
Author(s):  
Michael T. Curran ◽  
Lindsey K. Lepley ◽  
Riann M. Palmieri-Smith
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Joint ◽  
Anterior Cruciate Ligament Reconstruction ◽  
Ligament Reconstruction ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Knee Extension ◽  
Cruciate Ligament Reconstruction ◽  
Anterior Cruciate ◽  
Return To Activity

Context: Patients who undergo anterior cruciate ligament reconstruction (ACLR) present with strength and biomechanical deficits at return to activity (RTA). Deficits in strength and biomechanical symmetry impair function during activity and may predispose patients to subsequent injury.Objective: To compare strength and biomechanical function in patients with ACLR at RTA and more than 12 months post-ACLR.Design: Descriptive laboratory study.Setting: Research laboratory.Patients or Other Participants: A total of 20 participants (12 females, 8 males; age = 21.40 ± 5.60 years, height = 171.3 ± 10.2 cm, mass = 73.21 ± 19.41 kg) who had undergone ACLR and were cleared to RTA were recruited.Intervention(s): Strength was measured during knee extension and evaluated by the isometric and isokinetic quadriceps index. Biomechanical function was evaluated using symmetry values for sagittal-plane knee-joint rotations, changes in sagittal-plane knee-joint rotation, knee-extension moments, and changes in knee-extension moment that were recorded during a single-legged forward hop.Main Outcome Measure(s): Self-reported function was measured using the International Knee Documentation Committee Subjective Knee Evaluation Form. Participants were assessed at RTA (212.25 ± 28.11 days) and more than 12 months post-ACLR (556.25 ± 230.89 days).Results: At RTA, strength and biomechanical values were less than 80% symmetric. We observed improvements from RTA to more than 12 months post-ACLR for the isometric quadriceps index (F1,18 = 29.22, P &lt; .001), isokinetic quadriceps index (F1,18 = 10.88, P = .004), sagittal-plane knee-joint rotations (F1,19 = 9.58, P = .006), change in sagittal-plane knee-joint rotations (F1,19 = 7.83, P = .01), knee-extension moments (F1,19 = 5.73, P = .03), change in knee-extension moments (F1,19 = 21.10, P &lt; .001), and self-perceived function (F1,19 = 11.50, P = .003). Of the 7 variables that showed improvement at more than 12 months post-ACLR, only 3 met the recommended criteria (≥90%).Conclusions: Patients with ACLR showed asymmetry in strength and biomechanics at RTA. These asymmetries, along with self-perceived function, improved over time. However, despite improvements in strength and biomechanics at RTA, asymmetries of more than 10% were still present more than 12 months post-ACLR.

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