Local antibiotic therapy for severe open fractures. A review of 1085 consecutive cases

Does Local Aqueous Tobramycin Injection Reduce Open Fracture-Related Infection Rates?

OBJECTIVES

To examine the effect of local aqueous tobramycin injection adjunct to perioperative intravenous (IV) antibiotic prophylaxis in reducing fracture-related infections (FRIs) following reduction and internal fixation of open fractures.

METHODS

DESIGN

Retrospective cohort study.

SETTING

Single academic Level I trauma center.

PATIENTS SELECTION CRITERIA

Patients with open extremity fractures treated with reduction and internal fixation with (intervention group) or without (control group) 80 mg of local aqueous (2 mg/mL) tobramycin injected during closure at the time of definitive fixation were identified from December 2018 to August 2021 based on population-matched demographic and injury characteristics.

OUTCOME MEASURES AND COMPARISONS

The primary outcome was FRI within 6 months of definitive fixation. Secondary outcomes consisted of fracture nonunion and bacterial speciation. Differences in outcomes between the 2 groups were assessed and logistic regression models were created to assess the difference in infection rates between groups, with and without controlling for potential confounding variables, such as sex, fracture location, and Gustilo-Anderson classification.

RESULTS

An analysis of 157 patients was performed with 78 patients in the intervention group and 79 patients in the control group. In the intervention group, 30 (38.5%) patients were women with a mean age of 47.1 years. In the control group, 42 (53.2%) patients were women with a mean age of 46.4 years. The FRI rate was 11.5% in the intervention group compared with 25.3% in the control group ( P = 0.026). After controlling for sex, Gustilo-Anderson classification, and fracture location, the difference in FRI rates between groups remained significantly different ( P = 0.014).

CONCLUSIONS

Local aqueous tobramycin injection at the time of definitive internal fixation of open extremity fractures was associated with a significant reduction in FRI rates when administered as an adjunct to intravenous antibiotics, even after controlling for potential confounding variables.

LEVEL OF EVIDENCE

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

Prevention and treatment of osteomyelitis after open tibia fractures

Infection and chronic post-traumatic osteomyelitis of the tibia after open fracture are complex problems that cause significant morbidity and threaten the viability of a limb. Therefore, it is of utmost importance for the orthopaedic surgeon to understand both patient and treatment factors that modify the risk of developing these disastrous complications. Infection risk is largely based on severity of open injury in addition to inherent patient factors. Orthopaedic surgeons can work to mitigate this risk with prompt antibiotic administration, thorough and complete debridement, expedient fracture stabilization, and early wound closure. In the case osteomyelitis does occur, the surgeon should use a systematic multidisciplinary approach for eradication.

[Bone cement as a local antibiotic carrier]

BACKGROUND

There is widespread consensus that adjuvant local use of antimicrobial agents in combination with their systemic administration can better prevent and treat implant-associated musculoskeletal infections. The advantage of local antibiotics lies in their particular pharmacokinetics with initially high antibiotic concentrations at the implant site with only low systemic uptake.

AIM OF TREATMENT

The aim of local application is to protect the foreign bodies directly at the implantation site from bacterial colonization and biofilm formation (prophylaxis) and to support the eradication of an already established infection after surgical debridement (treatment). Since the observations of Prof. Buchholz, bone cement has been the most frequently used local carrier system.

APPLICATION

In cases of infection, surgeons should ideally work together with microbiologists, infectiologists or clinical pharmacists to determine which anti-infective agents are indicated systemically for the patient and which ones are indicated locally with PMMA cement, based on the pathogen(s) and antibiograms. However, for the anti-infective agents administered with bone cement, there is still uncertainty about which agents can be added to this carrier material and at what concentrations. Accordingly, the authors of this review article not only summarize the rationale and evidence for local antibiotic use but also elaborate on the points that must be considered for admixing these agents to the cement.

Local Antibiotic Therapy for Open Long Bone Fractures: Appropriate Prophylaxis or Unnecessary Exposure for the Orthopedic Trauma Patient?

INTRODUCTION

Prophylactic local antibiotic therapy (LAbT) to prevent infection in open long bone fracture (OLBF) patients has been in use for many decades despite lack of definitive evidence confirming a beneficial effect. We aimed to evaluate the effect of LAbT on outcomes of OLBF patients on a nationwide scale.

MATERIALS AND METHODS

In this retrospective analysis of 2017-2018 American College of Surgeons-Trauma Quality Improvement Program database, all adult (≥18 years) patients with isolated OLBF (non-extremity-Abbreviated Injury Scale < 3) were included. We excluded early deaths (<24 h) and those who had burns or non-extremity surgery. Outcomes were infectious complications (superficial surgical site infection, deep superficial surgical site infection, osteomyelitis, or sepsis), unplanned return to operating room, and hospital and intensive care unit length of stay (LOS). Patients were stratified into two groups: those who received LAbT and those who did not receive LAbT (No-LAbT). Propensity score matching (1:3) and chi-square tests were performed.

RESULTS

A total of 61,337 isolated OLBF patients were identified, among whom 2,304 patients were matched (LAbT: 576; No-LAbT: 1,728). Both groups were similar in terms of baseline characteristics. Mean age was 43 ± 17 years, 75% were male, 14% had penetrating injuries, and the median extremity-Abbreviated Injury Scale was 1 (1-2). Most common fracture locations were tibia (66%), fibula (49%), femur (24%), and ulna (11%). About 52% of patients underwent external fixation, 79% underwent internal fixation, and 86% underwent surgical debridement. The median time to LAbT was 17 (5-72) h, and the median time to debridement was 7 (3-15) h (85% within 24 h). The LAbT group had similar rates of infectious complications (3.5% vs. 2.5%, P = 0.24) and unplanned return to the operating room (2.3% vs. 2.0%, P = 0.74) compared to the No-LAbT group. Patients who received LAbT had longer hospital LOS (16 [10-29] vs. 14 [9-24] days, P < 0.001) but similar intensive care unit LOS (4 [3-9] vs. 4 [2-7] days, P = 0.19).

CONCLUSIONS

Our findings indicate that prophylactic LAbT for OLBF may not be beneficial over well-established standards of care such as early surgical debridement and systemic antibiotics. Prospective studies evaluating the efficacy, risks, costs, and indications of adjuvant LAbT for OLBF are warranted.

Prophylactic Intrawound Antibiotics Significantly Reduce the Risk of Deep Infections in Fracture Fixation: Subgroup Meta-analyses of the Type of Fracture, Antibiotics, and Organism

OBJECTIVES

To analyze the efficacy of subgroups of various intrawound local antibiotics in reducing the rate of fracture-related infections.

DATA SOURCES AND STUDY SELECTION

PubMed, MEDLINE via Ovid, Web of Science, Cochrane database, and Science Direct were searched for articles in English on July 5, 2022, and December 15, 2022.

STUDY SELECTION

All clinical studies comparing the incidence of fracture-related infection between the administration of prophylactic systemic and topical antibiotics in fracture repair were analyzed.

DATA EXTRACTION

Cochrane collaboration's assessment tool and the methodological bias and the methodological index for nonrandomized studies were used to detect bias and evaluate the quality of included studies, respectively.

DATA SYNTHESIS

RevMan 5.3 software (Nordic Cochrane Centre, Denmark) was used to conduct the meta-analyses and generate forest plots.

CONCLUSIONS

From 1990 to 2021, 13 studies included 5309 patients. Nonstratified meta-analysis showed that intrawound administration of antibiotics significantly decreased the overall incidence of infection in both open and closed fractures, regardless of the severity of open fracture and antibiotics class [OR = 0.58, ( P = 0.007)] [OR = 0.33, ( P < 0.00001)], respectively. The stratified analysis revealed that prophylactic intrawound antibiotics significantly lowered infection rate in open fracture patients with Gustilo-Anderson type I (OR = 0.13, P = 0.004), type II (OR = 0.29, P = 0.0002), type III (OR = 0.21, P < 0.00001), when either tobramycin PMMA beads (OR = 0.29, P < 0.00001) or vancomycin powder (OR = 0.51, P = 0.03) was applied. This study demonstrates prophylactic administration of intrawound antibiotics significantly decreases the overall incidence of infection in all subgroups of surgically fixated fractures but does not affect the patient's length of hospital stay.

LEVEL OF EVIDENCE

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

Effectiveness of an Antibiotic-impregnated Bioabsorbable Carrier for the Treatment of Chronic Intramedullary and Diffuse Osteomyelitis

Aim

The surgical management of chronic intramedullary osteomyelitis involves debridement of affected non-viable tissue and the use of antibiotics. Where surgery leaves a cavity, dead-space management is often through antibiotic-impregnated bone cement. These depots of local antibiotics are variable in elution properties and need removal. We review our unit's experience using a bioabsorbable synthetic calcium sulphate to deliver gentamicin as an adjunct in the treatment of osteomyelitis involving the medullary canal.

Materials and methods

We retrospectively reviewed 34 patients with chronic osteomyelitis who were treated using this method in our institute. Variables recorded included aetiology, previous interventions, diagnostic criteria, radiological features, serology, and microbiology. The Cierny-Mader system was used to classify. Follow-up involved a survival analysis to time to recurrence, clinical and functional assessment (AOFAS-Ankle/IOWA knee/Oxford Hip/DASH scores) and a general health outcome questionnaire (SF36). The primary outcome measure was clinical recurrence of infection.

Results

There were 24 male and 10 female patients. The mean age at presentation was 47 years (20-67). Clinical, laboratory, radiological, and patient reported outcomes were obtained at a median follow-up of 2.5 years (1.4-6.6 years). The bones involved were the femur (14, 41%), tibia (16, 47%), radius (1, 3%), and humerus (3, 9%). There were 13 cases classified as Cierny-Mader stage IV (diffuse with intramedullary osteomyelitis) and 21 cases as Cierny-Mader stage I. The median Oxford Hip score was 38 (11 patients, range 9-48). The median AOFAS score was 78 (14 patients, range 23-100). The median IOWA knee score was 71 (25 patients, range 22-95). The median DASH score was 33 (2 patients, range 1.7-64.2). There were two recurrences. The treatment success to date is 94%.

Conclusion

In our series of patients, bioabsorbable carriers of antibiotics appear to be effective adjuncts to surgical treatment of osteomyelitis and were associated with high clinical success rates.

How to cite this article

Selvaratnam V, Roche A, Narayan B, et al. Effectiveness of an Antibiotic-impregnated Bioabsorbable Carrier for the Treatment of Chronic Intramedullary and Diffuse Osteomyelitis. Strategies Trauma Limb Reconstr 2023;18(3):148-154.

Use of tobramycin-impregnated antibiotic beads in frontal sinus osteomyelitis

OBJECTIVE

Osteomyelitis of the frontal bone is a rare but devastating complication of frontal sinusitis. Treatment involves aggressive surgery to remove all sequestra in combination with long-term antibiotic therapy. However, systemic antibiotics may struggle to penetrate any remaining infection in devascularised areas, and the morbidity associated with surgical resection of some areas of the skull base is too high. In contrast, locally implanted antibiotics provide a reliable, high concentration of treatment to these areas while also minimising potential systemic side effects. The clinical application of tobramycin beads has primarily been used in orthopaedics as an adjunct to the treatment of tibial osteomyelitis or prosthetic joint infection.

CASE REPORT

To the best of the authors' knowledge, the two cases discussed here represent the first use of tobramycin antibiotic beads in frontal sinus osteomyelitis secondary to chronic rhinosinusitis.

CONCLUSION

These cases show promising use of tobramycin beads in recalcitrant frontal osteomyelitis.

The Effect of Local Administration of Vancomycin Suspended in Fibrin Glue for Prevention of Surgical Site Infection After Spinal Instrumentation: Comparison by Probability of Treatment Weighting Model

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To compare the surgical site infection (SSI) rate in patients undergoing spinal instrumentation surgery who received vancomycin suspended in fibrin glue at the surgical site and those who did not.

SUMMARY OF BACKGROUND DATA

The intrawound application of vancomycin powder for preventing SSI after spinal surgery remains controversial. Vancomycin suspended in fibrin glue is another option for local administration that may be effective. The present study assessed whether vancomycin suspended in fibrin glue could prevent SSI after spinal instrumentation surgery.

MATERIALS AND METHODS

We enrolled patients who underwent posterior spinal instrumentation surgery with or without fusion for degenerative conditions, spinal trauma, or tumor. A multiple logistic regression model with inverse probability of treatment weighting based on propensity score was used to assess the efficacy of vancomycin suspended in fibrin glue and to account for confounding. A secondary multivariate logistic regression analysis was performed to identify the risk factors associated with SSI.

RESULTS

Of the 264 patients enrolled in this study, 134 underwent application of vancomycin suspended in fibrin glue at the surgical site and 130 did not. The incidence of SSI was lower in patients who were treated with vancomycin suspended in fibrin glue (2.2% vs. 8.5%) even after inverse probability of treatment weighting adjustment (adjusted odds ratio: 0.25; 95% CI, 0.0768-0.91; P =0.03). Multivariate logistic regression analysis showed that the treatment with vancomycin suspended in fibrin glue was significantly associated with a lower odds of SSI (odds ratio: 0.2; 95% CI, 0.05-0.85; P =0.03).

CONCLUSIONS

The administration of vancomycin suspended in fibrin glue was significantly associated with a lower likelihood of SSI in patients undergoing spinal instrumentation surgery.

What Is the Safe Window from Definitive Fixation to Flap Coverage in Type 3B Open Tibia Fractures? Supporting Plastics and Orthopaedics Alliance in Reducing Trauma Adverse Events (SPARTA)

OBJECTIVES

To delineate whether a "safe" window exists for timing from definitive fixation to definitive soft tissue coverage in the treatment of open tibial diaphyseal fractures requiring flap coverage.

DESIGN

International multicenter, retrospective comparative cohort study.

PATIENTS/PARTICIPANTS

Three hundred and seventy-three (n = 373) patients who sustained an open tibial shaft fracture requiring flap coverage.

METHODS

We evaluated the deep infection rates based on the timing between the definitive fixation and flap coverage. We determined several intervals of time from the day of definitive fixation (regardless of time from injury) and flap coverage. If performed on the same operative setting these were considered day 0. We evaluated coverage after 2 and 5 days from definitive fixation based on time versus infection rate curve inflection points. We adjusted for time to debridement and antibiotics within an hour.

MAIN OUTCOME MEASUREMENT

Deep infection after definitive fixation and flap coverage.

RESULTS

The mean age of the cohort was 42.4 years (SD = 18.2) and 270 were male (72.4%). The deep infection rate after flap coverage was 20.6% (77/373). Definitive fixation to flap coverage time of up to 2 days was not associated with an increased risk of infection [relative risk (RR) = 1.12; 95% confidence interval, 0.92-1.37; P = 0.26]. There was an increased risk of deep infection for more than 2 days (RR = 1.59) and >5 days (RR = 1.64).

CONCLUSION

This study observed a "safe" window of up to 2 days between definitive fixation and flap coverage in open tibial shaft fractures requiring coverage before a statistical increase in risk of deep infection rate occurred.

LEVEL OF EVIDENCE

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

Antibiotic bead pouch versus negative pressure wound therapy at initial management of AO/OTA 42 type IIIB open tibia fracture may reduce fracture related infection: A retrospective analysis of 113 patients

INTRODUCTION

Fracture related infection (FRI) may be a devastating complication of open tibial shaft fractures. We sought to determine if antibiotic bead pouch, negative pressure wound therapy, or negative pressure wound therapy over antibiotic beads as the initial coverage method for type IIIB open tibial shaft fractures is associated with risk of FRI.

PATIENTS AND METHODS

Retrospective cohort study with radiograph and chart review of patients aged ≥16 years with isolated, displaced, extra-articular, Gustilo-Anderson type IIIB open diaphyseal AO/OTA 42 tibial fractures requiring rotational or free tissue transfer for soft tissue coverage at one Level 1 trauma center between 2007 and 2020. An association of dressing applied at the first surgical debridement (application of antibiotic bead pouch, negative pressure wound therapy, or combined therapy) with a primary outcome of FRI requiring debridement or amputation was analyzed by multivariable logistic regression considering demographic, injury, and treatment characteristics.

RESULTS

113 patients met eligibility criteria. Median follow-up was 33 months (interquartile range 5-88). 41 patients were initially treated with NPWT, 59 with ABP, and 13 with ABP+NPWT at the initial surgical debridement. 39 (35%) underwent subsequent debridement or amputation for FRI. One amputation occurred in the ABP group for refractory deep surgical site infection (p = 0.630). Initial wound management with an antibiotic bead pouch versus either negative pressure wound therapy alone or negative pressure wound therapy combined with an antibiotic bead pouch was associated with lower odds of debridement or amputation for FRI (β = -1.08, 95% CI -2.00 to -0.17, p = 0.02).

CONCLUSIONS

In our retrospective analysis, antibiotic bead pouch for initial coverage of type IIIB open tibial shaft fractures requiring flap coverage was associated with a lower risk of FRI requiring debridement or amputation than negative pressure wound therapy applied with or without antibiotic beads. A prospective clinical trial is warranted.

Effect of Local Antibiotic Prophylaxis on Postoperative Deep Infection in Fracture Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

Despite the use of systemic antibiotic prophylaxis, postoperative infection after fracture surgery remains an issue. The purpose of this systematic review and meta-analysis was to evaluate the effect of locally applied antibiotics on deep infection in fracture surgery in both the open and closed fractures.

DATA SOURCES

A comprehensive search of MEDLINE, Embase, and PubMed was performed from the date of inception to April 15, 2021, and included studies in all languages.

STUDY SELECTION

Cohort studies were eligible if they investigated the effect on the infection rate of local antibiotic prophylaxis on deep infection after fracture surgery.

DATA EXTRACTION

This study was conducted according to the Cochrane Handbook for Systematic Reviews and reported as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias was assessed using version 2 of the Cochrane risk-of-bias tool for randomized trials and the Methodological Index for Nonrandomized Studies tool where applicable.

DATA SYNTHESIS

An inverse variance random-effects model was the primary analysis model because of the anticipated diversity in the evaluated populations. Univariate models were used when a single outcome was of interest.

CONCLUSIONS

The risk of deep infection was significantly reduced when local antibiotics were applied compared with the control group receiving systemic prophylaxis only. This beneficial effect was observed in open fractures but failed to reach statistical significance in closed fractures. This meta-analysis suggests that there may be a significant risk reduction in deep infection rate after fracture surgery when local antibiotics are added to standard systemic prophylaxis, particularly in open fractures. Further high-powered Level I studies are needed to support these findings.

LEVEL OF EVIDENCE

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

Does prophylactic local tobramycin injection lower open fracture infection rates?

Objective: To determine whether local aqueous tobramycin injection in combination with systemic perioperative IV antibiotic prophylaxis will reduce the rate of fracture-related infection (FRI) after open fracture fixation. Other Outcomes of Interest: (1) To compare fracture nonunion rates and report differences between treatment and control groups and (2) compare bacterial speciation and antibiotic sensitivity among groups that develop FRI. Design: Phase 3 prospective, randomized clinical trial. Setting: Two level 1 trauma centers. Participants: Six hundred subjects (300 in study/tobramycin group and 300 in control/standard practice group) will be enrolled and assigned to the study group or control group using a randomization table. Patients with open extremity fractures that receive definitive internal surgical fixation will be considered. Intervention: Aqueous local tobramycin will be injected into the wound cavity (down to bone) after debridement, irrigation, and fixation, following closure. Main Outcome Measurements: Outcomes will look at the presence or absence of FRI, the rate of fracture nonunion, and determine speciation of gram-negative and Staph bacteria in each group with a FRI. Results: Not applicable. Conclusion: The proposed work will determine whether local tobramycin delivery plus perioperative standard antibiotic synergism will minimize the occurrence of open extremity FRI. Level of Evidence: Level 1.

A review of open pelvic fractures with concurrent genitourinary injuries

INTRODUCTION

Open pelvic fractures (OPFs) are uncommon but potentially lethal traumatic injuries. Often caused by high energy blunt trauma, they can cause severe injury to abdominal and pelvic structures. We sought to conduct a review of the literature in order to ascertain the rates of genitourinary injury and vaginal laceration after OPF and the rates of resulting infection and mortality.

METHODS

A review of PubMed was conducted to identify studies reporting the rates of genitourinary injury from OPF. Study characteristics, patient characteristics, and outcomes were collected. The data were pooled, and descriptive statistics were obtained.

RESULTS

Eight studies encompassing 343 patients were included. Average age was 35.1 years (10-85.9), 28% were female, and the average Injury Severity Score was 26.5 (4-75). 95.5% of patients had a blunt mechanism of injury. Motor vehicle collision (23.9%), motorcycle accident (19.7%), and pedestrian struck (19.3%) were the most common etiologies. Overall mortality and infection rates were 31.2% and 18.7%, respectively. 19.7% of patients suffered an injury to the genitourinary system, and 32.4% of females sustained a vaginal laceration.

DISCUSSION

OPFs have the potential for extremely high morbidity and mortality. While much research has been done to prevent early mortality from hemorrhage, there is comparatively little research into late mortality stemming from infection and sepsis. Intravenous antibiotics are the mainstay of treatment, and local antibiotics usage has been encouraged. In patients with a vaginal laceration, it is important to provide antibiotic coverage for vaginal flora.

Current opinions on the mechanism, classification, imaging diagnosis and treatment of post-traumatic osteomyelitis

Post-traumatic osteomyelitis (PTO) is a worldwide problem in the field of orthopaedic trauma. So far, there is no ideal treatment or consensus-based gold standard for its management. This paper reviews the representative literature focusing on PTO, mainly from the following four aspects: (1) the pathophysiological mechanism of PTO and the interaction mechanism between bacteria and the body, including fracture stress, different components of internal fixation devices, immune response, occurrence and development mechanisms of inflammation in PTO, as well as the occurrence and development mechanisms of PTO in skeletal system; (2) clinical classification, mainly the etiological classification, histological classification, anatomical classification and the newly proposed new classifications (a brief analysis of their scope and limitations); (3) imaging diagnosis, including non-invasive examination and invasive examination (this paper discusses their advantages and disadvantages respectively, and briefly compares the sensitivity and effectiveness of the current examinations); and (4) strategies, including antibiotic administration, surgical choices and other treatment programs. Based on the above-mentioned four aspects, we try to put forward some noteworthy sections, in order to make the existing opinions more specific.

Uncoated vs. Antibiotic-Coated Tibia Nail in Open Diaphyseal Tibial Fracture (42 according to AO Classification): A Single Center Experience

Implant-associated infections remain one of the main problems in the treatment of open tibia fractures. The role of systemic antibiotic prophylaxis is now agreed and accepted; nevertheless, recent literature also seems to emphasize the importance of local antibiotic therapy at the fracture site. Several therapeutic strategies have been proposed to overcome this new need. Antibiotic-coated nails play crucial role in this, allowing both infection prevention and favoring the fracture stabilization. We describe the outcome of patients with open diaphyseal tibia fracture treated either with a standard uncoated nail or a gentamicin-coated nail from January 2016 to December 2018 at our second level emergency-urgency department. Primary outcomes were infection rate and bone union rate. Other outcomes reported are reoperation rate, time between injury and nailing, and safety of antibiotic nail. Numerical variables were tabulated using mean, standard deviation, minimum, maximum, and number of observations. Categorical variables were tabulated using number of observations. 23 patients treated with uncoated nail and 23 patients treated with antibiotic-coated tibia nail were included in the study and were evaluated for a minimum follow-up of 18 months. Among the 46 patients, 9 were Gustilo-Anderson type I, 21 type II, and 16 type III open fracture. Regarding the bone healing rate at 12 months, 16 fractures in the first group and 18 in the second were completely healed. 4 infections were found in the first group (3 superficial surgical site infection and 1 osteomyelitis) and 3 superficial infections in the second one. No adverse events have been recorded with antibiotic-coated nails. In this unicentric retrospective study observed no deep wound infections and good fracture healing in the use of antibiotic-coated nails. Antibiotic nails have been shown to play a role in the treatment of fractures in critically ill patients with severe soft tissue damage.

Prophylactic Topical Antibiotics in Fracture Repair and Spinal Fusion

INTRODUCTION

The objective of this systematic review with meta-analysis is to determine whether prophylactic local antibiotics prevent surgical site infections (SSIs) in instrumented spinal fusions and traumatic fracture repair. A secondary objective is to investigate the effect of vancomycin, a common local antibiotic of choice, on the microbiology of SSIs.

METHODS

An electronic search of PubMed, EMBASE, and Web of Science databases and major orthopedic surgery conferences was conducted to identify studies that (1) were instrumented spinal fusions or fracture repair and (2) had a treatment group that received prophylactic local antibiotics. Both randomized controlled trials (RCTs) and comparative observational studies were included. Meta-analysis was performed separately for randomized and nonrandomized studies with subgroup analysis by study design and antibiotic.

RESULTS

Our review includes 44 articles (30 instrumented spinal fusions and 14 fracture repairs). Intrawound antibiotics significantly decreased the risk of developing SSIs in RCTs of fracture repair (RR 0.61, 95% CI: 0.40-0.93, I 2 = 32.5%) but not RCTs of instrumented spinal fusion. Among observational studies, topical antibiotics significantly reduced the risk of SSIs in instrumented spinal fusions (OR 0.34, 95% CI: 0.27-0.43, I 2 = 52.4%) and in fracture repair (OR 0.49, 95% CI: 0.37-0.65, I 2 = 43.8%). Vancomycin powder decreased the risk of Gram-positive SSIs (OR 0.37, 95% CI: 0.27-0.51, I 2 = 0.0%) and had no effect on Gram-negative SSIs (OR 0.95, 95% CI: 0.62-1.44, I 2 = 0.0%).

CONCLUSIONS

Prophylactic intrawound antibiotic administration decreases the risk of SSIs in fracture surgical fixation in randomized studies. Therapeutic efficacy in instrumented spinal fusion was seen in only nonrandomized studies. Vancomycin appears to be an effective agent against Gram-positive pathogens. There is no evidence that local vancomycin powder is associated with an increased risk for Gram-negative infection.

Evolution in the Acute Management of Open Fracture Treatment? Part 2

INTRODUCTION

In the first installment of this two-part series, we explored the history of open fracture treatment focusing primarily on bacteriology and antibiotic selection/stewardship. In this follow-up segment, we will analyze and summarize the other aspects of open fracture care such as time to debridement, pulsatile lavage, and open wound management (including time to closure)-finishing with summative statements and recommendations based on the current most up-to-date literature.

LEVEL OF EVIDENCE

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

[Open fractures]

Open fractures are associated with a higher rate of infections and delayed fracture healing; therefore, in addition to fracture fixation, infection prevention and soft tissue management are also important. Administration of antibiotics should be carried out as early as possible and over 24-72 h depending on the injury. The initial debridement and assessment of the severity of injury determine the treatment strategy. Fracture fixation follows the general traumatological principles. Simple injury patterns can be treated by primary fixation and wound closure. With substantial contamination, loss of bone or extensive soft tissue damage, temporary fixation and temporary wound closure are carried out. The definitive treatment with soft tissue coverage should be performed within 72 h in order to reduce the risk of fracture-related infections. For osseous segmental defects, different approaches are available to restore bone continuity, depending on the size and soft tissue situation.

Outcome analysis of antibiotic-loaded poly methyl methacrylate (PMMA) beads in musculoskeletal infections

Objective

Despite the availability of an extensive array of antibiotics, musculoskeletal infections are not cured successfully. It is necessary to remove sequestra, infected necrotic tissue, and implants. This study was undertaken to assess the efficacy of poly methyl methacrylate (PMMA) beads and identify the variables that influence eradication and recurrence in the treatment of musculoskeletal infections.

Methods

This study was conducted on 82 patients with chronic osteomyelitis who were treated over a period of 6 years at our tertiary care hospital. We followed up with 71 patients for one year. Clinicoradiological data for the control of infection and bone healing were assessed at the final follow up visit. The correlation between antibiotic sensitivity/resistance and infection was evaluated for Gentamicin + Cefuroxime and Gentamicin + Vancomycin combinations. Chi-squared testing, using SPSS version 16.0, was used for statistical analysis, and a p-value < 0.05 was considered significant.

Results

Fifty-three patients (65.4%) had an exogenous route of infection. Fifty-six patients (68.51%) presented with a discharging sinus on first presentation. In 42 patients (59%), the diagnosis was verified with a positive bacterial culture. In addition, we used antibiotic beads of Gentamicin + Cefuroxime in 74 patients (90%), while in 8 patients (10%), we used Gentamicin + Vancomycin, based on culture and sensitivity results. Recurrence was found in five cases of Gentamicin + Cefuroxime and two cases of Gentamicin + Vancomycin (p = 0.065).

Conclusion

Antibiotics containing PMMA beads are effective in the treatment of chronic osteomyelitis and in preventing the recurrence of infection. It is imperative to identify various factors responsible for the recurrence of infection. This may help clinicians predict the prognosis of the disease and minimise the risk of adverse outcomes.

Elution Kinetics from Antibiotic-Loaded Calcium Sulfate Beads, Antibiotic-Loaded Polymethacrylate Spacers, and a Powdered Antibiotic Bolus for Surgical Site Infections in a Novel In Vitro Draining Knee Model

Antibiotic-tolerant bacterial biofilms are notorious in causing PJI. Antibiotic loaded calcium sulfate bead (CSB) bone void fillers and PMMA cement and powdered vancomycin (VP) have been used to achieve high local antibiotic concentrations; however, the effect of drainage on concentration is poorly understood. We designed an in vitro flow reactor which provides post-surgical drainage rates after knee revision surgery to determine antibiotic concentration profiles. Tobramycin and vancomycin concentrations were determined using LCMS, zones of inhibition confirmed potency and the area under the concentration-time curve (AUC) at various time points was used to compare applications. Concentrations of antibiotcs from the PMMA and CSB initially increased then decreased before increasing after 2 to 3 h, correlating with decreased drainage, demonstrating that concentration was controlled by both release and flow rates. VP achieved the greatest AUC after 2 h, but rapidly dropped below inhibitory levels. CSB combined with PMMA achieved the greatest AUC after 2 h. The combination of PMMA and CSB may present an effective combination for killing biofilm bacteria; however, cytotoxicity and appropriate antibiotic stewardship should be considered. The model may be useful in comparing antibiotic concentration profiles when varying fluid exchange is important. However, further studies are required to assess its utility for predicting clinical efficacy.

Standards of open lower limb fracture care in the United Kingdom

Open fractures of the lower limb remain a potentially devastating group of injuries that are challenging to manage. The primary aims of treatment are to optimise limb function and avoid serious complications such as infection and non-union, which are costly for both the patient and healthcare system. The management of these fractures has evolved significantly, and this is evident following the creation of national open fracture guidelines and a formal trauma system. These have served to standardise care for these injuries in the United Kingdom. The aim of this review is to update our colleagues on the current standard of lower limb open fracture care in the United Kingdom, and the impact this has had on patient outcomes.

Effect of Vancomycin Soaking on Anterior Cruciate Ligament Graft Biomechanics

PURPOSE

To evaluate the effect of soaking of anterior cruciate ligament (ACL) grafts in vancomycin solution on graft biomechanical properties at the time of implantation.

METHODS

The central third of patellar tendons was harvested from mature bovine knees and prepared as a tendon-only graft or a bone-tendon-bone (BTB) graft. Tendons were wrapped in gauze soaked in vancomycin solution (VS) (5 mg/mL) or normal saline (NS) and left to stand for 30 minutes at room temperature, simulating graft exposure times in the operating room during ACL reconstruction. Tensile testing was carried out on a materials testing system with (1) low-magnitude loading (60 N at 3 mm/s) with repeated testing of tendon-only grafts; and (2) high-magnitude loading (600 N at 10 mm/min) of BTB grafts. For tendon-only grafts, specimens were first wrapped in NS-soaked gauze and underwent testing, with repeated testing performed after wrapping in gauze soaked in VS or buffered VS (pH 7.0). For BTB grafts, specimens were randomly assigned to treatment with VS or NS.

RESULTS

For tendon-only grafts, there was no difference in Young's modulus (YM) after soaking with VS soaking (baseline, 12.69 MPa; treatment, 16.07 ± 4.44 MPa; P = .99) or buffered VS (baseline, 12.45 ± 4.55 MPa; treatment, 15.56 ± 2.83 MPa; P = .99). For BTB grafts, there were no differences in elongation strain (VS, 46.8% ± 7.0%; NS, 31.5% ± 13.5%, P = .19) or YM (VS, 158.4 ± 15.8 MPa; NS, 158.5 ± 23.3 MPa, P = .99).

CONCLUSIONS

According to controlled biomechanical tests, vancomycin soaking of patellar tendon grafts does not adversely affect time-zero material properties.

CLINICAL RELEVANCE

This study suggests that vancomycin wrapping has no immediate adverse effects on the biomechanical properties of ACL grafts. Randomized controlled trials are warranted to validate the widespread use of vancomycin soaking of tendon grafts for infection prophylaxis during ACL reconstruction.

Antibiotic loaded β-tricalcium phosphate/calcium sulfate for antimicrobial potency, prevention and killing efficacy of Pseudomonas aeruginosa and Staphylococcus aureus biofilms

This study investigated the efficacy of a biphasic synthetic β-tricalcium phosphate/calcium sulfate (β-TCP/CS) bone graft substitute for compatibility with vancomycin (V) in combination with tobramycin (T) or gentamicin (G) evidenced by the duration of potency and the prevention and killing efficacies of P. aeruginosa (PAO1) and S. aureus (SAP231) biofilms in in vitro assays. Antibiotic loaded β-TCP/CS beads were compared with antibiotic loaded beads formed from a well characterized synthetic calcium sulfate (CS) bone void filler. β-TCP/CS antibiotic loaded showed antimicrobial potency against PAO1 in a repeated Kirby-Bauer like zone of inhibition assay for 6 days compared to 8 days for CS. However, both bead types showed potency against SAP231 for 40 days. Both formulations loaded with V + T completely prevented biofilm formation (CFU below detection limits) for the 3 days of the experiment with daily fresh inoculum challenges (P < 0.001). In addition, both antibiotic loaded materials and antibiotic combinations significantly reduced the bioburden of pre-grown biofilms by between 3 and 5 logs (P < 0.001) with V + G performing slightly better against PAO1 than V + T. Our data, combined with previous data on osteogenesis suggest that antibiotic loaded β-TCP/CS may have potential to stimulate osteogenesis through acting as a scaffold as well as simultaneously protecting against biofilm infection. Future in vivo experiments and clinical investigations are warranted to more comprehensively evaluate the use of β-TCP/CS in the management of orthopaedic infections.

Early application of topical antibiotic powder in open-fracture wounds: A strategy to prevent biofilm formation and infections

Despite meticulous surgical care and systemic antibiotics, open fracture wounds have high rates of infection leading to increased morbidity. To reduce infection rates, orthopaedic surgeons may administer local antibiotics using various carriers that may be ineffective due to poor antibiotic release from carriers, subsequent surgery to remove nondegradable carriers, and mismatch between release kinetics and material degradation. Biofilms form rapidly as bacteria that are within the wound multiply quickly and transform from the antibiotic-susceptible planktonic phenotype to the antibiotic-tolerant biofilm phenotype. This tolerance to antibiotics can occur within hours. Currently, local antibiotics are placed in the wounds using a carrier such as polymethylmethacrylate beads; however, this occurs after surgical debridement that can be hours to even a day after initial injury allowing bacteria enough time to form a biofilm that makes the antibiotic containing polymethylmethacrylate beads less effective. In contrast, emerging practices in elective surgical procedures, such as spine fusion, place antibiotic powder (e.g. vancomycin) in the wound at the time of closure. This has been shown to be extremely effective, presumably because of the very small-time period between potential contamination and local antibiotic application. There is evidence that suggests that the ineffectiveness of local antibiotic use in open fractures is primarily due to the delay in application of local antibiotics from the time of injury and propose a concept of topical antibiotic powder application in the prehospital or emergency department setting.

Delay of Antibiotic Administration Greater than 2 Hours Predicts Surgical Site Infection in Open Fractures

AIMS

Antibiotic administration, severity of injury, and debridement are associated with surgical site infection (SSI) after internal fixation of open fractures. We sought to validate a time-dependent treatment effect of antibiotic administration.

PATIENTS

Consecutive open fracture patients at a level 1 trauma center with minimum 30-day follow-up were identified from an orthopaedic registry from 2013-2017.

METHODS

The primary endpoint was SSI within 90 days. A threshold time to antibiotic administration associated with SSI was ascertained by receiver-operator analysis. A Cox proportional hazards model adjusted for age, smoking, and drug use determined the treatment effect of antibiotic administration within the threshold period.

RESULTS

Ten percent of 230 patients developed a SSI. There was a trend for patients who did not develop an SSI to receive antibiotics earlier than those who did develop an SSI (61 minutes, IQR 33-107 vs 83 minutes, IQR 40-186), p=0.053). Intravenous antibiotic administration after 120 minutes of presentation of an open fracture to emergency department was significantly associated with a 2.4 increased hazard of surgical site infection (p=0.036) within 90 days.

CONCLUSION

Antibiotic administration greater than 120 minutes after ED presentation of an open fracture was associated with an increased risk of SSI.

Staphylococcus aureus Osteomyelitis: Bone, Bugs, and Surgery

Osteomyelitis, or inflammation of bone, is most commonly caused by invasion of bacterial pathogens into the skeleton. Bacterial osteomyelitis is notoriously difficult to treat, in part because of the widespread antimicrobial resistance in the preeminent etiologic agent, the Gram-positive bacterium Staphylococcus aureus Bacterial osteomyelitis triggers pathological bone remodeling, which in turn leads to sequestration of infectious foci from innate immune effectors and systemically delivered antimicrobials. Treatment of osteomyelitis therefore typically consists of long courses of antibiotics in conjunction with surgical debridement of necrotic infected tissues. Even with these extreme measures, many patients go on to develop chronic infection or sustain disease comorbidities. A better mechanistic understanding of how bacteria invade, survive within, and trigger pathological remodeling of bone could therefore lead to new therapies aimed at prevention or treatment of osteomyelitis as well as amelioration of disease morbidity. In this minireview, we highlight recent developments in our understanding of how pathogens invade and survive within bone, how bacterial infection or resulting innate immune responses trigger changes in bone remodeling, and how model systems can be leveraged to identify new therapeutic targets. We review the current state of osteomyelitis epidemiology, diagnostics, and therapeutic guidelines to help direct future research in bacterial pathogenesis.

Temperature-responsive PNDJ hydrogels provide high and sustained antimicrobial concentrations in surgical sites

Local antimicrobial delivery is a promising strategy for improving treatment of deep surgical site infections (SSIs) by eradicating bacteria that remain in the wound or around its margins after surgical debridement. Eradication of biofilm bacteria can require sustained exposure to high antimicrobial concentrations (we estimate 100-1000 μg/mL sustained for 24 h) which are far in excess of what can be provided by systemic administration. We have previously reported the development of temperature-responsive hydrogels based on poly(N-isopropylacrylamide-co-dimethylbutyrolactone acrylate-co-Jeffamine M-1000 acrylamide) (PNDJ) that provide sustained antimicrobial release in vitro and are effective in treating a rabbit model of osteomyelitis when instilled after surgical debridement. In this work, we sought to measure in vivo antimicrobial release from PNDJ hydrogels and the antimicrobial concentrations provided in adjacent tissues. PNDJ hydrogels containing tobramycin and vancomycin were administered in four dosing sites in rabbits (intramedullary in the femoral canal, soft tissue defect in the quadriceps, intramuscular injection in the hamstrings, and intra-articular injection in the knee). Gel and tissue were collected up to 72 h after dosing and drug levels were analyzed. In vivo antimicrobial release (43-95% after 72 h) was markedly faster than in vitro release. Drug levels varied significantly depending on the dosing site but not between polymer formulations tested. Notably, total antimicrobial concentrations in adjacent tissue in all dosing sites were sustained at estimated biofilm-eradicating levels for at least 24 h (461-3161 μg/mL at 24 h). These results suggest that antimicrobial-loaded PNDJ hydrogels are promising for improving the treatment of biofilm-based SSIs.

Controlled Release of Vancomycin and Tigecycline from an Orthopaedic Implant Coating Prevents Staphylococcus aureus Infection in an Open Fracture Animal Model

Introduction

Treatment of open fractures routinely involves multiple surgeries and delayed definitive fracture fixation because of concern for infection. If implants were made less susceptible to infection, a one-stage procedure with intramedullary nailing would be more feasible, which would reduce morbidity and improve outcomes.

Methods

In this study, a novel open fracture mouse model was developed using Staphylococcus aureus (S. aureus) and single-stage intramedullary fixation. The model was used to evaluate whether implants coated with a novel “smart” polymer coating containing vancomycin or tigecycline would be colonized by bacteria in an open fracture model infected with S. aureus. In vivo bioluminescence, ex vivo CFUs, and X-ray images were evaluated over a 42-day postoperative period.

Results

We found evidence of a markedly decreased bacterial burden with the local release of vancomycin and tigecycline from the PEG-PPS polymer compared to polymer alone. Vancomycin was released in a controlled fashion and maintained local drug concentrations above the minimum inhibition concentration for S. aureus for greater than 7 days postoperatively. Bacteria were reduced 139-fold from implants containing vancomycin and undetected from the bone and soft tissue. Tigecycline coatings led to a 5991-fold reduction in bacteria isolated from bone and soft tissue and 15-fold reduction on the implants compared to polymer alone. Antibiotic coatings also prevented osteomyelitis and implant loosening as observed on X-ray.

Conclusion

Vancomycin and tigecycline can be encapsulated in a polymer coating and released over time to maintain therapeutic levels during the perioperative period. Our results suggest that antibiotic coatings can be used to prevent implant infection and osteomyelitis in the setting of open fracture. This novel open fracture mouse model can be used as a powerful in vivo preclinical tool to evaluate and optimize the treatment of open fractures before further studies in humans.

A Scoping Review on the Use of Antibiotic-Impregnated Beads and Applications to Vascular Surgery

INTRODUCTION

Surgical site infection (SSI) presents a ubiquitous concern to surgical specialties, especially in the presence of prosthetic material. Antibiotic-impregnated beads present a novel and evolving means to combat this condition. This review aims to analyze the quality of evidence and methods of antibiotic bead use, particularly for application within vascular surgery.

METHODS

A systematic scoping review was conducted within Embase, MEDLINE, and the Cochrane Registry of Randomized Controlled Trials. Articles were evaluated by 2 independent reviewers. Level of evidence was evaluated using the Oxford Center for Evidence-Based Medicine Criteria and the Cochrane Risk of Bias Tool for Randomized Controlled Trials.

RESULTS

The search yielded 6951 papers, with 275 included for final analysis. Publications increased in frequency from 1978 to the present. The most common formulation was polymethyl methacrylate; however publications on biodegradable formulations, including calcium sulfate beads, have been published with increasing frequency. Most publications had positive conclusions (94.2%); however, the data was mainly subjective and may be prone to publication bias. Only 11 randomized controlled trials were identified and all but one was evaluated to be at a high risk of bias. The most common indication was for osteomyelitis (52%), orthopedic prosthetic infections (20%), and trauma (9%). Within vascular surgery, beads have been used primarily for the treatment of graft infection, with freedom from recurrence rates being reported from 41% to 87.5%.

CONCLUSIONS

Antibiotic-impregnated beads provide a means to deliver high doses of antibiotic directly to a surgical site, without the risks of parenteral therapy. There has yet to be significant high-level quality data published on their use. There is a large body of evidence that suggests antibiotic beads may be used in SSIs in high-risk patients, prosthetic infections, and other complex surgical infections. Important potential areas of application in vascular surgery include graft infection, prevention of wound infection in high-risk patients, and diabetic foot infection.

Antibiotic Impregnated Cement Dowel in a Tibial Stump to Salvage Infected Below-Knee Amputation in a Diabetic

Case:

We describe the use of local antibiotics to salvage an infected below-knee amputation in a diabetic patient and prevent the need to convert to the above-knee level. After débridement, an antibiotic tibial “dowel” was fashioned and inserted into the intramedullary canal before closure. The wound was fully healed after four months, and the patient remained satisfied at 15 months.

Conclusion:

This case report offers an adjunct to the conventional management of diabetic stump infections. The addition of an antibiotic spacer could offer an alternative to a higher level of amputation and improve the survival rates of below-knee amputation in this difficult population.

Infectious Prophylaxis with Intrawound Vancomycin Powder in Orthopedic Surgeries: Systematic Review with Meta-Analysis

Despite many existing strategies used to reduce the rates of surgical site infection (SSI), these are still fairly frequent complications that pose a challenge for orthopedic surgeons. Therefore, the search for more effective methods of perioperative infection prophylaxis became a main subject of research, with the goal of decreasing postoperative morbidity, mortality, and costs. Thus, the present study sought to assess the effectiveness of intra-wound vancomycin powder in orthopedic surgery SSI prophylaxis. A systematic review and meta-analysis study was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols 2015 (PRISMA-P 2015). A comprehensive literature search was performed to identify controlled studies on the rates of SSI with or without the local use of vancomycin powder. Exclusion and inclusion criteria were applied. A meta-analysis with random effects was performed. Out of 412 titles that met the criteria, 7 studies regarding spine surgery were included: 4 prospective and 3 retrospective studies. A total of 6,944 cases were identified, and they were divided into 2 groups: the control group (3,814 patients), to whom intrawound vancomycin was not administered, and the intervention group (3,130 patients), to who vancomycin was administered locally. We observed that 64 (2.04%) patients in the intervention group developed SSI, in contrast to 144 (3.75%) patients in the control group. The results of the meta-analysis showed that the local use of vancomycin powder had an statistically significant protective effect against SSI in cases of spine surgery, with a relative risk (RR) of 0.59 and a 95% confidence interval (95%CI) of 0.35-0.98. The use of prophylactic intrawound vancomycin powder has a protective effect against SSI in spine surgeries; however, further prospective trials are needed to endorse its use in orthopedic surgeries.

Orthoplastic reconstruction of type IIIB open tibial fractures retaining debrided devitalized cortical segments: the Bristol experience 2014 to 2018

AIMS

Type IIIB open tibial fractures are devastating high-energy injuries. At initial debridement, the surgeon will often be faced with large bone fragments with tenuous, if any, soft-tissue attachments. Conventionally these are discarded to avoid infection. We aimed to determine if orthoplastic reconstruction using mechanically relevant devitalized bone (ORDB) was associated with an increased infection rate in type IIIB open tibial shaft fractures.

PATIENT AND METHODS

This was a consecutive cohort study of 113 patients, who had sustained type IIIB fractures of the tibia following blunt trauma, over a four-year period in a level 1 trauma centre. The median age was 44.3 years (interquartile range (IQR) 28.1 to 65.9) with a median follow-up of 1.7 years (IQR 1.2 to 2.1). There were 73 male patients and 40 female patients. The primary outcome measures were deep infection rate and number of operations. The secondary outcomes were nonunion and flap failure.

RESULTS

In all, 44 patients had ORDB as part of their reconstruction, with the remaining 69 not requiring it. Eight out of 113 patients (7.1%) developed a deep infection (ORDB 1/44, non-ORDB 7/69). The median number of operations was two. A total of 16/242 complication-related reoperations were undertaken (6.6%), with 2/16 (12.5%) occurring in the ORDB group.

CONCLUSION

In the setting of an effective orthoplastic approach to type IIIB open diaphyseal tibial fractures, using mechanically relevant debrided devitalized bone fragments in the definitive reconstruction appears to be safe. Cite this article: Bone Joint J 2019;101-B:1002-1008.

Clinical practice in prevention of fracture-related infection: An international survey among 1197 orthopaedic trauma surgeons

INTRODUCTION

Open fractures are still a challenge in orthopaedic trauma surgery, and compared to closed fractures, the rate of complications including fracture-related infection (FRI) remains significantly higher. Although different guidelines on prevention of FRI have been published in past decades, the current recommendations vary significantly. The objectives of this international questionnaire were to evaluate clinical practice procedures for the prevention of FRI in open fractures and to evaluate adherence to available guidelines.

METHODS

A 17-item questionnaire regarding prophylaxis against infection in fracture care was administered by SurveyMonkey® and was sent via blast e-mail to all users of AOTrauma (Davos, Switzerland).

RESULTS

Overall, 1197 orthopaedic trauma surgeons answered the survey. Although cephalosporins were the most commonly prescribed agents for perioperative antibiotic prophylaxis (PAP) in open fractures, a total of 13 different antibiotics were mentioned in the survey. Furthermore, the duration of PAP was extremely variable with a tendency towards longer treatment periods with increasing open fracture severity. The majority of surgeons (71%) agreed that the optimal duration of PAP was not well defined in the literature. The use of local anti-infective agents varied significantly, although all options received additional votes with increasing injury severity. Some of the other surgical aspects addressed in this review were associated with debridement and irrigation. A delay of six hours from injury to the first debridement was acceptable to 47% of surgeons, but delays were tolerable. Normal saline was the solution used most often for wound irrigation in open fractures (89%), with low-pressure irrigation being applied most commonly (55%).

CONCLUSIONS

This international survey provided an overview of clinical practice in FRI prevention, particularly in open fracture cases. The treatment of these serious injuries remains heterogeneous. A major issue is the lack of consensus concerning type and duration of PAP. Furthermore, there seems to be no agreement on the indication for the use of local anti-infective agents. Overall, it is unknown what the repercussions are of this lack of internationally accepted guidelines on daily clinical practice, but it is clear that standardised treatment protocols are preferable in the current medical landscape.

Increased perioperative C-reactive protein and decreased postoperative albumin is associated with acute posttraumatic osteomyelitis in patients with high-energy tibial fractures

BACKGROUND

Early diagnosis of acute posttraumatic osteomyelitis (POM) is of vital importance for avoiding devastating complications. Diagnosing POM is difficult due to the lack of a highly specific and sensitive test, such as in myocardial infarct, stroke and intracranial bleeding. Serum inflammatory markers, C-reactive protein (CRP), procalcitonin (PCT), white blood cells (WBC) can support clinical findings but they are not able to differentiate between inflammatory response to infection and the host response to non-infection insult with high specificity and sensitivity.

AIM

The objectives of the study were to investigate whether the biochemical and immunoinflammatory patient profile could facilitate postoperative monitoring, guide the antibiotic treatment and timing of revision surgery.

PATIENTS AND METHODS

This prospective nonrandomised cohort study included 86 patients after high-energy injury to the shin requiring primary surgical treatment (open or closed reduction and internal fixation of tibial fracture). Values of the biochemical and immunoinflammatory profile were measured on admission (ADD), first postoperative day (POD1) and fourth-postoperative day (POD4).

RESULTS

We discovered on our sample that the development of POM is associated with increased CRP on ADD, POD1 and decreased albumins on POD4. Further studies are needed to prove that these differences can be useful in diagnosing the risk of infection. The assessment of other important risk factors such as: the extent of soft tissue damage, multiple fractures, transfusion rate, need for conversion primary external fixation to intramedullary (IM) nailing or locking plate fixation can empower our clinical judgment of POM.

CONCLUSIONS

We can improve prediction of posttraumatic osteomyelitis by using the perioperative inflammatory biomarker CRP in combination with postoperative albumins levels and other associated independent risk factors.

Vancomycin elution from a biphasic ceramic bone substitute

Objectives

The aim of this study was to analyze drain fluid, blood, and urine simultaneously to follow the long-term release of vancomycin from a biphasic ceramic carrier in major hip surgery. Our hypothesis was that there would be high local vancomycin concentrations during the first week with safe low systemic trough levels and a complete antibiotic release during the first month.

Methods

Nine patients (six female, three male; mean age 75.3 years (sd 12.3; 44 to 84)) with trochanteric hip fractures had internal fixations. An injectable ceramic bone substitute, with hydroxyapatite in a calcium sulphate matrix, containing 66 mg of vancomycin per millilitre, was inserted to augment the fixation. The vancomycin elution was followed by simultaneously collecting drain fluid, blood, and urine.

Results

The antibiotic concentration in the drain reached a peak during the first six hours post-surgery (mean 966.1 mg/l), which decreased linearly to a mean value of 88.3 mg/l at 2.5 days. In the urine, the vancomycin concentration reached 99.8 mg/l during the first two days, followed by a logarithmic decrease over the next two weeks to reach 0 mg/l at 20 days. The systemic concentration of vancomycin measured in blood serum was low and decreased linearly from 2.17 mg/l at one hour post-surgery to 0 mg/l at four days postoperatively.

Conclusion

This is the first long-term pharmacokinetic study that reports vancomycin release from a biphasic injectable ceramic bone substitute. The study shows initial high targeted local vancomycin levels, sustained and complete release at three weeks, and systemic concentrations well below toxic levels. The plain ceramic bone substitute has been proven to regenerate bone but should also be useful in preventing bone infection.

Cite this article: M. Stravinskas, M. Nilsson, A. Vitkauskiene, S. Tarasevicius, L. Lidgren. Vancomycin elution from a biphasic ceramic bone substitute. Bone Joint Res 2019;8:49–54. DOI: 10.1302/2046-3758.82.BJR-2018-0174.R2.

Salvage of rib stabilization hardware with antibiotic beads

BACKGROUND

Surgical stabilization of rib fractures (SSRF) can be used to improve pulmonary mechanics; however, hardware infection is a morbid complication. Antibiotic impregnated beads have been used to suppress infection in orthopedic practices. We aimed to determine the efficacy of antibiotic beads for infected and at-risk SSRF hardware.

METHODS

This is a single institution retrospective review of adults (18 years or older) that received SSRF between 2009 and 2017. Infected and at-risk hardware were managed with antibiotic beads. The primary outcome was bony union of rib fractures.

RESULTS

There were 285 SSRF patients. Infection rate was 3.5%. Antibiotic beads were placed in 17 patients - 9 for infected hardware and 8 for prophylaxis. Increased body mass index (p = 0.04) and hemorrhagic shock at admission (p = 0.03) were risk factors for infection. There was 100% bony union post-operatively.

CONCLUSION

SSRF hardware infection is morbid. Antibiotic beads can salvage SSRF hardware until bony union.

Topical rifampin powder for orthopedic trauma part I: Rifampin powder reduces recalcitrant infection in a delayed treatment musculoskeletal trauma model

Open fractures become infected despite meticulous debridement and care. Locally applied antibiotics, commonly embedded in polymethylmethacrylate, deliver high doses of drug directly to the fracture site. Direct application of antibiotic powder, which is being applied prophylactically in spine surgery, is a recent interest in the trauma sector, where bacterial biofilms are more prevalent. Traditional antibiotics, such as vancomycin, are poor performers against bacterial biofilms thus are ineffective in delayed treatment. Rifampin is an effective eradicator of Staphylococcal biofilms. Here, a rat model of musculoskeletal trauma was used to evaluate the utility of locally applied rifampin powder for reducing established orthopedic Staphylococcal infections in a delayed treatment scenario that previously indicated the limited use of local vancomycin. By applying rifampin powder directly to the contaminated segmental defect, the number of bacteria, as well as clinical indications of infection, were significantly reduced compared to vancomycin and daptomycin. Considering the Infectious Disease Society of America's recommendation to use rifampin in combination with another antibiotic to reduce the onset of rifampin resistance, rifampin powder was also applied in combination with vancomycin or daptomycin with insignificant changes in eradication performance. No indications of rifampin resistance were identified. Clinical Significance: The use of locally applied rifampin is a promising therapy for mature and tolerant musculoskeletal infections. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. J Orthop Res 36:3136-3141, 2018.

Intrawound Vancomycin Powder Reduces Bacterial Load in Contaminated Open Fracture Model

OBJECTIVES

To compare the effectiveness of both vancomycin powder and antibiotic bead placement to irrigation and debridement alone in prevention of infection in a contaminated open fracture model in rats.

METHODS

In a previously described model of contaminated open fractures, 45 rats had simulated open fractures created, stabilized, and contaminated with Staphylococcus aureus. They were then treated 6 hours later with 3 interventions: irrigation and debridement alone (control group) or in combination with placement of polymethyl methacrylate beads containing vancomycin and tobramycin powders (antibiotic bead group) or placement of 10 mg of intrawound vancomycin powder (powder group). Rats were allowed to recover and then killed 14 days later for harvest of femurs and plates. Femurs and plates were both incubated overnight, and bacterial colonies were counted in each group for comparison.

RESULTS

Quantitative counts of bacteria in bone showed significantly reduced growth in both bead and powder groups when compared with control group (P < 0.0001). Quantitative counts of bacteria in plates showed significantly reduced growth in both bead and powder groups when compared with control group (P < 0.0003; 0.029). No significant differences were seen in bacterial growth between bead and powder groups for either bones (P = 0.13) or plates (P = 0.065).

CONCLUSIONS

When compared with irrigation and debridement alone, placement of intrawound vancomycin powder significantly decreased bacterial load in a contaminated open fracture model in rats similar to placing antibiotic beads. This may provide an additional adjuvant treatment that does not require a secondary surgery for bead removal.

[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.

The effect of local antibiotic prophylaxis when treating open limb fractures: A systematic review and meta-analysis

Objectives

As well as debridement and irrigation, soft-tissue coverage, and osseous stabilization, systemic antibiotic prophylaxis is considered the benchmark in the management of open fractures and considerably reduces the risk of subsequent fracture-related infections (FRI). The direct application of antibiotics in the surgical field (local antibiotics) has been used for decades as additional prophylaxis in open fractures, although definitive evidence confirming a beneficial effect is scarce. The purpose of the present study was to review the clinical evidence regarding the effect of prophylactic application of local antibiotics in open limb fractures.

Methods

A comprehensive literature search was performed in PubMed, Web of Science, and Embase. Cohort studies investigating the effect of additional local antibiotic prophylaxis compared with systemic prophylaxis alone in the management of open fractures were included and the data were pooled in a meta-analysis.

Results

In total, eight studies which included 2738 patients were eligible for quantitative synthesis. The effect of antibiotic-loaded poly(methyl methacrylate) beads was investigated by six of these studies, and two studies evaluated the effect of local antibiotics applied without a carrier. Meta-analysis showed a significantly lower infection rate when local antibiotics were applied (4.6%; 91/1986) than in the control group receiving standard systemic prophylaxis alone (16.5%; 124/752) (p < 0.001) (odds ratio 0.30; 95% confidence interval 0.22 to 0.40).

Conclusion

This meta-analysis suggests a risk reduction in FRI of 11.9% if additional local antibiotics are given prophylactically for open limb fractures. However, due to limited quality, heterogeneity, and considerable risk of bias, the pooling of data from primary studies has to be interpreted with caution.

Cite this article: M. Morgenstern, A. Vallejo, M. A. McNally, T. F. Moriarty, J. Y. Ferguson, S. Nijs, WJ. Metsemakers. Bone Joint Res 2018;7:447–456. The effect of local antibiotic prophylaxis when treating open limb fractures: A systematic review and meta-analysis. DOI: 10.1302/2046-3758.77.BJR-2018-0043.R1

Local control of polymicrobial infections via a dual antibiotic delivery system

BACKGROUND

Contaminated traumatic open orthopedic wounds are frequently complicated by polymicrobial contamination and infection. In high-risk wounds, the standard of care comprises debridement and irrigation combined with antibiotics which can be applied directly or combined with systemic antibiotics. Recently, bioabsorbable chitosan sponges have been shown to be an effective single-agent delivery device for local antibiotics with and without negative pressure wound therapy (NPWT). Severely contaminated orthopedic wounds, however, are often complicated by polymicrobial infections, necessitating multiple antibiotic agents. As such, the purpose of this study was to determine if a chitosan sponge would provide a suitable delivery vehicle for multiple antibiotics for the treatment of a polymicrobial infection in a large animal polytraumatic extremity wound model.

METHODS

A complex polytraumatic extremity wound was created in 11 adult male Boer goats. Each wound was contaminated with a bioluminescent strain of S. aureus (1 ml of 10⁸ colony forming units/ml) and of P. aeruginosa (1 ml of 10⁸ CFU/ml) which are genetically engineered to allow quantification with a photon-counting camera. Six hours following initial wound creation and contamination, wounds were debrided and irrigated with low-pressure normal saline. The animals were randomized into one of two treatments: wet-to-dry dressings alone or a commercially available chitosan sponge loaded with 1 g vancomycin and 1.2 g of tobramycin. Each animal was then recovered and reimaged 48 h later for total bacteria content; tissue samples were taken from the wound bed to determine relative bacterial colonization.

RESULTS

All animals in the chitosan sponge group saw significant reductions in overall bacterial load of S. aureus and P. aeruginosa (p = 0.001). The bioluminescence was also significantly reduced compared to the wet-to-dry dressing group (p = 0.0001). Furthermore, whereas the antibiotic sponge group displayed near complete eradication of bacteria, the wounds treated with the wet-to-dry dressings alone displayed a significant 2-log increase in total bacteria at 48 h p = 0.0001). S. aureus was the predominant species found in the wounds, comprising 95 and 99% of all bacteria found in the chitosan sponge and wet-to-dry, respectively.

CONCLUSION

Dual antimicrobial therapy loaded in a chitosan sponge is an effective way to reduce polymicrobial infections traumatic extremity wound.

Infection after fracture fixation: Current surgical and microbiological concepts

One of the most challenging complications in trauma surgery is infection after fracture fixation (IAFF). IAFF may result in permanent functional loss or even amputation of the affected limb in patients who may otherwise be expected to achieve complete, uneventful healing. Over the past decades, the problem of implant related bone infections has garnered increasing attention both in the clinical as well as preclinical arenas; however this has primarily been focused upon prosthetic joint infection (PJI), rather than on IAFF. Although IAFF shares many similarities with PJI, there are numerous critical differences in many facets including prevention, diagnosis and treatment. Admittedly, extrapolating data from PJI research to IAFF has been of value to the trauma surgeon, but we should also be aware of the unique challenges posed by IAFF that may not be accounted for in the PJI literature. This review summarizes the clinical approaches towards the diagnosis and treatment of IAFF with an emphasis on the unique aspects of fracture care that distinguish IAFF from PJI. Finally, recent developments in anti-infective technologies that may be particularly suitable or applicable for trauma patients in the future will be briefly discussed.

Use of antibiotic impregnated resorbable beads reduces pressure ulcer recurrence: A retrospective analysis

Recurrence of pressure ulcers remains common. We have employed resorbable antibiotic beads as a therapeutic strategy to deliver high local antibiotic concentrations to the debridement site. Our objective was to determine whether the use of resorbable antibiotic- beads would reduce pressure ulcer recurrence. We reviewed all stage IV pressure ulcers treated with excision, partial ostectomy and flap coverage over 16 years. Baseline patient factors (location of ulcer, presence of osteomyelitis, preoperative prealbumin), surgical factors (type of flap, use of antibiotic beads, bone culture results) and postoperative outcomes (ulcer recurrence at 1 year, dehiscence, seroma, cellulitis) were collected. Outcomes of patients who received antibiotic-impregnated beads were compared to those who did not. Eighty-six patients with 120 stage IV pressure ulcers underwent excision and flap coverage. This included 16 ulcers where antibiotic beads were used and 104 where they were not. The overall ulcer recurrence rate at 12 months was 35.8%. The recurrence rate in the group treated with antibiotic beads was significantly lower than the group without beads (12.5% vs. 39.4%, p = 0.03). Overall, complication rates between the two groups were similar (43.8% vs. 51.9%, p = 0.54). No systemic or local toxicity from antibiotic beads occurred. Scanning electron microscopy images of sacral bone from one case showed bacterial biofilm even after debridement. Pressure ulcer recurrence at 1 year after excision and flap coverage decreased significantly with the use of resorbable antibiotic beads.

Do local antibiotics reduce periprosthetic joint infections? A retrospective review of 744 cases

Periprosthetic joint infections (PJI) are uncommon but not rare and have significant morbidity and financial implications. Local antibiotics have been used successfully in other areas of orthopedics to reduce postoperative infections, but this method has not been proven in total joint arthroplasty (TJA). Beginning January 1, 2014, our primary investigators began using surgical site lavage with providone-iodine solution and administering 2 g of vancomcyin powder in the surgical wound prior to capsule closure for all primary and revision total hip and knee arthroplasties. We performed a retrospective chart review of patients two years prior to this date and two years after to compare occurrence of PJI. The groups were broken down into patients who received local antibiotics versus those who did not. The groups were further broken down by type of surgery performed; primary or revision total hip or knee arthroplasty. Administration of local antibiotics was preventative for PJI only in the primary total knee arthroplasty group (aOR = 0.28, 0.09-0.89). Administration of local antibiotics trended towards a preventative effect for PJI in the other groups but was not statistically significant. Patients receiving local antibiotics had similar blood urea nitrogen and creatinine levels postoperatively compared to the no antibiotics group indicating minimal systemic effects of local vancomycin powder. While the use of local antibiotics may prevent PJI, more data is required especially in the revision arthroplasty groups.

Circular external fixation and cemented PMMA spacers for the treatment of complex tibial fractures and infected nonunions with segmental bone loss

PURPOSE

The purpose of this study was to compare the outcome of combined circular external fixation and cemented polymethylmethacrylate (PMMA) spacer application between a cohort of patients with grade 3 open fractures and infected tibial nonunions and concomitant segmental bone loss.

METHODS

The study was designed as a retrospective cohort study. All patients who were treated for complex tibial fractures or infected nonunions with segmental bone loss between 2009 and 2013 were included if they were aged between 16 years and 60 years, sustained acute traumatic grade 3 open tibial fractures, presented with infected nonunion, and were followed up for a minimum of 12 months. Patients with a history of ipsilateral tibial fractures, contralateral lower extremity fractures, polytrauma, chest, or abdominal trauma and patients with head injuries were excluded. Both groups were treated with aggressive debridement, circular external fixation, and antibiotic-impregnated PMMA spacer. Outcome measures were the time in the external fixator (EFT) and the external fixation index (EFI).

RESULTS

Twenty-four patients with a mean age of 32 ± 14.7 years were included. Twelve patients with a mean age of 32 + 14 years and a mean bone defect of 82 + 36 mm were treated for acute complex grade 3 open tibial fractures, and 12 patients with a mean age of 35.1 + 15.7 years and a mean bone defect of 50 + 26 mm were treated for infected nonunions. There was no significant difference ( p = 0.44) between the groups for EFT (249 ± 99 days-tibial fractures; 255 ± 142 days-infected nonunion). There were significant between group differences ( p = 0.027) for EFI (37.3 ± 9.1 cm/days-tibial fractures; 56 ± 14.5 cm/days-infected nonunion).

CONCLUSION

The findings of this study suggest that patients were treated for infected nonunion with segmental bone loss using circular external fixation, distraction osteogenesis, and antibiotic-impregnated PMMA spacers, and the spacers may not offer any advantage over a conventional approach using the principles of osteogenesis only. In contrast, antibiotic-impregnated spacers for open tibial trauma were advantageous and reduced the EFI considerably.