Radiographic analysis of the Canale view for displaced talar neck fractures.

Fractures of the talar neck comprise almost 50% of fractures of the talus and may result in significant long-term morbidity. It is of paramount importance to ensure anatomic reduction of the fracture not only for fracture healing but also for minimizing future posttraumatic arthritic sequelae. In addition to conventional radiographs and computed tomography scans, the Canale view has proven to be beneficial, especially when evaluating for varus displacement. This study investigated whether the original method of performing the Canale view could be modified for improved evaluation for varus displacement. Simulated talar neck fractures were created in 6 cadaveric specimens. These were placed into varying amounts of varus displacement; the Canale view was performed with progressive degrees of eversion, from 0° to 25°, resulting in 108 total views. Blinded evaluation was performed, and a ranking system was used to determine the most beneficial degree(s) of eversion for evaluating varus malalignment. Multiple statistical analyses were performed. A significant difference was seen between the high and low range of values of eversion. A significantly lower ranking was achieved with 10° of eversion. As opposed to a single view taken at 15° of eversion, a range of angles may be most beneficial in evaluating varus displacement in talar neck fractures.

Controlling sensation intensity for electrotactile stimulation in human-machine interfaces.

A barrier to practical use of electrotactile stimulation for haptic feedback has been large variability in perceived sensation intensity due to changes in the impedance of the electrode-skin interface, such as when electrodes peel or users sweat. Here, we show how to significantly reduce this variability by modulating stimulation parameters in response to measurements of impedance. Our method derives from three contributions. First, we created a model between stimulation parameters and impedance at constant perceived sensation intensity by looking at the peak pulse energy and phase charge. Our model fits experimental data better than previous models (mean R2 > 0.9) and holds over a larger set of conditions (subjects, sessions, magnitudes of sensation, stimulation locations, electrode sizes). Second, we implemented a controller that regulates perceived sensation intensity by using our model to derive a new current amplitude and pulse duration in response to changes in impedance. Our controller accurately predicts subject-chosen stimulation parameters at constant sensation intensity (mean R2 > 0.9). Third, we demonstrated as a proof-of-concept on two subjects with below-elbow amputations-using a prosthesis with electrotactile touch feedback-that our controller can regulate sensation intensity in response to large impedance changes that occur in activities of daily living. These results make electrotactile stimulation for human-machine interfaces more reliable during activities of daily living.

An Epidermal Stimulation and Sensing Platform for Sensorimotor Prosthetic Control, Management of Lower Back Exertion, and Electrical Muscle Activation.

The design of an ultrathin, conformal electronic device that integrates electrotactile stimulation with electromyography, temperature, and strain sensing in a single, simple platform is reported. Experiments demonstrate simultaneous use of multiple modes of operation of this type of device in the sensorimotor control of robotic systems, in the monitoring of lower back exertion and in muscle stimulation.

Flexible Electronics: An Epidermal Stimulation and Sensing Platform for Sensorimotor Prosthetic Control, Management of Lower Back Exertion, and Electrical Muscle Activation (Adv. Mater. 22/2016).

The design of an ultrathin, conformal electronic device that integrates electrotactile stimulation with electromyography, temperature, and strain sensing in a single, simple platform is reported by J. A. Rogers and co-workers on page 4462. Demonstrated application possibilities include prosthetic control with sensory feedback, monitors, and stimulation signals related to lower back exertion, and electrical muscle stimulation with feedback control.

Pseudoseptic arthritis of the shoulder following pneumococcal vaccination.

Pseudoseptic arthritis is primarily described in rheumatoid arthritis and other systemic inflammatory conditions. To our knowledge, only 1 case report of pseudoseptic arthritis associated with intra-articular injection of a pneumococcal polyvalent vaccine (PPV) has been published. Here, a second case is presented in which a patient presented with swelling, pain, and erythema of the affected shoulder. A 59-year-old woman presented to the emergency department with a 3-day history of severe pain and decreased mobility of her left shoulder after receiving a PPV vaccination. Her clinical and laboratory workup was suspicious for septic arthritis; however, magnetic resonance imaging of the affected shoulder with and without contrast showed only a partial thickness tear of the rotator cuff, fluid in the subacromial/subdeltoid bursa, and subcutaneous edema without evidence of an abscess. Based on the clinical and laboratory data, she underwent arthroscopic debridement. There was inflammatory tissue throughout the shoulder but no obvious purulent material. She did well postoperatively with a supervised range of motion rehabilitation protocol. Her cultures remained negative. At 12 weeks, she was discharged from follow-up. We suspect that the vaccination was inadvertently injected into the glenohumeral joint directly through the rotator cuff given the lack of a full-thickness tear and the patient's thin body habitus, which could explain her aseptic inflammatory arthritis.

Additive effects of exogenous IL-12 supplementation and antibiotic treatment in infection prophylaxis.

The increasing clinical incidence and host risk of open fracture-associated infections, as well as the reduced effectiveness of conventional antibiotics to treat such infections, have driven the development of new therapies for the prophylaxis of open fracture-associated infections. We investigated percutaneous supplementation of a natural cytokine (i.e., interleukin 12p70 or IL-12) at an open fracture site to reduce open fracture-associated infections. We also determined the efficacy of the combination therapy of IL-12 and conventional antibiotic therapy in the prophylaxis of open fracture-associated infections. An open femur fracture infection model was produced by direct inoculation of a clinical isolate of Staphylococcus aureus after creating a femur fracture using rats. The animals were assigned to one of four groups: no drug administration, percutaneous supplementation of IL-12, intraperitoneal administration of the antibiotic ampicillin, or percutaneous IL-12 in combination with intraperitoneal ampicillin. Animals were euthanized at postoperative days 6, 10, 14, and 21. Percutaneous IL-12 led to a reduction in infection at postoperative days 6 and 10. For the first time, exogenous IL-12 was found to have additive effects in the prevention of infection when combined with conventional treatment (i.e., antibiotic therapy). Combination therapy of ampicillin and IL-12 substantially reduced the infection rate at postoperative day 6 and also decreased the time needed for complete inhibition of infection. Therefore, exogenous IL-12, providing a mechanism of protection independent of antibiotic resistance, complements the routine use of antibiotics.

Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects.

The use of xenogeneic tissues offers many advantages with respect to availability, quality control, and timing of tissue harvest. Our previous study indicated that implantation of premature tissue constructs from allogeneic synovium-derived stem cells (SDSCs) facilitated cartilage tissue regeneration. The present study investigated the feasibility of xenoimplantation of SDSC-based premature tissue constructs for the repair of osteochondral defects. Porcine SDSCs were mixed with fibrin gel, seeded in polyglycolic acid (PGA) scaffolds, and cultured in a rotating bioreactor system supplemented for 1 month with growth factor cocktails. The engineered porcine premature tissues were implanted to repair surgically induced osteochondral defects in the medial femoral condyles of 12 rabbits. Three weeks after surgery, the xenoimplantation group exhibited a smooth, whitish surface while the untreated control remained empty. Surprisingly, 6 months after surgery, the xenoimplantation group displayed some tissue loss while the untreated control group was overgrown with fibrocartilage tissue. In the xenoimplantation group, chronic inflammation was observed in synovial tissue where porcine major histocompatibility complex (MHC) class II antigen positively stained in the engulfed foreign bodies. In addition, porcine source cells also migrated from the implantation site and may have been responsible for the observed loss of glycosaminoglycans (GAGs) underneath surrounding articular cartilage. The histological score was much worse in the xenoimplanted group than in the untreated control. Our study suggested that SDSC-based xenogeneic tissue constructs might cause delayed immune rejection. Xenotransplantation may not be an appropriate approach to repair osteochondral defects.

Radiographic evaluation of the distal radius using two novel biplanar "pitch-and-roll" views: a preliminary cadaveric study.

This study's objective was to compare the use of two biplanar angled radiographs versus standard posterioanterior (PA) and lateral radiographs in determining preservation of the articular space with regard to pin placement in the distal radius. Various combinations of inclination (pitch) and clockwise/counterclockwise rotation (roll) were used to determine the best view of the distal radius articular surface. Optimum visualization of the articular surface presented at 12 degrees inclination plus 15 degrees counterclockwise rotation for the PA view and 22 degrees inclination and 15 degrees counterclockwise rotation for the lateral view. Ten cadaveric forearms were dissected, and ten Kirschner wires (K-wires) were placed at specific surfaces of the distal radius. Each K-wire was countersunk 2 mm below the chondral surface so all K-wires resided within the subchondral bone. Each forearm was radiographed in four views; PA, lateral, pitch-and-roll PA (PR-PA), and pitch-and-roll lateral (PR-lateral). Four blinded reviewers evaluated the radiographs and marked whether they were certain, relatively certain, or uncertain that the K-wires did not penetrate into the articular space. Reviewers demonstrated significantly less uncertainty about intraarticular penetration (p < 0.005) with both the PR-PA and PR-lateral views compared with standard PA and lateral views. The biconcave nature of the distal radius makes it extremely difficult to visualize placement of hardware with respect to the articular surface using standard radiographs. The use of PR-PA and PR-lateral views significantly improves the surgeon's ability to judge the position of hardware in the distal radius compared to standard radiographic views, thus allowing for more meaningful clinical decision in post-operative radiographs.

Multilayer polypeptide nanoscale coatings incorporating IL-12 for the prevention of biomedical device-associated infections.

Biomedical device-associated infection is one of the most common and problematic complications faced by millions of patients worldwide. The current antibiotic therapy strategies face challenges, the most serious of which is antibiotic resistance. Studies have shown that the systemic level of interleukin 12 (IL-12) decreases following major injuries resulting in decreased cell-mediated immune response. Here we report the development of IL-12 nanoscale coatings using electrostatic layer-by-layer self-assembly nanotechnology. We found that IL-12 nanoscale coatings at the implant/tissue interface substantially decrease infections in vivo, and IL-12 nanoscale coatings are advantageous over traditional treatments. This approach could be a revolutionary step toward preventing device-associated infections using a non-antibiotic approach.