Updates on Total Ankle Arthroplasty.

The newer generation total ankle arthroplasty constructs afford higher levels of long-term survivability, and for the first in the history of ankle arthroplasty procedures, results are comparable to arthrodesis. Much of the success hinges on appropriate patient selection. A comprehensive workup of the patient will allow selection of adjunctive procedures as well as allowing for the determination of single versus 2-stage deformity correction. With the continual addition of implants, it is important to understand the specialization and indications that are assigned to certain models because this will help in selecting the most appropriate implant for any given patient.

Tibialis Anterior Tendon Rupture Surgical Treatments and Outcomes: A Systematic Review and Meta-Analysis.

Tibialis anterior tendon ruptures are a rare condition with an often-delayed diagnosis due to transient pain and compensation of remaining anterior compartment tendons. Previous systematic reviews have limited their recommendations to surgical treatment over nonoperative cares given the relatively small sample size in the literature. This current systematic review and meta-analysis was performed to compare the outcomes amongst the various surgical techniques and define factors that may affect long term patients results. Twenty-six references (217 cases) were identified. Use of extensor tendon autograft (odds ratio [OR] 5.55; I2=46%), autograft repair through semitendinosus/gracilis/ plantaris/ Achilles tendon/ peroneus longus ([OR] 4.14; I2=71%), or direct repair ([OR] 3.59; I2=57%), provided the best postoperative outcomes, whereas allograft repair ([OR] .52; I2=77%),and ipsilateral split/ turn-down tibialis anterior tendon ([OR] .69; I2=71%), were associated with poorer outcomes. Ruptures fixed in the acute phase ([OR] 8.3; I2=26%), were associated with statistically significant better outcomes when compared to these ruptures fixed in the chronic phase ([OR] .52; I2=77%). Results of this systematic review and meta-analysis suggests that ruptures should be surgically repaired in the acute phase whenever possible and comparable outcomes can be achieved through extensor tendon autograft repair, autograft repair, and direct repair.

Assessment of Bone Mineral Density in the Distal Tibia Using Quantitative Hounsfield Samples From Computer Tomography.

The distal tibia bone quality is of paramount importance for ankle fractures, total ankle implants, ankle fusions, and osteotomy procedures. Despite this fact relatively little is known regarding the overall bone quality for this section of the tibia. Previous literature suggest that there is a statistically significant decrease in bone mineral density within the distal 5% to 10% segment of the tibia medullary canal. This segment of medullary bone is considerable in size and thus valuable for fixation constructs as it is oftentimes utilized for medial malleolar fractures, distal tibia fractures, total ankle replacements, ankle fusions, and other procedures. This study assessed bone attenuation between the distal 5% and 10% mark of the tibia in 1% slices via Hounsfield unit measurements on CT scans based on previously established correlation between Hounsfield units and bone mineral density found on DEXA scans. One hundred five distal tibia segments were assessed with an average interval in percentile slices of 3.8 mm. As expected there was a gradual decrease in bone attenuation noted with each proximal percentile segment. There exists a statistically significant difference in bone attenuation among males versus females as well as those older than 60 years versus younger than 60 years. The findings suggest fixation constructs in the tibia medullary canal may find limited benefit proximal from 7% segment in females ≥60, or 26.1 mm from tibial plafond. Fixation constructs in tibia medullary canal may find limited benefit proximal from 8% segment in males <60, or 32.3 mm from tibial plafond.

Medial Malleolar Screw Length to Achieve Thread Purchase in the Dense Bone of the Tibial Epiphyseal Scar Location Based on CT Model.

Medial malleolar ankle fractures are one of the most common surgically treated fractures of the ankle joint. Current AO guidelines for medial malleolar fractures recommend 2 partially threaded cancellous screws across the fracture line. For these screws to cross the fracture line, the threads must purchase the distal tibial metaphysis, which is an area of decreased bone density especially in elderly osteoporotic bone. The epiphyseal scar of the tibia is the densest portion of distal metaphysis of the tibia, and it has been determined that bone density decreases significantly further proximal through the tibia. One hundred eighty-three individual weightbearing coronal CT scans were assessed to measure the location of the epiphyseal scar and propose an ideal screw length to purchase this area and remain within the distal most portion of the tibia. In following with this criteria it was determined that a 34 mm ⅓ thread pattern screw and a 38 mm ½ thread pattern screw would suffice for 92.6% and 75.3% of males, respectively. It was determined that a 30 mm ⅓ thread pattern screw and a 32 mm ½ thread pattern screw would suffice for 93.4% and 85.3% of females, respectively. This study proposes optimal screw lengths in a theoretical area of increased bone density that may decrease complications in patients with compromised bone quality.

Predicting Postoperative Sagittal Plane Alignment of the Foot Using Intraoperative Simulated Weightbearing Lateral Imaging During Flatfoot Reconstructive Surgery: A Short-Term Retrospective Analysis.

The sagittal plane relationship of the hindfoot and midfoot joints is a primary determinant of proper alignment in flatfoot reconstructive surgery as assessed both clinically and on postoperative weightbearing (WB) lateral radiographs. The traditional approach to intraoperative radiographic imaging allows for accurate assessment of fixation placement but only a crude evaluation of final sagittal plane alignment. Surgeons employ various methods in an attempt to load the foot during lateral imaging. Skepticism exists regarding the ability of simulated WB fluoroscopy to predict the final outcome, and evidence is lacking to support this practice. A retrospective investigation was performed assessing the correlation of Meary's angle, calcaneal inclination angle, and calcaneal-1st metatarsal angle as demonstrated on intraoperative simulated WB lateral foot imaging to 10- week postoperative full WB lateral radiographs. A consistent simulated WB imaging protocol was used with 46 consecutive cases of flatfoot reconstruction in this analysis of secular trends. The average change in Meary's angle between intraoperative simulated WB and postoperative full WB was -1.09° with 89% of cases within ±5°. The average change in calcaneal-1st metatarsal angle between intraoperative simulated WB and full WB was -2.61° with 85% of cases within ±5°. The average change in calcaneal inclination angle between intraoperative simulated WB and full WB was -2.62° with 88% of cases within ±5°. These findings confirm the clinical utility of intraoperative simulated WB lateral imaging as a useful tool in predicting the postoperative sagittal plane alignment of the midfoot and rearfoot in patients undergoing flatfoot reconstructive surgery.

Flipped Classroom in Podiatric Medical Education.

BACKGROUND: The purpose of this study was to evaluate student learning outcomes in a flipped classroom versus a traditional classroom in a podiatric medical school. To date no published reports in podiatric medical schools have used the flipped classroom for the entirety of a medical school course. METHODS: Students from the class of 2017 completed the Emergency Medicine and Trauma course using traditional classroom lectures, and the class of 2018 used a flipped classroom approach. Each class took two assessments that contained 99 identical questions and completed a postcourse evaluation that contained student comments. A multivariate analysis of covariance was conducted to determine whether student performances were significantly affected by the differences in the teaching method. Student evaluation comments were analyzed using textual data analysis to determine the sentiments that students expressed regarding their exposure to the teaching method. RESULTS: The multivariate analysis of covariance results revealed that students scored slightly lower on assessments during the flipped classroom delivery compared with the traditional classroom delivery, when adjusted for Medical College Admission Test scores and grade point average, but not significantly (P = .4340). Similarly, the sentiment analysis of student comments indicated that the average positive sentiment score for the flipped classroom delivery was higher but was not significant (P = .08914). CONCLUSIONS: The analysis showed there was not a statistically significant change in examination scores based on teaching method. Sentiment analysis revealed that student sentiments were more positive with the flipped classroom group compared with the traditional lecture group, although not statistically significantly.

The Bacillus subtilis chemoreceptor McpC senses multiple ligands using two discrete mechanisms.

Bacillus subtilis can perform chemotaxis toward all 20 L-amino acids normally found in proteins. Loss of a single chemoreceptor, McpC, was previously found to reduce chemotaxis to 19 of these amino acids. In this study, we investigated the amino acid-sensing mechanism of McpC. We show that McpC alone can support chemotaxis to 17 of these amino acids to varying degrees. Eleven amino acids were found to directly bind the amino-terminal sensing domain of McpC in vitro. Sequence analysis indicates that the McpC sensing domain exhibits a dual Per-Arnt-Sim (PAS) domain structure. Using this structure as a guide, we were able to isolate mutants that suggest that four amino acids (arginine, glutamine, lysine, and methionine) are sensed by an indirect mechanism. We identified four candidate binding lipoproteins associated with amino acid transporters that may function in indirect sensing: ArtP, GlnH, MetQ, and YckB. ArtP was found to bind arginine and lysine; GlnH, glutamine; MetQ, methionine; and YckB, tryptophan. In addition, we found that ArtP, MetQ, and YckB bind the sensing domain of McpC, suggesting that the three participate in the indirect sensing of arginine, lysine, methionine, and possibly tryptophan as well. Taken together, these results further our understanding of amino acid chemotaxis in B. subtilis and gain insight into how a single chemoreceptor is able to sense many amino acids.