Intraoperative bacterial contamination in operations for joint replacement

Detecting contamination events during robotic total joint arthroplasty

BACKGROUND

Robot-assisted total joint arthroplasty (robotic-TJA) has become more widespread over the last 20 years due to higher patient satisfaction and reduced complications. However, robotic TJA may have longer operative times and increased operating room traffic, which are known risk factors for contamination events. Contamination of surgical instruments may be contact- or airborne-related with documented scalpel blade contamination rates up to 9%. The robot arm is a novel instrument that comes in and out of the surgical field, so our objective was to assess whether the robot arm is a source of contamination when used in robotic TJA compared to other surgical instruments.

METHODS

This was a prospective, single-institution, single-surgeon pilot study involving 103 robotic TJAs. The robot arm was swabbed prior to incision and after closure. Pre- and postoperative control swabs were also collected from the suction tip and scalpel blade. Swabs were incubated for 24 hours on tryptic soy agar followed by inspection for growth of any contaminating bacteria.

RESULTS

A contamination event was detected in 10 cases (10%). The scalpel blade was the most common site of contamination (8%) followed by the robot arm (2%) and suction tip (0%).

DISCUSSION

Robotic TJA is contaminated with bacteria at a rate around 10%. Although the robot arm is an additional source of potential contamination, the robot arm accrues bacterial contamination infrequently compared to the scalpel blade.

CONCLUSION

Contamination of the robot arm during robotic TJA is minimal when compared to contamination of the scalpel blade.

Bacterial contamination of surgical gloves during clean orthopedic surgery

This study examines the presence of bacterial contamination on surgical gloves and suggests appropriate measures for an aseptic surgical environment. To prevent glove contamination during surgery, surgeons and assistants should change gloves periodically, and scrub nurses should be careful when opening packages and handing over implants.

Influence of closed glove exchange on bacterial contamination of the hands of the surgical team

OBJECTIVE

To determine if closed glove exchange (CGE) increases hand contamination.

STUDY DESIGN

Prospective experimental study.

SAMPLE POPULATION

Surgical teams participating in 65 individual surgical procedures were included, resulting in 200 individual enrollments.

METHODS

At the completion of surgery, gloves were removed and hands were swabbed. The inside of the gown cuff was swabbed. Each participant regloved, using a closed gloving technique. The new gloves were removed, and hands were swabbed for culture a second time. Swabs underwent standard bacterial culture.

RESULTS

Before glove exchange, or baseline, contamination was found on 17/200 dominant hands and 13/200 nondominant hands. After performing CGE, contamination was found on 14/200 and 15/200 dominant and nondominant hands, respectively. No difference was detected between the number of CFUs cultured from a surgeon's hands before CGE and the number of CFUs cultured from a surgeon's hands post-CGE (one sided sign test, p = .61). Twelve (12) different bacterial species were identified, the most common were Staphylococcus spp. (97/154; 63%).

CONCLUSION

Closed glove exchange did not increase bacterial hand contamination over baseline levels.

CLINICAL SIGNIFICANCE

We found no evidence to support discontinuing CGE.

Wrap It! Preventive Antimicrobial Treatment Shows No Negative Effects on Tenocytes and Tendons-A Comprehensive Approach

Although the rate of infection after the reconstruction of a ruptured anterior cruciate ligament (ACL) is low, prophylactic incubation of the graft with vancomycin (Vanco-wrap or vancomycin soaking) is routinely performed. A cytotoxic effect of vancomycin is reported for several cell types, and the prophylactic treatment might prevent infection but harm the tissue and cells.

AIM

A comprehensive study was performed to investigate the effect of vancomycin on tendon tissue and isolated tenocytes using cell viability, molecular and mechanical analysis.

MATERIAL AND METHODS

Rat tendons or isolated tenocytes were incubated in increasing concentrations of vancomycin (0-10 mg/mL) for different times, and cell viability, gene expression, histology and Young's modulus were analyzed.

RESULTS

The clinically used concentration of vancomycin (5 mg/mL for 20 min) had no negative effect on cell viability in the tendons or the isolated tenocytes, while incubation with the toxic control significantly reduced cell viability. Increasing the concentration and prolonging the incubation time had no negative effect on the cells. The expression of Col1a1, Col3a1 and the tenocyte markers mohawk, scleraxis and tenomodulin was not affected by the various vancomycin concentrations. The structural integrity as measured through histological and mechanical testing was not compromised.

CONCLUSION

The results proved the safe application of the Vanco-wrap on tendon tissue.

LEVEL OF EVIDENCE

IV.

Are Hamstring Grafts a Predisposing Factor to Infection in R-ACL Surgery? A Comparative In Vitro Study

BACKGROUND

The objective of the present study was to evaluate the formation of biofilms in bone patellar tendon bone grafts (BPTB grafts), and to compare it to the formation of biofilm formation in quadrupled hamstring anterior cruciate ligament grafts (4×Ht graft).

METHODS

A descriptive in vitro study was conducted. One 4×Ht graft and one BPTB graft were prepared. They were then contaminated with a strain of S. epidermidis. Later, a quantitative analysis was conducted by means of microcalorimetry and sonication with plating. Additionally, a qualitative analysis was conducted by means of electron microscopy.

RESULTS

No significant differences were found between the bacterial growth profiles of the 4×Ht graft and the BPTB graft in microcalorimetry and colony counting. In the samples analyzed with electron microscopy, no specific biofilm growth pattern was identified upon comparing the BPTB graft to the 4×Ht graft.

CONCLUSIONS

There were no significant differences found at either the quantitative or qualitative level when comparing bacterial growth in the BPTB graft to that in the 4×Ht graft. Therefore, the presence of sutures in the 4×Ht graft cannot be established as a predisposing factor for increased biofilm growth in this in vitro study.

Cemented versus Cementless Total Hip Arthroplasty for Femoral Head Osteonecrosis: A Study Based on National Claim Data in South Korea

INTRODUCTION

The purpose of this study was to compare the rates of revision, periprosthetic joint infection (PJI), and periprosthetic fracture (PPF) between patients with osteonecrosis of the femoral head (ONFH) undergoing noncemented total hip arthroplasty (THA) and cemented THA using a national claim data in South Korea.

METHODS

We identified patients who received THA for ONFH from January 2007 to December 2018 using ICD diagnosis codes and procedural codes. Patients were categorized into two groups according to the fixation method: with or without cement. The survivorship of THA was calculated using the following end points: revision of both the cup and stem, revision of the single component, any type of revision, PJI, and PPF.

RESULTS

A total of 40,606 patients: 3,738 patients (9.2%) with cement and 36,868 patients (90.7%) without cement, received THA for ONFH. The mean age of the noncemented fixation group (56.2 ± 13.2 years) was significantly lower than that of the cemented fixation group (57.0 ± 15.7 years, P = 0.003). The risk of revision and PJI was notably higher in cemented THA (hazard ratio: 1.44 [1.21 to 1.72] and 1.66 [1.36 to 2.04], respectively). Noncemented THA had a higher 12-year survivorship compared with cemented THA with any revision and PJI as the end point.

DISCUSSION

Noncemented fixation had better survivorship than cemented fixation in patients with ONFH.

Do Cultures Obtained During Primary THA Predict the Likelihood of Revision?

BACKGROUND

There can be unexpectedly positive culture results during elective hip arthroplasty, but the degree to which these are associated with an increased risk of subsequent premature revision is not known.

QUESTION/PURPOSE

Are unexpectedly positive culture results obtained during elective THA associated with an increased likelihood of revision within 5 years of the procedure?

METHODS

Between March 2007 and March 2011, the hip unit at our institution performed elective primary THA in 829 patients. We systematically collected three samples in 52% (428 of 829) of the interventions. Of those, 26 patients were excluded because of sampling errors; 94% (402 of 428) had samples that were collected systematically and were eligible for the study. We only considered one hip randomly in bilateral procedures (4% [15 of 428]); patients presenting with acute (< 3 months) periprosthetic joint infection undergoing open debridement (4% [16 of 402]) and patients who died before 5 years of follow-up (2% [seven of 402]) were excluded from the study, leaving 91% (364 of 402) eligible for analysis in this retrospective study of a previous prospective trial. No patient included in the final analysis was lost to follow-up within 5 years from the index surgery. The patient group consisted of 52% (188 of 364) women, with a mean ± SD age of 64.8 ± 13.9 years.

RESULTS

Positives culture results were associated with a higher risk of revision within 5 years of the index surgery. The proportion of revision surgery was higher in the group with positive culture results than in those with negative results (10% [eight of 77] versus 2% [seven of 290]; p = 0.01). The difference was mainly attributable to a higher proportion of aseptic loosening in those with positive culture results than in those with negative results (8% [six of 74] versus 1% [four of 290]; p = 0.01). After a multivariable analysis, the only independent variable associated with 5-year revision surgery was the presence of positive results during THA (odds ratio 4.9 [95% confidence interval 1.72 to 13.99]).

CONCLUSION

Our findings suggest that bacterial contamination during THA is associated with an increased likelihood of early revision. This higher risk of revision is mainly because of presumed aseptic loosening; thus, efforts should focus on the need to rule out infection. These results not only open new questions that should be answered in new prospective and well-designed studies, but also may help to better select patients to obtain a more favorable outcome after THA.

LEVEL OF EVIDENCE

Level III, therapeutic study.

A Review of Evidence for Infection Reduction With Vancomycin-treated Anterior Cruciate Ligament Grafts

Septic arthritis after anterior cruciate ligament (ACL) reconstruction is a rare but devastating complication. Several risk factors and known sources of infection have been identified in the literature. There is growing interest and supportive evidence for a targeted invention aimed at graft decontamination, which has led some surgeons to adopt the use of antibiotic solution soaks and/or wraps applied to ACL grafts before graft implantation in an attempt to reduce the risk of postoperative infection. Despite this, adoption of this technique remains relatively low among surgeons because of a variety of factors: (1) lack of awareness, (2) confusion over optimal protocols, (3) concern for graft viability and clinical outcomes, and (4) efforts to minimize the cost of surgery. However, recently published literature demonstrates notable risk reduction for infection, acceptable safety, no detrimental effect on clinical outcomes, and overall cost-effectiveness with the use of vancomycin graft soaks and wraps. Currently, there is a lack of consensus for clinical protocols, and the protocol that is most efficacious remains unclear. The purpose of this review article was to present the current evidence for ACL graft treatment with vancomycin for the prevention of postoperative infection.

Efficacy of antimicrobial washes before shoulder surgery against Cutibacterium: a systematic review and meta-analysis

Background

Cutibacterium acnes is a commensal intradermal microorganism that is commonly isolated at revision shoulder arthroplasty. Standard practice chlorhexidine gluconate (CHG) skin preparation agents have limited effectiveness at eradicating C. acnes in the dermis. Benzoyl peroxide (BPO) has demonstrated effectiveness against C. acnes. This meta-analysis compares the efficacy of at-home shoulder decolonization before surgery using CHG vs. BPO to reduce shoulder C. acnes burden.

Methods

This was a Preferred Reporting Items for Systematic Reviews and Meta-Analyses systematic review. PubMed and MEDLINE databases were searched for studies evaluating the effects of CHG and BPO in reducing C. acnes at the shoulder. Trial results were extracted and pooled using a random effects model, separating data from randomized controlled trials (RCTs) and non-RCTs. Methodologic quality of studies was assessed using the Cochrane Risk of Bias Assessment Tools.

Results

Ten studies (589 patients) were included. RCTs showed that both BPO and CHG led to significant reductions in culture positivity compared with negative controls (risk ratio [RR] with 95% confidence interval [CI] = 0.20 [0.13, 0.30], P < .0001 and 0.46 [0.37, 0.57], P < .0001, respectively). Non-RCT data demonstrated similar results comparing BPO and CHG to the control (RR with 95% CI = 0.34 [0.21, 0.57], P < .0001 and 0.31 [0.20, 0.49], P < .0001, respectively). Comparing BPO and CHG, RCT data showed a significant reduction in culture positivity with BPO (RR with 95% CI = 0.46 [0.27, 0.77], P < .009). Of RCTs, 5 were low and one was of moderate risk of bias. Of non-RCTs, 3 had low risk of bias, whereas one had moderate risk of bias.

Conclusion

This review demonstrated that preoperative CHG and BPO can reduce C. acnes at the shoulder. However, BPO exhibits greater efficacy than CHG, potentially because of the compound's ability to penetrate the dermis. BPO is a simple and economical agent that may reduce joint exposure to C. acnes in shoulder surgery.

Contamination Associated With Glove Changing Techniques in the Operating Theatre

Background

Sterility of the operative field during surgery is imperative in reducing the risk of infection. Most commonly, double gloves are worn by surgeons. When contamination occurs, the top gloves are changed intra-operatively. No studies have investigated which glove changing technique is best. Therefore, in this study, we aim to identify which top glove changing technique causes the least surface contamination.

Methods

Glitterbug™ (UV fluorescent powder) was applied to the top gloves of 3 individuals who changed their top gloves according to a randomised method – Method 1: 3 pairs worn, remove the outer pair; Method 2: 2 pairs worn, remove the top glove, replace unassisted; and Method 3: 2 pairs worn, remove the top glove, and replace assisted by a scrub nurse. A blinded investigator inspected for Glitterbug™ contamination under UV light.

Results

Two hundred and ten trials were performed and two types of contamination were identified, namely, direct contact and airborne spread. For absolute contamination, Method 1 had 59/64 (92%) contaminated trials, Method 2 had 49/65 (75%) contaminated trials, and Method 3 had 64/81 (79%) contaminated trials. This was statistically significant (p = 0.031). For direct contamination only, Method 1 had 38/64 (59%) contaminated trials, Method 2 had 24/65 (37%) contaminated trials, and Method 3 had 20/81 (25%) contaminated trials. This was statistically significant (p < 0.0001).

Conclusions

Method 2 had a statistically significant lower contamination rate overall, with Method 3 having the lowest direct contamination rate. We believe that wearing 2 gloves, removing the top glove and replacing it, either assisted or unassisted, could decrease surface contamination of the sterile field.

Intraoperative Surgical Wound Contamination May Not Lead to Surgical-Site Infection in Patients Undergoing Clean Orthopaedic Procedures: A Prospective Clinical Study

Objectives  Surgical-site infections (SSIs) can complicate virtually any surgical procedure. While SSI can result from numerous causes, contamination of the surgical field can also contribute to it. Intraoperative bacterial contamination during clean orthopaedic procedures can be detected using perioperative cultures. We hypothesized that perioperative cultures could be used to predict possibility of development of SSI in patients undergoing clean orthopaedic surgeries.

Materials and Methods  We conducted a prospective cohort study at a tertiary care hospital over a 2-year period. Intraoperative surgical wound lavage fluid and closed suction drain tip obtained in the postoperative period were sent for aerobic culture. All patients were followed up to look for the development of SSI for a period of at least 30 days for those undergoing nonimplant surgery, and 90 days for those with implant surgery.

Statistical Analysis  Means with standard deviation of the continuous data were calculated. Fisher's exact test and chi-square test were used for the analysis of the categorical variables. Relative risk and odds ratio were calculated to evaluate the association of the parameters under study with SSI.

Results  A total of 384 patients satisfying the inclusion and exclusion criteria were included. Perioperative cultures detected surgical wound contamination in 39 patients (10.1%). Forty-five patients (11.7%) developed SSI during the follow-up period. Skin commensals constituted 59% of perioperative contaminants and accounted for 20% of the SSIs. The relative risk of developing SSI with perioperative contamination was 0.41 (95% confidence interval: 0.09–1.63).

Conclusion  Intraoperative surgical-site contaminants could be detected using perioperative cultures. However, these contaminants did not lead to SSI. Timely treatment of perioperative contamination with appropriate antibiotics and local wound care probably helped in the reduction of SSI.

Multiple deep tissue cultures in primary total hip arthroplasty: prognostic value for periprosthetic infection

BACKGROUND

The risk of infection after total hip replacement (THR) is significant, with negative impact on quality of life and high costs. Bacteria can contaminate the surgical site despite aseptic techniques; however, there is debate regarding the benefit of identifying bacteria during the primary procedure. Although taking multiple samples for culture is a well-established practice in revision arthroplasty, doing so in primary cases remains controversial. We aimed to investigate whether there is a prognostic value in the culture of samples taken during primary THR, seeking a correlation between the positivity of the cultures and subsequent prosthetic joint infection (PJI).

METHODS

Deep samples (capsule, femoral and acetabular bone) were collected from 426 patients undergoing elective primary THR. Follow-up was at least 3 years. Microbiological profiles of cultures were analysed. Patient data were reviewed for the identification of risk factors presumably associated with a higher risk of PJI.

RESULTS

54 surgeries (12.6%) had positive cultures. 16 cases (3.8%) developed infection, of which 5 had a positive culture in the primary surgery. Infection rate was 9.3% in patients with positive culture and 3% in those with negative culture (p < 0.05), with an odds ratio of 3.34 (95% CI, 1.09-10.24). Patients with previous hip surgery had an infection rate of 8.5%, compared to 2.9% in patients with no previous surgery (p < 0.05).

CONCLUSIONS

Routinely harvesting microbiologic samples in primary THR is not justified, as it has no consequence in clinical decision for most patients. It might be recommended in selected cases that are suspected to be at high risk for infection, especially previously operated patients (conversion arthroplasty).

Cryopreservation of autologous bone flaps following decompressive craniectomy: A new method reduced positive cultures without increase in post-cranioplasty infection rate

Introduction

Cranioplasty (CP) after decompressive craniectomy (DC) is a common neurosurgical procedure. Implementation of European Union (EU) directives recommending bacterial cultures before cryopreservation, lead to increased number of autologous bone flaps being discarded due to positive cultures. A new method for handling bone flaps prior to cryopreservation, including the use of pulsed lavage, was developed.

Research question

The aim was to evaluate the effect of a new method on proportion of positive bacterial cultures and surgical site infection (SSI) following CP surgery.

Material and methods

Sixty-one bone flaps from 53 consecutive DC surgery patients were retrospectively included and the study period was divided into before and after method implementation. Patient demographics, laboratory and culture results, type of CP and occurrence of SSI were analyzed.

Results

Twenty-six and 18 bone flaps were available for analysis during the first and second period, respectively. The proportion of positive bacterial cultures was higher in the first period compared to the second (n ​= ​9(35%) vs 0(0%); p ​= ​0.001), and thus the use of custom made implants was considerably higher in the first study period (p ​= ​0.001). There was no difference in the frequency of post-cranioplasty SSI between the first and second study period (n ​= ​3 (11.5%) vs 1 (4.8%), p ​= ​0.408).

Discussion and conclusion

The new method for handling bone flaps resulted in a lower frequency of positive bacterial cultures, without increased frequency of post-cranioplasty SSI, thus demonstrating it is safe to use, allows compliance with the EU-directives, and may reduce unnecessary discarding of bone flaps.

•

New method of bone flap handling and preservation reduced positive bacterial cultures from 35% to 0%.

•

The new method used pulsed lavage of bone flap with saline solution and subsequent swab culture.

•

There was no increase in post-cranioplasty surgical site infection following introduction of the new method.

INTRAOPERATIVE EVALUATION AND LEVEL OF CONTAMINATION DURING TOTAL KNEE ARTHROPLASTY

Introduction:

Despite numerous articles on intraoperative contamination in total knee arthroplasty (TKA) procedures, the available data on tissue contamination are scarce and mainly based on evaluating bacteriological swabs.

Methods:

Two hundred and forty specimens, divided between bone and soft tissue, were obtained from 40 consecutive unilateral primaries TKAs. The specimens were evaluated for aerobic and anaerobic bacterial growth. Colony-forming units/gram (CFU/g) were calculated on the contaminated specimens to determine the level of contamination.

Results:

The contamination rate in intraoperative specimens was 15% during TKA. The contamination level had a mean of 10.6 and a median of 5, ranging from 1-70 CFU/g. The most common contaminating organisms in all samples were Staphylococcus aureus (38.9%) and Staphylococcus epidermidis (30.6%). No clinical infections were detected in TKAs in the follow-up period.

Conclusion:

The contamination rate during TKA is relatively high, despite the practice of standard preventive measures. Contamination levels, measured by CFU/g, are considered low when compared to the infection threshold of 105 reported in the literature. However, contamination should not be underestimated due to the presence of foreign bodies (implants), which are known to significantly lower this threshold. Level of evidence IV; case series .

A Novel Biodegradable Composite Polymer Material Based on PLGA and Silver Oxide Nanoparticles with Unique Physicochemical Properties and Biocompatibility with Mammalian Cells

A method for obtaining a stable colloidal solution of silver oxide nanoparticles has been developed using laser ablation. The method allows one to obtain nanoparticles with a monomodal size distribution and a concentration of more than 108 nanoparticles per mL. On the basis of the obtained nanoparticles and the PLGA polymer, a nanocomposite material was manufactured. The manufacturing technology allows one to obtain a nanocomposite material without significant defects. Nanoparticles are not evenly distributed in the material and form domains in the composite. Reactive oxygen species (hydrogen peroxide and hydroxyl radical) are intensively generated on the surfaces of the nanocomposite. Additionally, on the surface of the composite material, an intensive formation of protein long-lived active forms is observed. The ELISA method was used to demonstrate the generation of 8-oxoguanine in DNA on the developed nanocomposite material. It was found that the multiplication of microorganisms on the developed nanocomposite material is significantly decreased. At the same time, the nanocomposite does not inhibit proliferation of mammalian cells. The developed nanocomposite material can be used as an affordable and non-toxic nanomaterial to create bacteriostatic coatings that are safe for humans.

Bacterial contamination of bone allografts in the tissue banks: a systematic review and meta-analysis

BACKGROUND

Bone allografts are harvested and transplanted under sterile conditions. However, the risk of bacterial contamination of grafts during these processes is a health concern. Bioburden testing and bacterial contamination detection are conducted to ensure allograft sterility.

AIM

The present study aimed to determine the incidence of bacterial contamination in bone allografts based on different classifications.

METHODS

PROSPERO registration number was received for the study. Systematic searches were conducted in PubMed and EMBASE databases with relevant keywords from January 2000 to March 2021. After choosing related studies according to the PRISMA flow diagram, Stata software was used for data analysis. We considered I² ˃ 50% as heterogeneity between studies.

FINDINGS

The overall incidence of bacterial contamination was 12.6% (95% CI 0.100, 0.152) among 19,805 bone allografts of 17 studies. The bacterial contamination rate among bone allografts was 10.8% before 2010 and 14.7% in 2010-March 2021. The contamination frequency in Asia, Europe, and Australia was 11.5%, 14.3%, and 5.2%, respectively. Bone contamination rates were higher in cadaver donors (19.9%), retrieval time sampling (13.5%), and swab samples (13.2%) compared to those in living donors (7.5%), implantation time sampling (6.9%), and bone fragments cultures (6.3%). Bacterial contamination was recovered 24.4%, 19.7%, 13.2%, and 21% from tibia, fibula, femoral, and other bones, respectively. Staphylococcus spp. was the predominant isolated bacteria from bones (63.2% of all isolated genera), followed by Propionibacterium spp. (10.6%).

CONCLUSION

The high contamination of bone allografts is a health concern, indicating the need for more health monitoring and improvement of standards.

New Organosilicon Composite Based on Borosiloxane and Zinc Oxide Nanoparticles Inhibits Bacterial Growth, but Does Not Have a Toxic Effect on the Development of Animal Eukaryotic Cells

The present study a comprehensive analysis of the antibacterial properties of a composite material based on borosiloxane and zinc oxide nanoparticles (ZnO NPs). The effect of the polymer matrix and ZnO NPs on the generation of reactive oxygen species, hydroxyl radicals, and long-lived oxidized forms of biomolecules has been studied. All variants of the composites significantly inhibited the division of E. coli bacteria and caused them to detach from the substrate. It was revealed that the surfaces of a composite material based on borosiloxane and ZnO NPs do not inhibit the growth and division of mammalians cells. It is shown in the work that the positive effect of the incorporation of ZnO NPs into borosiloxane can reach 100% or more, provided that the viscoelastic properties of borosiloxane with nanoparticles are retained.

Should we be prepping the foot? Stockinette use and drape contamination during hip arthroplasty: An experimental study

BACKGROUND

Meticulous prepping and draping of the surgical field is paramount to reduce the risk of infection. A consistent technique for draping for hip arthroplasty is not well established. One technique for preparing the operative field utilises a sterile stockinette over an unprepped foot. This study aims to assess surgical site contamination when draping for hip arthroplasty without disinfecting the foot.

METHODS

Ultraviolet (UV) fluorescent powder was used as a surrogate for microbial presence on the foot. Powder was applied to a volunteer's foot to a level where antibacterial prep would stop. The leg was then draped according to three methods; directly with stockinette only, wrapping the foot without using an adhesive seal followed by stockinette, and wrapping the foot with the adhesive seal followed by stockinette. Proximal spread of powder after draping was assessed with UV light.

RESULTS

Contamination of the sterile field was found with all draping methods. Spread was particularly noted in the groin, posterior to the thigh and distal to mid-thigh. Wrapping the foot in a small drape without the adhesive seal prior to stockinette application was associated with significantly greater contamination when compared with use of the seal (p = 0.004).

CONCLUSION

Routine formal prepping of the foot during hip arthroplasty is recommended to reduce the risk of surgical site contamination. Surgeons who select not to prep the foot should make use of a small drape with occlusive, adhesive seal prior to stockinette application and consider applying a further U drape to the hip.

Does the Duration of Primary and First Revision Surgery Influence the Probability of First and Subsequent Implant Failures after Extremity Sarcoma Resection and Megaprosthetic Reconstruction?

Simple Summary

Tumor endoprostheses are a common type of reconstruction after the resection of an extremity bone sarcoma. However, in the long-term, first and subsequent implant failures leading to revision surgery are common. One potential risk factor for implant failure is the length of surgery. This study investigates the impact of the length of surgery on prosthetic survival in 568 patients with sarcoma. Patients who had a first implant failure had a longer surgery; however, there were no differences in the infection-free survival, but only in the probability of mechanical failure. Patients with a subsequent revision surgery for infection had a shorter duration of surgery during the first revision. In conclusion, a shorter surgery appears beneficial; however, longer surgeries are not clearly associated with infection. In revision surgery, a longer operating time, indicating a more thorough debridement, may be desirable.

Abstract

Complications in megaprosthetic reconstruction following sarcoma resection are quite common. While several risk factors for failure have been explored, there is a scarcity of studies investigating the effect of the duration of surgery. We performed a retrospective study of 568 sarcoma patients that underwent megaprosthetic reconstruction between 1993 and 2015. Differences in the length of surgery and implant survival were assessed with the Kaplan–Meier method, the log-rank test and multivariate Cox regressions using an optimal cut-off value determined by receiver operating curves analysis using Youden’s index. 230 patients developed a first and 112 patients a subsequent prosthetic failure. The median duration of initial surgery was 210 min. Patients who developed a first failure had a longer duration of the initial surgery (225 vs. 205 min, p = 0.0001). There were no differences in the probability of infection between patients with longer and shorter duration of initial surgery (12% vs. 13% at 5 years, p = 0.492); however, the probability of mechanical failure was higher in patients with longer initial surgery (38% vs. 23% at 5 years, p = 0.006). The median length of revision surgery for the first megaprosthetic failure was 101 min. Patients who underwent first revision for infection and did not develop a second failure had a longer median duration of the first revision surgery (150 min vs. 120 min, p = 0.016). A shorter length of the initial surgery appears beneficial, however, the notion that longer operating time increases the risk of deep infection could not be reproduced in our study. In revision surgery for infection, a longer operating time, possibly indicating a more thorough debridement, appears to be associated with a lower risk for subsequent revision.

Performing a Safe and Effective Total Hip Arthroplasty on Patients With Inactive or Stably Active Systemic Lupus Erythematosus With Osteonecrosis

INTRODUCTION

Patients with systemic lupus erythematosus (SLE) are typically treated with total hip arthroplasty (THA) because of osteonecrosis of the femoral head (ONFH). This study evaluated the outcome of THA in this patient group.

METHODS

From January 2004 to January 2017, we retrospectively studied 92 THAs for patients with SLE and 92 THAs for age- and sex-matched patients suffering from ONFH due to nonrheumatic etiologies Both groups were treated with cementless THA and followed up for an average of 50.9 ± 30.6 months. Their surgical outcomes and complications were evaluated and compared.

RESULTS

No significant difference existed in age, sex, weight, height, follow-up time, and Ficat staging between the groups. All patients with SLE were in inactive or stably active disease conditions. For all patients, the Harris hip score (HHS) (from 52.6 to 92.8; P < 0.001), Physical Component Summary Scale score (PCS) (from 29.4 to 49.3; P < 0.001), and Mmental Component Summary Scale score (MCS) (from 50.5 to 55.5; P < 0.001) of the Short Form-12 improved significantly after surgery. At the final follow-up, the HHS and MCS were comparable between the two groups. The PCS remained lower in the SLE group (P = 0.017), and no recorded revision surgieries in either group. Corticosteroid intake and testing positive for antiphospholipid antibodies, rather than having a SLE disease activity index score greater than zero, were risk factors for higher complications.

DISCUSSION

Performing THA for patients with SLE in an inactive or stably active disease condition resulted in comparable postoperative HHS and MCS scores, a lower PCS score, and shorter term postoperative complications compared with patients with ONFH resulting from nonrheumatic diseases. Patients with SLE had a higher risk for postoperative complications. It is generally safe and effective to perform THA in patients with inactive or stably active SLE. However, they still have an increased risk of short-term complications.

After Incision, the Skin Knife Blade Is No More Contaminated Than a Fresh Knife Blade

INTRODUCTION

The rationale for discarding the skin knife blade and replacing it with another blade for deeper dissection is to prevent bacteria that may be present on the skin from being carried into the deeper layers of the wound. This practice is very controversial because numerous, yet limited, studies exist that support and refute the findings. The purpose of this study was to directly compare the rate of contamination of a skin knife blade with a control blade.

METHODS

We took the surface samples using Replicate Organism Detection and Counting plates of 344 knife blades immediately after making skin incision during the following four types of orthopaedic cases: total hip arthroplasty, total knee arthroplasty, lumbar spine surgery, and cervical spine surgery. At the same time, we sampled 344 control blades. The comparison of positives skin versus control, overall and within each subgroup was done using a bivariate two-sample z-test for the equality of proportions.

RESULTS

Overall, 35 (5.1%) of the 688 specimens had a positive result. No difference was noted in the rate of positive cultures for the 344 skin blades 4.9% and the 344 control blades 5.2%. No differences were observed in the rate of positive specimens for skin blades (7.4%, 3.4%, 7.7%, and 3.9%) and control blades (2.5%, 4.1%, 7.7%, and 9.2%) for total hip arthroplasty, total knee arthroplasty, C spine, and L spine, respectively. No differences were observed regarding skin prep, room number, case order, room turnover time, or in-room to incision time. Staphylococus species was the predominant bacteria identified.

CONCLUSION

We found no evidence to support the theoretical advantage of changing the knife blade after making skin incision to avoid contamination. Contamination rates were the same for both the skin and control blades overall and for all subgroup analysis.

Does intraoperative contamination during primary knee arthroplasty affect patient-reported outcomes for patients who are uninfected 1 year after surgery? A prospective cohort study of 714 patients

Background and purpose - It is well recognized that some knee arthroplasty (KA) patients present with prolonged postoperative inflammation and some develop persistent pain. It can reasonably be speculated that some of these problems develop because of low-grade infections with low virulence bacteria caused by intraoperative contamination. This prospective study was performed to investigate whether intraoperative contamination results in lower patient-reported outcomes (PRO) for patients who were clinically uninfected in the first year after surgery. Patients and methods - We combined data from 2 major prospective studies on patients undergoing primary KA at 2 Danish hospitals between September 2016 and January 2018. Pre- and postoperative (1.5, 3, 6, and 12 months) PROs and intraoperative microbiological cultures were obtained on a total of 714 patients who were included in the study. Based on the microbiological cultures, the patients were divided into 2 groups, contaminated and non-contaminated, and differences in PROs between the 2 groups were analyzed. Results - 84 of 714 (12%) patients were intraoperatively contaminated; none of the 714 patients developed clinical infection. The preoperative Oxford Knee Score was 24 and 23 for contaminated and non-contaminated patients, respectively, improving to 40 and 39 at 1 year (p = 0.8). 1-year AUC for Oxford Knee Score and absolute improvement at each postoperative time point for Forgotten Joint Score and EQ-5D-5L also were similar between contaminated and non-contaminated patients. Interpretation - Patient-reported outcomes from 714 patients do not indicate that intraoperative contamination affects the knee-specific or general health-related quality of life in primary KA patients who are clinically uninfected 1 year after surgery.

Intraoperative graft decontamination during ACL reconstruction surgery

Objective  To evaluate different decontaminants for tendon grafts, proposing an antiseptic protocol for contaminated grafts.

Methods  A total of 25 patients were tissue donors for the study. Each participant donated a 2.5-cm tendon sample, which was divided into 5 fragments with 5 mm each during anterior cruciate ligament (ACL) reconstruction surgery. The collected material was divided into 5 groups, totaling 125 samples. In total, four fragments of each patient were placed on the operating room floor for one minute for contamination, simulating the fall of the graft on the floor during surgery. The other fragment was immediately placed in a sterile container (group 1). One of the contaminated fragments was placed in the sterile container without being previously immersed in decontaminating solution (group 2). The remaining fragments were immersed for ten minutes in decontaminating solution: 0.5% chlorhexidine (group 3), 0.9% saline (group 4) and 0.55% ortho-phthalaldehyde (group 5), and, after this time, they were individually placed in a sterile container. The samples from the 5 groups were submitted to microbiological examination.

Results  Bacteria were detected in 26% of the total samples in the microbiological tests, and in group 1 there was no growth of microorganisms. In group 2, bacterial growth was observed in 16 samples. Considering the evaluation of test groups 3, 4 and 5, the percentage of decontamination was higher than the growth of microorganisms in the respective cultures.

Conclusion  The protocol suggested by the study showed that intraoperative graft decontamination is possible.

Bacterial Colonization of Irrigation Fluid during Aseptic Revision Knee Arthroplasty

Surgical risk factors for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) are the subjects of ongoing research. It is unclear if there are specific locations of the surgical area that might act as a pathogen source. Due to the fact that bacterial replication occurs preferably under humid conditions, it was our aim to investigate if irrigation fluid reservoirs on the surgical covers are subject to bacterial colonization. We prospectively observed 40 patients with scheduled aseptic 1-stage TKA revision. At time intervals of 30 min, irrigation samples were tested for microbiological colonization. Additionally, the suction tip was investigated at the end of surgery. Overall, a bacterial detection rate of 25% was found (57/232 samples). Analysis for any positive microbial detection revealed pathogen findings of irrigation fluid in 41.7% of samples after 30 min with a constant increase up to 77.8% after 90 min. Twenty-three percent of suction tips showed bacterial colonization. Coagulase-negative staphylococci, accounting for the majority of PJI, were the predominant pathogens. After an average follow-up of 17 months, no PJI was confirmed. Despite the substantial bacterial load of irrigation fluid, PJI rates were not elevated. Nevertheless, we recommend that irrigation fluid reservoirs should be prevented and not withdrawn by suction.

Sources of contamination in the operating room: A fluorescent particle powder study

This study utilized fluorescent particle powder to investigate 2 potential sources of sterile field contamination in the operating room (OR): forced-air warming blankets and OR light manipulation. In part 1, sterile draping for knee replacement surgery was performed on a mannequin in a sterile OR, comparing field contamination with the forced-air warming on versus off during draping. In part 2, OR lights coated with fluorescent powder were manipulated over a sterile field. Proper operation of these devices may reduce the particle burden on the surgical field.

Does an Antimicrobial Incision Drape Prevent Intraoperative Contamination? A Randomized Controlled Trial of 1187 Patients

BACKGROUND

The risk of periprosthetic joint infection (PJI), a serious complication after arthroplasty, has not changed for years. Interventions such as eradication of Staphylococcus aureus and antibiotic bone cement are used to diminish infection risk but despite these efforts, the percentage of infection in TKA remains constant. Antimicrobial drapes have a dual action, acting both as a physical and antimicrobial barrier to counter bacterial contamination of the surgical wound. To study the effect of antimicrobial drapes, we used intraoperative contamination as a proxy for infection in our investigation.

QUESTIONS/PURPOSES

(1) Do antimicrobial surgical drapes reduce the risk of intraoperative microbial contamination in patients undergoing primary knee arthroplasty? (2) Are other factors such as sex, season, age, type of arthroplasty and duration of surgery associated with an increased risk of contamination in patients undergoing primary knee arthroplasty? (3) Does loosening of the antimicrobial drape increase contamination risk?

METHODS

An investigator-initiated, two-arm, non-blinded, multicenter, randomized, controlled trial was performed at five different hospitals in the capital and central regions of Denmark. Twenty-four surgeons participated in the study. Participants were patients older than 18 years undergoing primary knee arthroplasty. We excluded patients with an iodine allergy, previous open knee surgery, previous septic arthritis, any antibiotics taken 4 weeks before surgery, and if they were unable to understand the implications of study participation. Patients were randomly assigned to operation with an antimicrobial drape (intervention group) or operation without (control group). We screened 1769 patients, of which 100 were ineligible and 10 declined to participate. In all, 94% (1659 of 1769) of patients consented and were randomized to the intervention group (51%, 838 of 1659) and control group (49%, 821 of 1659), respectively. In all, 36% (603 of 1659) of patients in the intervention group and 35% (584 of 1659) patients in the control group were available for final analysis. No crossover was performed, and analysis was done per-protocol. Patients were excluded due to logistic failures like lack of utensils, samples disappearing en route to the laboratory mainly caused by implementation of a new electronic patient chart (EPIC, Verona, WI, USA), and forgetful surgeons. Intraoperatively, we swabbed for bacteria at the surgical site and in a rinse from the surgeons' gloves. All samples were sent for cultivation, and colony forming units (CFUs) counts ≥ 1 were deemed contaminated. The primary outcome measure was the difference in the proportion of contaminated patients between the two randomized groups. Secondary outcome measures were the affiliation of sex, season, age, type of implant used, and duration of surgery on contamination risk. To investigate whether other factors were affiliated with contamination risk, we did a logistic regression to control for confounding variables, including sex, age, season, type of implant and duration of surgery.

RESULTS

Use of iodinated drapes reduced contamination, with contamination detected in 10% (60 of 603) procedures where iodinated drapes were used compared with 15% (90 of 584) when they were not (odds ratio 0.61 [95% CI 0.43 to 0.87]; p = 0.005), with a relative risk reduction of 35% (95% CI 12.3 to 52.5) and a number needed to treat of 18 patients. After controlling for confounding variables such as sex, age, type of implant, and duration of surgery, we found that not using an antimicrobial drape increased contamination risk by a factor of 1.6 (95% CI 1.08 to 2.35; p = 0.02). Female sex and undergoing surgery in the central region were associated with lower odds of contamination (OR 0.55 [95% CI 0.39 to 0.8]; p = 0.002 and OR 0.45 [95% CI 0.25 to 0.8]; p = 0.006, respectively). Patients with more than a 10-mm separation of the drape from the skin had higher odds of contamination (OR 3.54 [95% CI 1.64 to 11.05]; p = 0.0013).

CONCLUSIONS

The use of an antimicrobial drape resulted in lower contamination risk than operating without an antimicrobial drape. Our findings suggest that antimicrobial drapes are useful in infection prevention, but further studies are needed to investigate the effect of antimicrobial drapes on infection.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Contamination Rate of Burnt Necrotic Tissue after Electrocoagulation in Total Knee Arthroplasty

Background

Periprosthetic joint infection (PJI) is one of the commonly found catastrophic complications after total knee arthroplasty (TKA). Preoperative antibiotic prophylaxis, proper skin cleansing, shortened operative time, and sterility of surgical field and equipment are essential to minimize the risk of PJI. Although bacterial contamination of electrocautery tips has been reported, contamination of residual product of electrocoagulation, burnt necrotic tissue (BNT), is not well known. Therefore, we aimed to assess the contamination rate of BNT and association between contaminated BNT and PJI, and risk factors.

Methods

BNTs from 183 patients who had undergone unilateral primary TKA at our institution were retrospectively analyzed. In each patient, three to five specimens of BNT were routinely collected in the operative field of primary TKA. Collecting time was defined as the duration from start of using the electrocautery device to the first collection of BNT.

Results

Culture was positive in eight of 183 patients (4.4%; contaminated BNT group), and the most commonly isolated organism was coagulase-negative Staphylococcus (62.5%). The average operative time was 103.1 ± 44.2 minutes in the contaminated BNT group and 79.0 ± 16.7 minutes in the non-contaminated BNT group (p = 0.17), and collecting time was 48.0 ± 44.3 minutes and 29.7 ± 17.0 minutes (p = 0.28), respectively. None of the patients with contaminated BNT developed PJI, whereas four patients with culture-negative BNT developed PJI within 2 postoperative years.

Conclusions

BNT in surgical field can become a reservoir of contaminating bacteria. However, contamination of BNT was not associated with PJI. Therefore, routine removal of all BNTs may be unnecessary.

Periprosthetic Infections of the Shoulder: Diagnosis and Management

The use of shoulder arthroplasty is continuing to expand. Periprosthetic joint infection of the shoulder is a devastating complication occurring in approximately 1% of cases. The most common organisms responsible for the infection are Cutibacterium acnes (formerly Propionibacterium acnes) (∼39%) and coagulase-negative Staphylococcus (∼29%). Evaluation of patients includes history and physical examination, serologic testing, imaging, possible joint aspiration, and tissue culture. Diagnosing infections caused by lower virulence organisms (eg, C acnes) poses a challenge to the surgeon because traditional diagnostic tests (erythrocyte sedimentation rate, C-reactive protein, and joint aspiration) have a low sensitivity due to the lack of an inflammatory response. Periprosthetic joint infections of the shoulder due to Staphylococcus aureus and other highly virulent organisms are often easy to diagnose and are usually treated with two-stage revisions. However, for infections with C acnes and coagulase-negative Staphylococcus, single- and two-stage revision surgeries have shown similar ability to clear the infection. Unexpected positive cultures for C acnes during revision surgery are not uncommon; the proper management is still under investigation and remains a challenge.

Periprosthetic joint infection in aseptic total hip arthroplasty revision

PURPOSE

There is no consensus regarding systematic screening for infection in aseptic revision total hip arthroplasty (THA). The rationale for systematic intra-operative samples is to increase the sensitivity of latent infections detection, which may require specific treatment. However, the incidence of occult infection in revision THAs is not precisely known. As such, the aim of the study was to evaluate the incidence of occult infection in presumed aseptic revision THAs and identify associated risk factors.

METHOD

Bacteriological samples from 523 aseptic THA revisions performed for five years were analyzed. Revisions performed for periprosthetic joint infection (PJI) or clinical suspicion of PJI were excluded. Microbiological cultures were performed using tissue samples in 505 cases (97%), synovial fluid in blood culture vials in 158 (30%), and in dry tubes in 263 (50%). Implants were sent for sonication in 12 cases (2.6%). The mean number of microbiological samples per patient was 3.6 (range, 1-15). Histology samples were collected for 300 patients (57%).

RESULTS

The incidence of occult infection was 7% (36 cases) and contamination 8% (42 cases). Among occult infections, the primary reasons for revision were dislocation (42%), aseptic loosening (25%), fracture (19%), and others (14%). The infection rate in the dislocation group was significantly higher than that of other reasons for revision (p < 0.001). Among the patients determined with PJI, the revision THA was performed less than a year after primary in 19 (53%).

CONCLUSION

The incidence of occult PJI justifies systematic intraoperative sampling. A short time between primary arthroplasty and revision or an early postoperative dislocation is a factor to suspect infections.

Rate of surface contamination in the operating suite during revision total joint arthroplasty

Background

This study estimated operating room surface contamination rates during aseptic vs septic total joint arthroplasty and evaluated the similarity between clinically infecting organisms and those isolated from contaminated surfaces.

Methods

Patients undergoing total hip and knee revision arthroplasties were identified, and surface and tissue samples were collected. Cases were classified aseptic or septic based on Musculoskeletal Infection Society criteria for prosthetic joint infection. Positive surface cultures were compared with intraoperative tissue cultures. Positive cultures were speciated and tested for antimicrobial sensitivity.

Results

Samples were collected from 31 aseptic and 18 septic cases. Patients had similar demographics and time to explantation. Surface contamination rates for septic revisions were greater than those for aseptic revisions (77% vs 13%). During septic revisions, when intraoperative tissue cultures were positive, the surgical field was contaminated in 14 of 15 cases. The kappa correlation statistic for positive surgical cultures matching the surface sample was 0.9 (95% confidence interval: 0.78-1).

Conclusions

Septic revisions had a significantly higher rate of surgical field contamination than aseptic revisions. Cultures suggest that bacteria contaminating the septic revision surgical field likely originated from the infected joint. Although this observation seems obvious, it is an important piece of information when discussing best practices during a single-stage exchange revision. Further clinical studies will demonstrate the use of a preparation and reset period during a single-stage revision to remove contaminated surfaces.

Editorial Commentary: Bacterial Load and Contamination of Anterior Cruciate Ligament Grafts-Overamplified Dreadful Nuclear Assumption (DNA) or Underestimated Problem?

Bacterial DNA is present in a large percentage in failed anterior cruciate ligament reconstructions. A potential concern is the presence of biofilm on both failed anterior cruciate ligament reconstruction grafts and suture material. Despite the high prevalence of bacterial material observed, microbial cultures are rarely positive. However, it is currently unknown whether these findings have any clinical implications.

Fluid collection bags pose a threat for bacterial contamination in primary total hip arthroplasty: a prospective, internally controlled, non-blinded trial

INTRODUCTION

Surgical equipment, and especially the so-called 'splash basins' that are used intraoperatively, are a potential source of bacterial contamination in primary total hip arthroplasty (THA). With this risk in mind, many commercially available draping kits include plastic bags that can be used to collect fluid or to temporarily store instruments. Following this rationale, we hypothesised that first: the fluid collection bags are a potential reservoir of bacteria and second: there is a time dependency for bacterial contamination.

MATERIALS AND METHODS

After ethics approval, we investigated in a prospective, internally controlled, non-blinded trial 43 patients who received primary THA. At the beginning of the surgery, we took deep, representative, intracapsular tissue samples, which served as negative controls. At the end of surgery, tissue samples were taken from the bottom of the 'fluid collection bag' for microbiological analysis.

RESULTS

All 86 control samples were negative. Out of the samples taken from the bags, a pathogen could be detected in four patients (9.3%). All pathogens were detected after a surgery time lasting longer than 90 min.

CONCLUSION

We were able to show that fluid collection bags are a potential reservoir for bacteria in THA when surgery time was greater than a 90-min threshold. Our data suggest that the risks from fluid collection bags outweigh the advantages of using them. Therefore, we recommend against the use of fluid collection bags intraoperatively in primary THA.

Environment of care: Is it time to reassess microbial contamination of the operating room air as a risk factor for surgical site infection in total joint arthroplasty?

In the modern operating room (OR), traditional surgical mask, frequent air exchanges, and architectural barriers are viewed as effective in reducing airborne microbial populations. Intraoperative sampling of airborne particulates is rarely performed in the OR because of technical difficulties associated with sampling methodologies and a common belief that airborne contamination is infrequently associated with surgical site infections (SSIs). Recent studies suggest that viable airborne particulates are readily disseminated throughout the OR, placing patients at risk for postoperative SSI. In 2017, virtually all surgical disciplines are engaged in the implantation of selective biomedical devices, and these implants have been documented to be at high risk for intraoperative contamination. Approximately 1.2 million arthroplasties are performed annually in the United States, and that number is expected to increase to 3.8 million by the year 2030. The incidence of periprosthetic joint infection is perceived to be low (<2.5%); however, the personal and fiscal morbidity is significant. Although the pharmaceutic and computer industries enforce stringent air quality standards on their manufacturing processes, there is currently no U.S. standard for acceptable air quality within the OR environment. This review documents the contribution of air contamination to the etiology of periprosthetic joint infection, and evidence for selective innovative strategies to reduce the risk of intraoperative microbial aerosols.

Disinfection and healing effects of 222-nm UVC light on methicillin-resistant Staphylococcus aureus infection in mouse wounds

UVC radiation is known to be highly germicidal. However, exposure to 254-nm-UVC light causes DNA lesions such as cyclobutane pyrimidine dimers (CPD) in human cells, and can induce skin cancer after long-term repeated exposures. It has been reported that short wavelength UVC is absorbed by proteins in the membrane and cytosol, and fails to reach the nucleus of human cells. Hence, irradiation with 222-nm UVC might be an optimum combination of effective disinfection and biological safety to human cells. In this study, the biological effectiveness of 222-nm UVC was investigated using a mouse model of a skin wound infected with methicillin-resistant Staphylococcus aureus (MRSA). Irradiation with 222-nm UVC significantly reduced bacterial numbers on the skin surface compared with non-irradiated skin. Bacterial counts in wounds evaluated on days 3, 5, 8 and 12 after irradiation demonstrated that the bactericidal effect of 222-nm UVC was equal to or more effective than 254-nm UVC. Histological analysis revealed that migration of keratinocytes which is essential for the wound healing process was impaired in wounds irradiated with 254-nm UVC, but was unaffected in 222-nm UVC irradiated wounds. No CPD-expressing cells were detected in either epidermis or dermis of wounds irradiated with 222-nm UVC, whereas CPD-expressing cells were found in both epidermis and dermis irradiation with 254-nm UVC. These results suggest that 222-nm UVC light may be a safe and effective way to reduce the rate of surgical site and other wound infections.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management

INTRODUCTION

The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique.

METHODS

The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations.

RESULTS

The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices.

CONCLUSION

Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

Does laminar flow ventilation reduce the rate of infection?

Aims

To determine whether there is any difference in infection rate at 90 days between trauma operations performed in laminar flow and plenum ventilation, and whether infection risk is altered following the installation of laminar flow (LF).

Patients and Methods

We assessed the impact of plenum ventilation (PV) and LF on the rate of infection for patients undergoing orthopaedic trauma operations. All NHS hospitals in England with a trauma theatre(s) were contacted to identify the ventilation system which was used between April 2008 and March 2013 in the following categories: always LF, never LF, installed LF during study period (subdivided: before, during and after installation) and unknown. For each operation, age, gender, comorbidity, socio-economic deprivation, number of previous trauma operations and surgical site infection within 90 days (SSI90) were extracted from England’s national hospital administrative Hospital Episode Statistics database. Crude and adjusted odds ratios (OR) were used to compare ventilation groups using hierarchical logistic regression. Subanalysis was performed for hip hemiarthroplasties.

Results

A total of 803 065 trauma operations were performed during this time; 19 hospitals installed LF, 124 already had LF, 13 had PV and the type of ventilation was unknown in 28. Patient characteristics were similar between the groups. The rate of SSI90 was similar for always LF and PV (2.7% and 2.4%). For hemiarthroplasties of the hip, the rates of SSI90 were significantly higher for LF compared with PV (3.8% and 2.6%, OR 1.45, p = 0·001). Hospitals installing LF did not see any statistically significant change in the rate of SSI90.

Conclusion

The results of this observational study imply that infection rate is similar when orthopaedic trauma surgery is performed in LF and PV, and is unchanged by installing LF in a previously PV theatre. Cite this article: Bone Joint J 2016;98-B:1262–9.

Intra-articular steroid injection for osteoarthritis of the hip prior to total hip arthroplasty

Aims

Using a systematic review, we investigated whether there is an increased risk of post-operative infection in patients who have received an intra-articular corticosteroid injection to the hip for osteoarthritis prior to total hip arthroplasty (THA).

Methods

Studies dealing with an intra-articular corticosteroid injection to the hip and infection following subsequent THA were identified from databases for the period between 1990 to 2013. Retrieved articles were independently assessed for their methodological quality.

Results

A total of nine studies met the inclusion criteria. Two recommended against a steroid injection prior to THA and seven found no risk with an injection. No prospective controlled trials were identified. Most studies were retrospective. Lack of information about the methodology was a consistent flaw.

Conclusions

The literature in this area is scarce and the evidence is weak. Most studies were retrospective, and confounding factors were poorly defined or not addressed. There is thus currently insufficient evidence to conclude that an intra-articular corticosteroid injection administered prior to THA increases the rate of infection. High quality, multicentre randomised trials are needed to address this issue. Cite this article: Bone Joint J 2016;98-B:1027–35.

Single versus double blade technique for skin incision and deep dissection in surgery for closed fracture: a prospective randomised control study

PURPOSE

To compare blade cultures in surgery for closed fracture using a single or double blade technique to determine whether the current practice of double blade technique is justified.

METHODS

155 men and 29 women aged 20 to 60 (mean, 35) years who underwent surgery for closed fracture with healthy skin at the incision site were included. Patients were block randomised to the single (n=92) or double (n=92) blade technique. Blades were sent for bacteriological analysis. Outcome measures were early surgical site infection (SSI) within 30 days and cultures from the blades.

RESULTS

The 2 groups were comparable in baseline characteristics. In the single blade group, 6 surgical blades and 2 control blades showed positive cultures; 4 patients developed SSI, but only one had a positive culture from the surgical blade (with different organism isolated from the wound culture). In the double blade group, 6 skin blades, 7 deep blades, and 0 control blade showed positive culture; only 2 patients had the same bacteria grown from both skin and deep blade. Five patients developed SSI, but only one patient had a positive culture from the deep blade (with different organism isolated from the wound culture). The difference in incidence of culture-positive blade or SSI between the 2 groups was not significant. The relative risk of SSI in the single blade group was 0.8. Positive blade culture was not associated with SSI in the single or double blade group.

CONCLUSION

The practice of changing blade following skin incision has no effect on reducing early SSI in surgery for closed fracture in healthy patients with healthy skin.

Evaluation of the Sagittal Saw Blade as an Intraoperative Fomite During Diabetic Foot Surgery

Surgical site infection is a major potential complication of all operative interventions, and the diabetic foot is particularly at risk for bacterial recontamination and infectious sequelae. The objective of this study was to identify whether the sagittal saw blade used during partial foot amputations and diabetic foot debridements carries the potential to serve as a bacterial fomite. We physically cultured the sagittal saw blade during 20 foot debridements involving the resection of bone in patients diagnosed with a diabetic foot infection. The culture was taken after the initial debridement and during the irrigation phase of the procedure. We observed 16 positive routine intraoperative culture results, with positive saw blade culture results in 15 (93.8%; 15/16) of these cases. In 14 (93.3%; 14/15) of these cases, the saw blade culture grew at least one of the same bacteria as our other routine intraoperative cultures. We observed 4 negative routine intraoperative culture results, with negative saw blade culture results in 3 (75.0%; 3/4) of these cases. This results in agreement between routine intraoperative cultures and saw blade culture of 85.0% (17/20). The results of this investigation demonstrate that the sagittal saw blade used for osseous resection during diabetic foot debridements and partial foot amputations carries the potential for intraoperative bacterial transmission. We recommend changing at least the sagittal saw blade if more bone is resected following irrigation, particularly if it is used to obtain a "clean margin" for microbiological or histological examination.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Case series.

Retrospective, Demographic, and Clinical Investigation of the Causes of Postoperative Infection in Patients With Lumbar Spinal Stenosis Who Underwent Posterior Stabilization

Owing to the increasing population of elderly patients, a large number of patients with degenerative spondylosis are currently being surgically treated. Although basic measures for decreasing postoperative surgical infections (PSIs) are considered, it still remains among the leading causes of morbidity and mortality. The aim of this retrospective analysis is to present possible causes leading to PSI in patients who underwent surgery for lumbar degenerative spondylosis and highlight how it can be avoided to decrease morbidity and mortality. The study included 540 patients who underwent posterior stabilization due to degenerative lumbar stenosis between January 2013 and January 2014. The data before and after surgery was retrieved from the hospital charts. Patients with degenerative lumbar stenosis who were operated upon in this study had >2 levels of laminectomy and facetectomy. For this reason, posterior stabilization was performed for all the patients included in this study. Determining the causes of postoperative infection (PI) following spinal surgeries performed with instrumentation is a struggle. Seventeen different parameters that may be related to PI were evaluated in this study. The presence of systemic diseases, unknown glove perforations, and perioperative blood transfusions were among the parameters that increased the prevalence of PI. Alternatively, prolene sutures, double-layered gloves, and the use of rifampicin Sv (RIS) decreased the incidence of PI. Although the presence of systemic diseases, unnoticed glove perforations, and perioperative blood transfusions increased PIs, prolene suture material, double-layered gloves, and the use of RIS decreased PIs.

Surgical attire and the operating room: role in infection prevention

➤ Although there is some evidence that scrubs, masks, and head coverings reduce bacterial counts in the operating room, there is no evidence that these measures reduce the prevalence of surgical site infection.➤ The use of gloves and impervious surgical gowns in the operating room reduces the prevalence of surgical site infection.➤ Operating-room ventilation plays an unclear role in the prevention of surgical site infection.➤ Exposure of fluids and surgical instruments to the operating-room environment can lead to contamination. Room traffic increases levels of bacteria in the operating room, although the role of this contamination in surgical site infection is unclear.

Glove and gown effects on intraoperative bacterial contamination

OBJECTIVE

Experiments were performed to determine the risk of bacterial contamination associated with changing outer gloves and using disposable spunlace paper versus reusable cloth gowns.

BACKGROUND

Despite decades of research, there remains a lack of consensus regarding certain aspects of optimal aseptic technique including outer glove exchange while double-gloving and surgical gown type selection.

METHODS

In an initial glove study, 102 surgical team members were randomized to exchange or retain outer gloves 1 hour into clean orthopedic procedures; cultures were obtained 15 minutes later from the palm of the surgeon's dominant gloved hand and from the surgical gown sleeve. Surgical gown type selection was recorded. A laboratory strike-through study investigating bacterial transmission through cloth and paper gowns was performed with coagulase-negative staphylococci. In a follow-up glove study, 251 surgical team members, all wearing paper gowns, were randomized as in the first glove study.

RESULTS

Glove study 1 revealed 4-fold higher levels of baseline bacterial contamination (31% vs 7%) on the sleeve of surgical team members wearing cloth gowns than those using paper gowns [odds ratio (95% confidence interval): 4.64 (1.72-12.53); P = 0.0016]. The bacterial strike-through study revealed that 26 of 27 cloth gowns allowed bacterial transmission through the material compared with 0 of 27 paper gowns (P < 0.001). In glove study 2, surgeons retaining outer gloves 1 hour into the case had a subsequent positive glove contamination rate of 23% compared with 13% among surgeons exchanging their original outer glove [odds ratio (95% confidence interval): 1.97 (1.02-3.80); P = 0.0419].

CONCLUSIONS

Paper gowns demonstrated less bacterial transmission in the laboratory and lower rates of contamination in the operating room. Disposable paper gowns are recommended for all surgical cases, especially those involving implants, because of the heightened risk of infection. Outer glove exchange just before handling implant materials is also recommended to minimize intraoperative contamination.

Bacteriology of degenerated lumbar intervertebral disks

STUDY DESIGN

A prospective microbiological analysis of intervertebral disk material in surgically treated patients presenting lumbar disk degeneration.

OBJECTIVE

To determine the prevalence and species of bacteria in degenerated lumbar disks, their eventual role in the pathophysiology, and the possible influence of risk factors.

SUMMARY OF BACKGROUND DATA

Intervertebral disk degeneration results from biochemical, mechanical, genetic, and toxic factors. The hypothesis of low-grade infection has been raised but not elucidated to date.

METHODS

Eighty-three patients (34 males, 49 females, 41 y) were treated by lumbar disk replacement at L3-L4, L4-L5, or L5-S1. An intraoperative biopsy and microbiological culture were performed for each disk to determine if intradiskal bacteria were present. Magnetic resonance stages were Pfirrmann IV or V, with Modic I in 32, and Modic II in 25 cases. A preoperative discography was performed in 49 patients, 24 had previous nucleotomy.

RESULTS

Bacteria were found in 40 disks, 43 cultures were sterile. The following bacteria were evidenced: Propionibacterium acnes 18, coagulase-negative staphylococci 16, gram-negative bacilli 3, Micrococcus 3, Corynebacterium 3, others 5. Ten biopsies presented 2 different species. Multinucleated cells were evidenced histologically in 33% of positive biopsies. Bacteria were predominantly found in males (P=0.012). The mostly positive level was L4-L5 (P=0.075). There was no significant relationship between bacterial evidence and Modic sign. A preoperative discography or previous nucleotomy did not represent significant contamination sources. None of the patients presented infectious symptoms.

CONCLUSIONS

Although the hypothesis of biopsy contamination cannot be excluded, intradiskal bacteria might play a role in the pathophysiology of disk degeneration. However, the histologic presence of multinucleated cells may indicate an inflammatory process that could sustain the hypothesis of low-grade spondylodiscitis at 1 stage of the cascade of lumbar disk degeneration. These microbiological and histologic findings would need to be compared with nondegenerated disks.

LEVEL OF EVIDENCE

: Diagnostic level III.

Infection risk from surgeons' eyeglasses

PURPOSE

To assess bacterial contamination of 20 eyeglasses from surgeons.

METHODS

40 samples were taken from the nose pad (n=20) and earpiece (n=20) of 20 eyeglasses from orthopaedic surgeons using a sterile swab stick soaked in sterile distilled water. Swabs were incubated and inoculated onto 3 plates: Staphylococcus/Streptococcus agar plate, Mannitol salt plate, and Chromogenic agar plate. Organisms isolated were identified.

RESULTS

Of 20 eyeglasses, 19 were contaminated with Staphylococcus epidermidis (3 of them additionally grew S haemolyticus or S xylosus) and the remaining one grew S aureus .

CONCLUSION

Eyeglasses are a source of surgical infection. Contamination can be caused by direct contact of the eyeglasses to the wound and indirect contact by the surgeon's fingers, splashes from saline irrigation, and through air. Therefore, disinfection should be performed for eyeglasses of surgeons. The use of surgical visor masks or filtered exhaust helmets (space suits) are alternatives.

Sterile surgical helmet system in elective total hip and knee arthroplasty

PURPOSE

To evaluate the sterility of the sterile surgical helmet system (SSHS) during elective total hip and knee arthroplasty in theatres with (n=20) and without (n=20) laminar flow.

METHODS

Three surgeons performed 14 total knee arthroplasties (TKAs) and 6 total hip arthroplasties (THAs) in a laminar flow theatre and 15 TKAs and 5 THAs in a non-laminar flow theatre. An SSHS was used in all the procedures. Samples were taken from the hood at 30-minute intervals during surgery. Swabs were then broken into cooked meat broths for cultivation of organisms. The broths were then directly inoculated onto blood agar and fastidious anaerobic agar for culture of aerobic and anaerobic bacteria, respectively. After 24 hours, these plates were reinoculated with broths that had been incubated for 24 hours. Microbial growth was quantified as 0 (none), 1 (mild), 2 (moderate) and 3 (heavy). Bacterial contamination in the 2 groups at 30, 60 and 90 minutes was compared.

RESULTS

Respectively in the laminar and non-laminar flow theatres, 0 and 9 of the SSHSs showed bacterial growth after direct inoculation, and 14 and 18 of the SSHSs grew 18 and 24 types of organisms in the swab cultures after 24 hours of incubation. Respectively at 30, 60, and 90 minutes, the degree of contamination from direct incubation was significant, but the degree of contamination on swabs after 24 hours of inoculation was not significant. The mean time-dependent contamination after direct inoculation was 0 for the laminar flow group and 0.5, 0.75, and 1.0 for the non-laminar flow group, whereas the corresponding values after 24 hours of incubation were 1.8, 1.8, and 2.6, and 2, 2.75, and 2.95. Coagulase negative Staphylococcus aureus was the most common organism in both groups.

CONCLUSION

80% of SSHSs used were contaminated intra-operatively. Direct contact with the SSHS should be avoided by the operating team during surgery. Routine changing of gloves in case of contact with the SSHS should be practised.

Does the use of laminar flow and space suits reduce early deep infection after total hip and knee replacement?: the ten-year results of the New Zealand Joint Registry

We have investigated whether the use of laminar-flow theatres and space suits reduced the rate of revision for early deep infection after total hip (THR) and knee (TKR) replacement by reviewing the results of the New Zealand Joint Registry at ten years. Of the 51 485 primary THRs and 36 826 primary TKRs analysed, laminar-flow theatres were used in 35.5% and space suits in 23.5%. For THR there was a significant increase in early infection in those procedures performed with the use of a space suit compared with those without (p < 0.0001), in those carried out in a laminar-flow theatre compared with a conventional theatre (p < 0.003) and in those undertaken in a laminar-flow theatre with a space suit (p < 0.001) when compared with conventional theatres without such a suit. The results were similar for TKR with the use of a space suit (p < 0.001), in laminar-flow theatres (p < 0.019) and when space suits were used in those theatres (p < 0.001). These findings were independent of age, disease and operating time and were unchanged when the surgeons and hospital were analysed individually. The rate of revision for early deep infection has not been reduced by using laminar flow and space suits. Our results question the rationale for their increasing use in routine joint replacement, where the added cost to the health system seems to be unjustified.

Unexpectedly increased rate of surgical site infections following implant surgery for hip fractures: problem solution with the bundle approach

INTRODUCTION

Surgical site infections (SSIs) are the most common nosocomial infections after surgery.However, clinical guidance on how to handle any suspicious clusters of SSI in orthopaedic surgery is missing. We report on problem analysis and solution finding following the observation of an increased rate of SSI in trauma implant surgery.

SETTING

Trauma unit of a university hospital.

METHODS

Over a 2-year observation period, all patients (n = 370) following surgical stabilisation of proximal femur fractures in a trauma unit of a university hospital were consecutively followed using a standardised case report form. First, a retrospective cohort of 217 patients was collected for whom an increased SSI rate was detected. Based on risk analysis, new standard perioperative procedures were developed and implemented. The impact was evaluated in a prospective cohort of 153 comparable patients. Uni- and multivariable analysis of factors associated with the risk for SSI was undertaken.

RESULTS

The intervention bundle resulted in a significant reduction of an initially increased SSI incidence of 6.9 (down) to 2.0% (p = 0.029). Multivariable analysis revealed four risk factors significantly associated with a higher risk of SSI caused by different bacteria: duration of surgery (p = 0.002), hemiarthroplasty(p = 0.002), haematoma (p = 0.004) and the presence of two operating room staff members (p < 0.001 and 0.035).

CONCLUSIONS

A standardised prospective SSI protocol and detection system offering the simultaneous use of data should guarantee every institution immediate alarm registration to avoid comparable problem situations. Detailed interdisciplinary analysis followed by the implementation of coherent interventions, based on a best-evidence structured bundle approach, may adequately resolve similar critical incidence episodes.

The microbiology of the infected knee arthroplasty

We describe the results of a retrospective analysis of patients with microbiologically proven infection, who underwent revision TKA between 1994 and 2008. Of the 121 patients included in the study, 61 (50%) were male and 60 (50%) were female. The mean age was 71 (range 42-88) years. The most common organisms identified were Coagulase negative Staphylococcus (CNS) (49%) and Staphylococcus aureus (SA) (13%). The prevalence of CNS appears to be increasing, while that of SA and other organisms is decreasing. Vancomycin and teicoplanin were the most effective antibiotics with overall sensitivity rates of 100% and 96%, respectively. The results of our theoretical model suggest that gentamicin combined with vancomycin is the most effective empirical regimen. Staphylococcal species are the most common organisms encountered in deep infection of the knee. Gentamicin combined with vancomycin offers the most comprehensive protection and potentially allows for infected knee arthoplasties to be treated with a one-stage procedure.