Prevalence of Hallux Rigidus in Patients with Ankle Arthritis

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus (HR) is a degenerative disease of the first metatarsalphalangeal (MTP) joint, and the most common type of foot arthritis. It affects 2.5% of population aged over 50 years. During the gait cycle, the MTP joint normally carries a force of about 119% body weight. We hypothesize that the altered gait mechanics in patients with end stage ankle arthritis would increase the stress on the MTP joint resulting in hallux rigidus. The purpose of the study was to evaluate the prevalence of radiographic hallux rigidus in a population with ankle arthritis, its association with factors such as gender, age, and severity of the disease compared to the normal population. Methods: Patients from a prospectively-collected total ankle database were screened for the inclusion in the present study. All patients with ankle arthritis who underwent a primary total ankle arthroplasty (TAA) between November 2006 and November 2017 with anteroposterior and lateral views on foot x-rays within 3 months pre or postoperative were included. Foot x-rays were reviewed to assess the prevalence of radiographic hallux rigidus and to grade the severity of diagnosis according to Couglin and Shurnas Radiographic Classification. The association among the grades of severity, demographics, and bilateral involvement were evaluated. Results: A group of 870 patients out of 1044 patients who underwent TAA were included in the study. The mean age was 63 years (standard deviation 10.3). The prevalence of HR in the total group was 72.9% with a slightly higher proportion in males compared to females (51.7% versus 48.3%). The distribution among the grades of severity was grade 1, 58%; grade 2, 24%; and grade 3, 18%. Although, we did not find an association between prevalence and gender (P=0.2) or severity (P=0.37); HR grade 2 and grade 3 were higher in females. Bilateral involvement was found in 16.4% of patients with HR. Conclusion: The prevalence of radiographic hallux rigidus in a population with altered gait mechanics was significantly higher compared to that reported in the literature in the normal population. However, no association among demographic factors such as age or gender was found. Women tended to present a more severe diagnosis compared to men but the difference was no statistically significant

Effect of Deltoid Ligament Repair versus Syndesmosis Fixation on Ankle Joint Stability After Bimalleolar Equivalent Ankle Fracture

Category: Trauma Introduction/Purpose: The current standard for stabilization of the talus within the ankle mortise after bimalleolar equivalent ankle fracture is open reduction and internal fixation (ORIF) of the lateral malleolus followed by syndesmotic screw fixation of the syndesmosis. Syndesmotic fixation may be associated with complications such as mal-reduction, joint stiffness, altered ankle biomechanics, and potential additional surgery for hardware removal. Consequently, some surgeons advocate ORIF of the lateral malleolus in conjunction with deltoid ligament repair rather than syndesmosis fixation. To our knowledge, clinical reports of this treatment option lack biomechanical evidence to support this approach. The purpose of this investigation was to compare ankle joint stability and contact pressures in a bimalleolar equivalent ankle fracture model treated with trans-syndesmotic screw fixation versus deltoid ligament repair. Methods: We prepared and tested seven fresh frozen cadaveric whole lower leg specimens with an undisturbed proximal tibiofibular joint. We tested each leg was tested under five conditions: (1) intact, (2) syndesmosis disrupted and deltoid ligament sectioned, (3) syndesmosis reduced w/ screw fixation, (4) deltoid repaired, and (5) both syndesmosis and deltoid ligament repaired. Under a nominal axial load, we applied controlled anterior, posterior, lateral, and medial drawer stresses to the foot using a custom-built testing apparatus and documented the resulting talar translation relative to the tibia. We also applied controlled internal and external rotation stresses to the ankle model and measured the provoked ankle joint rotations. In each condition, we measured peak ankle contact pressure (PACP) using a Tekscan pressure sensor under a physiologic axial load simulating single-limb stance. Results: Concurrent disruption of the syndesmosis and the deltoid ligament significantly (p<.05) increased anterior drawer, lateral drawer, and internal and external rotation. Subsequent deltoid repair significantly reduced anterior displacement to normal levels, but syndesmosis fixation did not. Lateral drawer was not significantly corrected until both deltoid ligament and syndesmosis were repaired. Deltoid repair and syndesmosis fixation each reduced internal rotation significantly, with further reduction to normal levels when both were repaired. External rotation remained elevated relative to the intact condition regardless of which structures were repaired. Deltoid repair and syndesmosis fixation achieved similar levels of posterior, lateral and medial drawer reduction, but these measures did not approach normal values until both were repaired. No significant differences in PACP were identified among the five tested conditions. Conclusion: Isolated repair of the deltoid ligament after a bimalleolar equivalent ankle fracture achieves markedly better anterior displacement stability than does fixation of the syndesmosis with a screw. Under the described testing conditions, the two procedures offer similar posterior, medial, and lateral talar displacement stability and similar levels of internal and external rotational stability. Given the complications that may be associated with rigid syndesmotic screw fixation, our investigation suggests that deltoid repair may represent a reasonable alternative to syndesmosis fixation

Normal Variation of the Lisfranc Joint: Tridimensional Analysis using Weight-Bearing Computed Tomography Imaging

Category: Midfoot/Forefoot; Trauma Introduction/Purpose: Untreated Lisfranc injuries can lead to chronic pain, midfoot arthritis, and functional disability 1,2,5. Approximately 20% of Lisfranc injuries are misdiagnosed or completely missed on initial evaluation, which can be attributed to a lack of parameters of what is within normal limits for subjects without injury in the Lisfranc complex3,4. The purpose of this study is to identify anatomic variations of unidimensional, bidimensional, and tridimensional (1D, 2D, 3D) measurements of the Lisfranc complex of normal individuals using weight-bearing computed tomography (WBCT) imaging. Our hypothesis is that there is some variation among individuals with a difference between right and left of the same individual of less than 10%. Methods: A total of 191 subjects with bilateral WBCT scans of the foot were collected from three tertiary medical centers from 2019-2022. Exclusion criteria included: history of Lisfranc injury, first to fourth metatarsal base fractures, Charcot arthropathy, midfoot arthritis, cuneiform fractures, and forefoot surgery proximal to the metatarsal neck region. The following Lisfranc joint measurements were collected6 bilaterally: joint volume (3D), area of the joint on a consistent axial slice (2D), and distance between the second metatarsal and medial cuneiform (1D). Foot alignment was assessed using lateral talar-first metatarsal angle (Meary’s Angle). Patient demographics (age, sex, weight, height, BMI) were also collected. Descriptive statistics were calculated for quantitative variables. Percent difference was used to assess volume, area, and distance variation between sides.7 Correlation between demographic data and Lisfranc measurements was assessed using Pearson Correlation tests. A T-test was used for categorical variables. A p-value < 0.05 was considered statistically significant. Results: The cohort included 61% female and 39% male with an average age of 45.2±17.3 years. The mean volume, area, and distance measurements of the Lisfranc joint for both left and right sides are shown in Figure 1. Overall, the mean percent difference between left and right sides were 11.9%, 14.9% and 13.9% for volume, area and diastasis, respectively (Figure 1). No association was found between age, BMI, or weight and the volume, area or distance measurements. A correlation (r=0.48, p= < 0.001) was found between height and left Lisfranc joint volume, but no other measurements. Significant difference between sex in volume (p < 0.001) and area (p < 0.001) measurements were found. Foot alignment did not have a correlation with a variation of the Lisfranc complex measurements. Conclusion: This study provides an objective characterizing of the anatomic variations of the Lisfranc joint amongst healthy individuals. Differences in the measurements and the large standard deviation in absolute measurements of volume, area, and distance suggests that percent difference with the contralateral side may be a better metric to use to diagnose Lisfranc instability. Our results showed that the difference between bilateral sides in a patient is less than 15% for volume, area, and diastasis. The results of this study can set the foundation for future studies to determine the cut-off value for the diagnosis of Lisfranc instability using WBCT imaging

Chevron vs Oblique Medial Displacement Calcaneal Osteotomy - Which Is More Stable? Results From a Finite Element Analysis Study

Category: Hindfoot; Ankle Introduction/Purpose: The medial displacement calcaneal osteotomy is used to correct hindfoot valgus in adult-acquired flatfoot disease(AAFD). This is done by means of an oblique cut, which is then translated medially. The chevron variant of the MDCO has gained popularity in recent times. This osteotomy involves a V-cut, with the apex of the V placed anteriorly. This is thought to be inherently more stable than the conventional MDCO owing to its geometrical design and higher contact area, especially with higher magnitudes of translation of the osteotomized fragment. However, it is technically more demanding, and many surgeons may not be familiar with the technique. Moreover, there is no literature comparing the stability of the chevron and oblique MDCO. Hence, we conducted this study to address this knowledge gap. Methods: Computed Tomography (CT) scan of the foot of a patient diagnosed with Johnson stage 2 AAFD was segmented and converted into a 3D computational model. Subsequently, oblique and chevron (160o V-angle) calcaneal osteotomies were performed virtually. For each variant, the osteotomized fragment was translated medially by 8-, 10- and 12-mm and then fixed virtually with two 6.5 mm screws. The six models were imported into a Finite Element Software (ANSYS v19) and subjected to 500 N axial loading through the tibia to simulate a single-leg stance. The von Mises stresses at the osteotomy interfaces and the screws, and the total displacement of the posterior fragment was recorded for each model. Results: The compiled simulation results are presented in Table 1. For both osteotomies, the overall stresses at the osteotomy contact site and the screws increased incrementally with increasing medial translation. Similarly, sagittal plane displacement of the anterior fragment was noted to follow a similar trend. Across all translation levels, the stresses were recorded to be lower for chevron MDCO when compared to the oblique variants. Relative fragment displacement was also noted to be lower for the chevron MDCO. Conclusion: The chevron osteotomy results in lower contact stresses and osteotomy fragment displacement and may prove to be a more stable alternative to the oblique MDCO. However, these results need to be replicated in a larger cohort of patients, as well as in cadaveric studies to determine if surgeons can permit early weight-bearing with the chevron MDCO

3D Weightbearing CT for the Diagnosis of Lisfranc Instability: An Update

Category: Midfoot/Forefoot; Other Introduction/Purpose: Lisfranc instability is often a challenging injury to diagnose, with up to one-third being missed on initial evaluation. Lisfranc instability is assessed by widening of the space between the second metatarsal base and the medial cuneiform. This space is visualized on X-Ray; however, in subtle Lisfranc instability cases computed tomography (CT) imaging is often obtained. Given the 1D nature of diastasis measurement, X-ray should be an adequate means of evaluating this widening, yet clinical practice suggests weightbearing CT (WBCT) is more sensitive. This suggests the 3D location of the diastasis measurement is crucial. This study aimed to first compare weight-bearing X-ray and WBCT diastasis and area measurements of the Lisfranc complex, and second to compare WBCT diastasis measurements at various locations in the coronal plane. Methods: A total of 90 patients with both weight-bearing foot X-ray and bilateral foot WBCT were included: 37 patients had confirmed Lisfranc instability, and 53 patients had no history of midfoot injury. Lisfranc instability was confirmed intraoperatively or by clinical examination performed by the surgeon. For all 90 patients, the interosseous diastasis and area between the medial cortex of the second metatarsal and the lateral cortex of the medial cuneiform were measured on both weightbearing X-ray and axial slices of WBCT. For a subset of patients (12 in each cohort) the diastasis between second metatarsal and medial cuneiform was measured at 4 distinct axial locations using coronal slices of the WBCT (Figure 1). Results: A Wilcoxon test comparison of diastasis and area measurements on weightbearing X-ray and axial slices of WBCT revealed a significant difference in the weightbearing X-ray and WBCT measurements (p < 0.001) for both the control and Lisfranc cohorts. A comparison of weightbearing X-ray diastasis to dorsal, interosseous, and plantar diastasis measurements on coronal slices using Kruskal Willis analysis for the control cohort revealed a significant difference in all three measurements (Figure 1, p-values listed). Kruskal Willis analysis of the Lisfranc cohort demonstrated a significant difference between the X-ray diastasis and the plantar WBCT diastasis (p=0.01), but no difference from interosseous (p=0.08) or dorsal (p=0.33) diastases. A comparison of the axial WBCT diastasis measurements compared to the three coronal diastasis measurements revealed no difference in either cohort. Conclusion: Our results showed that for assessing the Lisfranc joint in subtle cases and healthy individuals, WBCT remains the most accurate imaging tool. However, in patients with confirmed Lisfranc instability, X-ray measurements are more reliable if the instability is at the dorsal and interosseous levels and not the plantar level. Hence, to assess the Lisfranc joint at different levels, WBCT has superiority over X-ray. Additionally, the axial diastasis of the Lisfranc joint on WBCT seems similar to coronal diastasis rendering both views reliable for measurements

The Accuracy of 3D Measurements in Weightbearing Computed Tomography to Diagnose Lisfranc Instability

Category: Midfoot/Forefoot; Other Introduction/Purpose: Up to one-third of Lisfranc injuries are missed on initial evaluation, resulting in significant morbidity. Prompt diagnosis of Lisfranc injuries is, therefore, critical in optimizing outcomes, and yet there remains a lack of consensus on diagnostic criteria to identify Lisfranc instability using anatomic measurements. Prior studies have underscored the utility of weight-bearing computed tomography (WBCT) in diagnosing Lisfranc instability, which allows for bilateral three-dimensional (3D) evaluation under physiologic load. The aim of this study was to quantify appropriate cutoff values using 3D anatomic measurements of Lisfranc instability under physiologic load and as compared to the uninjured extremity. Methods: A total of 234 adult patients with bilateral WBCT scans of the foot were included: 43 patients with Lisfranc instability & 191 patients without a history of midfoot injuries. Lisfranc instability was confirmed intraoperatively or by clinical evaluation by the surgeon. Patients with prior midfoot surgery, Charcot arthropathy, severe midfoot arthropathy, or significantly displaced fracture of the cuneiforms or 1st, 2nd, or 3rd metatarsal bases were excluded. Lisfranc joint measurements were conducted bilaterally, including C1-M2 diastasis, C1-M2 area and 3D WBCT volume. Patient demographics were collected. Descriptive statistics were calculated for quantitative variables. Percent difference as compared to the contralateral side was calculated for volume, area, and diastasis. Mann Whitney U tests were utilized to determine differences in measurements between patients in the Lisfranc cohort and patients in the uninjured cohort (p-value < 0.05). Diagnostic cutoffs for Lisfranc instability were determined with minimum distance to the corner analysis on ROC curves. Results: The distribution of patients with Lisfranc instability was 58% female with an average age of 38.5±17.6 years. Of the Lisfranc injuries, 36% were purely ligamentous, 18% demonstrated an avulsion injury, and 43% involved a metatarsal base fracture. In the Lisfranc cohort, the median percent difference between injured and uninjured feet was 28.2% (IQR: 20.9%) for volume, 36.3% (IQR: 31.1%) for C1-M2 area, and 40.0% (IQR: 23.3%) for C1-M2 diastasis. Mann-Whitney testing was significant for percent difference between left and right feet for Lisfranc patients versus patients with an uninjured midfoot (p < 0.001). The area under the curve and associated diagnostic cutoffs for Lisfranc instability, were 0.81 and 18% for volume, 0.84 and 20% for area, and 0.91 and 28% for diastasis (Figure 1). Conclusion: Diastasis (1D), area (2D), and volume (3D) measurements are effective measurements to diagnose Lisfranc instability on WBCT. With current diagnostic algorithms, however, 1D measurements afford superior diagnostic sensitivity as compared to 2D and 3D measurements when using WBCT, suggesting Lisfranc instability may be best appreciated in the axial plane. Additional studies are necessary to expand the sample population to assess for corroboration with the current results, especially for subtle Lisfranc instability

Should all Small Shell Posterior Malleolar Fractures be Considered for Fixation? Results from a 3D Fracture Mapping Study

Category: Ankle; Trauma Introduction/Purpose: Approximately 10-15% of posterior malleolar fractures (PMFs) are "small shell," extra-articular fragments. Current classification systems present difficulties to perform a uniform typification of PMFs and contain no consensus on whether they should be fixed. Anatomical studies have identified two distinct components of the posterior inferior tibiofibular ligament (PITFL); the superficial band is thought to be more important than its deep counterpart in imparting syndesmotic stability. However, the involvement of one or both bands of the PITFL by small shell PMFs has not been evaluated so far. Hence, we conducted this study to perform 3D mapping of small shell PMFs and to determine whether surgeons should fix these routinely. Methods: Ankle fracture patients with a ‘small shell’ PMF (Haraguchi 3/Mason 1/Bartoníček 1 or 2) were included. Demographics, radiological features, treatment, and outcomes were recorded. 3D models of the fractured tibiae were generated from CT scans and superimposed on a statistical shape model of the right tibia, which served as a template. Fracture lines along with footprints of superficial and deep PITFL were marked on the template. 3D fracture heat maps were generated. Size of the fracture fragments and involvement of the superficial and deep PITFL footprints were quantified using a custom MATLAB script (Figure 1). Sparing of the footprint was defined as an overlap of < 1% between the fracture line and the footprint areas. Odds ratios (OR) with 95% confidence intervals (CI) were determined to determine which variables correlated with sparing of the PITFL footprint; P-values of < 0.05 were considered significant. Results: Thirty-nine patients were included. The superficial PITFL footprint was spared in 15 (38%), deep PITFL in 10 (26%), and both in 4 cases (10%). Males and Weber C fractures had a higher likelihood of sparing the superficial and deep PITFL footprints, respectively (P = 0.04). Supination external rotation (SER) patterns were less likely to demonstrate syndesmotic widening if either PITFL footprint was spared. Direct fixation of the PMF was done in 1 case; syndesmotic fixation in 25 cases and in 14 cases, no syndesmotic fixation was done. Of these, 11 were SER injuries where stability was achieved after fixation of medial and lateral malleoli. In 1 SER and pronation external rotation (PER) injury case, the syndesmosis was stable after fixation of a large Chaput fragment. Conclusion: This study demonstrated that 48% of small shell PMFs spare either the superficial or deep footprint of the PITFL; in 10% both PITFL footprints were spared. Hence, 58 % of small-shell PMFs may not benefit from direct fixation. Additionally, SER injuries with small shell PMFs that spare either PITFL footprint may not demonstrate radiographic instability and may not need direct or indirect fixation after addressing other components of the ankle fracture. However, given the fact that syndesmotic stability is not dictated by the PITFL alone, it remains prudent to stress the syndesmosis per-operatively to determine if syndesmotic fixation is needed

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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