Effect of Initial Graft Tension During Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In Situ Forces of the Reconstructed Graft

2020 ◽  
Vol 48 (4) ◽  
pp. 916-922
Author(s):  
Yuzuru Sakakibara ◽  
Atsushi Teramoto ◽  
Tetsuya Takagi ◽  
Satoshi Yamakawa ◽  
Hiroaki Shoji ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Degrees Of Freedom ◽  
Anterior Talofibular Ligament ◽  
Principle Of Superposition ◽  
Initial Tension ◽  
Ankle Motion ◽  
Graft Tension ◽  
In Situ Force ◽  
Ankle Kinematics

Background: Although a variety of surgical procedures for anterior talofibular ligament (ATFL) reconstruction have been reported, the effect of initial graft tension during ATFL reconstruction remains unclear. Purpose/Hypothesis: This study investigated the effects of initial graft tension on ATFL reconstruction. We hypothesized that a high degree of initial graft tension would cause abnormal kinematics and laxity. Study Design: Controlled laboratory study. Methods: Twelve cadaveric ankles were tested with a robotic system with 6 degrees of freedom to apply passive plantarflexion and dorsiflexion motions and a multidirectional load. A repeated measures experiment was designed with the intact ATFL, transected ATFL, and reconstructed ATFL at initial tension conditions of 10, 30, 50, and 70 N. The 3-dimensional path and reconstructed graft tension were simultaneously recorded, and the in situ forces of the ATFL and reconstructed graft were calculated with the principle of superposition. Results: Initial tension of 10 N was sufficient to imitate normal ankle kinematics and laxity, which were not significantly different when compared with those of the intact ankles. The in situ force on the reconstructed graft tended to increase as the initial tension increased. In situ force on the reconstructed graft >30 N was significantly greater than that of intact ankles. The in situ force on the ATFL was 19 N at 30° of plantarflexion. In situ forces of 21.9, 30.4, 38.2, and 46.8 N were observed at initial tensions of 10, 30, 50, and 70 N, respectively, at 30° of plantarflexion. Conclusion: Approximate ankle kinematic patterns and sufficient laxity, even with an initial tension of 10 N, could be obtained immediately after ATFL reconstruction. Moreover, excessive initial graft tension during ATFL reconstruction caused excessive in situ force on the reconstructed graft. Clinical Relevance: This study revealed the effects of initial graft tension during ATFL reconstruction. These data suggest that excessive tension during ATFL reconstruction should be avoided to ensure restoration of normal ankle motion.

scholarly journals Investigation of the Effect of Initial Graft Tension During Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In-situ Force

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0041
Author(s):  
Yuzuru Sakakibara ◽  
Atsushi Teramoto ◽  
Tomoaki Kamiya ◽  
Kota Watanabe ◽  
Toshihiko Yamashita
Keyword(s):  
External Rotation ◽  
Anatomic Reconstruction ◽  
Anterior Talofibular Ligament ◽  
Ankle Sprains ◽  
Principle Of Superposition ◽  
Initial Tension ◽  
Graft Tension ◽  
In Situ Force ◽  
Ankle Kinematics

Category: Basic Sciences/Biologics Introduction/Purpose: Ankle sprains are the most common sports injuries, and anterior talofibular ligament (ATFL) injury comprised 85% of all ankle sprains. Most patients recover with conservative treatment, but 20% of them progress to chronic ankle instability. Some studies have reported that anatomic reconstruction using a tendon graft is one of the best procedures to restore the ankle to its condition before symptom development. However, the effect of initial graft tension during ATFL reconstruction is still unclear. Therefore, the objective of this study was to investigate the effect of the initial graft tension during ATFL reconstruction. Methods: Eight fresh-frozen cadaveric ankle specimens were subjected to passive plantarflexion (PF)-dorsiflexion (DF) movement from 15° DF to 30° PF using the 6-degree-freedom robotic system. In addition, 60 N of anterior-posterior load, 1.7 Nm of inversion-eversion (IV-EV) torque, and 1.7 Nm of internal-external rotation (IR-ER) torque were applied to the ankle. During testing, 3-dimensional paths of the ankle were recorded simultaneously. Furthermore, in-situ forces of the ATFL and reconstructed graft were calculated using the principle of superposition. A repeated experiment was designed with the intact condition (intact), ATFL transection, and ATFL reconstruction with four different initial graft tensions (10 N, 30 N, 50 N, and 70 N). Results: AP laxity, IV-EV laxity and IR-ER laxity with ATFL transection was significantly greater than those with intact. In ATFL transection, the talus was significantly translated anteriorly with inversion and internal rotations under passive PF-DF motion compared with intact. Kinematic patterns and laxity in ATFL reconstruction with initial tension of 10 N and 30 N almost imitated intact, but in ATFL reconstruction with initial tension 70 N, the talus was significantly translated with external rotation compared with intact. As the initial graft tension during ATFL reconstruction increased, in-situ force of the reconstructed graft tended to increase during PF-DF motion. In-situ force of the reconstructed graft tension was significantly greater with initial tensions of 50 N, and 70 N than with intact during PF-DF motion (Figure 1). Conclusion: ATFL deficiency altered ankle kinematics and laxity. Although the optimal initial graft tension during ATFL reconstruction might restore ankle kinematics and laxity, excessive initial graft tension caused abnormal kinematics and laxity. Furthermore, the reconstructed graft tension increased as the initial tension increased. Initial tension during ATFL reconstruction has the important effect of imitating the normal ankle condition. We suggest that over-tensioning during ATFL reconstruction should be avoided in order to imitate the conditions of a normal ankle.

Effects of the Ankle Flexion Angle During Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In Situ Forces of the Reconstructed Graft

2022 ◽  
pp. 107110072110693
Author(s):  
Yuzuru Sakakibara ◽  
Atsushi Teramoto ◽  
Tetsuya Takagi ◽  
Satoshi Yamakawa ◽  
Hiroaki Shoji ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Plantar Flexion ◽  
Flexion Angle ◽  
Anterior Talofibular Ligament ◽  
Neutral Position ◽  
Principle Of Superposition ◽  
Initial Tension ◽  
In Situ Force ◽  
Ankle Kinematics

Background: This study aimed to evaluate the effects of the ankle flexion angle during anterior talofibular ligament (ATFL) reconstruction on ankle kinematics, laxity, and in situ force of a graft. Methods: Twelve cadaveric ankles were evaluated using a 6–degrees of freedom robotic system to apply passive plantar flexion and dorsiflexion motions and multidirectional loads. A repeated measures experiment was designed using the intact ATFL, transected ATFL, and reconstructed ATFL. During ATFL reconstruction (ATFLR), the graft was fixed at a neutral position (ATFLR 0 degrees), 15 degrees of plantar flexion (ATFLR PF15 degrees), and 30 degrees of plantar flexion (ATFLR PF30 degrees) with a constant initial tension of 10 N. The 3-dimensional path and reconstructed graft tension were simultaneously recorded, and the in situ force of the ATFL and reconstructed grafts were calculated using the principle of superposition. Results: The in situ forces of the reconstructed grafts in ATFLR 0 degrees and ATFLR PF 15 degrees were significantly higher than those of intact ankles. The ankle kinematics and laxity produced by ATFLR PF 30 degrees were not significantly different from those of intact ankles. The in situ force on the ATFL was 19.0 N at 30 degrees of plantar flexion. In situ forces of 41.0, 33.7, and 21.9 N were observed at 30 degrees of plantar flexion in ATFLR 0, 15, and 30 degrees, respectively. Conclusion: ATFL reconstruction with the peroneus longus (PL) tendon was performed with the graft at 30 degrees of plantar flexion resulted in ankle kinematics, laxity, and in situ forces similar to those of intact ankles. ATFL reconstructions performed with the graft fixed at 0 and 15 degrees of the plantar flexion resulted in higher in situ forces on the reconstructed graft. Clinical Relevance: Fixing the ATFL tendon graft at 30 degrees of plantar flexion results in an in situ force closest to that of an intact ankle and avoids the excessive tension on the reconstructed graft.

scholarly journals Effect of Ankle Position during Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In-situ Force

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0006
Author(s):  
Yuzuru Sakakibara ◽  
Atsushi Teramoto ◽  
Hiroaki Shoji ◽  
Tonmoaki Kamiya ◽  
Kota Watanabe ◽  
...  
Keyword(s):  
External Rotation ◽  
Anterior Talofibular Ligament ◽  
Principle Of Superposition ◽  
Optimal Position ◽  
In Situ Force ◽  
Ankle Kinematics ◽  
Significant Difference ◽  
Intact Condition ◽  
Group A

Category: Ankle, Basic Sciences/Biologics Introduction/Purpose: Anatomical anterior talofibular ligament (ATFL) reconstruction is a standard surgical treatment for chronic lateral ankle instability. The optimal position during ATFL reconstruction is still uncertain. The purpose of this study was to investigate the effect of ankle position during ATFL reconstruction on ankle kinematics, laxity, and in-situ force on the graft. Methods: Twelve fresh-frozen cadaveric ankles were evaluated. First, ankle specimens were subjected to passive plantarflexion (PF)-dorsiflexion (DF) movement, from 15° DF to 30° PF, using a 6-degrees-of-freedom robotic system. Then, 60 N of anterior- posterior (AP) load, 1.7 Nm of inversion-eversion (IV-EV) torque, and 1.7 Nm of internal-external rotation (IR-ER) torque were applied to the ankle. During testing, 3-dimensional paths of the ankle were recorded simultaneously. In-situ forces on the ATFL and reconstructed graft were calculated using the principle of superposition. A repeat experiment was designed with intact (intact), ATFL transection, and ATFL reconstruction conditions, using 3 different flexion angles (Group A: 0°, Group B: PF 15°, Group C: PF 30°). Results: In ATFL transection condition, the talus was significantly translated anteriorly with internal rotation during PF-DF motion, compared to that in intact condition. In addition, laxity in AP, IV-EV, and IR-ER conditions was significantly greater than in intact condition. In each ATFL reconstruction group, kinematics and laxity showed no significant difference compared to that in intact condition. In intact condition, in-situ force was maximal at PF 30° (19.0±12.0 N). The in-situ force on the reconstructed graft in Group A, B, and C at PF 30° was 50.0±12.4 N, 33.7±13.0 N, and 21.9±7.5 N. The in-situ force in Group A and B was significantly greater than in intact condition. The in-situ force in Group C was not significantly different compared to that in intact condition (Figure 1). Conclusion: Ankle position during ATFL reconstruction affected in-situ force on the reconstructed graft. ATFL reconstruction at PF 30° is recommended to avoid excessive in-situ force on the reconstructed graft.

Effect of Initial Graft Tension During Calcaneofibular Ligament Reconstruction on Ankle Kinematics and Laxity

2018 ◽  
Vol 46 (12) ◽  
pp. 2935-2941 ◽  
Author(s):  
Yuzuru Sakakibara ◽  
Atsushi Teramoto ◽  
Tetsuya Takagi ◽  
Satoshi Yamakawa ◽  
Yohei Okada ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Degrees Of Freedom ◽  
Ligament Reconstruction ◽  
External Rotation ◽  
Calcaneofibular Ligament ◽  
Initial Tension ◽  
3 Dimensional ◽  
Graft Tension ◽  
Intact Condition ◽  
Lateral Ankle Ligament

Background: Although a variety of surgical procedures for lateral ankle ligament reconstruction have frequently been reported, little is known about the effects of initial graft tension. Purpose/Hypothesis: The purpose was to investigate the effects of initial graft tension in calcaneofibular ligament (CFL) reconstruction. It was hypothesized that a high degree of initial graft tension would cause abnormal kinematics, laxity, and excessive graft tension. Study Design: Controlled laboratory study. Methods: Twelve cadaveric ankles were tested with a 6 degrees of freedom robotic system to apply passive plantarflexion-dorsiflexion motion and multidirectional loads. A repeated-measures experiment was designed with the CFL intact, CFL transected, and CFL reconstructed with 4 initial tension conditions (10, 30, 50, and 70 N). The 3-dimensional path and reconstructed graft tension were simultaneously recorded. Results: The calcaneus in CFL reconstruction with an initial tension of 70 N had the most eversion relative to the intact condition (mean eversion translations of 1.2, 3.0, 5.0, and 6.2 mm were observed at initial tensions of 10, 30, 50, and 70 N, respectively). The calcaneus also moved more posteriorly with external rotation as the initial tension increased. The reconstructed graft tension tended to increase as the initial tension increased. Conclusion: Ankle kinematic patterns and laxity after CFL reconstruction tended to become more abnormal as the initial graft tension increased at the time of surgery. Moreover, excessive initial graft tension caused excessive tension on the reconstructed graft. Clinical Relevance: This study indicated the importance of initial graft tension during CFL reconstruction. Overtensioning during CFL reconstruction should be avoided to imitate a normal ankle.

scholarly journals TL 18049 - Influence of tibial component position on altered kinematics following total ankle arthroplasty during simulated gait

2019 ◽  
Vol 13 (Supl 1) ◽  
pp. 63S
Author(s):  
Guilherme Honda Saito ◽  
Daniel Sturnick ◽  
Jonathan Deland ◽  
Scott Ellis
Keyword(s):  
Ankle Joint ◽  
Tibial Component ◽  
Degrees Of Freedom ◽  
Lateral Position ◽  
Total Ankle Arthroplasty ◽  
Component Position ◽  
Ankle Arthroplasty ◽  
Ankle Motion ◽  
Ankle Kinematics ◽  
Ct Data

Introduction: Correct positioning of total ankle arthroplasty (TAA) implants has been associated with superior clinical outcomes. However, the correlation between implant position and ankle motion is unclear. The objective of this study was to assess the effect of tibial component position on ankle kinematics during simulated gait. Methods: The stance phase of gait was simulated pre and post-TAA with 8 mid-tibia cadaveric specimens using a six-degrees-of-freedom robotic platform. Ankle kinematics were measured based on reflective markers. A fixed-bearing total ankle system (Salto Talaris, Integra LifeSciences) was used. Using reconstructed CT data, the 3D tibial component position relative to a standard ankle joint reference was characterized (Fig 1A). The effect of the tibial component position on absolute differences in ankle kinematics (pre/post TAA) was assessed using linear regression with a level of significance set to p = 0.05. Results: Differences in ankle joint kinematics were only identified in the transverse plane, where internal talar rotation was significantly increased following TAA compared with the native condition (Fig 1B). The medial position of TAA tibial components was positively associated with increased internal talar rotation (Fig 1C; β = 1.861 degrees/mm, R2 = 0.72, p = 0.008). Conclusion: This study suggests that a medial-lateral position of the tibial implant affects ankle kinematics. During operative procedures, the tibial component is usually positioned to preserve the bone stock of the medial and lateral malleolus. However, little attention is given to the position of the implant in relation to the center of the tibial axis. This finding could have clinical implications for techniques.

scholarly journals IMPROVING SYSTEM READINESS, STAFF PREPAREDNESS AND PATIENT SAFETY IN A NEW SINGLE FAMILY ROOM NICU THROUGH IN SITU SIMULATION

2018 ◽  
Vol 23 (suppl_1) ◽  
pp. e16-e16
Author(s):  
Ahmed Moussa ◽  
Audrey Larone-Juneau ◽  
Laura Fazilleau ◽  
Marie-Eve Rochon ◽  
Justine Giroux ◽  
...  
Keyword(s):  
Patient Safety ◽  
Repeated Measures ◽  
Large Scale ◽  
Multidisciplinary Teams ◽  
Single Family ◽  
In Situ Simulation ◽  
Ensure Patient Safety ◽  
System Readiness ◽  
Dependent Samples

Abstract BACKGROUND Transitions to new healthcare environments can negatively impact patient care and threaten patient safety. Immersive in situ simulation conducted in newly constructed single family room (SFR) Neonatal Intensive Care Units (NICUs) prior to occupancy, has been shown to be effective in testing new environments and identifying latent safety threats (LSTs). These simulations overlay human factors to identify LSTs as new and existing process and systems are implemented in the new environment OBJECTIVES We aimed to demonstrate that large-scale, immersive, in situ simulation prior to the transition to a new SFR NICU improves: 1) systems readiness, 2) staff preparedness, 3) patient safety, 4) staff comfort with simulation, and 5) staff attitude towards culture change. DESIGN/METHODS Multidisciplinary teams of neonatal healthcare providers (HCP) and parents of former NICU patients participated in large-scale, immersive in-situ simulations conducted in the new NICU prior to occupancy. One eighth of the NICU was outfitted with equipment and mannequins and staff performed in their native roles. Multidisciplinary debriefings, which included parents, were conducted immediately after simulations to identify LSTs. Through an iterative process issues were resolved and additional simulations conducted. Debriefings were documented and debriefing transcripts transcribed and LSTs classified using qualitative methods. To assess systems readiness and staff preparedness for transition into the new NICU, HCPs completed surveys prior to transition, post-simulation and post-transition. Systems readiness and staff preparedness were rated on a 5-point Likert scale. Average survey responses were analyzed using dependent samples t-tests and repeated measures ANOVAs. RESULTS One hundred eight HCPs and 24 parents participated in six half-day simulation sessions. A total of 75 LSTs were identified and were categorized into eight themes: 1) work organization, 2) orientation and parent wayfinding, 3) communication devices/systems, 4) nursing and resuscitation equipment, 5) ergonomics, 6) parent comfort; 7) work processes, and 8) interdepartmental interactions. Prior to the transition to the new NICU, 76% of the LSTs were resolved. Survey response rate was 31%, 16%, 7% for baseline, post-simulation and post-move surveys, respectively. System readiness at baseline was 1.3/5,. Post-simulation systems readiness was 3.5/5 (p = 0.0001) and post-transition was 3.9/5 (p = 0.02). Staff preparedness at baseline was 1.4/5. Staff preparedness post-simulation was 3.3/5 (p = 0.006) and post-transition was 3.9/5 (p = 0.03). CONCLUSION Large-scale, immersive in situ simulation is a feasible and effective methodology for identifying LSTs, improving systems readiness and staff preparedness in a new SFR NICU prior to occupancy. However, to optimize patient safety, identified LSTs must be mitigated prior to occupancy. Coordinating large-scale simulations is worth the time and cost investment necessary to optimize systems and ensure patient safety prior to transition to a new SFR NICU.

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

scholarly journals Cyclic Deformation of Microcantilevers Using In-Situ Micromanipulation

2021 ◽  
Author(s):  
A. H. S. Iyer ◽  
M. H. Colliander
Keyword(s):  
Degrees Of Freedom ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Structural Components ◽  
Cyclic Testing ◽  
Phase Boundaries ◽  
Bulk Specimen ◽  
Arbitrary Position ◽  
Three Degrees Of Freedom

Abstract Background The trend in miniaturisation of structural components and continuous development of more advanced crystal plasticity models point towards the need for understanding cyclic properties of engineering materials at the microscale. Though the technology of focused ion beam milling enables the preparation of micron-sized samples for mechanical testing using nanoindenters, much of the focus has been on monotonic testing since the limited 1D motion of nanoindenters imposes restrictions on both sample preparation and cyclic testing. Objective/Methods In this work, we present an approach for cyclic microcantilever bending using a micromanipulator setup having three degrees of freedom, thereby offering more flexibility. Results The method has been demonstrated and validated by cyclic bending of Alloy 718plus microcantilevers prepared on a bulk specimen. The experiments reveal that this method is reliable and produces results that are comparable to a nanoindenter setup. Conclusions Due to the flexibility of the method, it offers straightforward testing of cantilevers manufactured at arbitrary position on bulk samples with fully reversed plastic deformation. Specific microstructural features, e.g., selected orientations, grain boundaries, phase boundaries etc., can therefore be easily targeted.

In-situ high-pressure study of the ordered phase of ethyl propionate

2007 ◽  
Vol 63 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Roman Gajda ◽  
Andrzej Katrusiak
Keyword(s):  
High Pressure ◽  
Degrees Of Freedom ◽  
Molecular Volume ◽  
Ethyl Propionate ◽  
Intermolecular Contacts ◽  
High Pressure Study ◽  
Pressure Phase ◽  
Three Degrees Of Freedom ◽  
Volume Difference

Ethyl propionate, C5H10O2 (m.p. 199 K), has been in-situ pressure-frozen and its structure determined at 1.34, 1.98 and 2.45 GPa. The crystal structure of the new high-pressure phase (denoted β) is different from phase α obtained by lowering the temperature. The freezing pressure of ethyl propionate at 296 K is 1.03 GPa. The molecule assumes an extended chain s-trans–trans–trans conformation, only slightly distorted from planarity. The closest intermolecular contacts in both phases are formed between carbonyl O and methyl H atoms; however, the ethyl-group H atoms in phase β form no contacts shorter than 2.58 Å. A considerable molecular volume difference of 24.2 Å3 between phases α and β can be rationalized in terms of degrees of freedom of molecules arranged into closely packed structures: the three degrees of freedom allowed for rearrangements of molecules confined to planar sheets in phase α, but are not sufficient for obtaining a densely packed pattern.

scholarly journals Forage yield and nutritive value of Elephant grass, Italian ryegrass and spontaneous growing species mixed with forage peanut or red clover

2014 ◽  
Vol 44 (10) ◽  
pp. 1845-1852 ◽  
Author(s):  
Michelle Schalemberg Diehl ◽  
Clair Jorge Olivo ◽  
Carlos Alberto Agnolin ◽  
Ricardo Lima de Azevedo Junior ◽  
Vinícius Felipe Bratz ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Nutritive Value ◽  
Red Clover ◽  
Experimental Period ◽  
Italian Ryegrass ◽  
Forage Yield ◽  
Neutral Detergent Fiber ◽  
Elephant Grass ◽  
Grazing Systems

The objective of this research was to evaluate of three grazing systems (GS) with elephant grass (EG), Italian ryegrass (IR) + spontaneous growing species (SGS); EG + IR + SGS + forage peanut (FP); and EG + IR + SGS + red clover (RC), during the winter and summer periods in rotational grazing with dairy cattle. Experimental design was completely randomized with three treatments, two replicates with repeated measures. Lactating Holstein cows receiving 1% BW-daily feed supplement with concentrate were used in the evaluation. Eight grazing cycles were performed during the experimental period. The values of pre forage mass and stocking rate were 2.52, 2.60 and 2.99 t ha-1 and 2.64, 2.77 and 3.14 animal unit ha-1, respectively for GS. Samples of forage were collected by hand-plucking technique to analyze the crude protein (CP), neutral detergent fiber (NDF), in situ dry matter digestibility (ISDMD), in situ organic matter digestibility (ISOMD) of forage present between rows of elephant grass, in the rows of elephant grass and the legumes. Higher value of CP, ISOMD and lower of NDF were observed for the grazing systems mixed with legumes forage.

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