Specimen-Specific Computational Models of Ankle Sprains Produced in a Laboratory Setting

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Keith D. Button ◽  
Feng Wei ◽  
Eric G. Meyer ◽  
Roger C. Haut
Keyword(s):  
Computational Models ◽  
External Rotation ◽  
Experimental Studies ◽  
Cadaver Study ◽  
Deltoid Ligament ◽  
Ankle Sprains ◽  
Tibiofibular Ligament ◽  
Maximum Angle ◽  
Injury Mechanisms ◽  
Ligament Strain

The use of computational modeling to predict injury mechanisms and severity has recently been investigated, but few models report failure level ligament strains. The hypothesis of the study was that models built off neutral ankle experimental studies would generate the highest ligament strain at failure in the anterior deltoid ligament, comprised of the anterior tibiotalar ligament (ATiTL) and tibionavicular ligament (TiNL). For models built off everted ankle experimental studies the highest strain at failure would be developed in the anterior tibiofibular ligament (ATiFL). An additional objective of the study was to show that in these computational models ligament strain would be lower when modeling a partial versus complete ligament rupture experiment. To simulate a prior cadaver study in which six pairs of cadaver ankles underwent external rotation until gross failure, six specimen-specific models were built based on computed tomography (CT) scans from each specimen. The models were initially positioned with 20 deg dorsiflexion and either everted 20 deg or maintained at neutral to simulate the cadaver experiments. Then each model underwent dynamic external rotation up to the maximum angle at failure in the experiments, at which point the peak strains in the ligaments were calculated. Neutral ankle models predicted the average of highest strain in the ATiTL (29.1 ± 5.3%), correlating with the medial ankle sprains in the neutral cadaver experiments. Everted ankle models predicted the average of highest strain in the ATiFL (31.2 ± 4.3%) correlating with the high ankle sprains documented in everted experiments. Strains predicted for ligaments that suffered gross injuries were significantly higher than the strains in ligaments suffering only a partial tear. The correlation between strain and ligament damage demonstrates the potential for modeling to provide important information for the study of injury mechanisms and for aiding in treatment procedure.

scholarly journals Stress vs. Non-Stress Radiographs in Subtle Syndesmotic Injuries

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0029
Author(s):  
Nicola Krähenbühl ◽  
Travis Bailey ◽  
Nathan Davidson ◽  
Heath Henninger ◽  
Charles Saltzman ◽  
...  
Keyword(s):  
Ankle Instability ◽  
External Rotation ◽  
Paired Comparison ◽  
Weight Bearing ◽  
Deltoid Ligament ◽  
Ankle Sprains ◽  
X Rays ◽  
Syndesmotic Injury ◽  
Stress Radiographs ◽  
Clear Space

Category: Sports Introduction/Purpose: Between 1-18% of all ankle sprains and 23% of all ankle fractures involve injury to the distal tibio-fibular syndesmosis. Syndesmotic injuries can create a substantial diagnostic and therapeutic challenge for orthopaedic surgeons. While acute injuries can be assessed using conventional radiographs, subtle syndesmotic injuries may be misdiagnosed using X-rays. Misdiagnoses may result in chronic ankle instability, pain and post-traumatic osteoarthritis of the tibio-talar joint. The purpose of this study was to investigate whether syndesmotic injury was more easily diagnosed with stress vs. non-stress radiographs.radiographs.sed with stress vs. non-stress radiographs. Methods: Five pairs of cadavers (tibia plateau to toe-tip, mean 61 years, range 52-70 years) were scanned with weight-bearing CT (170 lb, w/ and w/o 10 Nm static external rotation torque). Digitally reconstructed radiographs (DRRs), which are comparable to conventional radiographs, were reconstructed from the 3D CT data. The following conditions were tested: First, intact ankles (Native) were tested. Second, one specimen from each pair underwent AITFL resection, while the contralateral underwent deltoid resection (Condition 1). Third, the remaining intact deltoid ligament or AITFL was resected in each ankle (Condition 2). Finally, the interosseous membrane (IOM) was resected in all ankles (Condition 3). Condition 3 was defined as acute syndesmotic injury. Using antero-posterior (AP) views, the tibio-fibular clear space (TFCS), tibiofibular overlap (TFO) and medial clear space (MCS) were assessed. Statistical analysis was performed using paired (comparison within groups) and unpaired (comparison between groups) t-test where p=0.05 was considered significant. Results: Regarding the TFCS, Native vs. Condition 3 in 10 Nm stress radiographs was significantly different in the deltoid group (p=0.021). Using TFO in stress and non-stressed radiographs, Native vs. Condition 2 and 3 was significantly different for the deltoid group (p=0.043), and Native vs. Condition 3 in the syndesmotic group (p=0.027). Regarding the MCS in non-stress radiographs, Native vs. Condition 3 was significantly different in the deltoid group (p=0.007), while in stress views, Native vs. Condition 2 was significant different in the syndesmotic (p=0.026) and Native vs. Condition 3 in the deltoid group (p=0.030). No differences were found comparing the conditions of the AITFL with the same conditions of the deltoid group. Conclusion: The TFCS cannot be used to assess subtle or acute syndesmotic injuries in stress and non-stress radiographs. The TFO can be used to assess a combined injury to the AITFL and deltoid ligament in stress and non-stress radiographs. The MCS can be used to assess acute syndesmotic injuries in stress and non-stress radiographs. Radiographs (stress or non-stress) cannot be used to distinguish between injuries to the AITFL or deltoid ligament. Therefore, stress and non-stress radiographs are not useful in assessment of subtle syndesmotic injuries. Stress-radiographs are not superior compared to non-stress radiographs in assessment of acute syndesmotic injuries.

Impact of Torque on Assessment of Syndesmotic Injuries Using Weightbearing Computed Tomography Scans

2019 ◽  
Vol 40 (6) ◽  
pp. 710-719 ◽  
Author(s):  
Nicola Krähenbühl ◽  
Travis L. Bailey ◽  
Maxwell W. Weinberg ◽  
Nathan P. Davidson ◽  
Beat Hintermann ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Axial Load ◽  
External Rotation ◽  
Ct Scans ◽  
Deltoid Ligament ◽  
Tibiofibular Syndesmosis ◽  
Tibiofibular Ligament ◽  
Distal Tibiofibular Syndesmosis ◽  
Axial Ct ◽  
The Impact

Background: The diagnosis of subtle injuries to the distal tibiofibular syndesmosis remains elusive. Conventional radiographs miss a large subset of injuries that present without frank diastasis. This study evaluated the impact of torque application on the assessment of syndesmotic injuries when using weightbearing computed tomography (CT) scans. Methods: Seven pairs of male cadavers (tibia plateau to toe-tip) were included. CT scans with axial load application (85 kg) and with (10 Nm) or without torque to the tibia (corresponding to external rotation of the foot and ankle) were taken during 4 test conditions. First, intact ankles (native) were scanned. Second, 1 specimen from each pair underwent anterior inferior tibiofibular ligament (AITFL) transection (condition 1A), while the contralateral underwent deltoid transection (condition 1B). Third, the lesions were reversed on the same specimens and the remaining intact deltoid or AITFL was transected (condition 2). Finally, the distal tibiofibular interosseous membrane (IOM) was transected in all ankles (condition 3). Measurements were performed to assess the integrity of the distal tibiofibular syndesmosis on digitally reconstructed radiographs (DRRs) and on axial CT scans. Results: Torque impacted DRR and axial CT scan measurements in almost all conditions. The ability to diagnose syndesmotic injuries using axial CT measurements improved when torque was applied. No significant syndesmotic morphological change was observed with or without torque for either isolated AITFL or deltoid ligament transection. Discussion: Torque application had a notable impact on two-dimensional (2-D) measurements used to diagnose syndesmotic injuries for both DRRs and axial CT scans. Because weightbearing conditions allow for standardized positioning of the foot while radiographs or CT scans are taken, the combination of axial load and torque application may be desirable. Clinical Relevance: Application of torque to the tibia impacts 2-D measurements and may be useful when diagnosing syndesmotic injuries by DRRs or axial CT images.

Rotational Stiffness of Football Shoes Influences Talus Motion during External Rotation of the Foot

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Feng Wei ◽  
Eric G. Meyer ◽  
Jerrod E. Braman ◽  
John W. Powell ◽  
Roger C. Haut
Keyword(s):  
Ankle Joint ◽  
Joint Torque ◽  
Ankle Injuries ◽  
Design Parameters ◽  
Deltoid Ligament ◽  
Rotational Stiffness ◽  
Shoe Design ◽  
Tibiofibular Ligament ◽  
Ankle Ligament ◽  
Ligament Strain

Shoe-surface interface characteristics have been implicated in the high incidence of ankle injuries suffered by athletes. Yet, the differences in rotational stiffness among shoes may also influence injury risk. It was hypothesized that shoes with different rotational stiffness will generate different patterns of ankle ligament strain. Four football shoe designs were tested and compared in terms of rotational stiffness. Twelve (six pairs) male cadaveric lower extremity limbs were externally rotated 30 deg using two selected football shoe designs, i.e., a flexible shoe and a rigid shoe. Motion capture was performed to track the movement of the talus with a reflective marker array screwed into the bone. A computational ankle model was utilized to input talus motions for the estimation of ankle ligament strains. At 30 deg of rotation, the rigid shoe generated higher ankle joint torque at 46.2 ± 9.3 Nm than the flexible shoe at 35.4 ± 5.7 Nm. While talus rotation was greater in the rigid shoe (15.9 ± 1.6 deg versus 12.1 ± 1.0 deg), the flexible shoe generated more talus eversion (5.6 ± 1.5 deg versus 1.2± 0.8 deg). While these talus motions resulted in the same level of anterior deltoid ligament strain (approxiamtely 5%) between shoes, there was a significant increase of anterior tibiofibular ligament strain (4.5± 0.4% versus 2.3 ± 0.3%) for the flexible versus more rigid shoe design. The flexible shoe may provide less restraint to the subtalar and transverse tarsal joints, resulting in more eversion but less axial rotation of the talus during foot/shoe rotation. The increase of strain in the anterior tibiofibular ligament may have been largely due to the increased level of talus eversion documented for the flexible shoe. There may be a direct correlation of ankle joint torque with axial talus rotation, and an inverse relationship between torque and talus eversion. The study may provide some insight into relationships between shoe design and ankle ligament strain patterns. In future studies, these data may be useful in characterizing shoe design parameters and balancing potential ankle injury risks with player performance.

scholarly journals Kinematics after Syndesmotic Injury: Assessing the Magnitude of Talus and Fibula Rotation and Displacement

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0011
Author(s):  
Jonathan Bartolomei ◽  
Mark W. Bowers ◽  
Kenneth J. Hunt
Keyword(s):  
Repeated Measures ◽  
External Rotation ◽  
Deltoid Ligament ◽  
Ankle Sprains ◽  
Syndesmotic Injury ◽  
Suture Button ◽  
Clear Space ◽  
Lateral Translation ◽  
Radiographic Measurements

Category: Ankle; Sports; Other Introduction/Purpose: High ankle sprains, or injuries to the distal tibiofibular syndesmosis, are predictive of long-term ankle dysfunction. Our objectives were to evaluate ankle mortise stability, radiographically, and kinematically, using a cadaveric model with a simulated syndesmotic injury. We also measured the ability of a suture-button system to restore natural joint motion. Methods: Eight cadaveric specimens underwent serial sectioning of the anterior-inferior tibiofibular (AITFL), interosseous (IOL), posterior-inferior tibiofibular (PITFL), and deltoid ligaments. Specimens underwent external rotation and lateral translation testing after ligament release to obtain kinematic data (using a validated infrared LED motion capture system) and radiographic measurements. We then repeated external rotation and lateral translation testing after implementing a suture-button system. Repeated measures ANOVA with a Bonferroni/Dunn post-hoc test calculated the interspecimen comparisons. Results: Sectioning of each ligament, beginning with the AITFL, significantly increased talar external rotation. After releasing the AITFL and IOL, fibular external rotation increased significantly. Posterior displacement of the fibula began following the release of AITFL. Significant radiographic widening of the medial clear space and the syndesmosis occurred only after the release of the deltoid ligament. Syndesmotic and medial clear space widening was not significantly different from the intact state under lateral translation until after the release of the deltoid ligament. Placement of the suture-button system successfully reduced the medial clear space but was unable to restore the native stability of the ankle joint. Conclusion: This project addresses rotational and kinematic changes in the ankle after syndesmotic injury by quantifying the effect of ligamentous disruption on the tibiotalar articulation. The change in joint kinematics may explain why patients with moderate-to-severe syndesmosis injuries take longer to heal and develop long-term dysfunction. Significant talar rotation and posterior fibular displacement occur during external rotation, even with moderate syndesmosis injury, and before the disruption of the deltoid ligament. Stress radiography does not appear to be a reliable indicator of mild or moderate syndesmosis injuries.

The effect of rotational stiffness on ankle tibiocalcaneal motion and ligament strain during external rotation

2016 ◽  
Vol 230 (4) ◽  
pp. 264-274
Author(s):  
Keith D Button ◽  
Paige Thornton ◽  
Jerrod E Braman ◽  
Feng Wei ◽  
Roger C Haut
Keyword(s):  
Injury Risk ◽  
Model Simulation ◽  
External Rotation ◽  
Torsional Stiffness ◽  
Rotational Stiffness ◽  
Predictive Equations ◽  
Tibiofibular Ligament ◽  
Ankle Kinematics ◽  
Statistical Effect ◽  
Ligament Strain

The rotational stiffness of footwear has been previously shown to have an effect on ankle kinematics and injury risk, but this relationship has not yet been modeled. The aim of this study was to derive equations from experimental data that were able to predict ankle kinematics under various torsional stiffness constraints and use these equations to estimate ligament strains. Three athletic tapes were tested for their ability to constrain the ankle during external rotation. Six subjects then performed a voluntary external foot rotation using the selected tape designs to constrain the ankle, as well as with no constraints. The motion of the calcaneus with respect to the tibia (tibiocalcaneal motion) from 0° to 15° of tibia rotation and predictive equations were determined to establish tibiocalcaneal rotation, eversion, and flexion as a function of gross tibia motion and tape stiffness. These predictive equations were then used to drive a computational model in which ankle ligament strains were determined at 15° of tibia rotation and for ankle constraint stiffness ranging from 0 to 30 N m/deg. The three tapes provided significantly different constraint stiffnesses during external foot rotation. There was no statistical effect of ankle constraint on the dorsiflexion response of the ankle (p = 0.461). In contrast, there was an effect of constraint stiffness on tibiocalcaneal external rotation (p < 0.001) and tibiocalcaneal eversion (p < 0.001). Results of the model simulation revealed the highest ligament strains in the anterior tibiotalar ligament and anterior tibiofibular ligament. Anterior tibiotalar ligament strain increased with increasing constraint stiffness, while there was little effect of constraint stiffness on anterior tibiofibular ligament strain. Results from this study could aid in the design of footwear, as well as the analysis of clinical injuries.

External Rotation Ankle Injuries: Investigating Ligamentous Rupture

2009 ◽  
Author(s):  
Mark R. Villwock ◽  
Eric G. Meyer ◽  
John W. Powell ◽  
Roger C. Haut
Keyword(s):  
High Frequency ◽  
Failure Load ◽  
Sports Injuries ◽  
External Rotation ◽  
Experimental Studies ◽  
Soft Tissue Injuries ◽  
Ankle Injuries ◽  
Ankle Sprains ◽  
Severity Of Injury ◽  
Ankle Complex

Ankle sprains are one of the most common sports injuries [1], accounting for 10% to 15% of these injuries [2]. The severity of injury varies greatly and the player’s recovery time is related to the structures involved and their degree of damage. In contrast to the soft tissue injuries reported in many clinical studies on the ankle, experimental studies have typically generated a high frequency of bone fracture when the foot/ankle complex is externally rotated [3–5]. In a majority of these manuscripts, the cadaveric test specimens are of advanced or unknown age. These variables may substantially affect both the failure load and the mode of failure in the joint, since most ankle sprains occur in people under the age of 35 years [6].

scholarly journals Talar Motion is Constrained by Tricortical Screw Fixation of the Syndesmosis: A Cadaveric Robotic Study

2018 ◽  
Vol 6 (7_suppl4) ◽  
pp. 2325967118S0015
Author(s):  
Neel K. Patel ◽  
Thomas Rudolf Pfeiffer ◽  
Jan-Hendrik Naendrup ◽  
Conor Murphy ◽  
Jason Zlotnicki ◽  
...  
Keyword(s):  
Screw Fixation ◽  
External Rotation ◽  
Lateral Shift ◽  
Testing System ◽  
Ankle Sprains ◽  
Suture Button ◽  
Tibiofibular Ligament ◽  
Cortical Screw ◽  
Robotic Testing ◽  
Robotic Testing System

Objectives: High ankle sprains are a common injury that occur in up to 11% of ankle sprains. Injury to the structures of the syndesmosis, the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), and interosseous membrane (IOM), has been shown to be predictive of residual symptoms after ankle injury. When the syndesmosis is unstable, it is typically treated surgically with cortical screw fixation or suture button fixation. Studies have shown that a 1 mm lateral shift of the talus relative to the tibia significantly decreases the tibiotalar contact area by 42%. Thus, restoring the tibiotalar kinematics to those of the intact ankle with appropriate fixation is important to avoid accelerated tibiotalar arthritis. The objective of this study was to quantify tibiotalar joint motion after syndesmotic screw and suture button fixation compared to the intact ankle. Methods: Nine fresh-frozen human cadaveric specimens (mean age 60 yrs.; range 38-73 yrs.) were tested using a six degree-of-freedom robotic testing system. The subtalar joint was fused and the tibia and calcaneus were rigidly fixed to a robotic manipulator, while fibular length was maintained and fibular motion was unconstrained. Talar motion with respect to the tibia was measured using the robotic testing system. A 5 Nm external rotation moment and 5 Nm inversion moment were applied independently to the ankle at 0°, 15°, and 30° plantarflexion and 10° dorsiflexion. Outcome variables included talar medial-lateral (ML) translation, anterior-posterior (AP) translation, and internal/external rotation relative to the tibia in the following syndesmosis states: 1) intact, 2) AITFL transected, 3) AITFL, PITFL, and IOM transected, 4) 3.5 mm cannulated tricortical screw fixation, and 5) suture button fixation. An ANOVA with a post-hoc Tukey analysis was performed for statistical analysis. Statistical significance was set at p < 0.05. Results: There were significant differences in ML translation of the talus relative to the tibia between the tricortical screw fixation and the intact ankle. These significant changes were only present during states with no loads applied. Tricotical screw fixation resulted in a significant decrease in medial translation of the talus compared to the intact ankle at 30° plantarflexion and increased lateral translation at 0° flexion (p < 0.05) (Figure 1). The talus moved 1.1 mm less medially at 30° plantarflexion and 0.4 mm more laterally at 0° flexion in the tricortical screw fixation state compared to the intact ankle. The total medial translation of the talus relative to the tibia during plantarflexion decreased from 1.1 mm to only 0.4 mm. No significant difference in AP translation or external rotation of the talus existed between the tricortical screw fixation and the intact ankle. No significant differences existed in translation or rotation of the talus between the suture button fixation and intact ankle at any ankle positions. Conclusion: Suture button fixation restored tibiotalar motion in all planes, with no significant differences compared to the intact ankle. Tricortical screw fixation significantly increased lateral shift of the talus in a neutral ankle position and constrained motion during plantarflexion compared to the intact ankle, which can lead to accelerated tibiotalar arthritis. Thus, physicians should consider hardware removal after tricortical screw fixation for syndesmotic repair to avoid post-traumatic arthritis. [Figure: see text]

Ankle Injuries During Excessive External Foot Rotation May Depend on Foot Constraint: Development of a Computational Model

2010 ◽  
Author(s):  
Feng Wei ◽  
John W. Powell ◽  
Roger C. Haut
Keyword(s):  
Computational Model ◽  
Bone Fracture ◽  
Clinical Studies ◽  
External Rotation ◽  
Ankle Injuries ◽  
Deltoid Ligament ◽  
Calcaneofibular Ligament ◽  
Tibiofibular Ligament ◽  
Posterior Talofibular Ligament

Numerous studies on the mechanisms of ankle injury deal with injuries to the syndesmosis and anterior ligamentous structures, but previous sectioning and clinical studies also describe the important role of the posterior talofibular ligament (PTaFL) in the ankle’s resistance to external rotation of the foot. Foot constraint may influence subtalar motion and the movement of the bones in the foot, thereby influencing the mode of injury during external rotation [1]. Stiehl et al. [2] constrain the foot with fiberglass cast tape, externally rotate the foot 90°, and produce injury to the deltoid ligament and anterior tibiofibular ligament (ATiFL) with bone fracture. In contrast, Stormont et al. [3] fix the foot in a potting alloy and conclude the primary ligamentous restraints to external rotation are the PTaFL and calcaneofibular ligament (CaFL).

Determination of In Situ Ankle Ligament Strains in Cases of High and Medial Ankle Sprains

2012 ◽  
Author(s):  
Keith D. Button ◽  
Feng Wei ◽  
Eric G. Meyer ◽  
Kathleen Fitzsimons ◽  
Roger C. Haut
Keyword(s):  
Ankle Sprain ◽  
Ankle Injury ◽  
Ankle Injuries ◽  
Deltoid Ligament ◽  
Generic Model ◽  
Ankle Sprains ◽  
Ligament Injuries ◽  
Lateral Ankle Sprain ◽  
Lateral Ankle ◽  
Tibiofibular Ligament

Ankle sprain is a common occurrence in sports, accounting for 10–30% of injuries [1]. While approximately 85% of ankle sprains are lateral ankle injuries, syndesmotic (high) and medial injuries typically result in more time off the field. In order to help limit or mitigate ankle injuries, it is important to understand the mechanisms of injury. While numerous biomechanical studies have been conducted to investigate ankle injuries, most of them are designed to study ankle fractures rather than sprains. Ankle sprains have been graded in the clinical literature and associated with the degree of damage to a ligament resulting from excessive strains [2]. Recently, there have been studies of lateral ankle sprain in laboratory settings [3,4] and based on investigation of game films [5], providing considerable insight into the mechanism of lateral ankle sprain. On the other hand, few biomechanical studies have been conducted on high and medial ankle sprains. A more recent study from our laboratory used human cadaver limbs to investigate such injuries [6]. The study showed that the type of ankle injury, whether medial or high, under excessive levels of external foot rotation depends on the extent of foot eversion [6]. Everted limbs showed isolated anterior tibiofibular ligament injuries (high ankle sprain) only, while neutral limbs mostly demonstrated deltoid ligament failures (medial ankle sprain). Additionally, the study documented grade II (partial tears) and grade III (ruptures) ligament injuries. While a computational ankle model has also been developed and validated to help understand the mechanisms of injury [7], it is a generic model. The objective of the current study was to develop computational, subject-specific models from those cadaver limbs and determine the levels of ligament strain generated in the medial and high ankle injury cases, as well as correlate the grades of injury with ligament strains from the computational model.

Mechanism of Injury in a High Ankle Sprain: A Simulation Study

2011 ◽  
Author(s):  
Feng Wei ◽  
Jerrod E. Braman ◽  
Eric G. Meyer ◽  
John W. Powell ◽  
Roger C. Haut
Keyword(s):  
Ankle Sprain ◽  
Simulation Study ◽  
External Rotation ◽  
Recovery Period ◽  
Cadaver Study ◽  
Ankle Sprains ◽  
Mechanism Of Injury ◽  
Tibiofibular Syndesmosis ◽  
Lateral Ankle ◽  
High Ankle Sprain

Injury to the tibiofibular syndesmosis ligaments, which bind together the distal ends of the tibia and fibula, is commonly referred to as a high ankle sprain [8]. While lateral ankle sprains are the most common injury, high ankle sprains represent a more disabling problem and require a longer recovery period [1] and different treatment [4]. The mechanism associated with a high ankle sprain is primarily thought to involve external rotation of the foot [1,7]. However, both a cadaver study [6] and a simulation study [5] show that tibiofibular syndesmosis ligaments are not stretched the most during an excessive, pure external foot rotation.

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