Superiorly and transversely orienting the bicortical suspension device provides optimal anterolateral stability to the proximal tibiofibular joint: a finite-element study.

PURPOSE: Instability of the proximal tibiofibular joint (PTFJ) can be treated with bicortical suspension (BCS) fixation. However, the ideal location, orientation, and configuration to apply one or two BCS devices are not clear. METHODS: A finite-element model of the PTFJ was created from a female adult's CT dataset. Anterior and posterior ligaments at the PTFJ were modeled and suppressed to simulate stable and unstable joints. Fifty-six models simulated 56 device placements along guiding tunnel lines that connect eight entry locations on the fibular head to seven exit points on the anteromedial tibia. Doubling device stiffness created 56 more models. Combing any two placements created 1176 double-device configurations which were categorized to be crossed, divergent or parallel. Displacement of the fibular head relative to the fixed tibia under 100 N anterolateral and posteromedial forces was assessed. RESULTS: Different placements had 2.1-27.9 mm translation with 0.7-8.9° internal rotation under anterolateral loading, and 1.8-5.2 mm translation with 6.1-7.9° external rotation under posteromedial loading. More transverse and superior orientations were associated with smaller anterolateral translation; more posterior and superior entry locations were associated with smaller internal rotation. The median (IQR) reductions in anterolateral translation by doubling device stiffness and by adding a second device were 0.8 (IQR 0.5-1.0) and 0.8 (IQR 0-6.1) mm, respectively. The type of double-device configurations had no significant effect on fibular motion. CONCLUSION: Surgeons should drill the guiding tunnel superiorly and transversely to ensure the optimal restoration of the PTFJ anterolateral stability.

Treatment Order and Risk of Surgical Site Infection in Patients Undergoing Concurrent Operative Fixation of Closed and Open Fractures.

This study aimed to characterize postoperative infection rate among patients undergoing definitive fixation of both open and closed fractures during the same surgery. Outcomes between patients with open fractures (OF) treated first were compared to those with closed fractures (CF) treated first. We identified 303 adult patients with multiple (≥ 2) pelvis and extremity fractures who presented to our Level 1 Trauma hospital in 2017. Forty patients with at least one open and one closed fracture treated with operative fixation during the same surgery were included in analysis. Eight surgical site infections (SSI) developed in seven patients. There was no significant difference between treatment order groups (OF = 4 patients (5 fractures), CF = 3 patients (3 fractures); p > 0.99). This is the first study comparing different chronologies of operative fixation in coexisting open and closed fractures. Our study shows that the choice of treatment order does not influence SSI risk. (Journal of Surgical Orthopaedic Advances 31(3):181-186, 2022).

A Randomized Trial of Preoperative Practice in a Simulated Operative Environment: 3D Printed Pilon Model Improves Resident Performance.

This study assessed the effect of preoperative planning using a 3D-printed periarticular fracture model on operative performance. A complex pilon fracture was 3D-printed, and a preoperative plan was developed. Orthopaedic surgery residents (n = 20) were randomized into two groups. Group 1 performed routine preoperative planning, while Group 2 was also practiced using a 3D-printed construct before performing fixation of the 3D-printed model. Resident performance was assessed using a video motion capture system and evaluated by blinded reviewers. Three residents (3D group) completed fixation within the allotted 45 minutes. The 3D group had less hand distance traveled for step 1 (89 m vs. 162 m, p = 0.04). The 3D group had better performance on three of the four components and more acceptable reductions (6 vs. 0, p = 0.009). Average global rating scale was higher in the 3D group (3.0 vs. 1.7, p = 0.0095). Use of 3D-printed models for preoperative planning improved resident performance. (Journal of Surgical Orthopaedic Advances 31(3):187-192, 2022).

Neonatal growth restriction-related leptin deficiency enhances leptin-triggered sympathetic activation and central angiotensin II receptor-dependent stress-evoked hypertension.

BACKGROUND: Neonatal growth restriction (nGR) leads to leptin deficiency and increases the risk of hypertension. Previous studies have shown nGR-related hypertension is normalized by neonatal leptin (nLep) and exacerbated by psychological stress. With recent studies linking leptin and angiotensin signaling, we hypothesized that nGR-induced nLep deficiency increases adult leptin sensitivity; leading to leptin- or stress-induced hypertension, through a pathway involving central angiotensin II type 1 receptors. METHODS: We randomized mice with incipient nGR, by virtue of their presence in large litters, to vehicle or physiologic nLep supplementation (80 ng/g/d). Adult caloric intake and arterial pressure were monitored at baseline, during intracerebroventricular losartan infusion and during systemic leptin administration. RESULTS: nGR increased leptin-triggered renal sympathetic activation and hypertension with increased leptin receptor expression in the arcuate nucleus of the hypothalamus; all of those nGR-associated phenotypes were normalized by nLep. nGR mice also had stress-related hyperphagia and hypertension, but only the stress hypertension was blocked by central losartan infusion. CONCLUSION: nGR leads to stress hypertension through a pathway that involves central angiotensin II receptors, and nGR-associated leptin deficiency increases leptin-triggered hypertension in adulthood. These data suggest potential roles for preservation of neonatal growth and nLep supplementation in the prevention of nGR-related hypertension.

Nanomedicine strategies for central nervous system (CNS) diseases.

The blood-brain barrier (BBB) is a crucial part of brain anatomy as it is a specialized, protective barrier that ensures proper nutrient transport to the brain, ultimately leading to regulating proper brain function. However, it presents a major challenge in delivering pharmaceuticals to treat central nervous system (CNS) diseases due to this selectivity. A variety of different vehicles have been designed to deliver drugs across this barrier to treat neurodegenerative diseases, greatly impacting the patient's quality of life. The two main types of vehicles used to cross the BBB are polymers and liposomes, which both encapsulate pharmaceuticals to allow them to transcytose the cells of the BBB. For Alzheimer's disease, Parkinson's disease, multiple sclerosis, and glioblastoma brain cancer, there are a variety of different nanoparticle treatments in development that increase the bioavailability and targeting ability of existing drugs or new drug targets to decrease symptoms of these diseases. Through these systems, nanomedicine offers a new way to target specific tissues, especially for the CNS, and treat diseases without the systemic toxicity that often comes with medications used currently.

The use of xenogenic dermal matrices in the context of open extremity wounds: where and when to consider?

Optimal treatment of orthopaedic extremity trauma includes meticulous care of both bony and soft tissue injuries. Historically, clinical scenarios involving soft tissue defects necessitated the assistance of a plastic surgeon. While their expertise in coverage options and microvascular repair is invaluable, barriers preventing collaboration are common. Acellular dermal matrices represent a promising and versatile tool for orthopaedic trauma surgeons to keep in their toolbox. These biological scaffolds are each unique in how they are used and promote healing. This review explores some commercial products and offers guidance for selection in different clinical scenarios involving traumatic wounds.

Biomechanical Assessment of Bicortical Suspension Device Fixation for Proximal Tibiofibular Joint Instability: Single Versus Double Device.

BACKGROUND: Bicortical suspension device (BCSD) fixation treats proximal tibiofibular joint (PTFJ) instability in both the anterolateral and posteromedial directions. However, biomechanical data are lacking as to whether this technique restores the native stability and strength of the joint. PURPOSE: To test (1) if BCSD fixation restores the native stability and strength and (2) if using 2 devices is needed. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen pairs of fresh-frozen cadaveric specimens were obtained. Six pairs were assigned to the control group and 10 matched pairs assigned for transection to model PTFJ and subsequent BCSD fixation (one specimen with 1-device repair and the other with 2-device repair). Joint stability and strength were assessed by translating the fibular head relative to the fixed tibia either anterolaterally or posteromedially. Control specimens received 20 cycles of 0- to 2.5-mm joint displacement tests (subfailure) and then proceeded to load to failure (5 mm). For the experimental group, cyclic tests were repeated after ligament resection and after fixation. Forces and stiffness at 2.5- and 5-mm displacement were recorded for comparisons of joint strength and stability at subfailure and failure loads, respectively. RESULTS: After repair of anterolateral instability, both the single- and double-device fixations successfully restored near-native states, with no significant differences as compared with the intact group for forces at subfailure load (P = .410) or failure load (P = .397). Regarding posteromedial instability, single-device repair did not restore forces to the near-native state at subfailure load (intact: 92.9 N vs single: 37.4 N; P = .001) or failure load (intact: 170.7 N vs single: 70.4 N; P = .024). However, the double-device repair successfully restored near-native posteromedial forces at both subfailure load (P = .066) and failure load (P = .723). CONCLUSION: For treatment of the most common form of PTFJ instability (anterolateral), this cadaveric study suggests that 1 BCSD is sufficient to restore stability and strength. The current biomechanical results also suggest that 2 devices are needed for restoring PTFJ posteromedial stability and strength. Using 2 devices addresses both types of instability and provides more PTFJ posteromedial stability. CLINICAL RELEVANCE: The results suggest that 1 device should be used for treating anterolateral instability and 2 devices used for posteromedial instability based on the biomechanical study.

Modeling the blood-brain barrier for treatment of central nervous system (CNS) diseases.

The blood-brain barrier (BBB) is the most specialized biological barrier in the body. This configuration of specialized cells protects the brain from invasion of molecules and particles through formation of tight junctions. To learn more about transport to the brain, in vitro modeling of the BBB is continuously advanced. The types of models and cells selected vary with the goal of each individual study, but the same validation methods, quantification of tight junctions, and permeability assays are often used. With Transwells and microfluidic devices, more information regarding formation of the BBB has been observed. Disease models have been developed to examine the effects on BBB integrity. The goal of modeling is not only to understand normal BBB physiology, but also to create treatments for diseases. This review will highlight several recent studies to show the diversity in model selection and the many applications of BBB models in in vitro research.

ON Path: outpatient nonunion pathway for lower-extremity nonunions.

Objectives: The purpose of this study was to assess the safety and efficacy of outpatient and short-stay surgical nonunion treatment by incorporating minimally invasive surgical techniques, multimodal pain control, and a modernized postoperative protocol. Design: Retrospective case series. Setting: Tertiary referral hospital and hospital outpatient department. Patients: All consecutive nonunion surgeries performed by 1 surgeon between 2014 and 2019 were identified. Outpatient and short-stay surgeries for patients with nonunion of the tibia and femur were eligible (n = 50). Intervention: Outpatient and short-stay surgical nonunion treatment by incorporating minimally invasive surgical techniques, multimodal pain control, and a modernized postoperative protocol. Main Outcome Measurements: Length of stay, postoperative emergency department visits, all complications, reoperations, and time to union. Results: Fifty patients were eligible, with 32 male patients (64%) and an average age of 46.5 years. The patient cohort consisted of 28 femur (56%) and 22 tibia (44%) nonunions. The average length of stay was 0.36 days. Seven patients (14%) required reoperation, 6 patients because of deep infection and 1 patient because of painful implant removal. Four patients (8%) presented to the emergency department within 1 week of surgery. One patient requiring amputation and patients lost to follow-up were excluded from the union rate calculation. For the remaining patients (46/50), 100% (46/46) united their nonunion. The average time to radiographic union was 7.82 months. Conclusions: An outpatient pathway is safe and effective for medically appropriate patients undergoing nonunion surgery. Outpatient nonunion surgery is a reasonable alternative that achieves similar outcomes compared with inpatient nonunion studies in the published literature. Level of Evidence: IV.

Single-Stage Treatment of Fracture-related Infections.

SUMMARY: Fracture-related infections (FRIs) remain a significant problem. Many approach FRI cases in a staged fashion, focusing on infection eradication initially and fracture union during subsequent procedures. The literature quotes high success rates with this strategy. However, associated patient morbidity and economic impact are noteworthy. A single-stage FRI treatment, using an antibiotic-coated locked intramedullary nail, also exists. This video details low-cost, antibiotic-coated locked intramedullary nail fabrication in the operating room alongside preliminary results using this technique for acute FRI and septic nonunion treatment.

Mild and Severe Obesity Reduce the Effectiveness of Lumbar Fusions: 1-Year Patient-Reported Outcomes in 8171 Patients.

BACKGROUND: Elevated body mass index (BMI) is a well-known risk factor for surgical complications in lumbar surgery. However, its effect on surgical effectiveness independent of surgical complications is unclear. OBJECTIVE: To determine increasing BMI's effect on functional outcomes following lumbar fusion surgery, independent of surgical complications. METHODS: We retrospectively analyzed a prospectively built, patient-reported, quality of life registry representing 75 hospital systems. We evaluated 1- to 3-level elective lumbar fusions. Patients who experienced surgical complications were excluded. A stepwise multivariate regression model assessed factors independently associated with 1-yr Oswestry Disability Index (ODI), preop to 1-yr ODI change, and achievement of minimal clinically important difference (MCID). RESULTS: A total of 8171 patients met inclusion criteria: 2435 with class I obesity (BMI 30-35 kg/m2), 1328 with class II (35-40 kg/m2), and 760 with class III (≥40 kg/m2). Increasing BMI was independently associated with worse 12-mo ODI (t = 8.005, P < .001) and decreased likelihood of achieving MCID (odds ratio [OR] = 0.977, P < .001). One year after surgery, mean ODI, ODI change, and percentage achieving MCID worsened with class I, class II, and class III vs nonobese cohorts (P < .001) in stepwise fashion. CONCLUSION: Increasing BMI is associated with decreased effectiveness of 1- to 3-level elective lumbar fusion, despite absence of surgical complications. BMI ≥ 30 kg/m2 is, therefore, a risk factor for both surgical complication and reduced benefit from lumbar fusion.

Acute Distal Femoral Replacement for Fractures About the Knee in the Elderly.

Distal femoral replacement (DFR) is a reasonable treatment option when used for select indications. In the setting of comminuted intra-articular distal femoral fractures, distal femoral arthroplasty should be considered in low-demand patients with poor bone quality. This article summarizes the existing literature plus the authors' personal experience with DFR use for distal femoral fractures of the native knee.

Efficacy of Multimodal Analgesic Injections in Operatively Treated Ankle Fractures: A Randomized Controlled Trial.

BACKGROUND: Pain management following surgical treatment of an ankle fracture is an under-studied area of clinical practice. The present study evaluated the efficacy of a multimodal surgical-site injection as an adjunct to postoperative pain management in patients with an operatively treated, closed, rotational ankle fracture. METHODS: Patients indicated for operative fixation of a rotational ankle fracture were randomized to receive multimodal surgical-site injection (ropivacaine 200 mg, epinephrine 0.6 mg, and morphine 5 mg) or no injection (control). Visual analog scale (VAS) pain and opioid consumption data were collected every 4 hours until discharge from the hospital. Length of stay and discharge destination were recorded. Patients were sent automated text messages to report VAS pain and opioid usage during the first 2 weeks after discharge. RESULTS: One hundred patients (49 injection and 51 control) were enrolled. Demographic data were similar between the 2 groups. Mean VAS scores over the first 24 and 48 hours postoperatively were slightly lower in the injection group (42 ± 3 and 41 ± 3, respectively) compared with the control group (52 ± 3 and 50 ± 3, respectively; p = 0.01 and p < 0.01, respectively). The median opioid usage, in terms of morphine equivalent dose, was similar over the first 24 hours between the injection group (25.5; range, 0 to 74.7) and the control group (28.3; range, 2.5 to 91.0; p = 0.35). The median opioid usage from recovery room admission to discharge was also similar between the injection group (29.0; range, 0 to 85.3) and the control group (32.7; range, 4.3 to 215.0; p = 0.35). There were no differences in outpatient VAS scores or opioid consumption during the first 2 weeks postoperatively as assessed with use of automated text messaging. Median length of stay was 22.3 hours (range, 1.7 to 182.3 hours) for the injection group and 22.5 hours (range, 2.2 to 123.3 hours) for the control group (p = 0.71). The response rate for the post-discharge automated text messages was 85.1%. Complication rates were similar. CONCLUSIONS: The use of multimodal surgical-site injections in operatively treated rotational ankle fractures is associated with a reduction in immediate in-hospital pain scores that is statistically significant but below the minimal clinically important difference. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Neonatal Growth Restriction Slows Cardiomyocyte Development and Reduces Adult Heart Size.

Prematurity is associated with reduced cardiac dimensions and an increased risk of cardiovascular disease. While prematurity is typically associated with ex utero neonatal growth restriction (GR), the independent effect of neonatal GR on cardiac development has not been established. We tested the hypothesis that isolated neonatal GR decreases cardiomyocyte growth and proliferation, leading to long-term alterations in cardiac morphology. C57BL/6 mice were fostered in litters ranging in size from 6 to 12 pups to accentuate normal variation in neonatal growth. Regardless of litter size, GR was defined by a weight below the 10th percentile. On postnatal day 8, Ki67 immunoreactivity, cardiomyocyte nucleation status and cardiomyocyte profile area were assessed. For adult mice, cardiomyocyte area was determined, along with cardiac dimensions by echocardiography and cardiac fibrosis by Masson's trichrome stain. On day 8, cardiomyocytes from GR versus control mice were significantly smaller and less likely to be binucleated with evidence of persistent cell cycle activity. As adults, GR mice continued to have smaller cardiomyocytes, as well as decreased left ventricular volumes without signs of fibrosis. Neonatal GR reduces cardiomyocyte size, delays the completion of binucleation, and leads to long-term alterations in cardiac morphology. Clinical studies are needed to ascertain whether these results translate to preterm infants that must continue to grow and mature in the midst of the increased circulatory demands that accompany their premature transition to an ex utero existence. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.

Pupillary response abnormalities in depressive disorders.

Depressive disorders lack objective physiological measurements to characterize the affected population and facilitate study of relevant mechanisms. The melanopsin-mediated light signaling pathway may contribute to seasonal variation and can be measured non-invasively by pupillometry. We prospectively studied changes in melanopsin-mediated pupillary constriction in 19 participants with major depressive disorder (MDD) and 10 control across the summer and winter solstices. The melanopsin-mediated response, as measured by the pupil's sustained constriction six s after a high intensity blue light stimulus, was marginally attenuated in those with MDD relative to controls (p=0.071). The participants with MDD unexpectedly showed a significantly reduced transient pupillary response to low intensity red (p=0.011) and blue light (p=0.013), but not high intensity red and blue light. Sustained pupillary constriction in response to high intensity blue light was more pronounced with increasing daylight hours (p=0.037) and was more strongly related to objectively measured versus estimated light exposure. Melanopsin-mediated impairments in pupil response may serve as a biological marker for vulnerability to depression in low light conditions. Assessment of these and other responses to light stimuli, such as response to low intensity light, may be useful for the study of the neurobiology of MDD and related mood disorders.

DNA extraction method affects microbial community profiles from soils and sediment.

To evaluate whether different deoxyribonucleic acid (DNA) extraction procedures can affect estimates of bacterial community composition, based on the 16S ribosomal ribonucleic acid gene denaturing gradient gel electrophoresis (DGGE) profiles, we compared four in situ lysis procedures using three soils and one marine sediment. Analysis of DGGE profiles, generated by polymerase chain reaction of purified DNA extracts, demonstrated that the choice of DNA extraction method significantly influenced the bacterial community profiles generated. This was reflected both in the number of bands or ribotypes detected from each sample and in subsequent principle coordinate analysis and unweighted-pair group method using arithmetic average analyses. The methods also differed significantly in their robustness, i.e. reproducibility across multiple analyses. Two methods, both based on bead beating, were demonstrated to be suitable for comparative studies of a range of soil and sediment types.

Accessing the black box of microbial diversity and ecophysiology: recent advances through polyphasic experiments.

The microbial ecology of a range of anaerobic biological assemblages (granular sludge) from full- and laboratory-scale wastewater treatment bioreactors, and of crop-growing and peat soils, was determined using a variety of 16S rRNA gene-based techniques, including clone library, terminal restriction fragment length polymorphism (TRFLP) and denaturing gradient gel electrophoresis (DGGE) analyses. Fluorescent in situ hybridization (FISH) using 16S rRNA gene-targeted probes was employed to complete a "full-cycle rRNA approach" with selected biomass. Genetic fingerprinting (TRFLP and DGGE) was effectively used to elucidate community structure-crop relationships, and to detect and monitor trends in bioreactor sludge and specific enrichment cultures of peat soil. Greater diversity was resolved within bacterial than within archaeal communities, and unexpected reservoirs of uncultured Crenarchaeota were detected in sludge granules. Advanced radiotracer incubations and micro-beta imaging were employed in conjunction with FISH to elucidate the eco-functionalism of these organisms. Crenarchaeota clusters were identified in close associated with methanogenic Archaea and both were localised with acetate uptake in biofilm structure.