Lateral Process Of Talus Research Articles

Non-osseous coalition of accessory anterolateral talar facet-A case series.

The accessory anterolateral talar facet (AALTF) is an anatomical variation that broadens the apex of the lateral talar process. Studies have associated it with other tarsal coalitions as a cause of rigid painful flatfoot. However, a coalition of an AALTF has never been described before. With the advent of MRI, there has been an increase in the detection of these accessory facets. Nevertheless, owing to its small size and unfamiliarity, it is not easily identified. Proper assessment of imaging findings and associated conditions is needed to confirm the diagnosis. Imaging findings in a series of four patients with painful rigid flatfoot revealed the presence of an AALTF with adjacent marrow edema and reduced joint space. This was associated with hindfoot valgus and subfibular impingement. Radiographic suspicion of a non-osseous coalition of AALTF was raised, which was confirmed intraoperatively in one of the patients and demonstrated on CT and MR images in the other patients. This case series presents rare cases of non-osseous coalition of AALTF with a new radiographic sign, the 'reverse tip of the iceberg sign'.

LATERAL TRANSLIGAMENTOUS APPROACH TO THE TALAR DOME

IntroductionAnatomic reduction of talar body fractures is critical in restoring congruency to the talocrural joint. Previous studies have indicated a maximum of 25% talar body exposure without malleolar osteotomy. The aim of this study was to investigate the percentage talar body exposure when using the lateral transligamentous approach.MethodsThe lateral transligamentous approach to the talus was undertaken in 10 fresh frozen cadaveric specimens by surgeons inexperienced in the approach, following demonstration of the technique. An incision was made on the anterolateral aspect of the ankle augmented by the removal of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) from their fibular insertions. A bone lever was then placed behind the lateral aspect of the talus and levered forward with the foot in equinus and inversion.The talus was disarticulated and high resolution images were taken of the talar dome surface. The images were overlain with a reproducible nine-grid division. Accessibility to each zone within the grid with a perpendicular surgical blade was documented. ImageJ software was used to calculate the surface area exposed with each approach.ResultsThe mean percentage area of talar dome available through the transligamentous approach was 77.3 % (95% confidence interval 73.3, 81.3). In all specimens the complete lateral talar process was accessible, along with the lateral and dorsomedial aspect of the talar neck. This approach gives complete access to Zones 1,2, 3,5 & 6 with partial access to Zones 4,8 & 9.ConclusionThe lateral transligamentous approach to the talus provides significantly greater access to the talar dome as compared to standard approaches. The residual surface area that is inaccessible with this approach is predominantly within Zone 4 and Zone 7, the posteromedial corner.

Influence of Retrograde Intramedullary Beam Position Within Talar Body on Radiographic Failure of Medial Column Fusion

Category: Midfoot/Forefoot; Diabetes Introduction/Purpose: Intramedullary fixation in the form of retrograde beam or bolt has developed as an intriguing treatment option for unstable midfoot collapse. This is particularly true when it is desired to minimize the length of incision or to avoid surface implants in a compromised soft tissue envelope. However, prior studies have demonstrated high rates of complications associated with intramedullary midfoot fusion constructs (Ford et al., Butt et al). The goal of this study was to create a reproducible convention of classifying position of the terminal implant within the talar body and to uncover an association of relative position of the implant at the time of surgery with an increased risk of failure. Methods: Consecutive patients treated surgically from January 2017 to September 2022 with retrograde intramedullary fusion beam were identified; 44 were included in the final analysis. Average age was 62.7 years and mean radiographic follow up measured 12.86 months. Figure 1 demonstrates our classification of relative talar position. First, a line was drawn along the axis of the talar neck and carried posteriorly dividing the talar body into dorsal and plantar hemispheres. Then, a line was drawn from the anterior articular margin of the talar body to the lateral talar process. Parallel lines were then created in an equidistant fashion to divide the talar body into equal relative quartiles. At the time of surgery, the tip of the intramedullary beam was classified into relative axial and coronal position by a single observer. Our primary outcomes were hardware failure defined by implant fracture or cutout from the bone or additional surgery. Results: Successful midfoot fusion with intramedullary beam was achieved in 77% of our cases. 10 cases demonstrated hardware failure or the need for additional surgery. Relative implant position was classified as dorsal in 43% of cases and plantar in 57% of cases. Talar quartile depth was classified as 1st in 6% cases, 2nd in 32% of cases, 3rd in 30% of cases, and 4th in 32% of cases. There was no clinical or statistically significant difference between rates of failure based on relative implant position. Conclusion: Retrograde intramedullary fusion for medial column collapse remains a viable treatment option and our data supports successful fusion in most patients but a risk of failure remains significant. In this study, the relative position of the terminal implant within the talar body did not correlate with an increased risk of failure. There are likely other patient specific, or biomechanical factors leading to hardware fracture, cut out, or return of deformity. Continued analysis as sample size increases remains paramount to forming additional conclusions.

Distal Tibia Apex Posterior Angulation: A Normal Anatomic Variant with Side-To-Side Symmetry

Category: Trauma; Ankle Introduction/Purpose: The native sagittal plane alignment of the distal tibia has not been well-described and has implications during the fixation of tibia fractures. Cavovarus foot alignment has been previously thought to influence gastrocsoleus tightness and the potential for anterior talar escape in the setting of an osseous injury in this region. However, the relationship between midfoot alignment and sagittal distal tibia morphology is undescribed. Characterization of this osseous anatomy may be helpful to achieve adequate sagittal alignment during the reduction of distal tibia fractures. The purpose of this study was primarily to characterize distal tibia sagittal morphology and ankle radiographic parameters, determine whether symmetry exists from side-to- side, and secondarily to identify any differences based on midfoot alignment. Methods: 112 patients (60 females, mean age 45.8 years) with bilateral lateral weight-bearing ankle radiographs were retrospectively evaluated (224 ankles). Midfoot morphology was classified as normal, planus, or cavus using Meary's angle (MA) (Planus: MA <-4°, Normal: MA -4°≤x≤4°, Cavus: MA>4°). The angle between the proximal diaphyseal (Line 1) and distal tibia (Line 2) axes was measured, and the location of the center of rotation of angulation (CORA) relative to the plafond was recorded (Figure 1). The horizontal distance (via a line parallel to the floor) from the distal tibia axis (Line 2) to the lateral talar process was measured, as well as the anterior distal tibial angle, and the plafond radius of curvature (ROC). Bilateral ankles and midfoot morphologies were compared using a Mann-Whitney U test and ANOVA, respectively. Correlation was assessed using linear regression. Results: The average distal tibia had 2° of apex posterior angulation with the CORA located 8.0 cm proximal to the plafond. There was no difference by laterality in magnitude of the angulation (p=.358) or distance from the plafond to the CORA (p=.901). The angulation increased as foot alignment transitioned from cavus (1.25°), to normal (1.89°), to planus (3.05°) alignment (r=.32; R2=.102; p<.001). The angulation was larger in men (2.8°) than in women (1.4°) (p<.001) and decreased with increasing patient age (r=.279, R2=.078, p<.001). The lateral talar process was on average 5.9 mm anterior to the distal tibia axis (Line 2), more anterior with cavus versus planus alignment (6.7mm vs. 4.8mm) (p<.001). The average anterior distal tibial angle and plafond ROC were 83.6° and 22.9 mm, respectively, with no significant differences by laterality or midfoot morphology (p>.05 for both). Conclusion: The distal tibia has a consistent apex posterior bow that is symmetric from side-to-side, but variable from patient- to-patient. Distal tibia osseous morphology is related to midfoot alignment, sex, and age. Cavus alignment is additionally correlated with anterior translation of the lateral talar process relative to the distal tibia axis. Surgeons treating distal tibia fractures may consider the use of contralateral imaging as a reduction template to help restore patient-specific sagittal alignment. A tibial nail that ends anterior in the distal segment of a distal tibia fracture should prompt the surgeon to carefully evaluate whether sagittal alignment has been restored.

Isometric points in lateral ankle ligament reconstruction: A three-dimensional kinematic study

BackgroundTo optimize the biomechanical outcomes in lateral ankle ligament reconstruction, avoid stiffness or residual laxity, aiming for an isometric reconstruction of the anterior lateral talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) is mandatory. However, the localization of the optimal ligament insertion remains challenging to assess intraoperatively. MethodThree-dimensional (3D) surface models from 10 healthy ankles were generated. 30 insertion points of the CFL were defined on the lateral side of the calcaneus each 10% of its total length in the dorsal-to-ventral and proximal-to-distal plane. 6 insertion points were defined at the ventral ridge of fibula from the malleolar tip and 5 insertions were defined along the lateral talar process. The ligament length variation of ATFL and CFL was assessed after a simulation of the flexion/extension around a simulated tibiotalar axis and inversion/eversion around a simulated subtalar axis in 36 different positions. ResultsThe isometric point of CFL on the calcaneus is located at about 60% along the dorsal-to-ventral and between 60% and 70% along the proximal-to-distal plane. From maximal extension to flexion, these points present respectively a length variation of − 0.8 to − 1.1 mm (p = 0.46) and − 1.1 to − 0.8 mm (p = 0.56). A fibular insertion at 5 mm proximal to the malleolar tip present a length variation ranging from − 0.1–1 mm (p < 0.001) for ATFL and from − 0.7–0.5 mm (p < 0.001) for CFL. A talar insertion point of the ATFL located 5 mm proximal to the subtalar joint present the lowest variation, ranging from − 1.1–0.7 mm (p < 0.001), however an insertion at 20- or 25-mm present isometry (+0.1 to +0.9 mm p = 0.1, and +0.4 to +0.4 mm p = 1 respectively) if the fibular insertion is located at 5 mm proximal to the malleolar tip. ConclusionThis study provides anatomical references which are reproducible in daily practice. These insertion points allow to achieve a stable reconstruction while maintaining a tension-free mobilization of the ankle.

Recognition, Treatment, and Outcome of Calcaneal Fracture-Dislocation.

Calcaneal fracture-dislocations are rare but potentially disabling injuries that are regularly overlooked at first presentation. To date, only about 50 cases have been reported in the literature. Over a period of 8 years, 10 patients (average age 61.7 years) with acute fracture-dislocations of the calcaneus were treated at 2 level 1 trauma centers. The calcaneocuboid joint was involved in 9 patients. There was a concomitant fracture of the lateral talar process and of the tip of the distal fibula in 7 patients each. Open reduction and internal fixation was performed in 9 of 10 patients via an oblique lateral dislocation approach. One patient underwent primary subtalar fusion. All patients were seen for clinical and radiographic follow-up at an average of 3 years using patient-reported outcome scores. Anatomic fixation was achieved in all patients as judged by postoperative computed tomographic imaging. In the 9 patients treated with internal fixation, the Foot Function Index averaged 12.8, the EuroQol 5D score averaged 0.89 and the visual analog scale score for patient satisfaction averaged 79.3 at final follow-up. Signs of mild subtalar arthritis were seen in 6 patients. No secondary subtalar fusions were needed. When recognized and treated early, prognosis of calcaneal fracture-dislocation was favorable. A dislocation approach starting over the distal fibula, continuing over the sinus tarsi, and extending toward the calcaneocuboid joint allowed for adequate visualization of the subtalar joint and treatment of all components of the injury. Level IV, retrospective case series.

The lateral transligamentous approach to the talar dome

IntroductionAnatomic reduction of talar body fractures is critical in restoring congruency to the talocrural joint. Previous studies have indicated 43% talar body access with a single incision and without malleolar osteotomy. The aim of this study was to investigate the percentage talar body exposure when using the lateral transligamentous approach. MethodsThe lateral transligamentous approach to the talus was undertaken in 10 fresh frozen cadaveric specimens by surgeons inexperienced in the approach following demonstration of the technique. An incision was made on the anterolateral aspect of the ankle augmented by the removal of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) from their fibular insertions. A bone lever was then placed behind the lateral aspect of the talus and levered forward with the foot in equinus and inversion. A mark was made on the talar dome where an instrument could be placed 90 degrees to the talar surface. The talus was subsequently disarticulated and high-resolution images were taken of the talar dome surface. The images were overlain with a reproducible nine-grid division. Accessibility to each zone within the grid was documented using the mark made on the talar surface. ImageJ software was used to calculate the surface area exposed with each approach. ResultsThe mean percentage area of talar dome available through the transligamentous approach was 77.3% (95% confidence interval 73.3, 81.3). In all specimens the complete lateral talar process was accessible, along with the lateral and dorsomedial aspect of the talar neck. This approach gives complete access to Zones 1, 2, 3, 5 & 6 with partial access to Zones 4, 8 & 9. ConclusionThe lateral transligamentous approach to the talus provides significantly greater access to the talar dome as compared to standard approaches. The residual surface area that is inaccessible with this approach is predominantly within Zones 4,7 and 8, the posteromedial corner. Level of Clinical EvidenceV.

Anatomic considerations for retrograde fibular medullary screw insertion: a cadaveric study.

A retrograde fibular medullary screw may be utilized in certain fractures about the ankle. The purpose of this study is to investigate the anatomic considerations of a retrograde medullary screw inserted from a lateral starting point to nearby anatomic structures about the distal fibula. Ten fresh-frozen cadaveric lower extremities were utilized. A 1.6-mmKirschner wire was inserted into the distal fibula from a far-lateral starting point. A 3.2-mm cannulated drill bit was then inserted over the Kirschner wire. After placement of the drill bit, dissection of the lateral ankle was undertaken. The proximity of nearby anatomic structures to the drill bit was measured using calipers. A 4.5-mm cortical screw was then inserted using fluoroscopic guidance. Measurements were then taken again to assess the relationship of the screw head to adjacent structures. Mean distance from drill bit to nearby structures is as follows: Peroneus longus tendon 4.56mm, peroneus brevis tendon 6.62mm, sural nerve 4.13mm, superior peroneal retinaculum 7.52mm, inferior peroneal retinaculum 6.61mm, anterior talofibular ligament (ATFL) 6.1mm, calcaneofibular ligament (CFL) 6.7mm. Average distance from 4.5-mm screw head to nearby structures is as follows: peroneus longus tendon 6.79mm, peroneus brevis tendon 6.73mm, ATFL 4.16mm, CFL 5.14mm, lateral talar process 9.41mm. Retrograde medullary fibular screw fixation may be safely carried out through a lateral start point. Anatomic structures about the lateral ankle are nearby but not immediately adjacent to the drill bit.

Hamstring autograft and anatomical footprint evaluation for anterior talofibular ligament reconstruction: Cadaveric study.

The aim of the study was to evaluate whether or not there was any incompatibility between two-strand hamstring tendons taken from the same knee and the ATFL and it was the determination of suitable footprint points in the fibula and talus for anatomical ATFL reconstruction. 16 fresh frozen cadaver specimens were dissected to gracilis and semitendinosus tendons and the anterior talofibular ligament. The origins, insertions, distances from osseous landmarks of fibular talus of ATFL were determined. The diameters of gracilis, semitendinosus and ATFL were calculated. There was a moderate correlation between body height and the distance between the distal of inferior lateral malleolus and the fibular adhesion site of ATFL (r: 36.5 p: 0.036). There was a weak correlation between body height and the distance between the apex of the lateral talar process and the talus adhesion site of ATFL in a single bundle (r: 28.4 p: 0.002). There was no correlation between the distance from proximal and distal adhesion side of ATFL and body height in the double bundle (p: 0.241). There was no significant relationship between ATFL diameter and gracilis, semitendinosus and both hamstring in women. A significant relationship at 80.5% was determined between the ATFL and the gracilis diameter in man. A significant relationship at 92.6% was determined between the ATFL and the semitendinosus diameter in man. It was determined that there is not compatibility between the gracilis tendons, the semitendinosus tendon and ATFL in women. It should be supported by biomechanical and clinical studies whether this incompatibility has a clinical effect or not.

Analyse 3D scannographique des tunnels d’allogreffe ligamentaire anatomique dans l’instabilité chronique de cheville. À propos de 33 cas

IntroductionAlthough clinical results of anatomic reconstruction using allograft are reportedly good, studies on how accurately the tunnel has been made after surgery are very rare. The purpose of this study was to analyze the postoperative locations of the tunnels through 3-dimensional computed tomography (3D-CT) after anatomic ligament reconstruction and to evaluate its clinical results. HypothesisWe hypothesized that anatomic lateral ligament reconstruction could lead to excellent results in clinical outcomes by repositioning anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) accurately. Materials and methodsThirty-three special forces of soldiers who were diagnosed as chronic ankle instability (CAI) were included. Visual analogue scale (VAS), American orthopaedic foot and ankle society (AOFAS) ankle-hindfoot functional scores, and Tegner activity scale were comparatively analyzed before the surgery and at final follow-up. The locations of the talar, fibular and calcaneal tunnels were evaluated with 3D-CT taken after the surgery. Talar tilt and anterior drawer displacement were measured on stress radiographs. ResultsThe mean follow-up period was 26.8±3.6 months. The VAS decreased from 6.9±1.6 to 1.7±1.3, AOFAS ankle-hindfoot functional score increased from 61.3±14.8 to 88.7±9.2, and Tegner activity scale improved from 5.3±1.2 to 6.4±1.3 (p<0.001). Talar tunnel for ATFL was located about 68 % of the way from the lateral talar process, and fibular tunnels for ATFL and CFL were approximately 52 % and 20 % of the way from the fibular tip. The calcaneus tunnel was approximately 17mm posterosuperior from the peroneal tubercle on 3D-CT. Talar tilt decreased from 15.8±4.8 to 3.9±2.1 degrees (p<0.001). There were excellent inter-observer agreements for CT evaluation (Kappa values were from 0.83 to 0.92). There was no relapse of lateral instability. DiscussionAnatomic reconstruction of the lateral ligaments using allograft and the interference screw for CAI showed good results in postoperative stability and subjective clinical evaluation by repositioning the location of ATFL and CFL accurately on radiological determination. Level of evidenceIV, Case-series.

Three-Dimensional computed tomography tunnel assessment of allograft anatomic reconstruction in chronic ankle instability: 33 cases

IntroductionAlthough clinical results of anatomic reconstruction using allograft are reportedly good, studies on how accurately the tunnel has been made after surgery are very rare. The purpose of this study was to analyze the postoperative locations of the tunnels through 3-dimensional computed tomography (3D-CT) after anatomic ligament reconstruction and to evaluate its clinical results. HypothesisWe hypothesized that anatomic lateral ligament reconstruction could lead to excellent results in clinical outcomes by repositioning anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) accurately. Materials and methodsThirty-three special forces of soldiers who were diagnosed as chronic ankle instability (CAI) were included. Visual analogue scale (VAS), American orthopaedic foot and ankle society (AOFAS) ankle-hind foot functional scores, and Tegner activity scale were comparatively analyzed before the surgery and at final follow-up. The locations of the talar, fibular and calcaneal tunnels were evaluated with 3D-CT taken after the surgery. Talar tilt and anterior drawer displacement were measured on stress radiographs. ResultsThe mean follow-up period was 26.8±3.6 months. The VAS decreased from 6.9±1.6 to 1.7±1.3, AOFAS ankle-hindfoot functional score increased from 61.3±14.8 to 88.7±9.2, and Tegner activity scale improved from 5.3±1.2 to 6.4±1.3 (p<0.001). Talar tunnel for ATFL was located about68% of the way from the lateral talar process, and fibular tunnels for ATFL and CFL were approximately 52% and 20% of the way from the fibular tip. The calcaneus tunnel was approximately 17mm posterosuperior from the peroneal tubercle on 3D-CT. Talar tilt decreased from 15.8±4.8 to 3.9±2.1 degrees (p<0.001). There were excellent inter-observer agreements for CT evaluation (Kappa values were from 0.83 to 0.92). There was no relapse of lateral instability. DiscussionAnatomic reconstruction of the lateral ligaments using allograft and the interference screw for CAI showed good results in postoperative stability and subjective clinical evaluation by repositioning the location of ATFL and CFL accurately on radiological determination. Level of evidenceIV, Case-series.

Radiographic Assessment of Fibular Length Variance: The Case for “Fibula Minus”

Given the high prevalence of ankle fractures and morbidity of malalignment after fixation, an appropriate anatomic relationship between the distal fibula and adjacent tibia and talus is important. The tip of the lateral malleolus of the fibula has often been described to be at the level of the lateral talar process. However, no studies to date have examined the relationship of the distal fibular tip to the lateral process of the talus. We assessed 66 weightbearing mortise radiographs for variability of the distal fibular tip in relation to the lateral process of the talus. The subjects were all skeletally mature, with a mean age of 45.3 ± 14.6 years. We used a paired t test with a null hypothesis that the true mean difference in the distance from the distal fibula to the lateral process was equal to 0. The mean distance of the distal tip of the fibula was 0.257 ± 0.127 cm proximal to the tip of the lateral process of the talus. The 95% confidence interval was 0.226 to 0.288. Of the 66 subjects, 65 had the distal tip of the fibula proximal to the lateral process of the talus, corresponding to a negative fibular variance. In the remaining subject, the distal tip of the fibula was at the same level of the tip as the lateral process of the talus. The distal tip of the fibula is most commonly not at the level of the talus lateral process, as often described in published reports. Instead, it has a variance analogous to the relationship between the lengths of the ulna compared with the radius. The distal tip of the fibula in our study was more often proximal to the tip of the lateral process of the talus and can be described as a negative fibular variance, or “fibula minus.”

The V Sign in Lateral Talar Process Fractures

Category: Ankle, Hindfoot, Trauma Introduction/Purpose: Lateral talar process fractures (LTPF) constitute 15% of ankle injuries in snowboarders. They are often misdiagnosed on conventional radiographs, which are also susceptible to rotational malpositioning due to pain. A positive V sign is an interruption of the contour of the lateral talar process. It has been suggested to be pathognomonic for LTPF. However, there are very few studies about this topic. The objectives were to study whether the V sign is useful in diagnosing LTPF. Methods: In an experimental study, two investigators evaluated lateral radiographs (n=108) of high resolution, solid foam, radiopaque distal foot and ankle models. Two other investigators, who obtained the radiographs, defined the gold standard. Four different models (no fracture, type A, B, or C fractures according to Hawkins) and three varying ankle joint positions (0°, 20°, and 40° of inversion, plantar flexion, and internal rotation) were the independent variables. The correct detection of a V sign on lateral radiographs (Figure 2 showing a positive V sign on a lateral radiograph in a type B LTPF) was the primary dependent variable and the detection of the fracture type and uncertainty in making this decision were the secondary dependent variables. The chosen study size surpassed the sample size calculation. The chi-squared test was used for categorical data. Results: There were fair interobserver agreements on the V sign and fracture types (kappa coefficient [k]=0.35, 95% confidence interval [CI] 0.18-0.53, p&lt;0.001 and k=0.37, 95% CI 0.26-0.48, p&lt;0.001). For the detection of the V sign, the mean sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio, and mean uncertainty were 77% (95% CI 67-86%), 59% (95% CI 39-78%), 85% (95% CI 75-92%), 46% (95% CI 29-63%), 2, and 38%. Increased inversion and type B fractures were associated with better detection of the V sign (p=0.035 and p=0.011 as well as p=0.001 and p=0.013, for each investigator). Plantar flexion and internal rotation were not associated with the V sign (p=0.31 and 0.33 as well as 0.35 and 0.53, for each investigator). Conclusion: It is not recommended to exclusively use the V sign for the evaluation of LTPF. If negative, LTPF cannot be excluded. However, if positive, it may be a helpful surrogate parameter for the presence of LTPF, especially type B fractures. Inversion may lead to better visualization of the V sign. This knowledge about the V sign is a valuable asset for the diagnostic skillset of an orthopaedic surgeon. Future clinical studies may focus on validating these experimental findings. [Notes: Level of evidence is not applicable to this study. This abstract has also been submitted to the swiss orthopaedics congress 2017.]

The V sign in lateral talar process fractures: an experimental study using a foot and ankle model

BackgroundLateral talar process fractures (LTPF) are often missed on conventional radiographs. A positive V sign is an interruption of the contour of the LTP. It has been suggested, but not proven to be pathognomonic for LTPF. The objective was to study whether the V sign is pathognomonic for LTPF and if it can be properly assessed in different ankle positions and varying fracture types.MethodsAn experimental study was conducted. Two investigators assessed lateral radiographs (n = 108) of a foot and ankle model. The exposure variables were different ankle positions and fracture types. The primary outcome was the correct detection of a V sign. The secondary outcomes were the detection of the V sign depending on ankle position and fracture type as well as the uncertainty.ResultsThe interobserver agreement on the V sign and type of fracture were fair (κ = 0.35, 95% CI 0.18–0.53, p < 0.001 and κ = 0.37, 95% CI 0.26–0.48, p < 0.001). The mean sensitivity, specificity, PPV, NPV, and likelihood ratio for the detection of the V sign were 77% (95% CI 67–86%), 59% (95% CI 39–78%), 85% (95% CI 75–92%), 46% (95% CI 29–63%), and 2. The mean uncertainty in the V sign detection was 38%. The V sign identification stratified by ankle position and fracture type showed significant better results with increasing inversion (p = 0.035 and p = 0.011) and type B fractures (p = 0.001 and p = 0.013).ConclusionsThe V sign may not be pathognomonic and is not recommended as the only modality for the detection of LTPF. It is better visualized with inversion, but does not depend on plantar flexion or internal rotation. It is also better seen in type B fractures. It is difficult to detect and investigator-dependent. It may be helpful in a clinical setting to point into a direction, but a CT scan may be used if in doubt about a LTPF.

Metal Artifact Reduction MRI for Sagittal Balance Evaluation of Total Ankle Arthroplasty

Category: Ankle Arthritis Introduction/Purpose: Surgical restoration of the anatomical relationship between talus and tibia is considered crucial for longevity of total ankle arthroplasty (TAA). Weight-bearing (WB) radiographs are the current standard for evaluating the sagittal balance alignment, which are, however, prone to rotational misalignment and potentially altered measurements. Metal artifact reduction sequence (MARS) MRI is a cross-sectional technique that minimizes implant-induced artifacts and affords the visualization of bone-implant interfaces and periprosthetic bone without distortions. Although not weight-bearing, MARS MRI offers the ability to align the image plane to the true sagittal axis of the talar implant and anatomically correct measurements. Therefore, the purpose of this study was to compare sagittal balance alignment measurements on MARS MR images and standard WB radiographs in patients with TAA. Methods: In this IRB-approved, prospective study, 23 subjects [10 men/13 women, age 60(41-73) years; 13(3-24) months post- op] underwent MARS MRI and standard lateral WB radiographs. Standardized MARS MR images were obtained in alignment to the sagittal talar component axis and use of a boot-shaped MRI coil. Maximum-intensity-projection MR images that resemble lateral radiographs were created to bring anatomic landmarks, such as lateral talar process, talonavicular joint line, talar implant, tibial shaft, and posterior talus into one single image. Three board-certified foot ankle surgeons performed sagittal balance alignment measurements twice in an independent, random and blinded fashion. The second set of measurements was obtained 1 months after the first assessment. In accordance with published measurements, lateral talar station (LTS), tibial axis-to-talus (T-T) ratio, and normalized tibial axis-to-lateral-process (T-L) distance were measured. Pearson correlation coefficient (r), Concordance-Correlation-Coefficient (CCC) and Intraclass-Correlation-Coefficient (ICC) were used for statistical analysis. Bonferroni-corrected p-values ≤ 0.01 were considered significant. Results: The intra-observer agreement was excellent for radiographic (CCC = 0.93 - 0.97) and MRI (CCC = 0.90 - 0.97) measurements. Inter-observer agreements were good-to-excellent with overall higher agreements for MRI (ICC = 0.76 - 0.93) than for radiography (ICC = 0.58 - 0.95) measurements. There was statistically significant inter-method correlation between radiographic and MRI measurements including LTS (r=0.83, p &lt; 0.001), T-T ratio (r=0.86, p &lt; 0.001) and normalized T-L distance (r=0.72, p &lt; 0.001). The T-T ratios of radiographs and MRI were statistically not different (p=0.36), whereas LTS and normalized T-L distance were significantly lower on MR images when compared with radiographs (p &lt; 0.001). Conclusion: Sagittal balance measurements performed on standardized weight-bearing radiographs and standardized MARS MR images demonstrate substantial correlation and similarity. Given its high inter- and intra-observer agreement, MARS MRI may be helpful for the evaluation of sagittal balance following TAA.

Neglected lateral process of talus fracture presenting as a loose body in tarsal canal

Lateral process fractures of talus are rare injuries with a potential to cause significant morbidity if misdiagnosed. The appropriate management of these fractures is still controversial and only a few reports are avai- lable on this subject. We presented a case of a 37-year-old male with neglected fracture on the lateral process of talus which was misdiagnosed at the time of injury. The patient presented to 7 months after misdiagnosis with a chronic ankle pain. Our case is unique in the sense that it is a rare case of neglected fracture on the lateral process of talus which presented as a loose body in sinus tarsi. However, a surgery with an excision of the loose body presented a satis- factory outcome along with 2 years' follow-up. To our knowledge, it ought to be the first case reported in the English literature. Through this case report, we highlight the importance of high index of suspicion for such rare bony injuries while evaluating trauma to the lateral side of ankle and discuss the principles of management of these fractures.

Assessment of the feasibility of arthroscopic visualization of the lateral ligament of the ankle: a cadaveric study.

An anatomical study was performed to assess the feasibility of arthroscopic visualization of the lateral ligaments of the ankle. The fibular, talar and calcanear insertions of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) were identified by standard arthroscopy portals. After dissection of the ATFL and CFL, bone tunnels were created at the estimated centres of their footprints. Dissection was then performed to identify the footprints and their position in relation to bony landmarks. The distance from the real centre of the footprint to the corresponding tunnel entrance was measured. Fourteen fresh frozen ankles were included. The ATFL and CFL were identified in all cases. The centre of the fibular ATFL footprint was found to be 16.1±3.5mm from the tip of the fibula, and the talar footprint was 18.4±2.8mm from the apex of the lateral talar process. The centre of the fibular CFL footprint was 4.2±0.8mm from the tip of the fibula, and the calcaneal footprint was 18.4±2.5mm from the fibular process of the calcaneum. The fibular tunnel was 2.9±3mm proximally from the centre of the ATFL fibular footprint, the talar tunnel was 4.4±3.2mm proximally from the centre of the talar footprint, and the calcaneal tunnel was 3.3±2.8mm too anterior from the CFL calcaneal footprint. No iatrogenic lesions were noted. Arthroscopic identification of the ATFL, CFL and their corresponding footprints can be considered safe and reliable. Tunnels entrances, in preparation for arthroscopic ligament reconstruction, are precisely positioned. Arthroscopic anatomical ligament reconstruction is a feasible option.

Assessment of Ankle and Hindfoot Stability and Joint Pressures Using a Human Cadaveric Model of a Large Lateral Talar Process Excision

Assessment of Ankle and Hindfoot Stability and Joint Pressures Using a Human Cadaveric Model of a Large Lateral Talar Process Excision

Assessment of ankle and hindfoot stability and joint pressures using a human cadaveric model of a large lateral talar process excision: a biomechanical study.

Lateral talar process fragment excision may be followed by hindfoot instability and altered biomechanics. There is controversy regarding the ideal fragment size for internal fixation versus excision and a concern that excision of a large fragment may lead to significant instability. The aim of this study was to assess the effect of a simulated large lateral talar process excision on ankle and subtalar joint stability.A custom-made seesaw rig was designed to apply inversion/eversion stress loading on 7 fresh-frozen human cadaveric lower legs and investigate them in pre-excision, 5 cm3 and 10 cm3 lateral talar process fragment excision states. Anteroposterior radiographs were taken to assess ankle and subtalar joint tilt and calculate angular change from neutral hindfoot alignment to 10-kg forced inversion/eversion. Ankle joint pressures and contact areas were measured under 30-kg axial load in neutral hindfoot alignment.In comparison to the pre-excision state, no significantly different mediolateral angular change was observed in the subtalar joint after 5 and 10 cm3 lateral talar process fragment excision in inversion and eversion. With respect to the ankle joint, 10-cm3 fragment excision produced significantly bigger inversion tibiotalar tilt compared with the pre-excision state, P = .04. No significant change of the ankle joint pressure and contact area was detected after 5 and 10-cm3 excision in comparison with the pre-excison state.An excision of up to 10 cm3 of the lateral talar process does not cause a significant instability at the level of the subtalar joint but might be a destabilizing factor at the ankle joint under inversion stress. The latter could be related to extensive soft tissue dissection required for resection.

Radiographic Identification of the Primary Lateral Ankle Structures

Background: Lateral ankle ligament injuries rank among the most frequently observed athletic injuries, requiring repair or reconstruction when indicated. However, there is a lack of quantitative data detailing the ligament attachment sites on standard radiographic views. Purpose: To quantitatively describe the anatomic attachment sites of the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL) on standard radiographic views with respect to reproducible osseous landmarks to assist with intraoperative and postoperative assessment of lateral ankle ligament repairs and reconstructions. Study Design: Descriptive laboratory study. Methods: Twelve nonpaired, fresh-frozen cadaveric foot and ankle specimens were dissected to identify the origins and insertions of the 3 primary lateral ankle ligaments. Ligament footprint centers were marked with 2-mm stainless steel spheres shallowly embedded at the level of the cortical bone prior to obtaining standard lateral and mortise radiographs. Measurements were performed twice by 2 blinded raters independently to calculate mean distances and assess reliability via intraclass correlation coefficients (ICCs). Results: Radiographic measurements demonstrated excellent reproducibility between raters (all interobserver ICCs > 0.97) and across trials (all intraobserver ICCs >0.99). On the lateral view, the ATFL fibular attachment (mean ± SD) was 8.4 ± 1.8 mm proximal and anterior to the inferior tip of the lateral malleolus and attached on the talus 13.8 ± 2.0 mm proximal and anterior to the apex of the lateral talar process. The CFL originated 5.0 ± 1.4 mm superior and anterior to the inferior tip of the lateral malleolus and inserted on the calcaneus 18.5 ± 4.6 mm posterior and superior to the posterior point of the peroneal tubercle. On the mortise view, the ATFL origin was 4.9 ± 1.4 mm proximal to the inferior tip of the lateral malleolus and inserted on the talus 9.0 ± 2.1 mm medial and superior of the apex of the lateral talar process and 18.9 ± 3.1 mm inferior and slightly lateral to the superior lateral corner of the talar dome. The fibular CFL origin was 2.9 ± 1.6 mm proximal and slightly medial to the inferior tip of the lateral malleolus and inserted on the calcaneus 18.0 ± 5.1 mm distal to the apex of the lateral talar process. Conclusion: Radiographic parameters quantitatively describing the anatomic origins and insertions of the lateral ankle ligaments were defined with excellent reproducibility and agreement between reviewers. Clinical Relevance: Quantitative radiographic anatomy data will assist in preoperative planning, improve intraoperative localization, and provide objective measures for postoperative assessment of anatomic repairs and reconstructions.