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.

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.

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.