Summary. A meta-analysis was performed to compare rate of SSI after application of chlorhexidine vs. iodine in total joint arthroplasty. Chlorhexidine had significantly lower odds of SSI. Introduction. Surgical site infections (SSI) are a significant source of morbidity and mortality. The optimal preoperative skin preparation in lower extremity total joint arthroplasty (TJA) remains debatable between chlorhexidine and iodine-containing solutions. This meta-analysis sought compare SSI rates between chlorhexidine cloth application the night before surgery plus povidone-iodine-alcohol (povidone-iodine) solution at surgery or only povidone-iodine at surgery. Methods. A structured literature search was performed using Web of Science, PubMed, and EMBASE databases for randomized clinical trials (RCTs) and comparative studies that evaluated preoperative chlorhexidine-gluconate versus iodine-alcohol exclusively in TJA patients. Databases were searched from database inception to January 2, 2018, and studies were included if they had specific aims and 1) compared preoperative chlorhexidine-gluconate cloths to povidone-iodine at surgery, or 2) if they compared preoperative chlorhexidine-gluconate cloths and povidone-iodine at surgery, to solely povidone-iodine at surgery. The main outcome was deep or superficial SSI at or before 1 year postoperatively. If multiple studies reported the same patient cohort, the more recent study was used. To compare the chlorhexidine versus povidone-iodine groups, pooled odds ratios (OR) and 95% confidence intervals (95% CI) were used to calculate odds of SSI. Results. Four studies involving 2,997 TJA patients were included in this meta-analysis. Three were retrospective cohort studies, and one was a RCT. One retrospective cohort study assessed chlorhexidine to povidone-iodine using a historical control. One RCT compared chlorhexidine to povidone-iodine. The remaining two studies compared chlorhexidine in addition to povidone-iodine, to only povidone-iodine. Bias analysis showed low-to-moderate quality cohort studies and one moderate-quality RCT. Chlorhexidine had significantly lower odds of SSI compared to povidone iodine (OR=0.28; 95%CI: 0.15–0.51; p<0.0001). Conclusion. Preoperative chlorhexidine-gluconate was superior at reducing SSI risk in patients who underwent lower extremity TJA, compared to povidone-iodine. This can potentially lead to decreased morbidity and lower surgical revision rates for infections. For any figures or tables, please contact authors directly

Aims. Arthroplasty surgery of the knee and hip is performed in two to three million patients annually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiotics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria-specific hybrid tracer (. 99m. Tc-UBI. 29-41. -Cy5) and its ability to visualize the bacterial load on femoral implants using clinical-grade image guidance methods. Methods. 99m. Tc-UBI. 29-41. -Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cultured on femoral prostheses using fluorescence imaging and freehand single photon emission CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Results. Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be complemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were identified using imaging, which included 500 to 2,000 viable bacteria. Conclusion. The hybrid tracer . 99m. Tc-UBI. 29-41. -Cy5 allowed effective bacterial staining. Qualitative real-time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies. Cite this article: Bone Joint Res 2023;12(1):72–79

Introduction and Objective. The continued effectiveness of antibiotic loaded bone cements is threatened by antibiotic resistance. The common antiseptic, chlorhexidine (CHX), is a potential alternative to antibiotics in bone cements, but conventional salts are highly soluble, causing burst release and rapid decline to subinhibitory local CHX concentrations. Here, chlorhexidine triphosphate (CHX-TP), a low solubility CHX salt, is investigated as an alternative antimicrobial in PMMA bone cements. The aim was to assess duration of antimicrobial release and antimicrobial efficacy, along with handling, setting and mechanical properties of CHX-TP loaded cements, compared with an existing cement formulation containing gentamicin. Materials and Methods. Palacos R (Heraeus Medical, Newbury, UK) with 0, 1, 4, 7 and 12% CHX-TP (w/w) cements were prepared by combining solid CHX-TP with Palacos R components, and compared with Palacos R+G. All cements were prepared without vacuum and under ISO 5833:2002 conditions. Cements were tested under ISO 5833:2002 for compressive and bending properties, setting time, maximum temperature and doughing time. Antimicrobial release from the cements into deionised water was studied and antimicrobial efficacy of unaged and aged cements against Staphylococcus aureus (ATCC 29213) was assessed using a disc diffusion assay. Results. Compressive strength of CHX-TP loaded cements was not significantly different to Palacos R or Palacos R+G (p > 0.05, all exceeding ISO 5833:2002 minimum of 70 MPa). Mean bending strength was significantly lower with CHX-TP loading (p < 0.05) than bending strength of Palacos R and Palacos R+G, though all bending moduli exceeded the ISO 5833:2002 minimum (1800 MPa). All cements studied were within the ISO 5833:2002 limits for setting time (3 to 15 min), doughing time (≤ 5 min) and maximum temperature (90 . o. C). Mean doughing time for Palacos R, Palacos R+G and Palacos R + 12 % CHX-TP respectively: 52.5 s, 45 s and 45 s. Mean setting time and mean maximum temperature for Palacos R, Palacos R+G and Palacos R + 1, 4, 7 and 12% CHX-TP respectively: 11.00 min (73 . o. C), 11.25 min (72 . o. C), 12.25 min (66 . o. C), 10.50 min (70 . o. C), 10.00 min (70 . o. C), 10.75 min (62 . o. C). Sustained CHX release into deionised water was observed from all Palacos R + CHX-TP cements. Duration varied according to CHX-TP dosing and diminished over time, although to an extent that itself varied with dosing. 1 % CHX-TP ceased releasing CHX at 6.9 weeks; 4 % CHX-TP ceased at 67.7 weeks; 7 % and 12 % CHX-TP were ongoing at 75.5 weeks. Palacos R+G cements ceased releasing detectable levels of gentamicin after 14.4 weeks. Palacos R+G and Palacos R + CHX-TP cement discs showed efficacy against S. aureus (ATCC 29213) when applied as prepared (unaged) to S. aureus bacterial lawns in disc diffusion assays, with CHX-TP cements showing dose dependency. Zone of inhibition (ZOI) size was significantly reduced for Palacos R+G cements and Palacos R + 1% CHX-TP cements after 1 week and 6 weeks aging, compared to ZOI from unaged cements (p < 0.05). ZOI size produced by Palacos R + 4, 7, and 12 % CHX-TP cements did not decline significantly after 6 weeks aging (p > 0.05). Conclusions. CHX-TP can be incorporated into the Palacos R cement matrix up to 12% w/w without deterioration of compressive strength, bending modulus, doughing time, setting time or maximum temperature. Bending strength was significantly reduced at all CHX-TP loadings studied. Palacos R + 4, 7 and 12% CHX-TP cements provided sustained CHX release, exceeding the duration of gentamicin release from Palacos R+G, and showed sustained efficacy against S. Aureus after 6 weeks aging, which was not achieved by Palacos R+G cements

Purpose: Operative wounds are commonly washed with a more or less diluted antiseptic solution to prevent infection or to treated overt infection. Chlorhexidine is widely used. We report the cases of nine patients who developed joint destruction attributed to peroperative irrigation with a chlorhexidine solution. Material and methods: Nine patients (three men and six women) who had undergone surgery in another facility were referred to our unit for unexplained postoperative chondrolysis. The joint localisations were: wrists (n=7) after surgery for a dorsal arthrosynovial cyst (mean age 37 years); elbow (n=1) after surgery for epicondylalgia (age 49 years); shoulder (n=1) after arthroscopy for sub-acromial impingement (age 51 years). The time between surgery and the first consultation in our unit varied from three to nine years (mean five years four months). Persistent stiffness had been noted in the postoperative period with pain at joint mobilisation which worsened progressively. For the patients with chondrolysis of the wrist: the x-rays demonstrated destruction of the radius-first ray joint in one, the medio-carpal joint in four and overall destruction in two. Overall joint destruction was also observed in the elbow and shoulder patients. Search for other causes of joint destruction was negative; infection and inflammatory rheumatoid disease were ruled out. The common feature identified in all patients was joint irrigation with a chlorhexidine solution (Biseptine®). Results: Four of the nine patients underwent surgical treatment: a four-bone arthrodesis with scaphoidectomy was used for the three patients with mediocarpal involvement and a shoulder arthrodesis was performed in one patient. The pathology study demonstrated cartilage defects filled with dense strongly hyalinised acellular tissue. Bacteriological specimens were all negative. Discussion: The chondrolytic effect of chlorhexidine, a member of the biguanide family, was first reported in 1986 with a few cases described with knee involvement. Experimentally, there would be a dose-dependent effect. The mechanism involves a disorganisation of the cell membrane with cartilaginous necrosis and ostocartilaginous resorption. Individual predisposition cannot be ruled out. Conclusion: In light of these observations, it would be advisable to avoid peroperative joint irrigation with chlorhexidine solution

Previous studies have demonstrated higher infection rates following elective procedures on the foot and ankle as compared with procedures involving other area of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to ascertain that preoperative chlorhexidine bathing provide significant local flora reduction than placebo in elective foot and ankle surgery. From October 2005 to October 2006, a prospective study was undertaken to evaluate 50 consecutive patients undergoing planned, elective surgery of the foot and ankle. 50 patients were prospectively enrolled and randomly assigned to have preoperative footbath with Chlorhexidine Gluconate (Hibitane) (Group 1) or placebo (Group 2). Culture swabs were taken from all web spaces, nail folds, toe surfaces and proposed surgical incision sites before the preoperative antiseptics bath, during the procedures and immediately completion of surgery. 50 patients were enrolled (mean age: 42.6 years; range: 19–85; F: M = 29:21). 25 patients are assigned to each groups. 100% bacterial isolation preoperatively in both groups prior to antiseptics bathing. In group1, bacteria grew on intraoperative culture in 60% cases and 0% in immediate post-operative culture. In group 2, 96% in intraoperative swab culture and 16% in postoperative swab culture. The intraoperative swab culture bacterial count is statistically significant (p= 0.002). The postoperative swab culture bacterial count is marginally significant (p=0.055) when comparing 2 groups. No complications were recorded in both groups. These data indicate that chlorhexidine provides better reduction in skin flora than placebo. Based of these data, we recommend the use of chlorhexidine footbath as well as the surgical preparatory agent for the foot and ankle surgery

Background: Previous studies have demonstrated higher infection rates following elective procedures on the foot and ankle as compared with procedures involving other area of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to ascertain that preoperative chlorhexidine bathing provide significant local flora reduction than placebo in elective foot and ankle surgery. Methods: From October 2005 to October 2006, a prospective study was undertaken to evaluate 50 consecutive patients undergoing planned, elective surgery of the foot and ankle. 50 patients were prospectively enrolled and randomly assigned to have preoperative footbath with Chlorhexidine Gluconate (Hibitane) (Group 1) or placebo (Group 2). Culture swabs were taken from all web spaces, nail folds, toe surfaces and proposed surgical incision sites before the preoperative antiseptics bath, during the procedures and immediately completion of surgery. Results: 50 patients were enrolled (mean age: 42.6 years; range: 19 –85; F: M = 29:21). 25 patients are assigned to each groups. 100% bacterial isolation preoperatively in both groups prior to antiseptics bathing. In group 1, bacteria grew on intraoperative culture in 60% cases and 0% in immediate post-operative culture. In group 2, 96% in intraoperative swab culture and 16% in postoperative swab culture. The intraoperative swab culture bacterial count is statistically significant (p= 0.002). The postoperative swab culture bacterial count is marginally significant (p=0.055) when comparing 2 groups. No complications were recorded in both groups. Conclusions: These data indicate that chlorhexidine provides better reduction in skin flora than placebo. Based of these data, we recommend the use of chlorhexidine footbath as well as the surgical preparatory agent for the foot and ankle surgery

Purpose: Previous studies have demonstrated higher infection rates following elective procedures on the foot and ankle as compared with procedures involving other area of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to ascertain that preoperative chlorhexidine bathing provide significant local flora reduction than placebo in elective foot and ankle surgery. Method: From October 2005 to October 2006, a prospective study was undertaken to evaluate 50 consecutive patients undergoing planned, elective surgery of the foot and ankle. 50 patients were prospectively enrolled and randomly assigned to have preoperative footbath with Chlorhexidine Gluconate (Hibitane) (Group 1) or placebo (Group 2). Culture swabs were taken from all web spaces, nail folds, toe surfaces and proposed surgical incision sites before the preoperative antiseptics bath, during the procedures and immediately completion of surgery. Results: 50 patients were enrolled (mean age: 42.6 years; range: 19–85; F: M = 29:21). 25 patients are assigned to each groups. 100% bacterial isolation preoperatively in both groups prior to antiseptics bathing. In group1, bacteria grew on intraoperative culture in 60% cases and 0% in immediate post-operative culture. In group 2, 96% in intraoperative swab culture and 16% in postoperative swab culture. The intraoperative swab culture bacterial count is statistically significant (p= 0.002). The postoperative swab culture bacterial count is marginally significant (p=0.055) when comparing 2 groups. No complications were recorded in both groups. Conclusion: These data indicate that chlorhexidine provides better reduction in skin flora than placebo. Based of these data, we recommend the use of chlorhexidine footbath as well as the surgical preparatory agent for the foot and ankle surgery

Aim. The purpose of this study was to compare the presence of P.acnes on the skin after topical pre-operative application with benzoyl peroxide (BPO) to chlorhexidine soap (CHS) and whether this also affected skin recolonization after surgical preparation and draping. Method. Forty volunteers – twenty-four men and sixteen women were randomized to pre-operative topical treatment at home with either CHS or BPO in the area of a delto-pectoral approach of their left shoulder. The right served as a control. Five skin swabs were taken in a standardized manner on different occasions: before and after topical treatment, after surgical skin preparation and sterile draping and 120 minutes after draping. A fifth sample was taken on the contralateral untreated side as a control when the patient was draped. The draping took place in an operating room with laminar air flow and skin preparation was performed for 2 minutes with 0.5% chlorhexidine solution in 70% ethanol according to the recommendations of the Swedish National Board of Health and Welfare. Bacterial colonies were then analyzed on agar plates by colony forming units (CFU) and surface characteristics. P.acnes were identified with matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry. Results. Topical treatment with BPO significantly reduced the presence of P.acnes as CFU on the skin after surgical preparation. P.acnes was found in 1/20 subjects of the BPO group, and 7/20 in the CHS-group (p<0.044). The results remained after two hours (p<0.048). Topical treatment with BPO before surgical skin preparation significantly decreased the presence of CFU (p-value 0.035). Conclusions. Topical preparation with BPO before shoulder surgery may be effective in reducing P.acnes on the skin and prevent recolonization

Aim. The origin of surgical site and biomaterial-associated infection is still elusive. Microorganisms contaminating the wound may come from the air, the surgical team, or from the skin of the patient. Prior to surgery the skin of patients is disinfected, but bacteria deeper in the skin (e.g. in sweat glands or sebaceous glands), may not be reached. This study aims to assess a potential role of this intracutaneous bacterial reservoir in biomaterial-associated infection. Method. To study if cutaneous microbiota colonize the wound when released from the skin upon cutting, we isolated, quantified and identified aerobic and anaerobic bacteria from the skin of 99 patients undergoing trauma surgery, before and after skin disinfection, from the knife blades and from the wound directly after the first cut. Results. Ninety-nine percent of the patients were culture-positive before disinfection with chlorhexidine. Of these, 40% were still culture-positive after disinfection. Of these, 54% had a positive culture of the wound after the skin cut. Twenty percent of the patients with a negative culture after disinfection, nevertheless had a positive wound culture after cutting the skin. Staphylococcus epidermidis and Cutibacterium acnes were the most often cultured bacterial species. In 9%, more than 100 bacterial colonies were cultured from the wound, a dose that may cause biomaterial-associated infections. Conclusions. Bacteria residing in the skin and not eradicated by disinfection may enter the surgical wound upon cutting, resulting in contamination which may cause a biomaterial-associated infection. Use of two knifes likely reduces the risk of wound contamination

Introduction. Periprosthetic infection following lower extremity total joint arthroplasty often requires multiple surgical procedures and imposes a marked economic burden on the patient and hospital. The purpose of this study was to evaluate the incidence of surgical site infections in total joint arthroplasty patients who used an advance at-home pre-admission cutaneous preparation protocol and to compare these results to a cohort of patients who underwent standard in-hospital peri-operative preparation only. Methods. Patients scheduled for surgery were given two packets of 2% chlorhexidine gluconate-impregnated cloths, with instructions for use the evening before and morning of surgery. Records between 2007 and 2010 were reviewed to identify deep incisional and periprosthetic infections. The Centers for Disease Control and Prevention and the Musculoskeletal Infection Society definitions were used for diagnosis. Results. A significantly lower incidence of surgical site infections was found in the chlorhexidine preparation group. For total hip arthroplasty, three surgical site infections occurred in 557 patients (0.5%) of the chlorhexidine group compared to 32 of 1,901 patients (1.7%) in the control group. For total knee arthroplasty, three surgical site infections occurred in 478 patients (0.6%) who used the chlorhexidine cloths, compared to 38 surgical site infections in 1,735 patients (2.2%) in the control group. Discussion. The use of an advance pre-admission chlorhexidine protocol significantly reduced the incidence of surgical site infections in total joint arthroplasty when compared to patients who did not use this protocol. This study validates prior studies in orthopaedics suggesting this as an effective method to prevent periprosthetic infections

Hypochlorous acid (HOCl) is a potent anti-bacterial agent which could reduce periprosthetic joint infection. Early infection complications in joint replacements are often considered to be due to local contamination at the time of surgery and result in a significant socioeconomic cost. Current theatre cleaning procedures produce “clean” operating theatres which still contain bacteria (colony forming units, CFU). Reducing this bacterial load may reduce local contamination at the time of surgery. HOCl is produced naturally in the human neutrophil and has been implicated as the primary agent involved in bacterial killing during this process. In vitro research confirms its efficacy against essentially all clinically relevant bacteria. The recent advent of commercial production of HOCl, delivered as a fog, has resulted in extensive use in the food industry. Reported lack of corrosion and high anti-bacterial potency are seen as two key factors for the use of HOCl in the orthopaedic environment. Prior work by the authors comparing human cell toxicity of HOCl, chlorhexidine and iodine solutions shows favourable results. This study evaluates use of neutral HOCl applied as a dry room fog to decrease bacteria in the operating theatre environment. Using an animal operating theatre as the test site, bacterial swabs were taken from ten 100cm. 2. sample areas before standard cleaning with detergent, after standard cleaning, and again after 60 minutes exposure to HOCl fog. After standard cleaning, 6 of 10 sample sites recorded significant bacterial growth (>10 CFU/100cm. 2. ). After exposure to HOCl fog, growth in all 10 sites was below detection limits (<10 CFU/100cm. 2. ). This was repeated with specific exposure to Staphylococcus aureus and Escherichia coli. We can conclude that HOCl is effective when used as a fogging agent to reduce bacterial loading within an operating theatre environment and as such has significant potential to reduce intraoperative contamination and periprosthetic infection

Introduction. The use of irrigation solution during surgical procedures is a common and effective practice in reduction of bioburden and the risk of subsequent infection. The optimal irrigation solution to accomplish this feat remains unknown. Many surgeons commonly add topical antibiotics to irrigation solutions assuming this has topical effect and eliminates bacteria. The latter reasoning has never been proven. In fact a few prior studies suggest addition of antibiotics to irrigation solution confers no added benefit. Furthermore, this practice adds to cost, has the potential for anaphylactic reactions, and may also contribute to the emergence of antimicrobial resistance. We therefore sought to compare the antimicrobial efficacy and cytotoxicity of irrigation solution containing polymyxin-bacitracin versus other commonly used irrigation solutions. Methods. Using two in vitro breakpoint assays of Staphylococcus aureus (ATCC#25923) and Escherichia coli (ATCC#25922), we examined the efficacy of a panel of irrigation solutions containing topical antibiotics (500,000U/L Polymyxin-Bacitracin 50,000U/L; Vancomycin 1g/L; Gentamicin 80mg/L), as well as commonly used irrigation solutions (Normal saline 0.9%; Povidone-iodine 0.3%; Chlorhexidine 0.05%; Castile soap 0.45%; and Sodium hypochlorite 0.125%) following 1 minute and 3 minutes of exposure. Surviving bacteria were counted in triplicate experiments. Failure to eradicate all bacteria was considered to be “not effective” for that respective solution and exposure time. Cytotoxicity analysis in human fibroblast, osteoblast, and chrondrocyte cells exposed to each of the respective irrigation solutions was performed by visualization of cell structure, lactate dehydrogenase (LDH) activity and evaluation of vital cells. Toxicity was quantified by determination of LDH release (ELISA % absorbance; with higher percentage considered a surrogate for cytotoxicity). Descriptive statistics were used to present means and standard deviation of triplicate experimental runs. Results. Polymyxin-Bacitracin, Saline and Castile soap irrigation at both exposure times were not effective at eradicating S aureus or E coli (Figure 1). In contrast, Povidone-iodine, Chlorhexidine, and Sodium hypochlorite irrigation were effective at eradicating both S aureus and E coli. Vancomycin irrigation was effective at S aureus eradication but not against E coli, whereas Gentamicin irrigation showed partial efficacy against E coli eradication but none against S aureus. The greatest cytotoxicity was seen with Chlorhexidine (49.4% ± 1.9). This was followed by Castile soap (33.2% ±3.9), Vancomycin (9.01% ±5.1), Polymyxin-Bacitracin (8.45% ±1.5), and Gentamicin irrigation (4.72% ±2.3) (Figure 2 and Figure 3 microscopy images). Povidone-iodine and Sodium hypochlorite showed least cytotoxicity (0.05% ±0.08 and 0.11%±0.19, respectively). Similar trends were seen at both exposure times and across fibroblasts, osteoblasts and chondrocytes. Discussion. This in vitro study suggests that addition of polymyxin-bacitracin to saline irrigation solution is a futile exercise. Taken within the context of its associated expense, risk of hypersensitivity and impact upon antimicrobial resistance, our findings bring its widespread clinical usage into question. Povidone-iodine may be a more effective option, with a more favorable cytotoxicity profile than the other commonly used irrigation solutions. Clinical outcomes should be studied to determine the most effective agent, concentration, and exposure time for intraoperative irrigation

Post-surgical wound infections following total hip or knee arthroplasties can be a potentially catastrophic complication for the patient. Currently, several preventative measures exist to help combat this complication. One such method is skin disinfection with preadmission cutaneous chlorhexidine preparation. Although efficacious in reducing surgical site infections during total joint arthroplasty, orthopaedists should be aware of discrepancies between hip and knee arthroplasty. For example, Kapadia et al. performed a prospective study which evaluated the use of preadmission cutaneous chlorhexidine preparation on the reduction of surgical site infections following total hip arthroplasty; they found that there was a 3-fold higher relative risk of developing infection in patients who did not receive the chlorhexidine preparation as compared to those who did. In a similar study performed for total knee arthroplasty, the same authors founds a 6-fold higher relative risk of developing infection, which equated to double the risk as compared to total hip arthroplasty. In a study by Lewis et al. regarding timing to diagnosis of surgical site infections in post-hip and knee arthroplasties, the authors found a longer median time to diagnosis post-knee arthroplasty as compared to hip arthroplasty (25 vs. 42 days, p= <0.001). These finding suggest that orthopaedists should recognise that “A knee is not a hip” with regards to surgical site infections and should be aware of the discrepancies that exist between the two

Aim. Recent studies have indicated that the presence of P. acnes in the skin of the shoulder and around the acromion is higher than other body regions like the knee or the hip. The aim of this study was to estimate the presence of P. acnes in a real set of primary shoulder arthroplasty, after skin preparation with chlorhexidine and administration of empirical antibiotic therapy. Method. A prospective observational study involving 63 patients undergoing primary shoulder arthroplasty was designed. In all patients two skin biopsies with a 3 mm dermal punch and one subcutaneous tissue sample after surgical incision were obtained. Skin biopsies were obtained at the most anterior part of the surgical wound in case of superior approach and at the upper part in the deltopectoral approach. All patients underwent preoperative antibiotic prophylaxis with cefazolin 2g ev and skin preparation with 2% chlorhexidine alcoholic tinted before the start of surgery twice. The aerobic cultures were incubated at 37ºC for 7 days whereas the anaerobic ones incubated for 14 days. Results. A total of 63 consecutive patients who underwent shoulder arthroplasty (58 reverse shoulder arthroplasty and 5 anatomical) were analysed. 54 women and 9 men, mean age of 73.94 (SD 6.19). The indication for arthroplasty was a secondary arthropathy cuff injury in 42 cases, primary osteoarthritis in 3, acute fracture in 9 and fracture sequelae in 9. We obtained 189 tissue cultures (126 skin cultures and 63 subcutaneous) and 4 cultures were positive (2.02%) for P. acnes in 3 different patients. A first patient (female) had both positive skin cultures, the second patient (male) only had positive the subcutaneous tissue cultures and the third patient had positive also the subcutaneous tissue culture. The first patient underwent anatomical shoulder arthroplasty whereas the second and third patients underwent reverse shoulder arthroplasty. The time to grow was 15 days in first patient and 14 days in the second and third patient (mean 14.5 days). Conclusions. In a real setting of patients undergoing shoulder arthroplasty using antibiotic prophylaxis and standard preoperative skin preparation with chlorhexidine we found a low rate of positive cultures for P. acnes (2.02 %). The higher rate of P. acnes positive cultures in skin reported in previous studies may be caused by a different population study group (healthy and younger volunteers without antibiotic prophylaxis) or suboptimal culture technique (use of swaps)

Aim. The efficacy of various irrigation solutions in removing microbial contamination of a surgical wound and reducing the rate of subsequent surgical site infection (SSI), has been demonstrated extensively. However, it is not known if irrigation solutions have any activity against established biofilm. This issue is pertinent as successful management of patients with periprosthetic joint infection (PJI) includes the ability to remove biofilm established on the surface of implants and necrotic tissues. The purpose of this study was to evaluate the efficacy of various irrigation solutions in eradicating established biofilm, as opposed to planktonic bacteria, in a validated in vitro model. Method. Established biofilms of Staphylococcus aureus and Escherichia coli were exposed to different irrigation solutions that included Polymyxin 500,000U/L plus bacitracin 50,000U/L, Vancomycin 1g/L, Gentamicin 80mg/L, Normal saline 0.9%, off-the-shelf Betadine 0.3%, Chlorhexidine 0.05%, Benzalkonium 1.3g/L, Sodium hypochlorite 0.125%, and Povidone-iodine 0.5%. Each experiment was conducted in a 96-well microtiter plate with a peg lid and standardized per the MBEC assay manufacturer's protocol. Following 2 minutes of solution exposure to the irrigation solution, residual biofilms were recovered by sonication. Outcome measures for antibiofilm efficacy were residual colony forming units (CFU) and optical density (690nm). Experiments were conducted in 24 replicates and the observations recorded by two blinded observers. Statistical analysis involved t-tests with Bonferonni adjustment. Results. Povidone-iodine 0.5%, Betadine 0.3%, Benzalkonium 1.3g/L, and Sodium hypochlorite 0.125% were significantly more efficacious against S.aureus biofilm versus all other solutions (p<0.001). Against E.coli biofilm, Povidone-iodine-0.5%, Benzalkonium-1.3g/L and Sodium hypochlorite-0.125% were also most effective compared to other irrigation solutions (p<0.001). Polymyxin-bacitracin, Gentamicin, Vancomycin, and Saline solutions had minimal activity against both E.coli and S.aureus biofilms (p<0.001). Similar trends were observed using both experimental endpoints (CFU and Turbidity) and both investigators (interrater reliability; r=0.99). Conclusion. This in vitro study observed that topical antibiotic solutions do not have any activity against established biofilms. Irrigations solutions containing adequate amount of povidone-iodine, betadine, sodium hypochlorite, and benzalkonium appear to have activity against established biofilm by gram positive and gram negative organisms. The use of these irrigation solutions may need to be considered in patients with established PJI

Extremity injury and complications such as wound infection remain a significant problem for the military. This study investigates the anti-microbial efficacy of four dressings used in militarily relevant complex extremity injury. Under general anaesthesia, the flexor carpi ulnaris of 24 New Zealand White rabbits was exposed to a high-energy impact and then inoculated with 10. 6. colony forming units of Staphylococcus aureus. Dressings: gauze soaked in saline, Chlorhexidine, Betadine or Acticoat¯, were randomised and applied 3 hours post injury, to replicate casualty evacuation. Once recovered, animals were checked at least twice daily and body temperature recorded. Analgesia was administered once a day. At 48hrs animals were culled, the muscle harvested and analyzed by a blinded investigator. Group sizes of 6 were required to detect a statistically significant effect of a mean one log reduction in bacterial counts at 48 hours. No dressing gave a significant reduction in bacterial counts at 48 hours. A paired t-test of contamination versus recovered dose gave p values of 0.903, 0.648, 0.396 and 0.336 for saline, Acticoat¯, chlorhexidine and iodine respectively. Contamination dose between groups compared using ANOVA showed no significant difference (p=0.566). Recovered bacterial loads between groups revealed no significant difference (p=0.280). This study indicates that over a 48 hour period, dressings with reported anti-bacterial properties offer no advantage over saline soaked gauze in reducing the bacterial burden in a contaminated soft tissue injury. Future work will extend the study temporally and introduce multiple contaminants

Eradication of bacteria in forefoot surgery in necessary to prevent post-operative infections. Currently a lack of consensus exists on the optimum solution and preparation methods needed to achieve this. We compared the effect of povidine-iodine and chlorhexidine gluconate on lowering bacterial load and if any additional benefits are gained by pre-treatment with the use of a bristled brush. Fifty consecutive patients undergoing forefoot surgery were recruited into the study and randomised to receive one of two surgical skin preparations (Povidine-iodine 1% with isopropyl alcohol 23% or Chlorhexi-dine gluconate 0.5% with isopropyl alcohol 70%). In addition to the skin preparation of the foot with the randomised solution the other foot was also scrubbed with a sterile surgical bristled brush for a standardised period (3 minutes) and then painted again. Swabs were taken from three sites and analysed via qualitative and quantitative analysis. All four methods significantly decreased (p < 0.001), in all three sites, the number of colony forming units. Using two-way analysis of variance no significant interaction was observed between site of swab and method of preparation (p =0.970). This confirms that no preparation method was more superior in reducing the number of CFUs at any site than the others. We suggest that either povidone –iodine with no more that 23% isopropyl alcohol or chlorhexidine gluconate with 70% isopropyl alcohol be used for surgical preparation in forefoot surgery. No additional benefit in reduction in bacterial load is gained by scrubbing the foot prior to painting with bristles

Introduction. Cutibacterium acnes (C. acnes) is now recognized as a clinical entity in periprosthetic joint infections (PJI) of the shoulder and spine. However, the colonization rate of C. acnes in the adult hip is currently unknown. Therefore, the purpose of this study was to investigate the rate of C. acnes colonization from the skin of healthy subjects from various anatomic locations corresponding to direct anterior and lateral/posterolateral surgical approaches. Methods. 90 patients scheduled for hip or knee surgery were recruited for cultured biopsies. Four 3-mm dermal punch biopsies were collected after administration of anesthesia, but prior to delivery of perioperative antibiotics. Pre-biopsy skin prep consisted of a standardized pre-operative 2% chlorhexidine skin cleanse and an additional 70% isopropyl alcohol mechanical skin scrub immediately prior to biopsy collection. Two culture samples 10-cm apart were collected from a location approximating a standard direct anterior skin incision, and two samples 10-cm apart were collected from a location approximating a lateral skin incision (suitable for a posterior, direct-lateral or anterolateral surgical approach). Samples were cultured for two weeks. Results. 22 of the 90 (24%) patients had a positive culture biopsy, fourteen of which (16% of all patients) were positive for C. acnes. Ten (71%) of the culture positive biopsies for C. acnes were obtained from the anterior location with 50% of those obtained from the most proximal sample site. Conclusions. Approximately 16% of the patients in the study demonstrated positive C. acnes colonization about the hip, the majority of which occurred from an anterior location. C. acnes should be considered in the diagnosis of PJI after THA. Given the high rate of skin colonization, particularly as regards the direct anterior approach to the hip, these results have stimulated consideration for different skin preparations for the THA patient. For any tables or figures, please contact the authors directly

Prosthetic joint infections (PJI) are amongst the most feared postoperative complication of total joint replacement (TJR). PJIs are associated with significant morbidity ranging from functional impairment to amputation. Staphylococcus aureus (S. aureus) is one of the most common causative organisms involved in PJI. More than one quarter of the general population are S. aureus carriers, and carrier status has been shown to increase the risk of developing surgical site infections including PJIs. Decolonization of S. aureus carriers prior to surgery has demonstrated promising results in general surgery, however, solid evidence supporting decolonization in orthopaedic patients is lacking. We aimed to seek further evidence supporting pre-operative screening and S. aureus decolonization in patients undergoing primary or revision hip and knee TJR. A quasi-experimental quality improvement study was conducted to compare the 5-year baseline rates of deep PJIs to a one-year screening and decolonization intervention period. All consecutive patients who underwent primary or revision TJR at one tertiary care hospital in Hamilton, ON, Canada were included in both study periods. Nasal and throat screening for S. aureus carriage of all eligible TJR patients in the preoperative clinic was implemented as standard of care. Patients who tested positive were contacted and provided with details on the S. aureus decolonization protocol. Decolonization included a standardized treatment protocol of 2% intranasal mupirocin twice daily for five days prior to surgery date (excluding day of surgery), and chlorhexidine gluconate wipes (2%) to be used once daily for 4 days prior to surgery date and on the morning of surgery. Regardless of the colonization status at the visit in the preoperative clinic, all patients were re-swabbed on the day of surgery. Primary outcome of interest was the rate of deep PJI as per CDC/NHSN at one-year postoperative follow-up. Secondary outcomes included rate of deep PJIs due to S. aureus, adherence to the decolonization protocol, proportion of S. aureus carriers successfully decolonized, and the proportion of patients deemed as non-carriers following preoperative swab subsequently identified as carriers on the day of surgery. A total of 8,505 patients were included in the 5-year control group, and 1,883 during the intervention period, of which 424 (22.5%) were identified as S. aureus carriers. The deep PJI rate was similar in the two groups, 0.4% (7/1,883) in the intervention group and 0.5% (42/8,505) in the control group (OR 0.75, 95%CI 0.34–1.67, p=0.58). More importantly, we found a significant reduction in PJI due to S. aureus to only one case in the intervention period (0.05%) as compared to 29 cases (0.3%) in the historic control (OR 0.15, 95%CI 0.004–0.94, p=0.0376). We found a significant reduction in PJIs due to S. aureus by decolonizing S. aureus carriers prior to surgery. However, no significant difference in overall infection rates was observed. In conclusion, routine implementation of active screening for S. aureus and decolonization of carriers before TJR is feasible and helps to reduce PJI due to S. aureus

Effective pre-surgical preparation is an important step in limiting surgical wound contamination and prevention of surgical site infection. The purpose of this study is to evaluate bacterial skin contamination after surgical skin preparation in foot surgery prior to surgery and at the end of surgery, in order to determine if current techniques are satisfactory in eliminating harmful pathogens, and to compare the results of the cultures obtained pre and post operatively with infection rate. Twenty consecutive patients scheduled for Hallux Valgus procedures were studied. Each lower extremity was prepared in the regular method with a two-step technique, Septal scrub followed by a Alcohol Chlorhexidine antiseptic solution. After preparation and draping, cultures were obtained at three locations: the hallux nailfold, first, second, third and fourth web spaces, and the anterior ankle (control). Prior to surgery, positive cultures were obtained from 80% of hallux nailfolds and 5% of web spaces. At the end of surgery, positive cultures were obtained from 80% of hallux nailfolds and 25% of web spaces. None of the controls had positive culture. 5% of all cases developed post operative infection. Based on the findings of the current study, pre-surgical skin preparation with a two-step Septal scrub followed by a Alcohol Chlorhexidine antiseptic solution is not sufficient in eliminating pathogens in foot and ankle surgery. No statistical correlation was found between the results of the cultures obtained preoperatively or post operatively with post operative infection rate. The unique environment of the foot and its resident organisms probably plays a role in the higher infection rates associated with surgery of the foot. Better methods of preparing the surgical site should be searched for