Establishing a role for vancomycin powder application for prosthetic joint infection prevention-results of a wear simulation study

The Three-Month Wound Complication and Infection Rates after Vancomycin Powder and Dilute Povidone-Iodine Lavage for Infection Prophylaxis in High-Risk Total Joint Arthroplasty: A Multicenter Randomized Controlled Trial

BACKGROUND

Periprosthetic joint infection (PJI) is a high-cost and extremely morbid complication following total joint arthroplasty (TJA); thus, developing a better understanding of perioperative infection prevention strategies is prudent. Literature is mixed regarding the efficacy of vancomycin powder and dilute povidone-iodine lavage, and limited on the combination thereof. To our knowledge, no prospective orthopaedic clinical trials to date have evaluated the efficacy of local vancomycin powder, dilute povidone-iodine lavage, or a combination vancomycin-povidone-iodine-protocol (VPIP) against normal saline irrigation.

METHODS

In a large, prospective, multi-center, randomized-controlled study, four distinct infection prevention strategies were implemented in high-risk TJA patients. Local vancomycin powder, dilute povidone-iodine solution, combined VPIP, and saline control were used. Primary outcomes included PJI, wound complications, revisions, emergency department (ED) visits, readmissions, and serious adverse events within three months of index surgery. Chi-square tests were used to compare incidence rates. The criteria used for the diagnosis of PJI were the International Consensus Meeting (ICM) guidelines.

RESULTS

There were 821 total hip arthroplasty (THA) and 1,080 total knee arthroplasty (TKA) patients randomized into well-balanced study groups. In the THA and TKA cohorts, respectively, there were no statistically significant differences in rates of persistent wound drainage or dehiscence (P = 0.98, P = 0.95), cellulitis or abscess (P = 0.81, P = 0.51), 3-month infection rates (P = 0.14, P = 0.13), type of septic revisions performed (P = 0.51, P = 0.80), aseptic revision rates (P = 0.07, P = 0.90), ED visits (P = 0.61, P = 0.46), or readmissions (P = 0.78, P = 0.87) between the four treatment groups.

CONCLUSIONS

There were no statistically significant differences in PJI or other surgical outcomes following THA or TKA among the study groups. Therefore, the use of such prophylactic measures, including povidone-iodine and vancomycin powder in high-risk patients, can be left up to the surgeon or hospital discretion.

Feasibility of mNGS in joint replacement patients exhibiting elevated ESR and CRP levels without an underlying diagnosis

OBJECTIVE

The aim of this study is to investigate the viability of performing initial artificial joint replacement surgery in patients presenting with unexplained elevations in erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels.

METHODS

A cohort of 22 patients, comprising 11 cases each for knee and hip joint replacements, who underwent initial artificial joint replacement surgery between November 2020 and January 2022, was recruited. All patients exhibited elevated levels of ESR and CRP prior to surgery, the etiology of which remained undetermined. Intraoperatively, joint effusion and periarticular tissues were preserved for subsequent bacterial culture and metagenomic next-generation sequencing (mNGS). Postoperatively, a combination of intravenous and local antibiotics was administered for anti-infective management. In cases where bacterial culture and/or mNGS yielded positive results, patients were diagnosed with periprosthetic joint infections (PJI) and underwent one-stage revision; conversely, negative findings led to the discontinuation of intravenous and local antibiotics therapy.

RESULTS

Among the cohort of 22 patients, bacterial cultures yielded negative results, while mNGS identified bacterial infection in 14 patients (63.63%), viral infection in 1 patient (4.55%), and yielded negative results in 7 patients (31.82%). All surgical incisions achieved per primam. Subsequent follow-up assessments conducted for more than 1 year postoperatively revealed absence of PJI among the patients, all of whom exhibited satisfactory progress in their rehabilitation exercises. Notably, the Knee Society Score (KSS) for knee joint patients significantly improved from a preoperative mean of 48.7 ± 3.3 points to 84.3 ± 2.2 points postoperatively, whereas the Harris Hip Score for hip joint patients increased significantly from preoperative mean of 50.6 ± 3.6 points to 87.1 ± 1.6 points (P < 0.01).

CONCLUSION

In cases where patients present with unexplained elevations in ESR and CRP levels, primary artificial joint replacement can be undertaken following a one-stage revision approach for PJI.

Vancomycin powder in the prevention of infection in primary knee and hip arthroplasty: Case-control study with 1151 arthroplasties

BACKGROUND AND OBJECTIVE

Vancomycin powder (VP) has been positively used in spinal surgery to reduce the rate of infections. Hardly any data have been published on hip and knee joint replacement surgery, and its usefulness is questioned. Our objective was to investigate the effectiveness of VP in reducing prosthetic infection and its possible complications.

METHODS

Primary hip (THA) and knee (TKA) arthroplasties were reviewed, performed by five surgeons in one hospital center, between 2017 and 2018. 1g of VP was used on the implant prior to surgical closure based on the surgeon's preferences. With a 5-year follow-up in which the infection rate and local complications were analyzed.

RESULTS

One thousand one hundred and fifty one arthroplasties were performed, 748 were TKA and 403 were THA. Nine patients were diagnosed with prosthetic infection, of which five received VP and four did not (P=.555). Likewise, another 15 patients suffered wound complications, of which 11 received VP and 4 did not (P=.412). There were no differences, either, in the rest of the complications depending on the use or not of VP (P=.101). Likewise, the number of patients who needed reintervention was similar (P=.999). No systemic complications were detected due to the use of VP.

CONCLUSIONS

It has not been possible to demonstrate that the use of VP reduces the rates of prosthetic infection in the hip and knee, so we cannot recommend its use.

[Translated article] Vancomycin powder in the prevention of infection in primary knee and hip arthroplasty: Case-control study with 1151 arthroplasties

BACKGROUND AND OBJECTIVE

Vancomycin powder (VP) has been positively used in spinal surgery to reduce the rate of infections. Hardly any data have been published on hip and knee joint replacement surgery, and its usefulness is questioned. Our objective was to investigate the effectiveness of VP in reducing prosthetic infection and its possible complications.

METHODS

Primary hip (THA) and knee (TKA) arthroplasties were reviewed, performed by five surgeons in one hospital centre, between 2017 and 2018. One gram of VP was used on the implant prior to surgical closure based on the surgeon's preferences. With a 5-year follow-up in which the infection rate and local complications were analysed.

RESULTS

One thousand one hundred and fifty-one arthroplasties were performed, 748 were TKA and 403 were THA. Nine patients were diagnosed with prosthetic infection, of which five received VP and four did not (p=0.555). Likewise, another 15 patients suffered wound complications, of which 11 received VP and 4 did not (p=0.412). There were no differences, either, in the rest of the complications depending on the use or not of VP (p=0.101). Likewise, the number of patients who needed reintervention was similar (p=0.999). No systemic complications were detected due to the use of VP.

CONCLUSIONS

It has not been possible to demonstrate that the use of VP reduces the rates of prosthetic infection in the hip and knee, so we cannot recommend its use.

Intraarticular vancomycin decreased the risk of acute postoperative periprosthetic joint infection without increasing complication in primary total joint arthroplasty-a prospective study

OBJECTIVES

To investigate the preventive effect of intraarticularly administered vancomycin on acute postoperative periprosthetic joint infection (PJI) in total joint arthroplasty (TJA).

METHODS

Consecutive patients who underwent unilateral primary TJA were prospectively enrolled. The patients were divided into vancomycin group and control group according to whether 1 g of vancomycin powder suspended in 30 ml normal saline was intraarticularly administered after arthrotomy closure. Acute postoperative PJI and aseptic wound complication were evaluated within 3 months postoperatively. Vancomycin-associated toxicity including acute renal failure, ototoxicity and anaphylaxis was also evaluated.

RESULTS

In terms of demographic parameters and comorbidities, no significant difference was found between the two groups. Intra-articular vancomycin significantly lowered the risk of acute postoperative PJI after primary TJA (P = 0.015) and primary total knee arthroplasty (P = 0.031). However, for patients who underwent total hip arthroplasty, the PJI rate was comparable between the two groups. Overall, the risk of aseptic wound complication between the two groups was also similar. Vancomycin-associated acute renal injury, ototoxicity, or anaphylaxis was not observed.

CONCLUSIONS

Intra-articular injection of 1 g of vancomycin suspension after arthrotomy closure during TJA lowered the risk of acute postoperative PJI without increasing the risk of aseptic wound complication and vancomycin-associated systemic toxicity.

Use of topical vancomycin powder in total joint arthroplasty: Why the current literature is inconsistent?

Periprosthetic joint infection (PJI) is a rare but terrible complication in hip and knee arthroplasty, and the use of topical vancomycin powder (VP) has been investigated as a tool to potentially reduce its incidence. However, there remains no consensus on its efficacy. Therefore, the aim of this review is to provide an overview on the application of topical vancomycin in orthopaedic surgery focusing on the recent evidence and results in total joint arthroplasty. Several systematic reviews and meta-analyses on topical VP in hip and knee arthroplasty have been recently published reporting sometimes conflicting results. Apart from all being limited by the quality of the included studies (mostly level III and IV), confounding variables are often included potentially leading to biased conclusions. If taken into consideration the exclusive use of VP in isolation, the available data, although very limited, suggest that it does not reduce the infection rate in routine primary hip and knee arthroplasty. Therefore, we still cannot advise for a routinary application. A properly powered randomized-controlled trial would be necessary to clarify the role of VP in hip and knee arthroplasty. Based on the analysis of the current evidence, the use of topical VP appears to be safe when used locally in terms of systemic adverse reactions, hence, if proven to be effective, it could bring great benefits due to its low cost and accessibility.

Is the routine use of local antibiotics in the management of periprosthetic joint infections justified?

Periprosthetic joint infection (PJI) following total hip and total knee arthroplasty continues to be a leading cause of re-operation and revision arthroplasty. Not only is the treatment of PJI notoriously challenging, but success rates are variable. Regardless of the surgical strategy used, successful management of PJI requires a comprehensive surgical debridement focused at eradicating the underlying biofilm followed by appropriate antimicrobial therapy. Although systemic antimicrobial delivery continues to be a cornerstone in the treatment of PJI, many surgeons have started using local antibiotics to deliver higher concentrations of antibiotics directly into the vulnerable joint and adjacent soft tissues, which often have compromised vascularity. Available evidence on the use of topical powder, bone cement, and calcium sulphate carriers for local delivery of antibiotics during the initial treatment of PJI is limited to studies that are extremely heterogeneous. There is currently no level-1 evidence to support routinely using these products. Further, appropriately powered, prospective studies are needed to quantify the safety and efficacy of antibiotic-located calcium-sulphate carriers to justify their added costs. These products should not encourage surgeons to deviate from best practice guidelines, such as those recommended during the International Consensus Meeting on Musculoskeletal Infections.

Systematic Review and Meta-Analysis of Intrawound Vancomycin in Total Hip and Total Knee Arthroplasty: A Continued Call for a Prospective Randomized Trial

BACKGROUND

Periprosthetic joint injection (PJI) is a rare, but life-altering complication of total joint arthroplasty (TJA). Though intrawound vancomycin powder (IVP) has been studied in other orthopedic subspecialties, its efficacy and safety in TJA has not been established.

METHODS

PubMed and MEDLINE databases were used to identify studies utilizing IVP in primary and revision total hip (THA) and knee arthroplasty (TKA). Postoperative PJI data were pooled using random effect models with results reported as odds ratios (ORs) and 95% confidence intervals (CIs). Studies were weighted by the inverse variance of their effect estimates.

RESULTS

Overall, 16 of the 1871 studies identified were pooled for final analysis, yielding 33,731 patients totally. Of these, 17 164 received IVP. In aggregate, patients who received IVP had a decreased rate of PJI (OR 0.46, P < .05). Separately, TKA and THA patients who received IVP had lower rates of PJI (OR 0.41, P < .05 and OR 0.45, P < .05, respectively). Aggregate analysis of primary TKA and THA patients also revealed a decreased PJI rate (OR 0.44, P < .05). Pooled revision TKA and THA patients had a similar decrease in PJI rates (OR 0.30, P < .05). Although no publication bias was appreciated, these findings are limited by the low-quality evidence available.

CONCLUSION

While IVP may reduce the risk of PJI in primary and revision TJA, its widespread use cannot be recommended until higher-quality data, such as that obtained from randomized control trials, are available. This study underscores the continued need for more rigorous studies before general adoption of this practice by arthroplasty surgeons.

Intra-wound vancomycin powder for the eradication of periprosthetic joint infection after debridement and implant exchange: experimental study in a rat model

Background

Intra-wound vancomycin powder (VP) has been used in clinical practice to prevent periprosthetic joint infection (PJI) after primary knee/hip arthroplasty. The role of intra-wound VP in the setting of debridement and implant exchange after PJI remains undefined. This study aimed to explore the efficacy and safety of intra-wound VP in the control of methicillin-resistant S. aureus (MRSA) infection after debridement and implant exchange.

Methods

PJI modeling by knee prosthesis implantation and MRSA inoculation, debridement and implant exchange were performed in Wistar rats successively to mimic the one-stage exchange arthroplasty of PJI patients. Two weeks of systemic vancomycin (SV) or/and intraoperative intra-wound VP of single dosage were applied after revision surgery.

Results

No post-surgery deaths, incision complications and signs of drug toxicity were observed. The microbial counts of SV or intra-wound VP group were significantly reduced compared with the control group, while bacteria were still detected on the bone, soft-tissue and prosthesis. The elimination of bacterial counts, along with improvement of tissue inflammation and serum inflammatory markers, were observed in the rats with SV plus intra-wound VP. Serum levels of vancomycin in all groups were lower than that of causing nephrotoxicity, while no statistic difference was observed in the serum biochemical marker among the groups.

Conclusions

Intra-wound VP is effective after debridement and implant exchange in our current rat PJI model. Neither SV nor intra-wound VP alone could eradicate the bacteria within a two-weeks treatment course, while SV plus intra-wound VP could eliminate the MRSA infection, without notable hepatic or renal toxicity and any incision complications.

Risk of reinfection after two- or multiple-stage knee revision surgery using superficial vancomycin coating and conventional spacers

This study investigates the effect of superficial vancomycin coating (SVC) in two- or more-stage exchange procedures of prosthetic knee joint infections. We hypothesized that spacer treatment with SVC result in lower reinfection rates than conventional spacers after prosthetic reimplantation. Our secondary aim was to determine the demographic and treatment factors associated with reinfection rates. This retrospective cohort study compromised 96 cases with prosthetic knee infections. Twenty-four cases were treated with a temporary SVC spacer and 72 cases with conventional spacers. Prosthetic reinfection occurred after a median observation period of 1.7 ± 4.0 years in 24 cases (25%). The prevalence of having a reinfection was not significantly different between the two treatment groups (13% [3 cases] in the SVC group vs. 29% [21 cases] in the conventional spacer group [p = .104]). In seven cases (7.3%), two in the SVC group (8.3%) and five (6.9%) in the conventional spacer group (p ≥ .999), histological, respectively microbiological evaluations from the intraoperative specimens revealed persistent infection at the second stage. Nevertheless, in all seven cases no significant higher risk of periprosthetic reinfection was observed during follow-up (p = .750). Our secondary investigation of cofactors revealed that spacers additionally stabilized by nails were significantly associated with a 3.9-fold higher hazard ratio of sustaining a reinfection of revision prosthesis (p = .005).

Can Topical Vancomycin Prevent Periprosthetic Joint Infection in Hip and Knee Arthroplasty? A Systematic Review

BACKGROUND

Periprosthetic joint infection (PJI) after hip and knee arthroplasty is a leading cause of revision surgery, inferior function, complications, and death. The administration of topical, intrawound vancomycin (vancomycin powder) has appeared promising in some studies, but others have found it ineffective in reducing infection risk; for that reason, a high-quality systematic review of the best-available evidence is needed.

QUESTIONS/PURPOSES

In this systematic review, we asked: (1) Does topical vancomycin (vancomycin powder) reduce PJI risk in hip and knee arthroplasty? (2) Does topical vancomycin lead to an increased risk of complications after hip and knee arthroplasty?

METHODS

A search of Embase, MEDLINE, and PubMed databases as of June 2020 was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies comparing topical vancomycin in addition to standard infection prevention regimens (such as routine perioperative intravenous antibiotics) with standard regimens only in primary hip and knee arthroplasty were identified. Patients 18 years or older with a minimum follow-up of 3 months were included. No restrictions on maximal loss to follow-up or PJI definition were imposed. Studies were excluded if they included patients with a history of septic arthritis, used an antibiotic other than vancomycin or a different route of administration for the intervention, performed additional interventions that differed between groups, or omitted a control group. A total of 2408 studies were screened, resulting in nine eligible studies reviewing 3371 patients who received topical vancomycin (vancomycin powder) during a primary THA or TKA and 2884 patients who did not receive it. Groups were comparable with respect to duration of follow-up and loss to follow-up when reported. Study quality was assessed using the Newcastle-Ottawa scale, showing moderate-to-high quality for the included studies. The risks of PJI and overall complications in the topical vancomycin group were compared with those in the control group.

RESULTS

One of nine studies found a lower risk of PJI after primary THA or TKA, while eight did not, with odds ratios that broadly bracketed the line of no difference (range of odds ratios across the nine studies 0.09 to 1.97). In the six studies where overall complications could be compared between topical vancomycin and control groups in primary THA or TKA, there was no difference in overall complication risks with vancomycin (range of ORs across the six studies 0.48 to 0.94); however, we caution that these studies were underpowered to detect differences in the types of uncommon complications associated with vancomycin use (such as allergy, ototoxicity, and nephrotoxicity).

CONCLUSION

In the absence of clear evidence of efficacy, and without a sufficiently large evidence base reporting on safety-related endpoints, topical vancomycin (vancomycin powder) should not be used in routine primary THA and TKA. Adequately powered, multicenter, prospective trials demonstrating clear reductions in infection risk and large registry-driven audits of safety-related endpoints are required before the widespread use of topical vancomycin can be recommended.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Outcome of Irrigation and Debridement With Topical Antibiotics Delivery for the Management of Periprosthetic Joint Infection Occurring Within 3 Months Since the Primary Total Joint Arthroplasty

BACKGROUND

Irrigation and debridement with modular component exchange is appealing for surgeons to treat early-stage periprosthetic joint infection (PJI). However, the indication, perioperative protocol, and success rate remain controversial. This study is the first one to present results of debridement, antibiotics, and implant retention (DAIR) with integrated MIT (modular component exchange, povidone-iodine and topical antibiotics delivery) protocol for treating PJI occurring within 3 months since the primary total joint arthroplasty.

METHODS

We retrospectively analyzed patients who received DAIR with MIT protocol in our department between January 2011 and May 2018. Topical antibiotics were delivered in all cases. Topical antibiotics infusion was applied for those infected with multidrug-resistant bacteria, fungus, polymicrobial infection, and culture negative one. Failure was defined as additional surgical intervention for infection after DAIR; persistent sinus tract, drainage or excessive joint pain; need for suppressive antibiotics therapy due to the infection; infection relapse with the same pathogen; reinfection with different microorganism; and infection-related death.

RESULTS

A total of 73 patients with a mean age of 63.30 ± 10.97 years were included in this study, including 43 men and 30 women. There are 41 knees and 32 hips. Thirty patients had sinus tract. With a mean follow-up of 63.79 ± 18.57 months, there were 9 failures in total with an overall success rate of 87.67%. The success rate was 88.57% and 86.84% for those receiving topical antibiotics infusion postoperatively and those without.

CONCLUSIONS

DAIR with a standard MIT protocol is a viable and safe option for PJI occurring within 3 months since the primary total joint arthroplasty.

LEVEL OF EVIDENCE

Level 4, therapeutic study.

Vancomycin is toxic to human chondrocytes in vitro

INTRODUCTION

Vancomycin powder (VP) is a well-established topical antibiotic used in spinal surgery to prevent surgical site infections. More recently its extension to hip and knee arthroplasty was introduced. The aim of this study was to examine toxic effects of VP on the viability of human chondrocytes. Our hypothesis was that VP damages human chondrocytes in vitro with increasing concentration and length of exposure.

MATERIAL AND METHODS

Primary human chondrocytes were isolated and cultured from donated human knee joints. VP was added to these cultures with increasing concentrations (0-50 mg/ml) and length of exposure (0-336 h). Toxicity and viability were analyzed using LDH und XTT Elisa assays. Cell structure and determination of vital versus dead cells were visualized using light microscopy and fluorescence microscopy.

RESULTS

Light microscopy and fluorescence microscopy visualized defect cell structures and cell death proportional to increasing dose and length of exposure to VP. The analysis of LDH activity data showed toxic effects on chondrocytes as early as 2,5 min after exposure to VP. XTT activity data revealed a significant toxic threshold of a VP concentration above 12.5 mg/ml.

CONCLUSIONS

These results show that exposure to high VP concentrations yields to a damage of human chondrocytes in vitro. Chondrotoxicity is an immediate effect that is proportional to VP concentration. Therefore, the intraarticular use of high concentrations of vancomycin powder in the presence of native cartilage tissue must be considered critically.

Vancomycin Powder Use in Fractures at High Risk of Surgical Site Infection

OBJECTIVES

To determine if the use of intrawound vancomycin powder reduces surgical-site infection after open reduction and internal fixation of bicondylar tibial plateau, tibial pilon, and calcaneus fractures.

DESIGN

Retrospective analysis.

SETTING

Level I trauma center.

PATIENTS

All fractures operatively treated from January 2011 to February 2015 were reviewed; 583 high-risk fractures were included, of which 35 received topical vancomycin powder. A previously published prospectively collected cohort of 235 similar high-risk fractures treated at our center from 2007 through 2010 served as a second comparison group.

INTERVENTION

Topical vancomycin powder at wound closure.

MAIN OUTCOME MEASUREMENTS

Deep surgical-site infection. Analyses used both univariate comparison of all patients and 1:2 matching analysis using both nearest neighbor and propensity-based matching.

RESULTS

Compared with a control group of fractures treated during the same time period without vancomycin powder, the infection rate with vancomycin powder was significantly lower [0% (0/35) vs. 10.6% (58/548), P = 0.04]. Compared with our previously published historical infection rate of 13% for these injuries, vancomycin powder was also associated with significantly decreased deep surgical-site infection (0% vs. 13%, P = 0.02). These results agreed with the matched analyses, which also showed lower infection in the vancomycin powder group (0% vs. 11%-16%, P ≤ 0.05).

CONCLUSIONS

Vancomycin powder may play a role in lowering surgical-site infection rates after fracture fixation. A larger randomized controlled trial is needed to validate our findings.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Topical Vancomycin Powder Decreases the Proportion of Staphylococcus aureus Found in Culture of Surgical Site Infections in Operatively Treated Fractures

OBJECTIVES

To determine whether patients with operatively treated fractures and surgical site infection after use of topical vancomycin powder have a lower proportion of Staphylococcus aureus infections than patients who did not receive topical vancomycin powder.

DESIGN

Retrospective cohort study.

SETTING

Level I trauma center.

PATIENTS

Treatment group: 10 of 133 patients (145 fractures) with surgical site infections who received intrawound vancomycin powder at the time of wound closure for fracture fixation. Control group: 175 patients who sustained deep surgical site infections during the same period but did not receive vancomycin powder.

INTERVENTION

Vancomycin powder or no vancomycin powder.

MAIN OUTCOME MEASUREMENT

Proportion of patients' cultures positive for S. aureus.

RESULTS

The proportion of cultures positive for S. aureus was significantly lower in patients with surgical site infection who received vancomycin powder than in those who did not receive vancomycin powder (10% [1 of 10 patients in the treatment group] vs. 50% [87 of 175 patients in the control group]; P = 0.02). A trend was observed for a lower proportion of methicillin-resistant S. aureus (0% vs. 23%; P = 0.12).

CONCLUSIONS

Vancomycin powder might alter the bacteriology of surgical site infections and decrease the proportion in culture of the most common organism typically present after fracture surgery infection. These findings suggest that the application of vancomycin powder might change the bacteriology of surgical site infections when they occur, regardless of the effect on overall infection rates. Although our bacteriology results are clinically and statistically significant, these findings must be confirmed in larger randomized controlled trials.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Efficacy and safety of intrawound vancomycin in primary hip and knee arthroplasty

Aims

The efficacy and safety of intrawound vancomycin for preventing surgical site infection in primary hip and knee arthroplasty is uncertain.

Methods

A systematic review of the literature was conducted, indexed from inception to March 2020 in PubMed, Web of Science, Cochrane Library, Embase, and Google Scholar databases. All studies evaluating the efficacy and/or safety of intrawound vancomycin in patients who underwent primary hip and knee arthroplasty were included. Incidence of periprosthetic joint infection (PJI), superficial infection, aseptic wound complications, acute kidney injury, anaphylactic reaction, and ototoxicity were meta-analyzed. Results were reported as odds ratios (ORs) and 95% confidence intervals (CIs). The quality of included studies was assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) assessment tool.

Results

Nine studies involving 4,607 patients were included. Intrawound vancomycin was associated with lower incidence of PJI (30 patients (1.20%) vs 58 control patients (2.75%); OR 0.44, 95% CI 0.28 to 0.69) and simultaneous acute kidney injury (four patients (0.28%) vs four control patients (0.35%), OR 0.71, 95% CI 0.19 to 2.55). However, it did not reduce risk of superficial infection (four patients (0.67%) vs six control patients (1.60%), OR 0.60, 95% CI 0.17 to 2.12) and was associated with higher incidence of aseptic wound complications (23 patients (2.15%) vs eight in control patients (0.96%), OR 2.39, 95% CI 1.09 to 5.23). Four studies reported no anaphylactic reactions and three studies reported no ototoxicity in any patient group.

Conclusion

The current literature suggests that intrawound vancomycin used in primary hip and knee arthroplasty may reduce incidence of PJI, but it may also increase risk of aseptic wound complications.

Cite this article: Bone Joint Res 2020;9(11):778–788.

No effect of vancomycin powder to prevent infection in primary total knee arthroplasty: a retrospective review of 976 cases

PURPOSE

Vancomycin powder (VP) has been used to prevent periprosthetic joint infection (PJI). However, studies investigating the efficacy of VP to prevent infection in primary total knee arthroplasty (TKA) are very rare. The purpose of this study was to investigate the efficacy of VP application to prevent PJI in TKA.

METHODS

Between 2012 and 2016, 976 consecutive patients who underwent primary TKA were included in the present study. Patients were divided into two groups. There were 474 patients (48.6%) in the VP group and 502 patients in the control group (51.4%). Except for VP, all procedures were the same in both groups. In the VP group, 2 g of VP was poured into the joint just before the fascia was closed. Average follow-up was 53.2 months (24-84 months).

RESULTS

Infection was found in 4 (0.84%) of 474 patients in the VP group and 5 (0.99%) of 502 patients in the control group. There was no statistically significant difference between groups in terms of infection rates (p = 0.535). Staphylococcus aureus was found in 2 patients in the VP group. Two patients had S. aureus and 1 patient had Pseudomonas aeruginosa in the control group. There was no statistically significant difference between groups in terms of demographic parameters (p > 0.05).

CONCLUSION

Intrawound VP administration doesn't change the infection rates in primary TKA. The VP administration for preventing PJI is not recommended in primary TKA.

LEVEL OF EVIDENCE

III.

Intraarticular vancomycin powder is effective in preventing infections following total hip and knee arthroplasty

Locally applied vancomycin is increasingly being used in primary hip and knee arthroplasty to reduce the risk of infection. Despite encouraging initial results, considerable debate remains on the basis of the data currently available. In particular, it has been unclear up to now whether local vancomycin is suitable to further reduce the risk of infection even if the rate of infection is already low (< 1%). In this monocentric retrospective cohort study, all primary total hip and knee arthroplasties performed between 2013 and 2018 were included. After a change in procedure at the hospital, 1 g vancomycin powder was applied intraarticularly before wound closure. The remaining perioperative procedure was constant over the investigation period. The follow-up was one year. The presence of an infection according to the currently valid MSIS criteria was defined as the endpoint. In patients with TKA two infections (0.3%) were observed under vancomycin prophylaxis in contrast to 44 infections (1.3%) in the control group (p = 0.033). In patients with THA two infections (0.5%) were observed under vancomycin prophylaxis and 48 infections (1.1%) in the control group without local vancomycin but this difference was statistically not significant. No wound complications requiring revision were observed as a result of the vancomycin. On the basis of the results of this study, intraarticular application of vancomycin powder in total hip and knee arthroplasty may be considered. Prospective randomized studies have to confirm this promising results prior a common recommendation.Level of Evidence III Retrospective cohort study.

New developments and future challenges in prevention, diagnosis, and treatment of prosthetic joint infection

Prosthetic joint infection (PJI) is a devastating complication that results in substantial costs to society and patient morbidity. Advancements in our knowledge of this condition have focused on prevention, diagnosis, and treatment, in order to reduce rates of PJI and improve patient outcomes. Preventive measures such as optimization of patient comorbidities, and perioperative antibiotic usage are intensive areas of current clinical research to reduce the rate of PJI. Improved diagnostic tests such as synovial fluid (SF) α-defensin enzyme-linked immunosorbent assay, and nucleic acid-based tests for serum, SF, and tissue cultures, have improved diagnostic accuracy and organism identification. Increasing the diversity of available antibiotic therapy, immunotherapy, and alternative implant coatings remain promising treatments to improve infection eradication in the setting of PJI.

Does Intra-Wound Vancomycin Powder Affect the Action of Intra-Articular Tranexamic Acid in Total Joint Replacement?

The intra-articular use of tranexamic acid (TXA) has contributed to reduced blood loss in total joint arthroplasty (TJA). The purpose of this study is to assess the efficacy of simultaneously topical use of tranexamic acid and vancomycin powder within the TJA space. From 2016 to 2017, 219 consecutive total hip arthroplasties (THAs) and 272 total knee arthroplasties (TKAs) were performed in a tertiary care center, with a group of patients receiving intra-articular TXA and vancomycin, compared to patients receiving only TXA and to a control group that did not receive anything. Haemoglobin and hematocrit were measured preoperatively, on the first and third days. Transfusions and adverse events were recorded. Haemoglobin and hematocrit dropped significantly in all THA and TKA groups till the third day postoperatively, with a major reduction in the control group, compared to the other two treatment groups. Infections and thromboembolic events were similar in either group of the TJAs. In conclusion, the topical use of tranexamic acid mixed with the vancomycin powder within the joint space after the TJAs of the hip and knee did not alter the anti-fibrinolytic effect of TXA.

Role of intra-wound powdered vancomycin in primary total knee arthroplasty

BACKGROUND

No study has evaluated the effect of topical powdered vancomycin in patients undergoing primary total knee arthroplasty (TKA). The goal of this study is to determine if this method reduces postoperative infection rates following primary TKA.

PATIENTS AND METHODS

This retrospective study reviewed 855 consecutive patients undergoing TKA. The first 418 patients, who did not receive topical vancomycin, were grouped into the control group and the subsequent 437 patients, who received powdered vancomycin applied to the target joint prior to wound closure, were grouped into the treatment group.

RESULTS

The control group was found to have 18 infectious complications (4.3%) compared with 6 (1.4%) in the treatment group, which differed significantly (p<0.05). When comparing the rates of infectious complications independently, there was no significant difference in the rate of superficial infection (3.1% vs. 1.4%; p>0.05), while the difference in prevalence of periprosthetic joint infection (PJI) was statistically significant (1.2% vs. 0; p<0.05). No serious adverse events (AEs) occurred.

DISCUSSION

Topical application of powdered vancomycin may present a reasonable means of decreasing the risk of infectious complications following TKA. There were no serious AEs associated with topical vancomycin. Further research is needed to focus on its long-term efficacy and safety.

LEVEL OF EVIDENCE

III, retrospective, cohort study.

The Use of a Novel Antimicrobial Implant Coating In Vivo to Prevent Spinal Implant Infection

STUDY DESIGN

A controlled, interventional animal study.

OBJECTIVE

Spinal implant infection (SII) is a devastating complication. The objective of this study was to evaluate the efficacy of a novel implant coating that has both a passive antibiotic elution and an active-release mechanism triggered in the presence of bacteria, using an in vivo mouse model of SII.

SUMMARY OF BACKGROUND DATA

Current methods to minimize the frequency of SII include local antibiotic therapy (vancomycin powder), betadine irrigation, silver nanoparticles, and passive release from antibiotic-loaded poly(methyl methacrylate) cement beads, all of which have notable weaknesses. A novel implant coating has been developed to address some of these limitations but has not been tested in the environment of a SII.

METHODS

A biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics. The in vivo performance of this coating was tested in the delivery of either vancomycin or tigecycline in a previously established mouse model of SII. Noninvasive bioluminescence imaging was used to quantify the bacterial burden, and implant sonication was used to determine bacterial colony-forming units (CFUs) from the implant and surrounding bone and soft tissue.

RESULTS

The PEG-PPS-vancomycin coating significantly lowered the infection burden from postoperative day 3 onwards (P < 0.05), whereas PEG-PPS-tigecycline only decreased the infection on postoperative day 5 to 10 (P < 0.05). CFUs were lower on PEG-PPS-vancomycin pins than PEG-PPS-tigecycline and PEG-PPS pins alone on both the implants (2.4 × 10, 8.5 × 10, and 1.0 × 10 CFUs, respectively) and surrounding bone and soft tissue (1.3 × 10, 4.8 × 10, and 5.4 × 10 CFUs, respectively) (P < 0.05).

CONCLUSION

The biodegradable PEG-PPS coating demonstrates promise in decreasing bacterial burden and preventing SII. The vancomycin coating outperformed the tigecycline coating in this model compared to prior work in arthroplasty models, highlighting the uniqueness of the paraspinal infection microenvironment.

LEVEL OF EVIDENCE

N/A.

Clinical outcome evaluation of intraosseous vancomycin in total knee arthroplasty

Background

Vancomycin is a commonly used prophylactic antibiotic for total joint replacement surgery to protect against methicillin-resistant Staphylococcus aureus. Studies have suggested intraosseous (IO) infusions provide superior local tissue antibiotic concentration compared with intravenous (IV) access in total knee arthroplasty (TKA). We reviewed patients receiving IO vancomycin before TKA, comparing complication rates to a matched group receiving IV prophylactic vancomycin.

Methods

Retrospective review of TKA patients administered IO vancomycin (500 mg vancomycin in 200 mL normal saline), September 1, 2018 to March 1, 2019, was compared with TKAs performed with prophylactic IV vancomycin, January 1, 2018 to August 31, 2018. Before incision, an IO needle was inserted into the tibial tubercle region, delivering 100 mL of the mixed vancomycin solution. The needle was then removed and inserted into the distal femur, delivering 100 mL of the solution. Evaluation included preoperative and postoperative creatinine values, tourniquet time, and knee-related 30-day and 90-day complications. Data for primary and revision TKA surgery cases were analyzed independently.

Results

There were 100 primary and 29 revision TKA cases in the control (IV) arm and 100 primary and 19 revision TKA cases in the intervention (IO) arm, comprising a study group of 248 cases. There were fifteen 30-day complications and eighteen 90-day complications overall. No significant differences in the complication rate or creatinine values were identified between IO and IV groups.

Conclusions

IO vancomycin has an adequate safety profile in primary and revision TKA, eliminating the logistical challenge of timely prophylactic antibiotic administration.

Systematic Review and Meta-Analysis of Intrawound Vancomycin in Total Hip and Total Knee Arthroplasty: A Call for a Prospective Randomized Trial

BACKGROUND

Topical intrawound vancomycin has been used extensively in spine surgery to decrease surgical site infections. However, the efficacy of intrawound vancomycin in total hip (THA) and total knee arthroplasty (TKA) to prevent periprosthetic joint infection (PJI) has not been established.

METHODS

The PubMed and MEDLINE databases were searched to identify studies utilizing intrawound vancomycin in primary and revision THA and TKA. Data for postoperative infection were pooled using random effect models with results reported as odds ratios (ORs) and 95% confidence intervals. Studies were weighted by the inverse variance of their effect estimates.

RESULTS

Of the 91 studies identified, 6 low-quality retrospective studies (level III) were pooled for further analysis. A total of 3298 patients were assessed, 1801 of which were treated with intrawound vancomycin. Overall, patients who received vancomycin had a decreased rate of PJI (OR 0.2530, P < .0001). When analyzed separately, TKA patients and THA patients who received intrawound vancomycin had lower rates of PJI (OR 0.3467, P = .0005 and OR 0.3672, P = .0072, respectively). Pooled primary TKA and THA patients receiving vancomycin saw the rate of PJI decrease (OR 0.4435, P = .0046). Pooled revision TKA and THA patients saw a similar decrease in infection rates (OR 0.2818, P = .0013). No apparent publication bias was observed; however, the results from this analysis are limited by the low quality of evidence and inherent potential for bias.

CONCLUSION

Intrawound vancomycin may reduce the risk of PJI in primary and revision TKA and THA. However, only low-quality evidence exists, highlighting the need for randomized controlled trials before broad adoption of this practice can be recommended given the potential implications of widespread use of vancomycin in hip and knee arthroplasty.

Intrawound vancomycin powder increases post-operative wound complications and does not decrease periprosthetic joint infection in primary total and unicompartmental knee arthroplasties

PURPOSE

A frequent reason for revision surgery after total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is periprosthetic joint infection (PJI). The efficacy of intrawound VP in preventing PJI after primary TKA or UKA is rarely reported. The purpose of this study was to investigate the efficacy and side effects of local high-dose VP application to the joint to prevent PJI in TKA and UKA.

METHODS

From 2010 to 2017, 166 consecutive patients that underwent primary TKA or UKA were enrolled. Seventy-five patients (92 knees) did not receive VP (control group), while 90 patients (110 knees, VP group) received VP (intrawound, 1 g) before capsule closure during TKA and UKA. Aseptic wound complications, such as skin erosion, wound dehiscence, and prolonged wound healing, were evaluated within 3 months post-operatively. PJI was assessed within a year post-operatively.

RESULTS

Seven patients (7.6%) in the control group and five patients (4.5%) in the VP group had PJI. No significant differences existed in the PJI rates between the groups. Aseptic operative wound complications occurred in 4 patients (4.3%) and 13 patients (11.8%), whereas prolonged operative wound healing occurred in 3 patients (3.3%) and 14 patients (12.7%) of patients in the control and VP group, respectively. Operative wound complications were significantly frequent in the VP group.

CONCLUSIONS

Intrawound VP administration does not decrease PJI occurrence in primary TKA and significantly causes aseptic wound complications. The use of intrawound VP for the prevention of PJI after primary TKA and UKA is not recommended.

LEVEL OF EVIDENCE

Level II.

Intrawound vancomycin in primary hip and knee arthroplasty: a safe and cost-effective means to decrease early periprosthetic joint infection

Background

Periprosthetic joint infection (PJI) is a devastating complication after hip and knee arthroplasty. Intrawound vancomycin has been described extensively in the spine literature; however, information regarding use in arthroplasty is limited. We investigate the efficacy and safety of intrawound vancomycin in arthroplasty surgery.

Methods

All primary total hip and knee arthroplasty cases (n = 460) performed by a single surgeon from April 2016 to October 2017 were reviewed. Starting in October 2016, intrawound vancomycin was used in all total joints. Baseline characteristics, infection rates, 90-day readmission, and other complications were compared between untreated subjects and those who received intrawound vancomycin. In addition, cost data were considered. Mean follow-up durations for the control and vancomycin groups were 11.3 and 7.7 months, respectively.

Results

Baseline characteristics and comorbidities were similar for the control (n = 112) and vancomycin groups (n = 348). The vancomycin cohort demonstrated decreased both overall infection rate (0.57% vs 2.7%; P = .031) and PJI rate (0.29% vs 2.7%; P = .009) compared with the untreated group. There was no statistical difference in incidence of ototoxicity or acute kidney injury. Although there was no difference in overall 90-day readmission rate, the vancomycin subset demonstrated lower readmission rate due to infection (0.57% vs 2.7%; P = .031). Based on the cost of vancomycin powder and calculated number needed to treat (NNT = 47.5), the cost to prevent 1 infection with the addition of intrawound vancomycin was $816.

Conclusions

These findings suggest that intrawound vancomycin may be a safe, cost-effective means that shows promise in reducing PJI in early follow-up. Future prospective studies are warranted.

Use of Intrawound Antibiotics in Orthopaedic Surgery

Intrawound antibiotics have been used in orthopaedic surgery procedures to prevent the development of surgical site infections. Local delivery of antibiotic powder has demonstrated a notable reduction in surgical site infection in rabbit and rodent in vivo models, as well as in other surgical fields, including vascular, colorectal, cardiothoracic, and dermatologic surgery. Intrawound antibiotic powder has been used in many orthopaedic applications, including spine surgery, total joint arthroplasty, trauma, foot and ankle reconstruction, and elbow surgery. Although the theory behind the use of intrawound antibiotic powder is promising, it has potential adverse effects, including antibiotic resistance, circulatory collapse, and decreased bone healing. In addition, most studies in the orthopaedic literature on the use of intrawound antibiotic powder are retrospective in nature.

Intraoperative Vancomycin Powder Reduces Staphylococcus aureus Surgical Site Infections and Biofilm Formation on Fixation Implants in a Rabbit Model

OBJECTIVES

To evaluate the effectiveness of intraoperative vancomycin powder in prevention of surgical site infection and biofilm formation on implants in a contaminated animal fixation model.

METHODS

We created a rabbit surgical model including fixation implants at a tibial surgical site seeded with methicillin-resistant Staphylococcus aureus. Our study cohort included 18 rabbits. Nine received vancomycin powder at the surgical site, and the other 9 did not. Serum vancomycin levels were measured at scheduled time points over 24 hours. Bone infection and implant biofilm formation were determined based on the number of colony-forming units present 2 weeks after surgery. Radiography, histology, and electron microscopy aided in evaluation.

RESULTS

No bone infection or implant colonization occurred in the vancomycin powder group. Six bone infections and 6 implant biofilm formations (67%; 95% confidence interval, 45%-88%) occurred in the group that did not receive vancomycin powder (P = 0.009). Serum vancomycin levels were detectable at minimal levels at 1 and 6 hours only. Pathological changes occurred in the specimens that were positive for infection.

CONCLUSIONS

Intraoperative vancomycin powder application at the time of fixation decreases risk for bone infection and biofilm formation on implants in a rabbit model, with minimal increase in serum vancomycin levels. The results are encouraging and support the rationale for a clinical trial investigating the use of local vancomycin powder to reduce the rate of surgical site infections.

CLINICAL RELEVANCE

Infection is a common complication of surgery, especially with implants. Simple methods to prevent or decrease the occurrence of infection would benefit the patient and the health care system.

Intrawound Vancomycin Powder in Primary Total Hip Arthroplasty Increases Rate of Sterile Wound Complications

Purpose

Total hip arthroplasty (THA) is a successful surgery for the treatment of hip osteoarthritis; however, the risk of a post-operative prosthetic joint infection (PJI) remains at 1% to 2%. The purpose of this study was to investigate the safety profile of using vancomycin powder (VP) to reduce infection rates by reviewing acute postoperative complications.

Materials and Methods

A retrospective review of 265 consecutive patients undergoing THA was performed. The first 128 patients, the control group, did not receive VP, and the subsequent 137 patients, the VP group, received VP at the time of wound closure. Patient demographic data, medical comorbidities, and perioperative information were compared.

Results

The primary outcome was a post-operative surgical complication within 90 days from surgery. The control and VP group's demographic, medical comorbidities and perioperative information data were statistically similar. Deep infection rate in the control group was 5.5%, whereas the deep infection rate in the VP group was 0.7% (P=0.031). Sterile wound complication rate was 4.4% in the VP group, and 0% in the control group (P=0.030). Remaining complications were not statistically different between the groups.

Conclusion

VP was associated with an increase rate of sterile wound complications compared to the control group. The rate of PJI was decreased with the use of VP. We do not recommend for or against the use of VP at time of wound closure to prevent PJI, and higher powered studies will need to be performed to demonstrate the efficacy of VP.

Superficial Vancomycin Coating of Bone Cement in Orthopedic Revision Surgery: A Safe Technique to Enhance Local Antibiotic Concentrations

BACKGROUND

The use of antibiotic-loaded cement has become a well-accepted method to develop high local antibiotic concentrations in revision surgery of infected arthroplasty. A new surgical technique has been established to further increase the local antibiotic concentration and thereby minimizes the risk of reinfection. Our study aim was to investigate the safety of additional superficial vancomycin coating (SVC) by analyzing postoperative joint and serum vancomycin concentrations, as well as the creatinine levels of patients with orthopedic revision surgery.

METHODS

A longitudinal case series was performed by reviewing collected data of patients who were treated by SVC during revision surgery (1- or 2-stage exchange) because of prosthetic joint infections. Vancomycin levels were obtained, local from drains and systemic from blood samples, on postoperative days 1 to 5. Furthermore, preoperative and postoperative serum creatinine levels were analyzed.

RESULTS

Highest median local vancomycin levels were documented on postoperative day 1 with 546.8 μg/mL (range, 44.4-1485 μg/mL) in the reimplantation group and 408.7 μg/mL (range, 24.7-1650 μg/mL) in the spacer group. Median serum vancomycin level was 4.4 μg/mL (range, <2.0-11.7 μg/mL) on the first postoperative day in the reimplantation group and <2.0 μg/mL (range, <2.0-3.9 μg/mL) in the spacer group, and lower than 2.0 μg/mL (range, <2.0-7.5 μg/mL) from postoperative day 2 to 5 in both groups. Neither an anaphylactic reaction nor other side effects to SVC were observed.

CONCLUSION

Our data showed that SVC of bone cement is an effective technique to enhance local concentrations of vancomycin without leading to systemic side effects.

The cost effectiveness of vancomycin for preventing infections after shoulder arthroplasty: a break-even analysis

BACKGROUND

Increasing methicillin resistance and recognition of Propionibacterium acnes as a cause of infection in shoulder arthroplasty has led to the adoption of local vancomycin powder application as a more effective method to prevent expensive periprosthetic infections. However, no study has analyzed the cost effectiveness of vancomycin powder for preventing infection after shoulder replacement.

METHODS

Cost data for infection-related care of 16 patients treated for deep periprosthetic shoulder infection was collected from our institution for the break-even analysis. An equation was developed and applied to the data to determine how effective vancomycin powder would need to be at reducing a baseline infection rate to make prophylactic use cost effective.

RESULTS

The efficacy of vancomycin (absolute risk reduction [ARR]) was evaluated at different unit costs, baseline infection rates, and average costs of treating infection. We determined vancomycin to be cost effective if the initial infection rate decreased by 0.04% (ARR). Using the current costs of vancomycin reported in the literature (range: $2.50/1000 mg to $44/1000 mg), we determined vancomycin to be cost effective with an ARR range of 0.01% at a cost of $2.50/1000 mg to 0.19% at $44/1000 mg. Baseline infection rate does not influence the ARR obtained at any specific cost of vancomycin or the cost of treating infection.

CONCLUSIONS

We have derived and used a break-even equation to assess efficacy of prophylactic antibiotics during shoulder surgery. We further demonstrated the prophylactic administration of local vancomycin powder during shoulder arthroplasty to be a highly cost-effective practice.

Intra-Articular Vancomycin Powder Eliminates Methicillin-Resistant S. aureus in a Rat Model of a Contaminated Intra-Articular Implant

BACKGROUND

Periprosthetic joint infection following hip and knee arthroplasty leads to poor outcomes and exorbitant costs. Topical vancomycin powder has been shown to decrease infection in many procedures such as spine surgery. The role of vancomycin powder in the setting of total joint arthroplasty remains undefined. Our aim was to evaluate the efficacy of intra-articular vancomycin powder in preventing infection in a rat model of a contaminated intra-articular implant.

METHODS

Thirty-two female Sprague-Dawley rats underwent knee arthrotomy and implantation of a femoral intramedullary wire with 1 mm of intra-articular communication. The knee joint was also inoculated with 1.5 × 10 colony forming units (CFU)/mL of methicillin-resistant Staphylococcus aureus (MRSA). Four treatment groups were studied: (1) no antibiotics (control), (2) preoperative systemic vancomycin, (3) intra-articular vancomycin powder, and (4) both systemic vancomycin and intra-articular vancomycin powder. The animals were killed on postoperative day 6, and distal femoral bone, joint capsule, and the implanted wire were harvested for bacteriologic analysis. Statistical analyses were performed using Wilcoxon rank sum and Fisher exact tests.

RESULTS

There were no postoperative deaths, wound complications, signs of vancomycin-related toxicity, or signs of systemic illness in any of the treatment groups. There were significantly fewer positive cultures in the group that received vancomycin powder in combination with systemic vancomycin compared with the group that received systemic vancomycin alone (bone: 0% versus 75% of 8, p = 0.007; Kirschner wire: 0% versus 63% of 8, p = 0.026; whole animal: 0% versus 88% of 8, p = 0.01). Only animals that received both vancomycin powder and systemic vancomycin showed evidence of complete elimination of bacterial contamination.

CONCLUSIONS

In a rat model of a contaminated intra-articular implant, use of intra-articular vancomycin powder in combination with systemic vancomycin completely eliminated MRSA bacterial contamination. Animals treated with systemic vancomycin alone had persistent MRSA contamination.

CLINICAL RELEVANCE

This animal study presents data suggesting that the use of intra-articular vancomycin powder for reducing the risk of periprosthetic joint infections should be investigated further in clinical studies.

Local Intra-wound Administration of Powdered Antibiotics in Orthopaedic Surgery

Surgical site infection (SSI) is one of the most common complications after orthopaedic surgery, leading to significant morbidity and its associated costs. Surgical guidelines strongly recommend the use of systemic antibiotic prophylaxis to reduce the risk for developing SSI. Locally administered powdered antibiotics have the potential to provide remarkably high intra-wound concentrations without risk for systemic toxicity. However, a paucity of high quality evidence in the orthopaedic literature has prevented widespread adoption of this technique. The majority of clinical studies on local intra-wound antibiotics have evaluated the use of topical powdered vancomycin in spinal surgery, though only a single prospective study currently exists. This review will discuss all the available evidence describing the effectiveness, pharmacokinetics, and potential adverse effects with the use of topical powdered antibiotics in orthopedic surgery.

In Vivo Efficacy of a "Smart" Antimicrobial Implant Coating

BACKGROUND

Postoperative infection is a devastating complication following arthroplasty. The goals of this study were to introduce a "smart" implant coating that combines passive elution of antibiotic with an active-release mechanism that "targets" bacteria, and to use an established in vivo mouse model of post-arthroplasty infection to longitudinally evaluate the efficacy of this polymer implant coating in decreasing bacterial burden.

METHODS

A novel, biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics both passively and actively. In vitro-release kinetics were studied using high-performance liquid chromatography (HPLC) quantification in conditions representing both the physiologic environment and the more oxidative, hyperinflammatory environment of periprosthetic infection. The in vivo efficacy of the PEG-PPS coating delivering vancomycin and tigecycline was tested using an established mouse model of post-arthroplasty infection. Noninvasive bioluminescence imaging was used to quantify the bacterial burden; radiography, to assess osseointegration and bone resorption; and implant sonication, for colony counts.

RESULTS

In vitro-release kinetics confirmed passive elution above the minimum inhibitory concentration (MIC). A rapid release of antibiotic was noted when challenged with an oxidative environment (p < 0.05), confirming a "smart" active-release mechanism. The PEG-PPS coating with tigecycline significantly lowered the infection burden on all days, whereas PEG-PPS-vancomycin decreased infection on postoperative day (POD) 1, 3, 5, and 7 (p < 0.05). A mean of 0, 9, and 2.6 × 10(2) colony-forming units (CFUs) grew on culture from the implants treated with tigecycline, vancomycin, and PEG-PPS alone, respectively, and a mean of 1.2 × 10(2), 4.3 × 10(3), and 5.9 × 10(4) CFUs, respectively, on culture of the surrounding tissue (p < 0.05).

CONCLUSIONS

The PEG-PPS coating provides a promising approach to preventing periprosthetic infection. This polymer is novel in that it combines both passive and active antibiotic-release mechanisms. The tigecycline-based coating outperformed the vancomycin-based coating in this study.

CLINICAL RELEVANCE

PEG-PPS polymer provides a controlled, "smart" local delivery of antibiotics that could be used to prevent postoperative implant-related infections.

Principles of Antibiotic Prophylaxis in Total Joint Arthroplasty: Current Concepts

Infection is a rare, serious complication following total joint arthroplasty and constitutes a considerable emotional and financial burden for patients, surgeons, and healthcare systems. Prevention of surgical site and periprosthetic joint infections is crucial. This requires knowledge of the microorganisms that commonly cause these infections, including Staphylococcus species. Selection of the appropriate antibiotic regimen to treat infection remains controversial, but cefazolin and cefuroxime are the most commonly recommended antibiotics for prophylaxis. Appropriate timing of administration before surgery, with redosing performed as needed, can help to ensure optimal antibiotic concentration during surgery. Given the increasing evidence that S aureus colonization is a risk factor for periprosthetic joint infection, an exploration of the potential benefits of preoperative S aureus carrier screening and decolonization protocols is warranted. The use of antibiotic-loaded bone cement in primary total joint arthroplasty and antibiotic powder at wound closure are other controversial topics that require additional research.

Prosthetic joint infections-a clinico-microbiological perspective: Review article

Prosthetic joint infections (PJIs), although not very common, currently pose a very significant threat since they are associated with severe complications, high morbidity rates and substantial costs. PJIs are most commonly caused by Staphylococcus aureus and coagulase-negative staphylococci. The diagnosis of implant-associated infections is very challenging since no single routinely used laboratory or clinical test has been shown to demonstrate adequate results with respect to sensitivity, specificity and accuracy. In most cases, a sum of clinical signs and symptoms, histopathology, blood tests, radiography, bone scans and microbiological testing is considered to arrive at an accurate diagnosis. Treatment of PJIs is also very difficult since most of the infections are caused by biofilm-producing microorganisms which are significantly more resistant to the hosts natural defense mechanisms and antibiotic treatment. For successful management, a combination of both antibiotic and surgical treatment is most often required, and early diagnosis is of the utmost importance. Thus, a multidisciplinary approach is potentially the best option in dealing with PJI, and should include the involvement of microbiologists, orthopedic specialists, clinicians, pathologists and radiologists in order to improve decision-making processes and ensure overall success. The following review aims at briefly outlining the microbiology, diagnostic and treatment options, and preventive measures associated with such infections.