Local Intra-wound Administration of Powdered Antibiotics in Orthopaedic Surgery

Preventive strategies to reduce the rate of periprosthetic infections in total joint arthroplasty; a comprehensive review

The increasing frequency of total hip (THA) and knee arthroplasties (TKA) is marred by the rise in periprosthetic joint infections (PJIs) and surgical site infections (SSIs), with PJIs incurring costs over $1.62 billion as of 2020 and individual case management averaging $90,000. SSIs additionally burden the U.S. healthcare economy with billions in expenses annually. PJI prevalence in primary THA and TKA ranges from 0.5% to 2.4%, spiking to 20% in revisions and representing 25% of TKA revision causes. Projections estimate up to 270,000 annual PJI cases by 2030. Often caused by gram-positive bacteria, particularly methicillin-resistant staphylococci, these infections demand preventive measures. This review dissects PJI prevention across preoperative, intraoperative, and perioperative phases, aligning with evidence-based CDC and WHO guidelines. Preoperative measures include managing diabetes, obesity, tobacco use, Staphylococcus aureus screening and nasal decolonization, nutritional optimization, and management of inflammatory arthropathies. Intraoperatively, antibiotic prophylaxis, skin preparation, operative room environmental controls, surgical technique precision, and irrigation options are scrutinized. Perioperative concerns focus on anticoagulation, blood management, and infection risk mitigation. Integrating these strategies promotes a patient-centric care model, aiming to reduce PJI incidence, improve patient outcomes, and increase care cost-effectiveness in joint arthroplasty.

Does Topical Vancomycin Powder Use in Fracture Surgery Change Bacteriology and Antibiotic Susceptibilities? An Analysis of the VANCO Trial

OBJECTIVE

To determine whether intrawound vancomycin changes the bacteriology of surgical site infection pathogens and investigate the emergence of antibiotic-resistant pathogens.

METHODS

DESIGN

Secondary analysis of phase III, prospective, randomized clinical trial.

SETTING

Thirty-six US trauma centers.

PATIENT SELECTION CRITERIA

Patients who became infected after fixation of tibial plateau or pilon fracture.

OUTCOME MEASURES AND COMPARISONS

Pathogen types and bacterial susceptibilities as determined from routine clinical culture in the operating room.

RESULTS

Seventy-four patients were studied who were 67.5% male with a mean age of 48.6 years. A lower proportion of gram-positive cocci was observed in the vancomycin powder compared with the standard-of-care group (3.7% vs. 8.0%, P = 0.01). Methicillin-resistant Staphylococcus aureus infection incidence was comparable in both the vancomycin powder and the standard-of-care groups, but rates of methicillin-susceptible S. aureus infections were lower in the treatment group (1.4% vs. 4.8%, P = 0.01). The incidence of coagulase-negative Staphylococci and gram-negative rod infections were similar in both groups. There was no significant difference in susceptibilities between groups in rates of vancomycin-resistant enterococcus.

CONCLUSIONS

Topical vancomycin powder decreases the likelihood of gram-positive infections consistent with the biologic activity of vancomycin. Fewer methicillin-susceptible S. aureus and coagulase-negative Staphylococci infections were observed in the group treated with vancomycin powder. An effect of vancomycin powder on methicillin-resistant S. aureus infection risk was not detected given the low incidence in both the intrawound vancomycin and the standard-of-care groups. There was no emergence of gram-negative rod infections or increased resistance patterns observed. Use of topical vancomycin powder does not seem to produce infections in these patients with greater antibiotic resistance than would have occurred without its use.

LEVEL OF EVIDENCE

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

Effectiveness of combined local therapy with antibiotics and fibrin vs. vacuum-assisted wound therapy in soft tissue infections: a retrospective study

PURPOSE

Soft tissue infections can be severe and life-threatening. Their treatment consists currently in radical surgical wound debridement and combined systemic antimicrobial therapy. Different side effects are possible. Local antibiotic therapy represents a new approach to reduce side effects and improve healing. The aim of this study is to assess the effectiveness of the local sprayed use of antibiotics with fibrin sealing compared with negative pressure wound therapy as an established treatment of soft-tissue infections.

METHODS

In this retrospective study, patients with soft tissue infections who underwent surgical treatment were analysed. One group consists of patients, who received local fibrin-antibiotic spray (FAS) (n = 62). Patients treated by vacuum-assisted wound therapy (VAWT) as the established treatment were the control group (n = 57). Main outcomes were differences in the success of healing, the duration until healing and the number of needed operations.

RESULTS

Clinical healing could be achieved for 55 patients (98.21%) in the FAS group vs. 47 patients (92.16%) in the VAWT group (p = 0.19). Time to require this was 10.65 ± 10.38 days in the FAS group and 22.85 ± 14.02 days in the VAWT group (p < 0.001). In the FAS group, patients underwent an average of 1.44 ± 0.72 vs.3.46 ± 1.66 operations in the VAWT group (p < 0.001).

CONCLUSION

Compared to vacuum-assisted wound therapy in soft tissue infections, local fibrin-antibiotic spray shows faster clinical healing and less needed operations. Leading to shorter hospital stays and more satisfied patients. The combination of sprayed fibrin and antibiotics can be seen as a promising and effective method.

The application of topical antibiotics for the prevention of infections in primary joint arthroplasty. An umbrella review of systematic reviews and meta-analysis

This umbrella review aim to explore the effect of topical antibiotics in infection prevention after primary joint arthroplasty, and provide a specific theoretical basis for clinical treatment. The review process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched PubMed, EMBASE, Medline, and the Cochrane Library on infection prevention by topical antibiotics from inception to 10 April 2023. The two researchers individually and strictly screened the literature according to the inclusion and exclusion criteria, performed the literature quality evaluation and data extraction, and used Stata 17 for data analysis. This study included six studies with one systematic review and five meta-analyses. The pooled analysis showed that topical antibiotic administration effectively reduced the incidence of overall infection and periprosthetic joint infection. However, it does not reduce the risk of superficial infection. Besides, the topic of antibiotics significantly increases the incidence of other sterile complications of the incision. According to the current evidence, topical application of antibiotics can reduce the incidence of overall infection and periprosthetic joint infection after primary joint arthroplasty. Although it increases the incidence of complications such as delayed healing of incisions, the pros and cons should be weighed in clinical decision making. However, they should not be discarded due to side effects.

Effect of Vancomycin, Gentamicin and Clindamycin on Cartilage Cells In Vitro

BACKGROUND

The treatment of grafts with vancomycin for ligament reconstruction in knee surgery is the current standard. However, high antibiotic concentrations have chondrotoxic effects.

PURPOSE

To test the chondrotoxicity of clindamycin, gentamicin and vancomycin in comparable concentrations. In vitro and in vivo effective concentrations hugely vary from drug to drug. To allow for comparisons between these three commonly used antibiotics, the concentration ranges frequently used in orthopedic surgical settings were tested.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human cartilage from 10 specimens was used to isolate chondrocytes. The chondrocytes were treated with clindamycin (1 mg/mL and 0.5 mg/mL), gentamicin (10 mg/mL and 5 mg/mL) or vancomycin (10 mg/mL and 5 mg/mL), at concentrations used for preoperative infection prophylaxis in ligament surgery. Observations were taken over a period of 7 days. A control of untreated chondrocytes was included. To test the chondrotoxicity, a lactate dehydrogenase (LDH) test and a water-soluble tetrazolium salt (WST-1) assay were performed on days 1, 3 and 7. In addition, microscopic examinations were performed after fluorescence staining of the cells at the same time intervals.

RESULTS

All samples showed a reasonable vitality of the cartilage cells after 72 h. However, clindamycin and gentamicin both showed higher chondrotoxicity in all investigations compared to vancomycin. After a period of 7 days, only chondrocytes treated with vancomycin showed reasonable vitality.

CONCLUSIONS

The preoperative treatment of ligament grafts with vancomycin is the most reasonable method for infection prophylaxis, in accordance with the current study results regarding chondrotoxicity; however, clindamycin and gentamicin cover a wider anti-bacterial spectrum.

CLINICAL RELEVANCE

The prophylactic antibiotic treatment of ligament grafts at concentrations of 5 mg/mL or 10 mg/mL vancomycin is justifiable and reasonable. In specific cases, even the use of gentamicin and clindamycin is appropriate.

Local Administration of Antibiotics in Orthopedics and Traumatology

2022 marks the 50th anniversary of the development of the antibiotic loaded PMMA chain. The loading of bone cements with antibiotics was a major advance in the treatment of musculoskeletal infections and is still a proven standard today. The research and use of novel antibiotic carriers continues to be an important part of research in the context of musculoskeletal infections. The article provides an overview of the various local antibiotics available and their specifics. In addition, current adapted treatment concepts are discussed.

Clinical Characteristics of 96 Patients Presenting With Hematogenous Spinal Osteomyelitis- a Retrospective Study

OBJECTIVE

To report clinical characteristics and course of care for patients diagnosed with hematogenous spinal osteomyelitis (HVO).

METHODS

Medical records of patients presenting to two tertiary care centers with HVO were reviewed.

RESULTS

96 consecutive patients with HVO were identified. Mean follow-up was 8.9 months. Most infections occurred in the lumbar region (50.0%). Of the cultures taken, MRSA accounted for 9%; MSSA, 26%; Streptococcus species, 12%; other gram-positive bacteria, 23%; gram-negative, 17%; fungal, 2.6%; and 11.5% of cultures returned no growth. 57 patients underwent surgery. Of these, 79% of the patients had undergone a trial of empiric antibiotics (cefepime and vancomycin) of the day prior to surgery. 44% underwent secondary surgeries, typically due to a heavy wound burden of necrotic tissue and pus. Postoperative antibiotics were prescribed to all patients. 51.6% of the patients were prescribed antibiotic therapy >6 months. Overall mortality rate was 3.8%. Major cause of all deaths was septic shock. Post-infection sequelae occurred in 47.4% of patients. The most common sequelae were persistent or new sites of infection, sepsis, and abscess.

CONCLUSIONS

Diabetes, hypertension, and renal failure appear to increase the risk of post-infection sequelae and death. While non-operative management was attempted in nearly 47%, ultimately 73% had surgery. This high rate may reflect our population of patients hospitalized in a tertiary care center. Available data suggests that patients presenting with hematogenous osteomyelitis be followed closely as failure of non-operative management, and resulting morbidity, was high.

Topical Antibiotic Powder and Nonunion Risk in Surgically Treated Tibial Plateau and Pilon Fractures

INTRODUCTION

High-energy periarticular tibia fractures are challenging injuries with a significant risk of complications. Postoperative infection rates, although improved, remain unacceptable. Intrawound topical antibiotic (TA) application has been popularized to reduce postoperative infections. Although TA may minimize infections, it remains unclear whether TAs have any impact on the development of nonunion. Recent investigations of TA use in fracture care have questioned its efficacy in vivo and suggested a potentially deleterious effect on fracture healing. This study investigates the impact of TA on nonunion rates in surgically treated high-energy periarticular tibia fractures.

METHODS

Retrospective analysis of surgically treated periarticular tibia fractures at a single Level 1 trauma center was conducted. Intervention in question was the clinical effect of intrawound TA powder application at definitive closure. A total of 222 high-energy periarticular tibia fractures were included, 114 with TA use and 108 without. The primary outcome was the occurrence of nonunion, with secondary outcomes being superficial and deep postoperative surgical site infections.

RESULTS

Twenty-seven patients (12.1%) were diagnosed with nonunions (14 pilons and 13 plateaus). There was no statistically significant difference in nonunion rates among patients who received topical antibiotics (15.8%) versus the group of patients who did not (8.3%) ( P = 0.23). Odds of developing nonunion was significant for open injuries (odds ratio 6.16, P < 0.001) and patients with a provisional external fixator (odds ratio 8.72, P = 0.03) before definitive fixation. No notable difference in the number of superficial and deep infections was identified between groups.

CONCLUSION

The use of TA in high-energy periarticular tibia fractures showed no statistically significant increase in nonunion rates but did not conclusively rule out nonunion as a possible effect of intrawound TA. Additional large-scale multicenter prospective studies are needed to confirm these findings. The current body of literature regarding high-energy periarticular tibia fractures does suggest that TAs lower the risk of postoperative infections, but the nonunion risk remains unclear.

LEVEL OF EVIDENCE

Level III, Retrospective Cohort Study.

Effect of Vancomycin Applied to the Surgical Site on Fracture Healing in a Diabetic Rat Model

BACKGROUND

Prophylactic vancomycin treatment decreases the prevalence of surgical site and deep infections by >70% in diabetic patients undergoing reconstructive foot and ankle surgery. Thus, determining whether clinically relevant local vancomycin doses affect diabetic fracture healing is of medical interest. We hypothesized that application of vancomycin powder to the fracture site during surgery would not affect healing outcomes, but continuous exposure of vancomycin would inhibit differentiation of osteoblast precursor cells and their osteogenic activity in vitro.

METHODS

The vancomycin dose used to treat the diabetic rats was a modest increase to routine surgical site vancomycin application of 1 to 2 g for a 70-kg adult (21 mg/kg). After femur fracture in BB-Wistar type 1 diabetic rats, powdered vancomycin (25 mg/kg) was administered to the fracture site. Bone marrow and periosteal cells isolated from diabetic bones were cultured and treated with increasing levels of vancomycin (0, 5, 50, 500, or 5000 µg/mL).

RESULTS

Radiographic scoring, micro-computed tomography (µCT) analysis, and torsion mechanical testing failed to identify any statistical difference between the vancomycin-treated and the untreated fractured femurs 6 weeks postfracture. Low to moderate levels of vancomycin treatment (5 and 50 µg/mL) did not impair cell viability, osteoblast differentiation, or calcium deposition in either the periosteum or bone marrow-derived cell cultures. In contrast, high doses of vancomycin (5000 µg/mL) did impair viability, differentiation, and calcium deposition.

CLINICAL RELEVANCE

In this diabetic rodent fracture model, vancomycin powder application at clinically relevant doses did not affect fracture healing or osteogenesis.

Use of Antibiotic Lavage in Total Knee Replacement to Prevent Postoperative Infection

Purpose To determine the effectiveness of using antibiotic lavage in preventing postoperative infections in total knee replacement (TKR) patients. Methods Data on all patients who underwent TKR, either primary or secondary, during the period from May 2015 to April 2019 were collected. Many factors (both patient-related and surgery-related) that can increase the risk of surgical site infection (SSI) were taken into consideration to eliminate confounding factors. Results A total of 685 patients were identified; out of those, 232 patients received intraoperative antibiotic lavage and 453 did not. We noted that out of all 13 patients who developed SSI, only one patient (7.7%) had received antibiotic lavage, while the other 12 (92.3%) patients did not receive antibiotic lavage. However, the difference was not statistically significant (p=0.078). Conclusion Using intraoperative vancomycin lavage was associated with a decrease in the incidence of SSI post-TKR, but the difference was not statistically significant. However, more studies are needed in this area.

Soaking ACL grafts in vancomycin solution (1 mg/ml) reduces the infection rate without increasing the risk for re-rupture and arthrofibrosis

PURPOSE

The aim of the present study was to evaluate if the vancomycin (1 mg/ml) is effective for the prevention of septic arthritis after ACL reconstruction. The hypothesis was that local antibiotic prophylaxis by soaking ACL grafts in vancomycin results in significantly less infections than ACL reconstruction without local antibiosis.

METHODS

In group 1, 636 patients who were operated between 1.9.2014 and 31.8.2016 received no local antibiotic treatment with vancomycin. In group 2, 536 patients who were operated between 1.9.2016 and 31.8.2018 received local antibiotic treatment with vancomycin (1 mg/ml). In this group the graft was soaked in the vancomycin solution for 10 min prior to graft passage and fixation.

RESULTS

In group 1 (ACL reconstruction without vancomycin application), a postoperative infection was detected in ten patients (infection rate: 1.6%). In group 2 (ACL reconstruction with 1 mg/ml vancomycin), no postoperative infection was detected (infection rate: 0%). The statistical analysis showed a clear significant difference between the two groups (p = 0.002). The re-rupture rate and the rate of arthrofibrosis differed not significantly between the two treatment groups (p = 0.526).

CONCLUSION

The results of the present study show that graft soaking in vancomycin (1 mg/ml) is effective for the prevention of septic arthritis after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Supratherapeutic Antibiotic Levels and Acute Kidney Injury from Absorption of Topical Antibiotics: A Case Report

CASE

A 96-year-old woman with no baseline renal dysfunction presented with a distal femoral shaft fracture after a ground-level fall. Treatment was with a retrograde intramedullary nail and included placement of topical antibiotics. Postoperatively, she developed acute kidney injury and was found to have supratherapeutic antibiotic levels.

CONCLUSION

This case report demonstrates the risk of clinically relevant systemic absorption along with associated downstream end organ damage with the use of topical antibiotics in certain circumstances. We present this case as an illustration of a rare hazard associated with topical antibiotic use.

Infection after primary total knee arthroplasty: a randomized controlled prospective study of the addition of antibiotics to bone cement

Objective  The present prospective, randomized and controlled study was conducted with 286 patients submitted to primary total knee arthroplasty (TKA) with the objective of evaluating the efficacy of the addition of antibiotics to bone cement as a way to prevent post arthroplasty infection (PAI).

Methods  The patients were randomized into two groups: bone cement without antibiotic (No ATB, n  = 158) or cement with antibiotic (ATB, n  = 128), in which 2 g of vancomycin was added to 40 g of cement. The patients were followed up for 24 months after surgery.

Results  Regarding preoperative demographic data, the distribution of patients between groups was homogeneous ( p  < 0.05). In the 24-month period, the overall infection rate was of 2.09% (6/286), with no difference (odds ratio [OR] = 1.636; 95% confidence interval [CI]: 0.294–9.080; p  = 0.694) between the ATB group (1.56%; 2/128) and the No ATB group (2.53%; 4/158). In the No ATB group, the infection was caused by methicillin-resistant Staphylococcus aureus (MRSA) ( n  = 2), methicillin-sensitive S. aureus (MSSA) ( n  = 1) and Eschirichia coli ( n  = 1). Proteus mirabilis and MSSA were isolated from patients in the ATB group. Among the comorbidities, all patients with PAI were hypertensive and nondiabetic. Two rheumatoid arthritis patients who developed PAI were from the ATB group.

Conclusion  The use of cement with ATB reduced the absolute number of infections, but without statistical difference between the groups; thus, routine use should not be encouraged.

Titania Nanotube Architectures Synthesized on 3D-Printed Ti-6Al-4V Implant and Assessing Vancomycin Release Protocols

The aim of this study is to synthesize Titania nanotubes (TNTs) on the 3D-printed Ti-6Al-4V surface and investigate the loading of antibacterial vancomycin drug dose of 200 ppm for local drug treatment application for 24 h. The antibacterial drug release from synthesized nanotubes evaluated via the chemical surface measurement and the linear fitting of Korsmeyer–Peppas model was also assessed. The TNTs were synthesized on the Ti-6Al-4V surface through the anodization process at different anodization time. The TNTs morphology was characterized using field emission scanning electron microscope (FESEM). The wettability and the chemical composition of the Ti-6Al-4V surface and the TNTs were assessed using the contact angle meter, Fourier transform infrared spectrophotometer (FTIR) and the X-ray photoelectron spectroscopy (XPS). The vancomycin of 200 ppm release behavior under controlled atmosphere was measured by the high-performance liquid chromatography (HPLC) and hence, the position for retention time at 2.5 min was ascertained. The FESEM analysis confirmed the formation of nanostructured TNTs with vertically oriented, closely packed, smooth and unperforated walls. The maximum cumulative vancomycin release of 34.7% (69.5 ppm) was recorded at 24 h. The wetting angle of both Ti-6Al-4V implant and the TNTs were found below 90 degrees. This confirmed their excellent wettability.

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.

Intrawound vancomycin application after spinal surgery: a propensity score-matched cohort analysis

OBJECTIVE

Surgical site infection (SSI) following spine surgery is associated with increased morbidity and healthcare costs. In an effort to reduce SSI rates, the application of intrawound vancomycin powder has gained popularity. However, there is limited high-quality evidence to support the safety and efficacy of this practice. The authors sought to determine if intrawound application of vancomycin powder improves 90-day overall SSI rates.

METHODS

The authors performed a retrospective, vancomycin exposure-matched cohort study at a single tertiary care hospital over 21 months. They included all patients undergoing elective spinal surgery and stratified the patients into two groups: those who received intrawound vancomycin powder application and those who received no application of vancomycin powder. The primary outcome of interest was the 90-day overall SSI rate. Secondary outcomes included rates of superficial SSI, deep SSI, wound disruption, and a post hoc analysis of the microbiology and minimum inhibitory concentrations. Baseline patient demographics, clinical presentation, comorbidities, perioperative factors, and 90-day postoperative outcomes were manually abstracted from patient charts. To mitigate bias, we performed 1:1 matching after calculating propensity scores and identified 1 patient from the no-vancomycin cohort for each patient in the vancomycin cohort.

RESULTS

A total of 997 patients met our inclusion criteria (473 patients receiving vancomycin and 524 patients not receiving vancomycin). Propensity score matching produced 221 matched pairs. Risk-adjusted analysis demonstrated similar overall SSI rates between the groups (OR 1.9, p = 0.329). On unadjusted analysis, the overall 90-day SSI rate was greater in the vancomycin group (n = 10 [4.5%]) than in the no-vancomycin group (n = 5 [2.3%]) (p < 0.001), as were the superficial SSI rate (7 [3.2%] vs 4 [1.8%], p < 0.001), deep SSI rate (3 [1.4%] vs 1 [0.5%], p < 0.001), and wound disruption rate (5 [2.3%] vs 1 [0.5%], p < 0.001). No cultured isolate demonstrated vancomycin resistance.

CONCLUSIONS

The authors observed no difference in SSI rates after the intrawound application of vancomycin powder during spine surgery. Vancomycin use did not contribute to antimicrobial resistance; however, it may select out gram-negative bacteria and increase rates of wound disruption.

Antibacterial hydrogel coating in joint mega-prosthesis: results of a comparative series

PURPOSE

Joint mega-prosthesis after bone tumors, severe trauma or infection is associated with high rates of post-surgical septic complications. A fast-resorbable antibacterial hydrogel coating (DAC®, Defensive Antibacterial Coating) has previously been shown to be able to significantly reduce surgical site infection in various clinical settings. Aim of the present study was to evaluate the safety and efficacy of the DAC hydrogel coating to prevent early periprosthetic joint infection after joint mega-prosthesis.

METHODS

In this three-centers, case-control study, 43 patients, treated with an antibacterial hydrogel coated mega-prosthesis for oncological (N = 39) or non-oncological conditions (N = 4), were retrospectively compared with 43 matched controls, treated with mega-implants without the coating. Clinical, laboratory and radiographic examinations were performed to evaluate the occurrence of post-surgical infection, complications and adverse events.

RESULTS

At a mean follow-up of 2 years, no evidence of infection or adverse events were observed in the DAC-treated group, compared to six cases of post-surgical infection in the control group.

CONCLUSION

This matched case-control study shows that a fast-resorbable, antibiotic-loaded coating can be safely used to protect joint mega-prosthesis, providing a reduction of early surgical site infections with no side effects. Larger prospective trials with longer follow-ups are warranted to confirm this report.

TRIAL REGISTRATION

RS1229/19 (Regina Elena National Cancer Institute Experimental Registry Number).

Systemic Absorption and Nephrotoxicity Associated With Topical Vancomycin Powder for Fracture Surgery

OBJECTIVES

To determine whether using topical vancomycin powder in fracture surgery may result in low levels of vancomycin in the serum and not result in nephrotoxicity.

DESIGN

Prospective observational at a single site as a substudy of the VANCO trial.

SETTING

Single, large urban level I trauma center.

PATIENTS/PARTICIPANTS

Fifty-eight patients with tibial plateau and pilon fractures randomized to the treatment arm at the principal investigator's site.

INTERVENTION

Topical vancomycin powder (1000 mg) applied directly in the wound over all metal implants at the time of wound closure.

MAIN OUTCOME MEASUREMENTS

Serum vancomycin levels at 1 hour and 6-8 hours after surgery. Secondary outcomes included serum creatinine before surgery, a day after surgery, and at 2 weeks postoperatively and complete blood count at 2 weeks postoperatively.

RESULTS

Except in 2 patients who also received intravenous vancomycin, none of the study patients had detectable (>5 µg/mL) serum vancomycin levels at 1 hour and 6-8 hours after surgery. One patient with a history of elevation of serum creatinine had a minor increase of serum creatinine but had undetectable vancomycin levels. None of the other patients had a clinically significant increase in creatinine levels.

CONCLUSIONS

Despite its relatively widespread usage, little data exist regarding the systemic levels and nephrotoxicity associated with the topical use of vancomycin powder in orthopaedic fracture surgery. These prospective data indicate that there seems to be little clinical concern regarding toxicity associated with systemic absorption of vancomycin powder in this specific clinical application.

LEVEL OF EVIDENCE

Therapeutic Level IV. See instructions for authors for a complete description of levels of evidence.

Ciprofloxacin-Collagen-Based Materials with Potential Oral Surgical Applications

We report in this paper the synthesis and characterization of a new collagen-based material. This material was obtained in a spongy form and was functionalized with an antibiotic, ciprofloxacin. The targeted applications of these kind of materials concern the post-operative prophylaxis. The in vitro tests (antimicrobial, cytotoxic, drug release) showed that sponges with a concentration of 0.75 g of ciprofloxacin per gram of collagen could be beneficial for the desired applications.

Evidence-Based Recommendations for Local Antimicrobial Strategies and Dead Space Management in Fracture-Related Infection

Fracture-related infection (FRI) remains a challenging complication that imposes a heavy burden on orthopaedic trauma patients. The surgical management eradicates the local infectious focus and if necessary facilitates bone healing. Treatment success is associated with debridement of all dead and poorly vascularized tissue. However, debridement is often associated with the formation of a dead space, which provides an ideal environment for bacteria and is a potential site for recurrent infection. Dead space management is therefore of critical importance. For this reason, the use of locally delivered antimicrobials has gained attention not only for local antimicrobial activity but also for dead space management. Local antimicrobial therapy has been widely studied in periprosthetic joint infection, without addressing the specific problems of FRI. Furthermore, the literature presents a wide array of methods and guidelines with respect to the use of local antimicrobials. The present review describes the scientific evidence related to dead space management with a focus on the currently available local antimicrobial strategies in the management of FRI. LEVEL OF EVIDENCE:: Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Topical Vancomycin for Surgical Prophylaxis in Pediatric Craniofacial Surgeries

Topical vancomycin has been demonstrated to be safe and effective for reducing surgical site infections (SSIs) following spine surgery in both adults and children, however, there are no studies of its efficacy in reducing SSIs in craniofacial surgery. The SSIs are one of the most common complications following craniofacial surgery. The complexity of craniofacial procedures, use of grafts and implants, long operative durations and larger surgical wounds all contribute to the heightened risk of SSIs in pediatric craniofacial cases. A retrospective review of all open and endoscopic pediatric craniofacial procedures performed between May 2014 and December 2017 at a single children's hospital was conducted to examine SSI rates between patients receiving topical vancomycin and a historical control group. The treatment group received topical vancomycin irrigation before wound closure. An ad-hoc cost analysis was performed to determine the cost-savings associated with topical vancomycin use. A total of 132 craniofacial procedures were performed during the study period, with 50 cases in the control group and 82 cases in the vancomycin group. Overall, SSI rate was 3.03%. Use of topical vancomycin irrigation led to a significant reduction in SSIs (4/50 SSI or 8.0% in control group vs 0/82 or 0% in vancomycin group, P = 0.04). No adverse events were observed with topical vancomycin use. The potential cost-savings associated with the use of topical vancomycin as SSI prophylaxis in this study was $102,152. Addition of topical vancomycin irrigation as routine surgical infection prophylaxis can be an effective and low-cost method for reducing SSI in pediatric craniofacial surgery.

Is Implant Coating With Tyrosol- and Antibiotic-loaded Hydrogel Effective in Reducing Cutibacterium (Propionibacterium) acnes Biofilm Formation? A Preliminary In Vitro Study

BACKGROUND

Studies have suggested that Cutibacterium acnes (formerly known as Propionibacterium) is the most frequently isolated pathogen after shoulder arthroplasty. To address the burden of periprosthetic joint infections associated with this pathogen, new prevention methods are needed. Tyrosol has a promising record of effectiveness in the field of biofilm-associated infections; however, to our knowledge, it has not been tested against C. acnes thus far.

QUESTIONS/PURPOSES

In this in vitro study, we asked: (1) Is tyrosol effective in inhibiting and eradicating C. acnes planktonic growth? (2) Is there synergy between tyrosol and rifampicin? (3) Is supplementation of hydrogel with tyrosol at the minimum inhibitory and subinhibitory concentrations efficacious in reducing free-floating C. acnes growth? (4) Is implant hydrogel coating (either alone or combined with tyrosol, rifampicin, or vancomycin) beneficial in reducing C. acnes biofilm formation? (5) Is the administration of soluble tyrosol an effective measure against C. acnes biofilm formation?

METHODS

We assessed C. acnes planktonic growth and eradication by inspecting visually the results of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. We also evaluated macroscopically the presence of synergy among tyrosol and rifampicin by means of the MIC checkerboard testing. Thereafter, we addressed colorimetrically the efficacy of tyrosol-loaded Defensive Antibacterial Coating (DAC®) hydrogel against the C. acnes free-floating form by means of the XTT cell proliferation reduction assay. Then, we explored photometrically the effect of hydrogel and soluble tyrosol at reducing C. acnes biofilm formation on titanium alloy disks that simulated orthopaedic implants by using the minimum biofilm inhibition concentration assay. In particular, 16 disks were sequentially allocated to each of the following testing conditions: (1) hydrogel alone; (2) tyrosol-loaded hydrogel; (3) rifampicin-supplemented hydrogel; (4) vancomycin-loaded hydrogel; and (5) soluble tyrosol. Subsequently, implants were sonicated and cell viability was evaluated in terms of the XTT assay.

RESULTS

Tyrosol was effective in inhibiting C. acnes planktonic (free-floating) growth demonstrating MIC values of 63 mM (9 mg/mL) and MBC values of 250 mM (35 mg/mL). Concerning synergy assessment, the checkerboard testing revealed additivity among tyrosol and rifampicin with a fractional inhibitory concentration index of 0.56. In addition, a hydrogel coating with tyrosol at the MIC showed no difference in the inhibition of free-floating C. Acnes form over control (median absorbance [MA] for tyrosol-supplemented hydrogel versus control groups were 0.21 [interquartile range {IQR}, 0.19-0.24] versus 0.26 [IQR, 0.23-0.31], p = 0.066). Furthermore, loaded hydrogel with tyrosol at 597 mg/mL (1 M) was no more effective than control in reducing C. acnes biofilm formation (MAs for tyrosol versus control were 0.12 [IQR, 0.11-0.13] versus 0.14 [IQR, 0.12-0.16], respectively; p = 0.076). This was also the case when we considered hydrogel in conjunction with vancomycin and rifampicin (MAs for vancomycin at 2% and 5% and rifampicin at 1% versus biofilm control were 0.139 [IQR, 0.133-0.143] and 0.141 [IQR, 0.133-0.143] and 0.135 [IQR, 0.128-0.146] versus 0.142 [IQR, 0.136-0.144], correspondingly). In contrast, soluble tyrosol at 597 mg/mL (1 M) inhibited biofilm formation compared to control (MAs for tyrosol and control groups were 0.11 [IQR, 0.09-0.13] versus 0.13 [IQR, 0.12-0.14], p = 0.007).

CONCLUSIONS

Although the implant coating with hydrogel (either pure or supplemented with antimicrobial agents) did not diminish C. acnes biofilm development in vitro, soluble tyrosol at 597 mg/mL (1 M) exceeded the meaningful biofilm inhibition threshold of 80%.

CLINICAL RELEVANCE

The results of the current preclinical investigation did not support the use of a fast, bioresorbable hydrogel as a coating method against C. acnes biofilms. Instead, direct local administration of soluble tyrosol at high concentrations should be further tested in future animal studies.

Impact of Gentamicin-Loaded Bone Graft on Defect Healing in a Sheep Model

Infections of bone are severe complications, and an optimization of grafting material with antimicrobial drugs might be useful for prevention and treatment. This study aimed to investigate the influence of gentamicin-loaded bone graft on the healing of bone defects in a sheep model. Metaphyseal and diaphyseal drill hole defects (diameter: 6 mm, depth: 15 mm) were filled with graft or gentamicin-loaded graft (50 mg/g graft) or were left untreated. Analysis of regeneration after three and nine weeks, micro-computed tomography (μCT), and histology revealed a significant increase in bone formation in the drill hole defects, which began at the edges of the holes and grew over time into the defect center. The amount of graft decreased over time due to active resorption by osteoclasts, while osteoblasts formed new bone. No difference between the groups was seen after three weeks. After nine weeks, significantly less mineralized tissue was formed in the gentamicin-loaded graft group. Signs of inflammatory reactions were seen in all three groups. Even though the applied gentamicin concentration was based on the concentration of gentamicin mixed with cement, the healing process was impaired. When using local gentamicin, a dose-dependent, compromising effect on bone healing should be considered.

Local Versus Systemic Antibiotics for Surgical Infection Prophylaxis in a Rat Model

BACKGROUND

The purpose of this study was to compare the local application of a variety of antimicrobial agents with intravenous (IV) antibiotics for infection prophylaxis in a rat model.

METHODS

A total of 120 adult male Sprague-Dawley rats were implanted with an expanded polytetrafluoroethylene (ePTFE) vascular graft in a submuscular position and challenged with 2 × 10 colony-forming units of methicillin-sensitive Staphylococcus aureus (MSSA). Twenty rats received pretreatment with IV cefazolin and 20 rats were pretreated with IV vancomycin. The remaining 80 rats had application of local antimicrobials in the wound at the conclusion of the procedure: 20 rats received vancomycin powder; 20 rats, cefazolin powder; and 20 rats, tobramycin powder; 20 rats underwent dilute 0.35% Betadine (povidone-iodine) lavage for 3 minutes. One week after surgery, the grafts were retrieved and cultured.

RESULTS

Twenty (100%) of 20 rats in each of the IV cefazolin, IV vancomycin, and dilute Betadine lavage groups had grossly positive cultures for MSSA (95% confidence interval [CI], 84% to 100%). Eighteen (90%) of 20 rats in the cefazolin local powder group demonstrated positive cultures for MSSA (95% CI, 77% to 100%). Four (20%) of 20 rats in the tobramycin local powder and vancomycin local powder groups demonstrated positive cultures for MSSA (95% CI, 3% to 38%). The infection rates for the local application of vancomycin and tobramycin powder were significantly lower compared with Betadine lavage, IV vancomycin, IV cefazolin, and local cefazolin powder (p < 0.000001).

CONCLUSIONS

Local antimicrobial prophylaxis with vancomycin and tobramycin powder for infections in the rat model was statistically superior to systemic prophylaxis with IV antibiotics, local cefazolin powder, and Betadine lavage.

CLINICAL RELEVANCE

This study supports the findings of prior clinical reports that intrawound vancomycin powder reduces the risk of surgical site infection. Local application of tobramycin powder was equivalent to vancomycin powder in this model. Additionally, the superiority of local antibiotic surgical prophylaxis suggests that clinical studies should be considered to determine the relative efficacy of local versus systemic antibiotics for surgical infection prophylaxis in humans.

[Local antibiotic therapy]

The treatment of superficial wound infections with local antibiotics is considered to be problematic as it is accompanied by an increased risk of resistance development and ineffectiveness in deeper regions. On the contrary, the local application of antibiotics is useful in arthroplasty and necessary if implants are utilized. The reason for this is the prevention of a rapid biofilm formation on foreign implants and a resulting infection may remain undiscovered until it becomes chronic. Apart from exogenous material, necrotic tissue (e. g. bone sequestra) provides suitable retreat areas for pathogens in the body. Because of the characteristics of bone and joint infections and an exceptional infection recurrence rate, a combined approach is required. Systemic antibiotic prophylaxis is able to reduce the number of pathogens acquired by perioperative contamination or hematogenic spread from another focus of infection; however, systemically applied antibiotics often fail to form an effective colonization barrier around the implant because their ability to penetrate the bone is relatively low. On the other hand, the high concentration of locally released antibiotics leads to an effective protection of the implant from bacteria in situ. Thus, for the treatment of implant-associated infections, systemic and local application of anti-infective agents is a reliable adjuvant measure that improves the therapeutic success. Polymethylmethacrylate (PMMA) bone cement is the most commonly used local drug carrier. Based on clinical and microbiological results, microbiologists and infectious disease experts together with the surgeon and pharmacist determine which anti-infective agents are indicated for systemic and local, PMMA cement-related application. Because there is no evident concept for the local application, unlike the recommendation for systemic use of anti-infective agents, this review article describes which aspects should be taken into account.

Impact of Vancomycin Treatment on Human Mesenchymal Stromal Cells During Osteogenic Differentiation

BACKGROUND

Vancomycin is frequently applied locally to the operative site during foot and ankle procedures to help prevent infection. Although the efficacy of locally applied vancomycin has been demonstrated in spine surgery, there is no consensus on dosing and indication within foot and ankle surgery. Osteogenic differentiation of human mesenchymal stromal cells (hMSCs) is key to healing of both fractures and arthrodesis. The purpose of this research was to determine the impact of vancomycin on human hMSCs during the process of osteogenic differentiation.

METHODS

hMSCs were cultured in osteogenic differentiation media to promote osteogenic differentiation. Cells were treated with vancomycin at differing concentrations of 0, 50, 500, and 5000 µg/mL. Viability and cell growth were assessed via LIVE/DEAD viability/cytotoxicity kit (Invitrogen, Waltham, MA) after 1, 3, and 7 days of vancomycin treatment. Differentiation and mineralization was assessed via alizarin red staining after 21 days of treatment. Mean cell viability, cell number, and mineralization were compared between treatment groups using 1-way analysis of variance and the Tukey-Kramer method for post hoc pairwise comparisons.

RESULTS

At the highest concentrations of vancomycin, there was a significant reduction in cell viability and proliferation after 3 days compared with all other treatment groups. Mineralization was also significantly decreased with higher doses of vancomycin.

CONCLUSION

At high concentrations, vancomycin may impair hMSC viability and osteogenic differentiation.

CLINICAL RELEVANCE

Surgeons should exercise caution and consider the limited soft tissue envelope when applying vancomycin locally during foot and ankle surgery, especially during arthrodesis procedures.

Postoperative Infection in Patients Undergoing Posterior Lumbosacral Spinal Surgery: A Pictorial Guide for Diagnosis and Early Treatment

Surgical site infections after posterior spinal surgery may lead to spondylodiscitis, pseudarthrosis, correction loss, adverse neurological sequelae, sepsis, and poor outcomes if not treated immediately. Infection rates vary depending on the type and extent of operative procedures, use of instrumentation, and patients' risk factors. Image evaluation is crucial for early diagnosis and should be complementary to clinical routes, laboratory survey, and treatment timing. Magnetic resonance imaging detects early inflammatory infiltration into the vertebrae and soft tissues, including hyperemic changes of edematous marrow, vertebral endplate, and abscess or phlegmon accumulation around the intervertebral disk, epidural, and paravertebral spaces. Aggressive surgical treatment can eradicate infection sources, obtain a stable wound closure, decrease morbidity, and restore spinal integrity. Organ/space infection is defined as any body parts opened to manipulate other than superficial/deep incision. Advanced magnetic resonance imaging evaluating abnormal fluid accumulation, heterogenous contrast enhancement of the endplate erosion due to cage/screw infection is categorized to inform a presumptive diagnosis for early implant salvage. However, patients' defense response, infection severity, bacteriology, treatment timing, spinal stability, and available medical and surgical options must be fully considered. Revision surgery is indicated for pseudarthrosis, implant loosening with correction loss, recalcitrant spondylodiscitis, and adjacent segment diseases for infection control.

Antibiotic Prophylaxis and Prevention of Surgical Site Infection in Shoulder and Elbow Surgery

Infection after orthopedic procedures is a devastating and serious complication associated with significant clinical and financial challenges to the health care system and unfortunate patient. The time and resource-intensive nature of treating infection after orthopedic procedures has turned attention toward enhancing prevention and establishing quality improvement measures. Prevention strategies throughout the perioperative period include host optimization, risk mitigation, reducing bacterial burden and proper wound management. Understanding the most common offending organisms of the shoulder, Propionibacterium acnes and coagulase negative Staphylococcus species, and their hypothesized mechanism of infection is crucial to selecting appropriate preventative measures.

Local Antimicrobial Treatment in Orthopaedic Surgery

The purpose of this special issue of Journal of Bone and Joint Infection is to provide orthopaedic surgeons with basic science explanations as to how these local antimicrobials work, clinical evidence that supports these local treatments, and the role of these local treatments against biofilm.