Validation of an Image-based Subject-Specific Dynamic Model of the Ankle Joint Complex and its Applications to the Study of the Effect of Articular Surface Morphology on Ankle Joint Mechanics

2021 ◽  
Author(s):  
Vishnuvardhan Balakrishnan
Keyword(s):  
Surface Morphology ◽  
Dynamic Model ◽  
Ankle Joint ◽  
Articular Surface ◽  
Joint Mechanics ◽  
Subject Specific

scholarly journals Determination of the Optimal Syndesmosis Fixation Angle Using Mortise View of The Ankle Joint

2021 ◽  
Author(s):  
Oğuzhan Tanoğlu ◽  
İzzet Özay Subaşı ◽  
Mehmet Burak Gökgöz
Keyword(s):  
Ankle Joint ◽  
Articular Surface ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Functional Results ◽  
Practical Method ◽  
Medial Malleolus ◽  
Significant Difference ◽  
Horizontal View ◽  
Mortise View

Background: Syndesmosis is an important soft tissue component supporting the ankle stability and commonly injured accompanying with ankle fractures. The accurate reduction and fixation of syndesmosis is essential to obtain better functional results. Therefore, we aimed to find a practical method using the mortise view of ankle to determine the optimal syndesmosis fixation angle intraoperatively. Methods: We randomly selected 200 adults (100 women and 100 men) between 18 - 60 years of age. Three-dimensional anatomical models of tibia and fibula were created using Materialise MIMICS 21. We created a best fit plane on articular surface of medial malleolus and a ninety degrees vertical plane to medial malleolus plane. We determined two splines on cortical borders of tibia and fibula distant from the most superior point of ankle joint in horizontal view. We created two spheres that fit to the predefined splines. The optimal syndesmosis fixation angle was determined measuring the angle between the line connecting the center points of spheres, and the ninety degrees vertical plane to medial malleolus plane. Results: We observed no statistically significant difference between gender groups in terms of optimal syndesmosis fixation angles. The mean age of our study population was 47.1 {plus minus} 10.5. The optimal syndesmosis fixation angle according to mortise view was found as 21 {plus minus} 4.3 degrees. Conclusions: We determined the optimal syndesmosis fixation angle as 21 {plus minus} 4.3 degrees in accordance with the mortise view of ankle. The surgeon could evaluate the whole articular surface of ankle joint with the medial and lateral syndesmotic space in mortise view accurately and at the same position syndesmosis fixation could be performed at 21 {plus minus} 4.3 degrees.

scholarly journals Characterization and clinical implications of ankle impedance during walking in chronic stroke

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amanda L. Shorter ◽  
James K. Richardson ◽  
Suzanne B. Finucane ◽  
Varun Joshi ◽  
Keith Gordon ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Clinical Care ◽  
Joint Stiffness ◽  
Mechanical Impedance ◽  
Chronic Stroke ◽  
Joint Mechanics ◽  
Clinical Assessments ◽  
Post Stroke ◽  
Joint Damping

AbstractIndividuals post-stroke experience persisting gait deficits due to altered joint mechanics, known clinically as spasticity, hypertonia, and paresis. In engineering, these concepts are described as stiffness and damping, or collectively as joint mechanical impedance, when considered with limb inertia. Typical clinical assessments of these properties are obtained while the patient is at rest using qualitative measures, and the link between the assessments and functional outcomes and mobility is unclear. In this study we quantify ankle mechanical impedance dynamically during walking in individuals post-stroke and in age-speed matched control subjects, and examine the relationships between mechanical impedance and clinical measures of mobility and impairment. Perturbations were applied to the ankle joint during the stance phase of walking, and least-squares system identification techniques were used to estimate mechanical impedance. Stiffness of the paretic ankle was decreased during mid-stance when compared to the non-paretic side; a change independent of muscle activity. Inter-limb differences in ankle joint damping, but not joint stiffness or passive clinical assessments, strongly predicted walking speed and distance. This work provides the first insights into how stroke alters joint mechanical impedance during walking, as well as how these changes relate to existing outcome measures. Our results inform clinical care, suggesting a focus on correcting stance phase mechanics could potentially improve mobility of chronic stroke survivors.

scholarly journals Long-term Stress Distribution Patterns Across the Ankle Joint in Soccer Players: A Computed Tomography Osteoabsorptiometry Study

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096308
Author(s):  
Junki Shiota ◽  
Daisuke Momma ◽  
Takayoshi Yamaguchi ◽  
Norimasa Iwasaki
Keyword(s):  
Bone Density ◽  
Stress Distribution ◽  
Ankle Joint ◽  
Subchondral Bone ◽  
Articular Surface ◽  
Distribution Patterns ◽  
High Density ◽  
Soccer Players ◽  
Subchondral Bone Density

Background: The distribution pattern of subchondral bone density is considered to accurately reflect the stress distribution over a joint under long-term physiologic loading. The biomechanical characteristics of the surface of the ankle joint in soccer players can be determined by measuring this distribution pattern under long-term loading. Purpose: To evaluate the distribution of subchondral bone density across the ankle joint in soccer players and to determine the effects of soccer activities, including kicking motion, on the ankle joint surface under long-term loading conditions by computed tomography (CT) osteoabsorptiometry (CTOAM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: CT imaging data were obtained from both ankles of 10 soccer players (soccer group) and 10 nonathletic volunteers (control group). The distribution patterns of subchondral bone density across the articular surface of the ankle joints were assessed by CTOAM. Quantitative analysis was performed of the locations and percentages of high-density areas on the articular surface. Results: Stress distribution patterns over the ankle joint differed between the soccer players and controls. In the soccer players, the high-density areas were found in the anterior part of the distal tibia and proximal talus as well as the distal fibula. The percentages of high-density areas were greater in the soccer players compared with controls ( P < .0001). Conclusion: Stress distribution over the articular surface of the ankle joint was affected by soccer activities. A high stress concentration was seen in soccer players in the anterior part of the tibia and talus and in the fibula; such excessive stress may lead to anterior impingement.

scholarly journals Syndesmotic Instability After Total Ankle Replacement

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0010
Author(s):  
Roxa Ruiz ◽  
Lukas Zwicky ◽  
Beat Hintermann
Keyword(s):  
Ankle Joint ◽  
Tibial Component ◽  
External Rotation ◽  
Articular Surface ◽  
Cyst Formation ◽  
Total Ankle Replacement ◽  
Hindfoot Alignment ◽  
Additional Degree ◽  
Component Design ◽  
Ankle Replacement

Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement (TAR) evolved over the last decades and has been shown to be an effective concept in the treatment of ankle osteoarthritis (OA). In three-component designs, the second interface between polyethylene insert (PI) and tibial component allows the PI to find its position according the individual physiological properties. This was believed to decrease shear forces within the ankle joint. However, it is not clarified to which extent such an additional degree of freedom may overload the ligamentous structures of the ankle joint over time. This may in particular be the case for the syndesmotic ligaments. Therefore, the purpose of this study was to analyze all ankles after TAR that showed a symptomatic overload of the syndesmotic ligaments and to determine the potential consequences. Methods: Between 2003 and 2017, 31 ankles (females, 17; males 14; mean age 60 [40-79] years) were treated with a tibio-fibular fusion for a symptomatic instability of the syndesmosis. The indication for TAR was posttraumatic OA in 27 (87%), primary OA in 3 (10%), and hemochromatosis in one ankle (3%). The 31 ankles included 23 primary TAR (74%), 6 revision TAR (19%), and two take-down of a fusion and conversion to TAR (7%). Criteria for fusion were the presence of at least two of the followings: (1) tenderness over the syndesmosis, (2) pain while compressing the fibula against the tibia (squeeze test), (3) pain while rotating the foot externally (external rotation test), (4) widening of the syndesmosis on an anteroposterior view. Alignment of TAR (tibial articular surface [TAS] angle) and hindfoot alignment were measured on standard radiographs. Intraoperatively, the syndesmotic instability was confirmed before fusion. The wear of PI was documented. Results: After a mean of 63 (range, 4 – 152) months after TAR, all patients evidenced pain at the level of the syndesmosis of at least 3 months. 25 ankles (81%; 24 after posttraumatic OA) showed a widening of the syndesmotic space and 22 ankles (71%) of the medial clear space with lateral translation of the talus. The PI was seen to overlap the tibial component in 15 ankles (48%). Nine ankles (29%) evidenced cyst formation, and eight ankles (26%) showed a decrease in height of the PI; whereas, in 3 ankles (10%) a fracture of the PI was found. A valgus misalignment of the heel was found in 25 ankles (81%), a valgus TAS in 16 (52%) and a varus TAS in 11 ankles (36%). Conclusion: A syndesmotic instability after a three-component TAR apparently occurred mostly after posttraumatic OA, in particular if the heel was left in valgus. If the talus starts to move lateralward, the PI seems to be at risk for increased wear and finally mechanical failure (Figure 1). Therefore, a valgus misaligned heel should always be corrected during TAR implantation. If there is any sign of syndesmotic instability, a fusion should be considered. Further studies must proof whether in cases with a syndesmotic instability the use of a two-component design will be superior, as it stabilizes the talus in the coronal plane.

INVERSE DYNAMICS OF THE LOWER EXTREMITIES: NOVEL APPROACH CONSIDERING TALOCRURAL AND SUBTALAR JOINT AXIS

2011 ◽  
Vol 11 (03) ◽  
pp. 515-527 ◽  
Author(s):  
TILLE KAROLINE RUPP ◽  
SYN SCHMITT
Keyword(s):  
Ankle Joint ◽  
Inverse Dynamics ◽  
Reaction Force ◽  
Lower Extremities ◽  
Ankle Injuries ◽  
Ankle Sprains ◽  
Joint Mechanics ◽  
Talocrural Joint ◽  
Joint Torques ◽  
Injury Mechanisms

A recent survey of epidemiological studies lists ankle injuries as one common sport injury. However, the details of the injury mechanisms of ankle sprains — the majority of ankle injuries — remain not well understood. The purpose of the presented study is twofold. The first aim is to introduce a new, widely applicable method to calculate ankle joint torques during movement using inverse dynamics. The subtalar and talocrural joint are modeled as anatomically based revolute joints. The kinematics of the lower extremities and ground reaction force are used as input data. Second, a comparison of two calculation approaches (dynamic versus static) is reported, aimed at verifying and simplifying the introduced method to have a more convenient tool at hand for applications in the field. For one first movement measurement (hopping), the calculated joint torques show a good match for the two calculation approaches. After further application, the evaluation of the resulting joint torques will provide further insights into the joint mechanics and can contribute to a better understanding of the respective injury mechanisms. Hence, this approach is interesting for researchers to be used in order to understand ankle injuries and to determine the influence of landing grounds and shoes on ankle joint torques.

scholarly journals The Function Axis of Rotation of the Ankle Joint during Simulated Gait

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0003
Author(s):  
Daniel Sturnick ◽  
Constantine Demetracopoulos ◽  
Guilherme Honda Saito
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Force Plate ◽  
Implant Design ◽  
Joint Mechanics ◽  
Center Of Rotation ◽  
Axis Of Rotation ◽  
Ankle Kinematics ◽  
Flexion Extension ◽  
Joint Center

Category: Ankle, Ankle Arthritis, Hindfoot Introduction/Purpose: Implant component positioning is considered as an important factor in function and longevity in total ankle arthroplasty (TAA). However, accurate and repeatable positioning remains a limitation with current techniques and instrumentation. In addition, further investigation is needed to objectively define the optimum component positioning. Cadaveric gait simulation is a valuable tool for investigating foot and ankle joint mechanics during functional tasks such as the stance phase of gait. The objective of this study was to investigate the functional axis of rotation of the native ankle joint during simulated gait. Methods: The stance phase of healthy gait was simulated with six mid-tibia cadaveric specimens using a previously validated device and methodology. A robotic platform reproduced tibial-ground kinematics by moving a force plate relative to the stationary specimen while physiologic loads were applied to the extrinsic tendons to actuate the foot. (Figure 1A). Ankle kinematics were measured from reflective markers attached to the tibia and talus via surgical pins. The helical axes of rotation of the talus with respect to the tibia was calculated during three portions of stance: initial plantarflexion during earlier-stance after heal strike, dorsiflexion during mid-stance, and final plantarflexion during late-stance. The position and orientation of these kinematic-defined axes of rotation were compared to the transmalleolar axis and reduced to its anteroposterior position and transverse plane angle (Figure 1B). Results: Analyses revealed that ankle joint functional axis of rotation varied from the anatomic reference throughout stance. The kinematic center of rotation was located 16.4 ± 5.8 mm, 16.5 ± 6.6 mm, and 15.6 ± 6.5 mm anterior to the transmalleolar axis during early-, mid- and late-portions of stance, respectively. Conclusion: This study revealed that the position of the flexion-extension axis varies greatly between specimens during simulated gait. While previous reports have suggested that the transmalleolar axis is an acceptable approximation for the ankle joint center, these findings suggest that further research in warranted to better describe the complex tibiotalar kinematics. This work may provide future insight to guide implant design and advance techniques, to better place articular constraints of a total ankle in the native center of rotation of the joint.

Development and Evaluation of a Subject-Specific Lower Limb Model With an Eleven-Degrees-of-Freedom Natural Knee Model Using Magnetic Resonance and Biplanar X-Ray Imaging During a Quasi-Static Lunge

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
David Leandro Dejtiar ◽  
Christine Mary Dzialo ◽  
Peter Heide Pedersen ◽  
Kenneth Krogh Jensen ◽  
Martin Kokholm Fleron ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Knee Joint ◽  
Joint Model ◽  
Joint Kinematics ◽  
Contact Forces ◽  
Joint Mechanics ◽  
X Ray ◽  
Knee Mechanics ◽  
Subject Specific

Abstract Musculoskeletal (MS) models can be used to study the muscle, ligament, and joint mechanics of natural knees. However, models that both capture subject-specific geometry and contain a detailed joint model do not currently exist. This study aims to first develop magnetic resonance image (MRI)-based subject-specific models with a detailed natural knee joint capable of simultaneously estimating in vivo ligament, muscle, tibiofemoral (TF), and patellofemoral (PF) joint contact forces and secondary joint kinematics. Then, to evaluate the models, the predicted secondary joint kinematics were compared to in vivo joint kinematics extracted from biplanar X-ray images (acquired using slot scanning technology) during a quasi-static lunge. To construct the models, bone, ligament, and cartilage structures were segmented from MRI scans of four subjects. The models were then used to simulate lunges based on motion capture and force place data. Accurate estimates of TF secondary joint kinematics and PF translations were found: translations were predicted with a mean difference (MD) and standard error (SE) of 2.13 ± 0.22 mm between all trials and measures, while rotations had a MD ± SE of 8.57 ± 0.63 deg. Ligament and contact forces were also reported. The presented modeling workflow and the resulting knee joint model have potential to aid in the understanding of subject-specific biomechanics and simulating the effects of surgical treatment and/or external devices on functional knee mechanics on an individual level.

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