Dual Plate Minifragment Fixation of Clavicle Fractures- Technique and Approach

SUMMARY

The treatment of midshaft clavicle fractures continues to evolve, with a variety of fixation techniques and constructs used. Symptomatic hardware is a common complication related to plate fixation of the clavicle, and often results in secondary surgery for implant removal. The minifragment dual plate fixation technique for clavicle fractures provides a construct that may result in fewer implant related complications with comparable fixation stability to precontoured locking plates. Our case presentation demonstrates our approach to midshaft clavicle fractures, the benefits of this surgical technique, and reported outcomes from this fixation method.

Variation in practice for preoperative antibiotic prophylaxis: a survey from an academic tertiary referral center in the United States

Background

Antibiotic surgical prophylaxis is a core strategy for prevention of surgical site infections (SSI). Despite best practice guidelines and known efficacy of antibiotic prophylaxis in decreasing SSI risk, there is often wide variation in its use. This study was designed to determine the individual perspectives of perioperative providers at an academic tertiary referral center regarding their knowledge of preoperative antibiotic choice, dosing, and timing.

Methods

A prospective survey was conducted amongst surgical and anesthesia team members involved in preoperative antibiotic decision making. The survey addressed ten key principles relating to preoperative antibiotic use, including antibiotic choice, timing and rate of infusion, and dosing. The survey was distributed among orthopaedic surgeons, residents, and anesthesia providers at their respective monthly service line meetings between August 2017 to June 2019. The data was stored and analyzed in a Microsoft Excel worksheet.

Results

A total of 73 providers completed the survey. Twenty-two (30 %) of the providers agreed and 47 (64 %) disagreed that both vancomycin and cefazolin are equally effective for antibiotic prophylaxis. As for antibiotic choice in patients with penicillin allergies, 37 (51 %) agreed with vancomycin, 21 (29 %) agreed with clindamycin, and 15 (21 %) disagreed with both alternatives. When providers were surveyed regarding the appropriateness of standard versus weight adjusted dosing, 67 (92 %) agreed that vancomycin should be weight adjusted and 63 (86 %) agreed that cefazolin should be weight adjusted.

Conclusions

There is no clear consensus amongst providers for which antibiotic to administer for antibiotic prophylaxis despite existing guidelines. Discrepancy also exists between orthopaedic surgery and anesthesia providers in regards to appropriate antibiotic choice for patients with reported penicillin allergies. Institutions should implement evidence-based protocols for preoperative antibiotic prophylaxis and continue to prospectively monitor compliance in order to identify any inconsistencies that could result in inappropriate antibiotic prophylaxis for patients.

Juvenile psammomatoid ossifying fibroma of the calcaneus

Juvenile ossifying fibromas (JOFs) are a rare group of fibro-osseous lesions, typically of odontogenic origin. Juvenile psammomatoid ossifying fibroma (JPOF) is one variant, that is, histopathologically distinguished by spherical ossicles resembling psammoma bodies. JPOF tumours are most commonly found in craniofacial skeletal structures and can be locally aggressive. Thus, early management by complete surgical excision is crucial for good outcomes, although recurrence is still possible. Secondary aneurysmal bone cyst (ABC) formation has been reported with JOF lesions, but less commonly with the JPOF variant. We describe an unusual case of JPOF that presented in the calcaneus with secondary ABC formation.

The role of preoperative vascular imaging and embolisation for the surgical resection of bilateral hip heterotopic ossification

The surgical excision of heterotopic ossification can provide improved function for patients; however, complications can include damage to nearby vessels and nerves, blood loss and recurrence. In the preoperative planning for excision, our case report describes the combination of CT angiography, preoperative embolisation of involved vascular structures and the use of intraoperative vascular surgery for dissection around key structures to aid in the reduction of morbidity in these patients.

Group B streptococcus septic arthritis of the hip following spontaneous abortion

Group B streptococcus (GBS) infection of the hip in otherwise healthy adults is a rare entity that is previously only reported following peripartum gynaecological procedure and instrumentation. We report a case of infection of the hip with GBS following spontaneous abortion. Delay in identification of infection as the cause of pain ultimately leads to irreversible joint destruction. This case report will heighten the awareness of the first contact providers as well as orthopaedic surgeons to be more vigilant for possible septic complications associated with gynaecological procedures/complications and subsequent painful joints. To our knowledge, this is the only case report showing association of GBS infection in hip associated with spontaneous abortion.

Septic Arthritis of the Wrist: Incidence, Risk Factors, and Predictors of Infection

Septic arthritis of the wrist can result in permanent damage to the joint, making timely diagnosis crucial to initiate empiric antibiotics and surgical intervention. Although septic arthritis is routinely included in the differential diagnosis of atraumatic wrist pain, the incidence is unknown. Unlike large joints, there is no consensus on cell count values considered pathognomonic for wrist septic arthritis. The goal of this retrospective study was to determine the incidence of wrist septic arthritis and to identify the clinical, serum, and joint fluid values that predict infection. The records of patients who presented to a single urban hospital with a swollen, painful wrist without trauma during a 10-year period were reviewed. For patients who had a joint fluid analysis, the records were examined for history as well as demographic and laboratory data. Joint fluid analysis consisted of cell count, Gram stain, and cultures. Of 892 patients who met the inclusion criteria, 1.5% had wrist septic arthritis. Variables associated with septic arthritis included serum white blood cell count above 11,000/µL, core temperature above 100.4°F within 24 hours of aspiration, history of intravenous drug abuse, and smoking. No joint cell count analysis predicted septic arthritis, although patients with septic wrists had an elevated joint white blood cell count above 97,000/µL. Wrist septic arthritis is uncommon; however, objective factors can help identify patients at risk. Because joint cell count analysis cannot reliably predict a septic wrist, priority for joint aspirations with limited fluid should be given instead to Gram stain, culture, and crystal analysis. [Orthopedics. 2017; 40(3):e526-e531.].

Insulin Regulates Hepatic Triglyceride Secretion and Lipid Content via Signaling in the Brain

Hepatic steatosis is common in obesity and insulin resistance and results from a net retention of lipids in the liver. A key mechanism to prevent steatosis is to increase secretion of triglycerides (TG) packaged as VLDLs. Insulin controls nutrient partitioning via signaling through its cognate receptor in peripheral target organs such as liver, muscle, and adipose tissue and via signaling in the central nervous system (CNS) to orchestrate organ cross talk. While hepatic insulin signaling is known to suppress VLDL production from the liver, it is unknown whether brain insulin signaling independently regulates hepatic VLDL secretion. Here, we show that in conscious, unrestrained male Sprague Dawley rats the infusion of insulin into the third ventricle acutely increased hepatic TG secretion. Chronic infusion of insulin into the CNS via osmotic minipumps reduced the hepatic lipid content as assessed by noninvasive (1)H-MRS and lipid profiling independent of changes in hepatic de novo lipogenesis and food intake. In mice that lack the insulin receptor in the brain, hepatic TG secretion was reduced compared with wild-type littermate controls. These studies identify brain insulin as an important permissive factor in hepatic VLDL secretion that protects against hepatic steatosis.

Brain insulin lowers circulating BCAA levels by inducing hepatic BCAA catabolism

Circulating branched-chain amino acid (BCAA) levels are elevated in obesity/diabetes and are a sensitive predictor for type 2 diabetes. Here we show in rats that insulin dose-dependently lowers plasma BCAA levels through induction of hepatic protein expression and activity of branched-chain α-keto acid dehydrogenase (BCKDH), the rate-limiting enzyme in the BCAA degradation pathway. Selective induction of hypothalamic insulin signaling in rats and genetic modulation of brain insulin receptors in mice demonstrate that brain insulin signaling is a major regulator of BCAA metabolism by inducing hepatic BCKDH. Short-term overfeeding impairs the ability of brain insulin to lower BCAAs in rats. High-fat feeding in nonhuman primates and obesity and/or diabetes in humans is associated with reduced BCKDH protein in liver. These findings support the concept that decreased hepatic BCKDH is a major cause of increased plasma BCAAs and that hypothalamic insulin resistance may account for impaired BCAA metabolism in obesity and diabetes.

Binge drinking induces whole-body insulin resistance by impairing hypothalamic insulin action

Individuals with a history of binge drinking have an increased risk of developing the metabolic syndrome and type 2 diabetes. Whether binge drinking impairs glucose homeostasis and insulin action is unknown. To test this, we treated Sprague-Dawley rats daily with alcohol (3 g/kg) for three consecutive days to simulate human binge drinking and found that these rats developed and exhibited insulin resistance even after blood alcohol concentrations had become undetectable. The animals were resistant to insulin for up to 54 hours after the last dose of ethanol, chiefly a result of impaired hepatic and adipose tissue insulin action. Because insulin regulates hepatic glucose production and white adipose tissue lipolysis, in part through signaling in the central nervous system, we tested whether binge drinking impaired brain control of nutrient partitioning. Rats that had consumed alcohol exhibited impaired hypothalamic insulin action, defined as the ability of insulin infused into the mediobasal hypothalamus to suppress hepatic glucose production and white adipose tissue lipolysis. Insulin signaling in the hypothalamus, as assessed by insulin receptor and AKT phosphorylation, decreased after binge drinking. Quantitative polymerase chain reaction showed increased hypothalamic inflammation and expression of protein tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin signaling. Intracerebroventricular infusion of CPT-157633, a small-molecule inhibitor of PTP1B, prevented binge drinking-induced glucose intolerance. These results show that, in rats, binge drinking induces systemic insulin resistance by impairing hypothalamic insulin action and that this effect can be prevented by inhibition of brain PTP1B.

Short term voluntary overfeeding disrupts brain insulin control of adipose tissue lipolysis

Insulin controls fatty acid (FA) release from white adipose tissue (WAT) through direct effects on adipocytes and indirectly through hypothalamic signaling by reducing sympathetic nervous system outflow to WAT. Uncontrolled FA release from WAT promotes lipotoxicity, which is characterized by inflammation and insulin resistance that leads to and worsens type 2 diabetes. Here we tested whether early diet-induced insulin resistance impairs the ability of hypothalamic insulin to regulate WAT lipolysis and thus contributes to adipose tissue dysfunction. To this end we fed male Sprague-Dawley rats a 10% lard diet (high fat diet (HFD)) for 3 consecutive days, which is known to induce systemic insulin resistance. Rats were studied by euglycemic pancreatic clamps and concomitant infusion of either insulin or vehicle into the mediobasal hypothalamus. Short term HFD feeding led to a 37% increase in caloric intake and elevated base-line free FAs and insulin levels compared with rats fed regular chow. Overfeeding did not impair insulin signaling in WAT, but it abolished the ability of mediobasal hypothalamus insulin to suppress WAT lipolysis and hepatic glucose production as assessed by glycerol and glucose flux. HFD feeding also increased hypothalamic levels of the endocannabinoid 2-arachidonoylglycerol after only 3 days. In summary, overfeeding impairs hypothalamic insulin action, which may contribute to unrestrained lipolysis seen in human obesity and type 2 diabetes.

Central endocannabinoid signaling regulates hepatic glucose production and systemic lipolysis

OBJECTIVE

The endocannabinoid (EC) system has been implicated as an important regulator of energy homeostasis. In obesity and type 2 diabetes, EC tone is elevated in peripheral tissues including liver, muscle, fat, and also centrally, particularly in the hypothalamus. Cannabinoid receptor type 1 (CB₁) blockade with the centrally and peripherally acting rimonabant induces weight loss and improves glucose homeostasis while also causing psychiatric adverse effects. The relative contributions of peripheral versus central EC signaling on glucose homeostasis remain to be elucidated. The aim of this study was to test whether the central EC system regulates systemic glucose fluxes.

RESEARCH DESIGN AND METHODS

We determined glucose and lipid fluxes in male Sprague-Dawley rats during intracerebroventricular infusions of either WIN55,212-2 (WIN) or arachidonoyl-2'-chloroethylamide (ACEA) while controlling circulating insulin and glucose levels through hyperinsulinemic, euglycemic clamp studies. Conversely, we fed rats a high-fat diet for 3 days and then blocked central EC signaling with an intracerebroventricular infusion of rimonabant while assessing glucose fluxes during a clamp.

RESULTS

Central CB₁ activation is sufficient to impair glucose homeostasis. Either WIN or ACEA infusions acutely impaired insulin action in both liver and adipose tissue. Conversely, in a model of overfeeding-induced insulin resistance, CB₁ antagonism restored hepatic insulin sensitivity.

CONCLUSIONS

Thus central EC tone plays an important role in regulating hepatic and adipose tissue insulin action. These results indicate that peripherally restricted CB₁ antagonists, which may lack psychiatric side effects, are also likely to be less effective than brain-permeable CB₁ antagonists in ameliorating insulin resistance.

Brain insulin controls adipose tissue lipolysis and lipogenesis

White adipose tissue (WAT) dysfunction plays a key role in the pathogenesis of type 2 diabetes (DM2). Unrestrained WAT lipolysis results in increased fatty acid release, leading to insulin resistance and lipotoxicity, while impaired de novo lipogenesis in WAT decreases the synthesis of insulin-sensitizing fatty acid species like palmitoleate. Here, we show that insulin infused into the mediobasal hypothalamus (MBH) of Sprague-Dawley rats increases WAT lipogenic protein expression, inactivates hormone-sensitive lipase (Hsl), and suppresses lipolysis. Conversely, mice that lack the neuronal insulin receptor exhibit unrestrained lipolysis and decreased de novo lipogenesis in WAT. Thus, brain and, in particular, hypothalamic insulin action play a pivotal role in WAT functionality.