Introduction:. Deep infection after total joint arthroplasty is a devastating complication with reported incidence of 1–3% with projection to increase to 6.8% by 2030. The direct costs of revision surgery due to septic failure are estimated at over $55,000 per case. Antibiotic-Loaded Bone Cement (ALBC) has been proposed as a preventive measure to decrease post-operative infection rates. Its efficacy has been compared with plain bone cement (PBC) in multiple studies. There has been no study to our knowledge examining its efficacy in “high risk” patients. The purpose of this study is to compare infection rates in three cohorts of patients: (1) all patients receiving only PBC, (2) all patients receiving only ALBC, and (3) only “high risk” patients receiving ALBC. Methods:. A standard cement protocol was instituted at our hospital for primary total knee arthroplasties (pTKA). From January 2000 to 2005 all pTKAs were performed with PBC. From February 2005 to May 2010, all pTKAs were performed with ALBC. From June 2010 to March 2012, all patients received regular bone cement unless they had previous diagnoses of rheumatoid arthritis, obesity, and/or diabetes mellitus. Our institutional joint registry was queried and the three cohorts' individual charts were retrospectively reviewed. Infection rates amongst cohorts were compared at 30 days, 6 months, and 1 year from index surgery date utilizing two sided proportion tests. Results:. A total of 3,292 consecutive primary TKAs with full follow up were included. Overall infection rate at one year for the entire study was 0.76%. There were 1,025 patients who received PBC, 1486 ALBC, and 781 in the risk stratified cohort. The 30-day infection rates for cohorts 1, 2, 3 were .0.29%, 0.20%, and 0.13% respectively. The 6-month infection rates for cohorts 1, 2, 3 were 0.39%, 0.54% and 0.38% respectively. The 1-year infection rate for cohorts 1, 2, 3 were 0.78%, 0.61%, and 0.64% respectively. The differences in infection rates between each cohort at all three time intervals were not statistically significant. Conclusions:. Antibiotic loaded bone cement does not significantly decrease infection rates for primary total knee arthroplasty. Even risk stratified usage of ALBC for “high risk” patients may be unnecessary and add undue costs to both the patient and hospital, without any appreciable benefit

Background. Tigecycline, the first member of glycylcycline family, has effective antimicrobial activity against resistant and implant associated infectious organisms. The objectives of this study are to assess the compressive and tensile mechanical strength characteristics of tigecycline loaded bone cement and to compare them with vancomycin and daptomycin loaded bone cements which are used in prosthetic joint infections with resistant microorganisms. Methods. A control group without antibiotics and three antibiotic loaded bone cement groups with varying concentrations (1g, 2g and 3g vancomycin, 0.5g, 1g and 1.5g daptomycin and 50mg, 100mg and 150mg tigecycline) were prepared and tested according to ASTM F451 and ISO 5833 standards. Statistical analysis of the obtained data done by using LSD (least significant difference) and Bonferroni corrected Mann Whitney tests. Results. Both compression and tension tests showed that all determined antibiotic concentrations resulted in significant decrease when compared to the control group. Despite heterogenous statistical results, it was seen that the mechanical strength of tigecycline loaded bone cement was not significantly lower (even higher in some comparisons) when compared to vancomycin and daptomycin loaded bone cements. Conclusion. When used at defined concentrations, tigecycline loaded bone cement does not have mechanical disadvantage compared to vancomycin and daptomycin loaded bone cements. Thus, it should be kept in mind as an option in appropriate clinical situations

Objectives. Investigate the incorporation of an antibiotic in bone cement using liposomes (a drug delivery system) with the potential to promote osseointegration at the bone cement interface whilst maintaining antibiotic elution, anti-microbiological efficacy and cement mechanical properties. Prosthetic joint infection and aseptic loosening are associated with significant morbidity. Antibiotic loaded bone cement is commonly used and successfully reduces infection rates; however, there is increasing resistance to the commonly used gentamicin. Previous studies have shown gentamicin incorporated into bone cement using liposomes can maintain the cement's mechanical properties and improve antibiotic elution. The phospholipid phosphatidyl-l-serine has been postulated to encourage surface osteoblast attachment and in a liposome could improve osseointegration, thereby reducing aseptic loosening. Preliminary clinical isolate testing showed excellent antimicrobial action with amoxicillin therefore the study aims were to test amoxicillin incorporated into bone cement using liposomes containing phosphatidyl-l-serine in terms of antibiotic elution, microbiological profile and mechanical properties. Methods. Amoxicillin was encapsulated within 100nm liposomes containing phosphatidyl-L-serine and added to PMMA bone cement (Palacos R (Heraeus Medical, Newbury, UK)). Mechanical testing was performed according to Acrylic Cement standards (ISO BS 5833:2002). Elution testing was carried out along with microbiological testing utilising clinical isolates. Results. Liposomal encapsulated amoxicillin PMMA bone cement exceeded minimum ISO BS 5833:2002 standards, had better elution at 12.9% when compared with plain amoxicillin (p=0.036 at 48 hours) or commercial gentamicin cement (Palacos R+G, Heraeus Medical, Newbury, UK – previous studies showed 6% elution over the same time period). Amoxicillin showed superior antimicrobial action when compared with gentamicin of the same concentration. However, liposomal encapsulated amoxicillin in solution and liposomal encapsulated amoxicillin in PMMA were both less effective than free amoxicillin in bacterial growth inhibition. The liposomal amoxicillin also seemed to decrease the cement setting time. Conclusions. Phosphatidyl-l-serine containing liposomes maintained the cement's mechanical properties and seemed to have better antibiotic elution, however, had less effective antibacterial action than plain amoxicillin. This difference in antibacterial action requires further investigation along with investigation of osteoblast attachment to phosphatidyl-l-serine containing liposomes within cement. Plain amoxicillin, for those not penicillin allergic, seems to be a credible alternative to gentamicin for incorporation in PMMA bone cement. It has shown superior antibacterial action, which may improve infection rates, whilst maintaining the cement's mechanical properties

Infection prevention in shoulder arthroplasty is an evolving challenge as further understanding of the pathogens becomes available. Infection rates for reverse TSA is higher than anatomic TSA. Standard decolonization protocols from our hip and knee colleagues has decreased the acute post-operative infection risk to less than 1%. By identifying at risk populations anti-MRSA precautions including intranasal antibiotics and anti-bacterial soaps for pre-surgical skin preparation have reduced the incidence of staphylococcus infections. The emerging understanding of propionibacterium acnes (P. acnes) as a primary pathogen in late shoulder periprosthetic joint infection (PJI) has led to new recommendations including pre-operative skin cleansing with 5% benzoyl peroxide to reduce infection risk. Pre-operative IV antibiotic is recommended and chlorhexidine skin prep for surgery. In the operating room, the concern is the surgeon's exposure to skin and sebaceous glands where P. acnes is prevalent. After skin incision the surgeon should use a new blade for deep incision. Application of vancomycin powder to the subcutaneous tissue may be beneficial after incision to treat potential contamination from the incision through skin. Glove change prior to handling implants and thorough irrigation before implantation is prudent. The role of antibiotic loaded bone cement for infection prevention remains unproven. Topical vancomycin powder at closure is a low cost option and has shown benefit in spine surgery but efficacy is unproven in the shoulder. Silver impregnated wound dressings may also prevent infection and are a convenient option for patient care with regards to bathing. Preventing infections in shoulder arthroplasty, particularly P. acnes, remains a challenge. A significant number of revision TSAs are found to have positive cultures for P. acnes creating a significant burden for patients and surgeons

INTRODUCTION. Surgical site infections (SSI) in orthopaedics are a major source of postoperative morbidity. Although perioperative antibiotic prophylaxis is a common practice, orthopaedic infections are still high in numbers, due to the increasing use of osteosynthesis material and implants. Implants are avascular and can be easily colonized with biofilm-producing germs. For both, effective prophylaxis and treatment of orthopaedic infections, the right choice of the antibiotics used, the mode of application (only systemic or systemic & local), the timing, dosage and the duration of antibiotics are of extremely high importance. Their inappropriate use does not only lead to failures in prevention or treatment of infections, but may also promote microbial resistance development and may cause serious side effects for the patients. SELECTION & USE OF ANTIBIOTICS. Prophylaxis. Broad-spectrum prophylactic antibiotics should help to eliminate the germs before they start to colonize the implant. For prophylactic purposes the recently published AAOS guidelines [1] recommend the use of cephalosporins, such as cefazolin or cefuroxim, administered within one hour prior to surgery. In cases of suspected beta-lactam allergy, clindamycin or vancomycin can be used. The latter one is also recommended in cases of MRSA colonisation. Due to extended infusion times, vancomycin should be started within two hours prior to incision. In cases of blood loss or long op duration, antibiotic administration must be repeated (e.g. cefazolin, every 2–5 hrs; vancomycin, every 6–12 hrs). There is no evidence of a benefit of continued antibiotic administration past 24 hrs of end of surgery [2]. Treatment. In cases of established infections, use of antibiotics is only considered as an adjuvant to surgical debridement. Typically, the choice of the appropriate antibiotic depends on the bacteria, its antibiotic sensitivity profile and the health state of the patient. A combination of rifampicin & a quinolone (or rifampicin & vancomycin in cases of MRSA) for at least 2 wks up to several months has shown good results [3]. In chronic infections with biofilm involvement, all foreign material must be removed and locally delivered antibiotics via e.g. PMMA as carrier (spacers, PMMA-chains) are of additional clinical benefit. ROLE OF LOCAL ANTIBIOTICS. There is general consensus that PMMA chains or PMMA spacers loaded with specific antibiotics support the eradication of bone and joint infections, because of the high local concentrations achieved. The exact treatment time is, however, variable, ranging from few weeks up to several months. Only small amounts of these local antibiotics are systemically detectable and do not represent a major risk for side effects. Still a matter of debate is the benefit of antibiotic impregnated PMMA for infection prophylaxis. Although common practice in Europe, its routine use in e.g. primary arthroplasty is still discussed in other world regions. Meanwhile, evidence accumulates that joint infection rates are, indeed, lower, if antibiotic loaded bone cement with high initial release rates is routinely used in arthroplasty. 4.