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The extension-type pediatric supracondylar humerus fracture accounts for nearly two-thirds of all pediatric hospitalizations due to elbow trauma. The Gartland classification guides the standard of care for treatment of this entity. Type I injuries are treated with cast immobilization while type II and III injuries are treated operatively. The reported interobserver reliability ranges from moderate to full agreement, which is on par with other frequently referenced classification systems such as Lauge-Hansen for adult ankle fractures. In this study, 4 fellowship-trained pediatric orthopedic surgeons reviewed radiographs of 72 pediatric supracondylar fractures and classified them based on Gartland's system. They recommended their preferred treatment of cast immobilization for type I fractures and of closed reduction and pinning in the operating room for type II and type III fractures. The interobserver and intraobserver reliability for each set of radiographs was then analyzed. There was moderate agreement comparing all fractures and comparing types I and II fractures, while there was full agreement for type III fractures. There was full agreement for the intraobserver reliability. The preferred treatment (casting vs operative intervention) differed in 35% of patients, if based on the fracture classification.

Both erythromycin and clarithromycin have been reported to cause QT prolongation and the cardiac arrhythmia torsade de pointes in humans, however direct evidence documenting that these drugs produce this effect by blocking human cardiac ion channels is lacking. The goal of this study was to test the hypothesis that these macrolide antibiotics significantly block the delayed rectifier current (IKr) encoded by HERG (the human ether-a-go-go-related gene) at drug concentrations, temperature and ionic conditions mimicking those occurring in human subjects. Potassium currents in HEK 293 cells stably transfected with HERG were recorded using a whole cell voltage clamp method. Exposure of cells to erythromycin reduced the HERG encoded potassium current in a concentration dependent manner with an IC50 of 38.9 +/- 1.2 microM and Hill Slope factor of 0.4 +/- 0.1. Clarithromycin produced a similar concentration-dependent block with an IC50 of 45.7 +/- 1.1 microM and Hill Slope factor of 1.0 +/- 0.1. Erythromycin (25-250 microM) and clarithromycin (5 or 25 microM) also produced a significant decrease in the integral of the current evoked by an action potential shaped voltage clamp protocol. The results of this study document that both erythromycin and clarithromycin significantly inhibit the HERG potassium current at clinically relevant concentrations.

Background Infection of total knee arthroplasty is a complex problem often resulting in multiple surgeries for the patient. We examined the early to midterm results of a retained cemented “low-friction” metal-on-polyethylene articulating antibiotic spacer in total knee arthroplasty. Methods We retrospectively reviewed patients with a total knee cemented articulating antibiotic spacer performed for joint sepsis. Patients were allowed full weight bearing and normal activities after eradication of the infection at 6 weeks postop. Two months later, patients were given the option of conversion to a revision implant vs retention of the spacer. We examined infection cure rate, mechanical failure, Knee Society Scores, range of motion, and patient factors associated with spacer retention. Results Fifty-five knees were studied with average follow-up of 1.8 years (0.2-8.4). Among patients choosing spacer retention (40%), the average follow-up time of the spacer was 3.3 years (0.6-8.4). Five patients (9.1%) required a repeat spacer for recurrent infection. Conclusions Usage of articulating cement antibiotic spacers with a metal-on-polyethylene bearing couple provides excellent infection eradication, while also resulting in good functional outcomes. Early evidence suggests that use of the implant can be extended beyond typical timeframes and, in certain patient populations, may be suitable for a single-stage procedure.

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