Acinetobacter baumannii is recognized as an emerging bacterial pathogen because of traits such as prolonged survival in a desiccated state, effective nosocomial transmission, and an inherent ability to acquire antibiotic resistance genes. A pressing need in the field of A. baumannii research is a suitable model strain that is representative of current clinical isolates, is highly virulent in established animal models, and can be genetically manipulated. To identify a suitable strain, a genetically diverse set of recent U.S. military clinical isolates was assessed. Pulsed-field gel electrophoresis and multiplex PCR determined the genetic diversity of 33 A. baumannii isolates. Subsequently, five representative isolates were tested in murine pulmonary and Galleria mellonella models of infection. Infections with one strain, AB5075, were considerably more severe in both animal models than those with other isolates, as there was a significant decrease in survival rates. AB5075 also caused osteomyelitis in a rat open fracture model, while another isolate did not. Additionally, a Tn5 transposon library was successfully generated in AB5075, and the insertion of exogenous genes into the AB5075 chromosome via Tn7 was completed, suggesting that this isolate may be genetically amenable for research purposes. Finally, proof-of-concept experiments with the antibiotic rifampin showed that this strain can be used in animal models to assess therapies under numerous parameters, including survival rates and lung bacterial burden. We propose that AB5075 can serve as a model strain for A. baumannii pathogenesis due to its relatively recent isolation, multidrug resistance, reproducible virulence in animal models, and genetic tractability.

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Through an iteration of various advancements, both short stem and stemless options for humeral fixation have been proposed and have shown clinical promise. The proposed benefits of a stemless humeral implant include greater bone preservation, less stress shielding, less risk of a diaphyseal stress riser, decreased surgical time, and less intraoperative blood loss. Potential downsides include the dependence on proximal bone quality for fixation, increased cost, the dependence on the strength of subscapularis fixation, and pending FDA approval for multiple implants. The purpose of this article is to review the evidence behind stemless implants including the biomechanical advantages and disadvantages, surgical technique, and clinical outcomes.

Concussion policies are increasingly being developed and adopted among professional sports organizations. We sought to compare the policies of the National Hockey League (NHL), the National Basketball Association (NBA), the National Football League (NFL), and Major League Baseball (MLB). Our objective was to summarize each policy and evaluate the extent to which each policy is organization-specific and/or consistent with medical guidelines. We visited websites for the NHL, NBA, NFL, and MLB. We searched media articles reporting concussion policy. We utilized only publically available data. We collected information on each league's approach to the definition of concussion, education provided about concussion, baseline testing requirements, minimum return to play time and return to play protocol. We found that concussion policies vary across these organizations. Most organizations utilize the Concussion in Sport Group (CISG) definition (2013) to define concussion. The NFL and NBA mandate preseason education. All organizations require some type of baseline testing. All organizations require sideline evaluation after suspected concussion. The NFL and MLB require Sport Concussion Assessment Tool (SCAT) testing for sideline evaluation of suspected concussion. MLB is the only organization to require minimum time before return to play. There is a return to play protocol in place for each organization. The NFL and MLB require independent neurologic consultation as part of their return to play protocol. There is variability in concussion policy among the professional sports organizations. The most pronounced variation from the CISG consensus statement is the variability in the minimum time to return to play. Further, the rules of the individual sports have a role in how concussion policy can be designed and implemented. Professional sports set an example for thousands of recreational sports enthusiasts so their publically available policies on concussion have a large impact.

Open-book pelvic fractures in the obese patient are accompanied by an increased risk of fixation failure. We report on the use of a recently described anterior subcutaneous pelvic internal fixator, the "INFIX" technique, in a morbidly obese patient. In this case, single and double rod constructs alone did not maintain adequate fixation due to the extreme forces in a morbidly obese patient. Successful salvage of the construct and satisfactory healing was achieved with the addition of 2 cross-links between the double rods of the INFIX.

Arthroscopic rotator cuff repairs (ARCRs) are common procedures that have been increasing in incidence. When performing ARCR, the surgeon often identifies an undesirable flap or fold, referred to as a "dog-ear" deformity, between sutures or knots. The height and/or thickness of a dog-ear deformity may decrease the rotator cuffetoeacromion distance, resulting in possible impingement and repair compromise. Furthermore, the goal of ARCR is to achieve complete restoration of the tendon-to-footprint relation. To restore the entire footprint, this lesion must be reduced and stabilized. We present a technique using looped sutures to augment the rotator cuff repair and prevent dog-ear formation.

Superior capsular reconstruction (SCR) is increasingly being used as a procedure for addressing irreparable rotator cuff tears. The procedure was initially described for failed rotator cuff repairs where the retears are severely retracted and when grade 3-4 fatty infiltration and atrophy exist. The SCR procedure can also be considered for irreparable rotator cuff tears in patients that are either too young or too high demand to be appropriate candidates for arthroplasty. Early short and medium term follow up studies support SCR with favorable outcomes compared with other salvage procedures.

No abstract