Aims. There is a considerable challenge in treating bone infections and orthopaedic device-associated infection (ODAI), partly due to impaired penetration of systemically administrated antibiotics at the site of infection. This may be circumvented by local drug administration. Knowledge of the release kinetics from any carrier material is essential for proper application. Ceftriaxone shows a particular constant release from calcium sulphate (CaSO. 4. ) in vitro, and is particularly effective against streptococci and a large portion of Gram-negative bacteria. We present the clinical release kinetics of ceftriaxone-loaded CaSO. 4. applied locally to treat ODAI. Methods. A total of 30 operations with ceftriaxone-loaded CaSO. 4. had been performed in 28 patients. Ceftriaxone was applied as a single local antibiotic in 21 operations and combined with vancomycin in eight operations, and in an additional operation with vancomycin and amphotericin B. Sampling of wound fluid was performed from drains or aspirations. Ceftriaxone concentrations were measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Results. A total of 37 wound fluid concentrations from 16 operations performed in 14 patients were collected. The ceftriaxone concentrations remained approximately within a range of 100 to 200 mg/l up to three weeks. The median concentration was 108.9 mg/l (interquartile range 98.8 to 142.5) within the first ten days. No systemic adverse reactions were observed. Conclusion. Our study highlights new clinical data of locally administered ceftriaxone with CaSO. 4. as carrier material. The near-constant release of ceftriaxone from CaSO. 4. observed in vitro could be confirmed in vivo. The concentrations remained below known local toxicity thresholds. Cite this article: Bone Joint Res 2022;11(11):835–842

Objectives

Irrigation is the cornerstone of treating skeletal infection by eliminating pathogens in wounds. A previous study shows that irrigation with normal saline (0.9%) and ethylenediaminetetraacetic acid (EDTA) could improve the removal of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) compared with normal saline (NS) alone. However, it is still unclear whether EDTA solution is effective against infection with drug-resistant bacteria.

We present the first systematic review conducted by the UK Defence Medical Services in conjunction with the Cochrane Collaboration. Irrigation fluids are used to remove contamination during the surgical treatment of traumatic wounds in order to prevent infection. This review aims to determine whether there is evidence that one wound irrigation fluid is superior to another at reducing infection. A pre-published methodology was used and two reviewers independently assessed the search results. The search produced 917 studies, of which three met the inclusion criteria. All were studies in open fractures, incorporating a total of 2,903 patients. Each RCT involved a distinct comparison, precluding meta-analysis: i) sterile saline vs. distilled/boiled water; ii) antibiotic solution vs. soap solution; iii) saline vs. soap solution. The odds ratios of infection following irrigation with various fluids was as follows: i) saline vs. distilled or boiled water 0.25 (95%CI 0.08–0.73); ii) antibiotic solution vs. soap 1.42 (95%CI 0.82–2.46); iii) saline vs. soap solution 1.00 (95%CI 0.80–1.26). These results suggest that neither soap nor antibiotic solution is superior to saline and that saline is inferior to distilled or boiled water

Aims. Calcium sulphate (CaSO. 4. ) is a resorbable material that can be used simultaneously as filler of a dead space and as a carrier for the local application of antibiotics. Our aim was to describe the systemic exposure and the wound fluid concentrations of vancomycin in patients treated with vancomycin-loaded CaSO. 4. as an adjunct to the routine therapy of bone and joint infections. Patients and Methods. A total of 680 post-operative blood and 233 wound fluid samples were available for analysis from 94 implantations performed in 87 patients for various infective indications. Up to 6 g of vancomycin were used. Non-compartmental pharmacokinetic analysis was performed on the data from 37 patients treated for an infection of the hip. Results. The overall systemic exposure remained within a safe range, even in patients with post-operative renal failure, none requiring removal of the pellets. Local concentrations were approximately ten times higher than with polymethylmethacrylate (PMMA) as a carrier, but remained below reported cell toxicity thresholds. Decreasing concentrations in wound fluid were observed over several weeks, but remained above the common minimum inhibitory concentrations for Staphylococcus up to three months post-operatively. . Conclusion. This study provides the first pharmacokinetic description of the local application of vancomycin with CaSO. 4. as a carrier, documenting slow release, systemic safety and a release profile far more interesting than from PMMA. In particular, considering in vitro data, concentrations of vancomycin active against staphylococcal biofilm were seen for several weeks. Cite this article: Bone Joint J 2017;99-B:1537–44

Aim. Determine the time concentration profile required to achieve vancomycin-mediated eradication of Staphylococcus aureus biofilm. This is critical for the identification of performance targets for local antibiotic delivery, yet has not been described. Method. Mature S. aureus UAMS-1 biofilms were grown on titanium-aluminum-niobium discs in Mueller Hinton broth (MHB). After 7 days, the discs were incubated in MHB containing vancomycin at 100, 200, 500, 1′000 and 2′000 mg/L. Both static and shaking conditions were tested. Samples were retrieved at intervals for up to 28 days for quantification of residual biofilm by sonication and serial dilution plating. One additional disc was processed per time point for scanning electron microscopy. Results. Progressive and significant reduction of viable bacteria was observed over time at all vancomycin concentrations in both static and shaking conditions. After 28 days under static conditions, the S. aureus biofilm was completely eradicated at 200 mg/L vancomycin and higher concentrations. Biofilm could could however not be eradicated under shaking conditions at any concentration. Logistic regression documents time of exposure at ≥200 mg/L as being the essential determinant of eradication. Conclusions. The clinical relevance of the present study is that it is not impossible to eradicate mature S. aureus biofilm from metal implants by vancomycin alone, fostering efforts to optimize local delivery. The required time concentration profile cannot be achieved yet by systemic administration or any of the local delivery vehicles available. Even longer exposure as 28 days might be required as wound fluid flow might influence unfavourably biofilm resistance to vancomycin

Introduction. Calcium sulphate is a resorbable void filler that can be used for local antibiotic delivery. Results from clinical studies on chronic osteomyelitis thus treated with local vancomycin have already been published. Despite significant exposure to this drug, there are no pharmacokinetic studies published so far. Based on observations in our patients, a model predicting vancomycin serum and wound fluid levels and toxicity potential is presented. Methods. Following implantation of Osteoset® added with vancomycin, serum and wound fluid concentrations of this antibiotic have been monitored systematically. The pharmacokinetic analysis was performed using a non-linear mixed-effects model based on a one-compartment model with first-degree absorption. Results. Data from 43 patients treated between October 2006 and August 2010 were analysed. Serum concentrations remained far below the usually accepted trough levels of 10 mg/L, and were still acceptable in two cases of post-operative renal failure. Wound fluid concentrations around 1,000 mg/l were observed for the first 7–10 days, and remained above usual minimal inhibitory concentrations for approximately a month. Discussion and Conclusion. This is the first pharmacokinetic exploration of calcium sulphate added with vancomycin for local antibiotic therapy. The systemic exposure to vancomycin is low and appears safe even after implantation of up to 6 g vancomycin, except in case of markedly impaired renal function. Wound fluid concentrations of vancomycin appear extremely interesting for further studies

We compared the biological characteristics of extrinsic fibroblasts infiltrating the patellar tendon with those of normal, intrinsic fibroblasts in the normal tendon in vitro. Infiltrative fibroblasts were isolated from the patellar tendons of rabbits six weeks after an in situ freeze-thaw treatment which killed the intrinsic fibroblasts. These intrinsic cells were also isolated from the patellar tendons of rabbits which had not been so treated.

Proliferation and invasive migration into the patellar tendon was significantly slower for infiltrative fibroblasts than for normal tendon fibroblasts. Flow-cytometric analysis indicated that expression of α5β1 integrin at the cell surface was significantly lower in infiltrative fibroblasts than in normal tendon fibroblasts. The findings suggest that cellular proliferation and invasive migration of fibroblasts into the patellar tendon after necrosis are inferior to those of the normal fibroblasts. The inferior intrinsic properties of infiltrative fibroblasts may contribute to a slow remodelling process in the grafted tendon after ligament reconstruction.

Introduction Blood loss and requirement for blood transfusion is a recognized and common complication of major joint replacement arthroplasty. In 2001, the authors began using an autologous blood transfusion (ABT) drainage system for total hip and knee arthroplasty. This paper illustrates changes in post-arthroplasty transfusion practice in a rural orthopaedic hospital. Methods Retrospective review of all 289 patients undergoing 132 primary hip and 157 knee replacement arthroplasties in 2001 to 2002 was performed. ABT drainage was used in 187 patients (64%). Wound fluid collected during the first six post-operative hours was filtered by the ABT device and reinfused to the patient intravenously. The observational database was explored by general linear modeling to investigate whether using the reinfusion drain resulted in higher post-operative haemoglobin concentrations. Various multifactor models were explored, re-fitted and regressions diagnostics examined. A final model directed further prospective analysis. Results Independent of all variables, post-operative haemoglobin was on average 0.3g/dl higher (p=0.0308) when ABT was used. Levels were significantly higher for knee compared with hip replacement (p=0.0083) and significantly higher by 0.55g/dl for uncemented compared to cemented/hybrid knee arthroplasty (p=0.0271). ABT reduced blood transfusion requirements from 46.5% to 22% following hip replacement and from 23.6% to 16.3% following knee replacement. Conclusions Introduction of the ABT system resulted in significantly higher post-operative haemoglobin levels and decreased blood transfusion rates following hip and knee replacement arthroplasty. Uncemented component fixation further increased post-operative haemoglobin levels. The authors advise routine use of this system for joint replacement. In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source

A randomised, double-blind study was performed in two groups of 15 patients undergoing total hip replacements, using antibiotic-loaded acrylic cement containing 0.5 g and 1.0 g gentamicin base respectively per 40 g pack of powdered polymer. Postoperatively, the gentamicin levels in the blood, in the urine and in the wound drainage fluid were measured. In both groups of patients, the serum gentamicin concentrations were low whereas the wound drainage fluid contained highly effective antibacterial concentrations. Serum, urine and wound secretion levels showed approximately two-fold higher concentrations in the group of patients receiving the higher gentamicin load