Evaluation of the Intact Anterior Talofibular and Calcaneofibular Ligaments, Injuries, and Repairs With and Without Augmentation: A Biomechanical Robotic Study

2021 ◽  
pp. 036354652110186
Author(s):  
Christopher G. Larkins ◽  
Alex W. Brady ◽  
Zachary S. Aman ◽  
Grant J. Dornan ◽  
Craig T. Haytmanek ◽  
...  
Keyword(s):  
Surgical Treatment ◽  
Degrees Of Freedom ◽  
Anterior Drawer ◽  
Anterior Translation ◽  
Intact State ◽  
Time Zero ◽  
Ankle Stability ◽  
Talar Tilt ◽  
6 Degrees Of Freedom ◽  
Suture Tape

Background: Acute ankle sprains are common injuries. The anterior talofibular (ATFL) and calcaneofibular ligaments (CFL) are the most injured lateral structures. However, controversy exists on the optimal surgical treatment when the injury is both acute and severe or becomes chronic and unstable. Studies have evaluated the biomechanics of these ligaments, but no studies have robotically evaluated injury effects and surgical treatment of ATFL or ATFL and CFL injuries. Purpose: To quantitatively evaluate biomechanical effects of ATFL and CFL lesions, ATFL repair, ATFL and CFL repair, and augmentation of ATFL on ankle stability. Study Design: Controlled laboratory study. Methods: Ten nonpaired cadaveric ankles were tested using a 6 degrees of freedom robot. Each ankle underwent testing in the following states sequentially: (1) intact, (2) ATFL cut, (3) CFL cut, (4) ATFL repair + CFL cut, (5) ATFL repair + CFL repair, and (6) ATFL repair with augmentation with suture tape + CFL repair. Testing included 88 N anterior drawer and 5 N·m varus talar tilt tests at 0° and 30° of plantarflexion, and 88 N Cotton test at 0° of plantarflexion. Results: After all surgical treatments ankles still had increased laxity compared with intact state testing, except after augmented ATFL repair + CFL repair in anterior drawer testing at 30° of plantarflexion ( P = .393). Sectioning the CFL caused a significant increase in talar tilt compared with the ATFL cut state at 0° ( P < .001) and 30° of plantarflexion ( P < .001), but no increase in anterior drawer or Cotton tests. Conclusion: Complete native stability may not be attainable at time zero repair with the tested treatments. The option that best returned stability in anterior translation was augmented ATFL repair with nonaugmented CFL repair. The importance of the CFL as a primary ligamentous stabilizer for talar tilt was confirmed. Clinical Relevance: Evaluating lateral ankle stability and treatment with a 6 degrees of freedom robot should help delineate optimal treatment options. Findings in this study show that none of the repair methods at time zero restored kinematics to the intact state. Of the tested states, the augmented ATFL repair with CFL repair was the best option for controlling anterior translation at time zero. The importance of addressing the CFL to correct talar tilt instability was suggested as was the importance of a period of immobilization before beginning protected rehabilitation. The benefit of ATFL repair augmentation with suture tape is in limiting the postoperative motion in an anterior drawer motion to just 0.5 to 1 mm, but there was no significant improvement to talar tilt even with CFL repair, suggesting that further consideration should be given to CFL augmentation in future studies.

scholarly journals Diagnosing the Impact of the Syndesmotic Injury on Lateral Ankle Stability using Dynamic Ultrasound

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0013
Author(s):  
Rohan Bhimani ◽  
Jirawat Saengsin ◽  
Go Sato ◽  
Noortje Hagemeijer ◽  
Bart Lubberts ◽  
...  
Keyword(s):  
Anterior Talofibular Ligament ◽  
Syndesmotic Injury ◽  
Lateral Ankle ◽  
Anterior Drawer ◽  
Intact State ◽  
Tibiofibular Ligament ◽  
Ankle Stability ◽  
Clear Space ◽  
Lateral Ankle Ligament ◽  
The Impact

Category: Ankle; Basic Sciences/Biologics; Sports; Trauma Introduction/Purpose: There is a high prevalence of coexisting lateral ankle ligament injuries and syndesmotic ligamentous injuries. However, it is unclear whether syndesmotic ligaments directly contribute toward the stability of the lateral ankle. Dynamic ultrasonography (US) is an imaging modality increasingly used for the care of orthopaedic foot and ankle patients because it allows dynamic evaluation of structures at the point of care with little risk to the patient and at low-cost. The aim of this study is to assess the effect of syndesmotic injury as well as combined syndesmotic and lateral ankle injury on the stability of the lateral ankle. Methods: Sixteen fresh frozen above-knee amputated cadaveric specimens, divided into two groups, underwent ultrasound evaluation for lateral ankle stability. In both the groups, the assessment was first done with all ligaments intact and later with sequential transection of anterior inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), posterior inferior tibiofibular ligament (PITFL), anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). In all scenarios, two loading conditions were considered: (1) Anterior drawer test: 50N and 80N and (2) Lateral clear space (LCS): 1.7Nm torque. The talar translation and LCS to the fixed tibial plafond were measured using Image J. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. A p-value <0.05 was considered statistically significant. Results: In group 1 after transection of the all syndesmotic ligament and ATFL, an increase in the anterior drawer and lateral clear space values were found as compared to the intact state. Similarly, in group 2 the anterior drawer and lateral clear space values significantly increased after transection of the AITFL and ATFL as compared to the intact state (p-values = 0.01). Conclusion: Ultrasound can be used to evaluate the impact of the syndesmotic injury on lateral ankle stability while performing dynamic stress maneuvers. Lateral ankle instability appears after injury to all syndesmotic ligaments and ATFL, or after one syndesmotic ligament rupture (AITFL) with a concomitant anterior talofibular ligament rupture (ATFL). These findings suggest that surgeons should lower their threshold for stabilizing the syndesmosis if there is a concomitant lateral ankle ligament injury. [Table: see text]

scholarly journals Arthroscopic Brostrom technique

2020 ◽  
Vol 14 (2) ◽  
pp. 138-143
Author(s):  
Thiago Penido Moreira Ferreira ◽  
Mateus Martins Marcatti ◽  
Fabrício Melo Bertolini ◽  
Otaviano de Oliveira Junior ◽  
Gustavo Araújo Nunes
Keyword(s):  
Surgical Treatment ◽  
Case Series ◽  
High Rate ◽  
Tilt Test ◽  
Lateral Ligament ◽  
Level Of Evidence ◽  
Chronic Instability ◽  
Anterior Drawer ◽  
Ankle Stability

Objective: To present the clinical and functional results of surgical treatment of patients with chronic instability of the ankle using the arthroscopic Brostrom technique. Methods: This is a case series of patients who underwent surgical treatment for chronic instability of the lateral ligament of the ankle using the arthroscopic Brostrom technique. Clinical assessments of ankle stability were performed preoperatively and at the last follow-up using the American Orthopedic Foot and Ankle Score (AOFAS), a visual analog scale (VAS) for pain, and the anterior drawer and talar inversion tilt tests. Surgical complications and patient satisfaction ratings were also analyzed. Results: A total of 16 patients were analyzed, with a mean follow-up of 14 months. There was a statistically significant (p<0.001) improvement in mean AOFAS, which increased from 67.2 to 90.8 points and the mean VAS for pain score reduced from 6.5 to 1.5 points. All ankles were stable and had normal results for the anterior drawer test and the talar inversion tilt test. Three patients (19%) reported that resumption of sporting activities provoked subjective pain in the ankle, which improved progressively during follow-up. Two patients (12.5%) exhibited neurapraxia of the superficial peroneal nerve. A majority of the patients (81%) rated treatment as good or excellent. Conclusion: Treatment of chronic instability of the ankle ligament using the arthroscopic Brostrom technique restored ankle stability and achieved good clinical results. There was a high rate of early complications, but the majority were transitory and underwent complete remission during follow-up. Level of Evidence IV; Therapeutic Studies; Case Series.

scholarly journals Dynamic Evaluation Of The Effect Of Syndesmotic Injury On Lateral Ankle Stability Using Fluoroscopy

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0002
Author(s):  
Rohan Bhimani ◽  
Go Sato ◽  
Jirawat Saengsin ◽  
Noortje Hagemeijer ◽  
Bart Lubberts ◽  
...  
Keyword(s):  
Ankle Instability ◽  
Anterior Talofibular Ligament ◽  
Lateral Ankle ◽  
Anterior Drawer ◽  
Intact State ◽  
Tibiofibular Ligament ◽  
Clear Space ◽  
Lateral Ankle Ligament ◽  
Talar Tilt ◽  
The Stability

Category: Ankle; Sports; Trauma Introduction/Purpose: There is a high incidence of concomitance between lateral ankle ligament injuries and syndesmotic ligamentous injuries. However, it is unclear whether syndesmotic ligaments directly contribute toward the stability of the lateral ankle. Stress radiographs are an accepted technique to assess the degree of lateral ankle instability by providing a static view of the ankle when subjected to the anterior drawer (AD) and talar tilt (TT) tests. The aim of this study is to assess the effect of syndesmotic injury as well as combined syndesmotic and lateral ankle injury on the stability of the lateral ankle. Methods: Sixteen fresh frozen above-knee amputated cadaveric specimens, divided into two groups, underwent fluoroscopic evaluation for lateral ankle stability. In both the groups, the assessment was first done with all ligaments intact and later with sequential transection of anterior inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), posterior inferior tibiofibular ligament (PITFL), anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). In all scenarios, two loading conditions were considered: (1) Anterior drawer test: 50N and 80N and (2) Talar tilt and Lateral clear space (LCS): 1.7Nm torque. The talar translation, talar tilt, and LCS were measured using Image J. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. A p-value <0.05 was considered statistically significant. Results: In group 1 after transection of the AITFL and IOL, an increase in the anterior drawer, talar tilt, and lateral clear space values was found as compared to the intact state. Similarly, in group 2 the anterior drawer, talar tilt, and lateral clear space values significantly increased after transection of the AITFL and ATFL as compared to the intact state (p-values = 0.001). Conclusion: Lateral ankle instability appears after injury to two syndesmotic ligaments (AITFL and IOL), or after one syndesmotic ligament rupture (AITFL) with a concomitant anterior talofibular ligament rupture (ATFL). These findings suggest that surgeons should lower their threshold for stabilizing the syndesmosis if there is a concomitant lateral ankle ligament injury.

scholarly journals Influence of the Anterolateral Ligament on Knee Laxity: A Biomechanical Cadaveric Study Measuring Knee Kinematics in 6 Degrees of Freedom Using Dynamic Radiostereometric Analysis

2018 ◽  
Vol 6 (8) ◽  
pp. 232596711878969 ◽  
Author(s):  
Emil Toft Nielsen ◽  
Kasper Stentz-Olesen ◽  
Sepp de Raedt ◽  
Peter Bo Jørgensen ◽  
Ole Gade Sørensen ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Acl Reconstruction ◽  
Knee Flexion ◽  
Degrees Of Freedom ◽  
Knee Kinematics ◽  
Knee Laxity ◽  
Anterolateral Ligament ◽  
Single Bundle ◽  
Anterior Translation ◽  
6 Degrees Of Freedom

Background: An anterior cruciate ligament (ACL) rupture often occurs during rotational trauma to the knee and may be associated with damage to extracapsular knee rotation–stabilizing structures such as the anterolateral ligament (ALL). Purpose: To investigate ex vivo knee laxity in 6 degrees of freedom with and without ALL reconstruction as a supplement to ACL reconstruction. Study Design: Controlled laboratory study. Methods: Cadaveric knees (N = 8) were analyzed using dynamic radiostereometry during a controlled pivotlike dynamic movement simulated by motorized knee flexion (0° to 60°) with 4-N·m internal rotation torque. We tested the cadaveric specimens in 5 successive ligament situations: intact, ACL lesion, ACL + ALL lesion, ACL reconstruction, and ACL + ALL reconstruction. Anatomic single-bundle reconstruction methods were used for both the ACL and the ALL, with a bone-tendon quadriceps autograft and gracilis tendon autograft, respectively. Three-dimensional kinematics and articular surface interactions were used to determine knee laxity. Results: For the entire knee flexion motion, an ACL + ALL lesion increased the mean knee laxity ( P < .005) for internal rotation (2.54°), anterior translation (1.68 mm), and varus rotation (0.53°). Augmented ALL reconstruction reduced knee laxity for anterior translation ( P = .003) and varus rotation ( P = .047) compared with ACL + ALL–deficient knees. Knees with ACL + ALL lesions had more internal rotation ( P < .001) and anterior translation ( P < .045) at knee flexion angles below 40° and 30°, respectively, compared with healthy knees. Combined ACL + ALL reconstruction did not completely restore native kinematics/laxity at flexion angles below 10° for anterior translation and below 20° for internal rotation ( P < .035). ACL + ALL reconstruction was not found to overconstrain the knee joint. Conclusion: Augmented ALL reconstruction with ACL reconstruction in a cadaveric setting reduces internal rotation, varus rotation, and anterior translation knee laxity similar to knee kinematics with intact ligaments, except at knee flexion angles between 0° and 20°. Clinical Relevance: Patients with ACL injuries can potentially achieve better results with augmented ALL reconstruction along with ACL reconstruction than with stand-alone ACL reconstruction. Furthermore, dynamic radiostereometry provides the opportunity to examine clinical patients and compare the recontructed knee with the contralateral knee in 6 degrees of freedom.

Biomechanical analysis of anterior versus posterior instrumentation following a thoracolumbar corpectomy

2014 ◽  
Vol 21 (4) ◽  
pp. 577-581 ◽  
Author(s):  
Stephanus V. Viljoen ◽  
Nicole A. DeVries Watson ◽  
Nicole M. Grosland ◽  
James Torner ◽  
Brian Dalm ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Degrees Of Freedom ◽  
Screw Fixation ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Lateral Bending ◽  
Short Segment ◽  
Intact State ◽  
Flexion Extension ◽  
6 Degrees Of Freedom

Object The objective of this study was to evaluate the biomechanical properties of lateral instrumentation compared with short- and long-segment pedicle screw constructs following an L-1 corpectomy and reconstruction with an expandable cage. Methods Eight human cadaveric T10–L4 spines underwent an L-1 corpectomy followed by placement of an expandable cage. The spines then underwent placement of lateral instrumentation consisting of 4 monoaxial screws and 2 rods with 2 cross-connectors, short-segment pedicle screw fixation involving 1 level above and below the corpectomy, and long-segment pedicle screw fixation (2 levels above and below). The order of instrumentation was randomized in the 8 specimens. Testing was conducted for each fixation technique. The spines were tested with a pure moment of 6 Nm in all 6 degrees of freedom (flexion, extension, right and left lateral bending, and right and left axial rotation). Results In flexion, extension, and left/right lateral bending, posterior long-segment instrumentation had significantly less motion compared with the intact state. Additionally, posterior long-segment instrumentation was significantly more rigid than short-segment and lateral instrumentation in flexion, extension, and left/right lateral bending. In axial rotation, the posterior long-segment construct as well as lateral instrumentation were not significantly more rigid than the intact state. The posterior long-segment construct was the most rigid in all 6 degrees of freedom. Conclusions In the setting of highly unstable fractures requiring anterior reconstruction, and involving all 3 columns, long-segment posterior pedicle screw constructs are the most rigid.

4D in in vivo 2-photon laser scanning fluorescence microscopy with sample motion in 6 degrees of freedom

2011 ◽  
Vol 200 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Sabine Scheibe ◽  
Mario M. Dorostkar ◽  
Christian Seebacher ◽  
Rainer Uhl ◽  
Frank Lison ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Laser Scanning ◽  
Degrees Of Freedom ◽  
Sample Motion ◽  
6 Degrees Of Freedom

Workspace, dexterity and dimensional optimization of microhexapod

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Screw Theory ◽  
Design Parameters ◽  
Dimensional Synthesis ◽  
Content Type ◽  
Workspace Analysis ◽  
The Difference ◽  
Flexure Joints ◽  
6 Degrees Of Freedom

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.

An improved calibration curve between soil pH measured in waterand CaCl2

Soil Research ◽  
2002 ◽  
Vol 40 (8) ◽  
pp. 1399 ◽  
Author(s):  
B. L. Henderson ◽  
E. N. Bui
Keyword(s):  
Statistical Analysis ◽  
Water Resources ◽  
Soil Ph ◽  
Calibration Curve ◽  
Smooth Function ◽  
Degrees Of Freedom ◽  
Additive Model ◽  
Smoothing Spline ◽  
Look Up Table ◽  
6 Degrees Of Freedom

A new pH water to pH CaCl2 calibration curve was derived from data pooled from 2 National Land and Water Resources Audit projects. A total of 70465 observations with both pH in water and pH in CaCl2 were available for statistical analysis. An additive model for pH in CaCl2 was fitted from a smooth function of pH in water created by a smoothing spline with 6 degrees of freedom. This model appeared stable outside the range of the data and performed well (R2 = 96.2, s = 0.24). The additive model for conversion of pHw to pHCa is sigmoidal over the range of pH 2.5 to 10.5 and is similar in shape to earlier models. Using this new model, a look-up table for converting pHw to pHCa was created.

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