Utility of an allograft tendon for scoliosis correction via the costo-transverse foreman.

Current convex tethering techniques for treatment of scoliosis have centered on anterior convex staples or polypropylene tethers. We hypothesized that an allograft tendon tether inserted via the costo-transverse foramen would correct an established spinal deformity. In the pilot study, six 8-week-old pigs underwent allograft tendon tethering via the costo-transverse foreman or sham to test the strength of the transplanted tendon to retard spine growth.

Chitosan coating to enhance the therapeutic efficacy of calcium sulfate-based antibiotic therapy in the treatment of chronic osteomyelitis.

We demonstrate that coating calcium sulfate with deacetylated chitosan enhances the elution profile of daptomycin by prolonging the period during which high concentrations of antibiotic are released. Coatings reduced initial bolus release of daptomycin by a factor of 10 to approximately 1000 µg/ml, and levels remained above 100 µg/ml for up to 10 days. Chitosan-coated and uncoated calcium sulfate implants with and without 15% daptomycin were evaluated in an experimental model of staphylococcal osteomyelitis through bacteriology scores, radiology, histopathology, and Gram staining.

Use of xylitol to enhance the therapeutic efficacy of polymethylmethacrylate-based antibiotic therapy in treatment of chronic osteomyelitis.

Using a rabbit model of postsurgical osteomyelitis, we demonstrate that incorporation of xylitol into polymethylmethacrylate (PMMA) bone cement enhances the elution of daptomycin under in vivo conditions. We also demonstrate that this can be correlated with an improved therapeutic outcome in the treatment of a chronic bone infection following surgical debridement.

Evaluation of dynamic [18F]-FDG-PET imaging for the detection of acute post-surgical bone infection.

Diagnosing bone infection in its acute early stage is of utmost clinical importance as the failure to do so results in a therapeutically recalcitrant chronic infection that can only be resolved with extensive surgical intervention, the end result often being a structurally unstable defect requiring reconstructive procedures. [(18)F]-FDG-PET has been extensively investigated for this purpose, but the results have been mixed in that, while highly sensitive, its specificity with respect to distinguishing between acute infection and sterile inflammatory processes, including normal recuperative post-surgical healing, is limited. This study investigated the possibility that alternative means of acquiring and analyzing FDG-PET data could be used to overcome this lack of specificity without an unacceptable loss of sensitivity.

Optimized elution of daptomycin from polymethylmethacrylate beads.

We demonstrate that xylitol can be added to polymethylmethacrylate (PMMA) bone cement to enhance the elution of daptomycin in terms of both the peak and sustained release of antibiotic. We also demonstrate that a PMMA-xylitol formulation optimized for daptomycin can be used to enhance the elution of both vancomycin and gentamicin.

Sucrose, xylitol, and erythritol increase PMMA permeability for depot antibiotics.

Release of antibiotics from antibiotic-loaded PMMA is dependent on its permeability. Loading PMMA with soluble particulate filler has been proposed to increase permeability and antibiotic release for beads and spacers. We therefore assessed particulate sucrose, xylitol, and erythritol as fillers to increase the permeability and elution kinetics of filler-loaded PMMA.

Xylitol and glycine fillers increase permeability of PMMA to enhance elution of daptomycin.

The elution of antibiotics from hand mixed antibiotic-laden polymethylmethacrylate (PMMA) must be increased to achieve clinical performance equivalent to commercially manufactured antibiotic beads (not available in the USA) in the management of musculoskeletal infections. Adding fillers such as glycine and dextran to polymethylmethacrylate increases the elution of antibiotics from antibiotic-laden PMMA. We propose xylitol, a naturally occurring sweetener with direct antibiofilm properties, as a filler material.

Phenolphthalein used to assess permeability of antibiotic-laden polymethylmethacrylate: a pilot study.

Elution of antibiotics from polymethylmethacrylate laden with antibiotics is dependent on the permeability of the polymethylmethacrylate. Increasing polymethylmethacrylate permeability by adding fillers has been suggested to increase antibiotic elution but the resulting increase in permeability has not been assessed directly. A simple method to assess polymethylmethacrylate permeability is proposed.

Is aseptic loosening truly aseptic?

Surgeons who treat osteomyelitis or infected implants think that microorganisms can live on and around implanted biomaterials and necrotic bone without clinical manifestations of infection. Gristina and Costerton, in their seminal work, suggested that such bacteria persist within biofilms and that they are often overlooked when diagnosis is based on standard microbiologic culture techniques. Subsequent studies using specialized techniques including sonication to remove adherent bacteria and direct detection using various forms of microscopy have confirmed that bacteria are present in many culture-negative cases.

Early detection of bone infection and differentiation from post-surgical inflammation using 2-deoxy-2-[18F]-fluoro-D-glucose positron emission tomography (FDG-PET) in an animal model.

Diagnosing bone infection in the context of post-surgical inflammation is problematic since many of the early signs of infection are similar to normal post-surgical changes. We used a rabbit osteomyelitis model to evaluate the use of 2-deoxy-2-[(18)F]-fluoro-d-glucose positron emission tomography (FDG-PET) as a means of detecting post-operative infection in the context of post-surgical inflammation. Comparisons were made between infected and non-infected rabbits in which infection with Staphylococcus aureus was initiated at the time of surgery.

The effect of glycine filler on the elution rate of gentamicin from acrylic bone cement: a pilot study.

Elution of antibiotics from acrylic bone cement (polymethylmethacrylate [PMMA]) is dependent on the access of fluid to the depths of the cement that contains the antibiotic. Commercially prepared antibiotic beads that are porous have higher elution rates than hand-mixed, nonporous antibiotic PMMA mixtures. To increase the elution of gentamicin from hand-mixed PMMA, glycine was added as a filler to produce porosity.

Surgical hand scrub practices in orthopaedic surgery.

The purpose of this study was to determine whether the practice of surgical hand scrubbing among orthopaedic surgeons, faculty, residents, and nurses met the institution's recommended 5-minute scrub policy and how often a 2-minute surgical hand scrub was used. Forty-eight subjects' hand scrub times were recorded discreetly for a total of 125 observations. All individuals scrubbed for a mean of 2.

The effect of sampling method on the elution of tobramycin from calcium sulfate.

Release rate is a critical property of all drug delivery vehicles, including antibiotic-laden bioerodibles. In vitro elution studies, used to evaluate release rates, use different sampling methods, including changing the entire amount of buffer and partial exchanges each day. Two groups of 10% calcium sulfate-tobramycin pellets were eluted in 20 mL of buffer for 30 days.

Detecting bacterial colonization of implanted orthopaedic devices by ultrasonication.

Glycocalyx-producing bacteria have been observed on orthopaedic devices that were removed for reasons other than infection. It has been suggested that the bacteria adhere to foreign surfaces within a biofilm and elude standard culture techniques. The authors adapted previously used ultrasonication protocols that disrupt the surface biofilm before culturing removed orthopaedic devices from patients without clinical evidence of infection.

The treatment of experimental osteomyelitis by surgical debridement and the implantation of calcium sulfate tobramycin pellets.

Calcium sulfate was used as a biodegradable delivery system for the administration of antibiotics in musculoskeletal infection. New Zealand white rabbits were infected with Staplylococcus aureus, debrided, and randomized to one of four treatment groups: calcium sulfate pellets with 10% tobramycin sulfate, placebo calcium sulfate pellets and IM tobramycin, placebo calcium sulfate pellets, or debridement. Serum and wound exudate tobramycin concentrations and serum calcium levels were measured.