Prophylactic antibiotics in hip and knee arthroplasty

Increased rates of periprosthetic joint infection following hip hemiarthroplasty with clindamycin prophylaxis compared to cefazolin

PURPOSE

To compare the efficacy of clindamycin versus cefazolin in preventing periprosthetic joint infection (PJI) in patients undergoing hip hemiarthroplasty (HA) for femoral neck fractures.

METHODS

This retrospective cohort study included 1,139 patients aged ≥ 65 years who underwent HA for femoral neck fractures between January 2017 and October 2023. Patients received either Cefazolin + Gentamicin (n = 1001) or Clindamycin + Gentamicin (n = 138). Propensity score matching was performed at a 6:1 ratio, resulting in 828 patients in the cefazolin group and 138 in the clindamycin group. PJI rates, causative organisms, and mortality were compared. Multivariate logistic regression adjusted for potential confounders.

RESULTS

The PJI rate was significantly higher in the clindamycin group compared to the cefazolin group (7.2% vs. 3.5%, p = 0.042). Multivariate analysis confirmed that clindamycin prophylaxis was independently associated with increased PJI risk (adjusted OR = 2.41, 95% CI: 1.16-4.99, p = 0.018). Other independent risk factors for PJI included age (adjusted OR = 1.03 per year, 95% CI: 1.01-1.05, p = 0.045), diabetes mellitus (adjusted OR = 1.76, 95% CI: 1.10-2.81, p = 0.018), and surgery duration (adjusted OR = 1.07 per minute, 95% CI: 1.01-1.16, p = 0.035). Staphylococcus aureus was the most common pathogen, with no significant differences in bacterial distribution between the groups. No significant differences were found in 30-day or 1-year mortality rates.

CONCLUSION

Clindamycin prophylaxis in hip hemiarthroplasty for femoral neck fractures is associated with a significantly higher risk of PJI compared to cefazolin. These findings support the preferential use of cefazolin in patients without contraindications and demonstrate the critical need for accurate assessment of reported beta-lactam allergies. Results suggest potential benefit from pre-operative allergy evaluation when feasible, as alternative prophylaxis choices may carry increased infection risk. Further research is needed to explore alternative prophylactic strategies for patients with beta-lactam allergies.

Review of the national usage of antibiotics in arthroplasty surgery: a need for evidence-based prescribing

INTRODUCTION

Surgical site infections (SSI) remain one of the most serious complications of arthroplasty surgery. The role of antibiotic prophylaxis in preventing SSI post-arthroplasty is well established. However, there is considerable heterogeneity in prophylactic prescribing across the United Kingdom (UK), which is contradicted by the contemporaneous evidence. This descriptive study aimed to compare the current first-line antibiotic recommendations across hospitals in the UK and The Republic of Ireland for elective arthroplasty procedures.

METHODS

The MicroGuide mobile phone application was used to access hospital antibiotic guidelines. First-line antibiotic recommendation and dosing regimen for primary elective arthroplasties were recorded.

FINDINGS

A total of nine distinct antibiotic regimens were identified through our search. The most frequently used first-line antibiotic was cefuroxime. This was recommended by 30 of the 83 (36.1%) hospitals in the study. This was followed by a combination of flucloxacillin and gentamicin, which was used by 38 of 124 (31%) hospitals. There was also significant heterogeneity in dosing regimens. A single prophylactic dose was most commonly recommended (52%); 4% of hospitals recommended two prophylactic doses, 19% three doses and 23% four doses.

CONCLUSIONS

Single-dose prophylaxis is recognised as at least noninferior to multiple-dose prophylaxis in primary arthroplasty. There is considerable variation in the local antibiotic recommendations for surgical site prophylaxis post-primary arthroplasty surgery, with respect to both recommended first-line antibiotic and dosing regimens. With increasing emphasis on the importance of antibiotic stewardship and the emergence of antibiotic resistance, this study highlights the need for an evidence-based approach to prophylactic dosing across the UK.

The efficacy and safety of intra-articular injection of corticosteroids in multimodal analgesic cocktails in total knee arthroplasty-a historically controlled study

Background

Total knee arthroplasty (TKA) is a common and effective procedure. Optimizing pain control and reducing postoperative discomfort are essential for patient satisfaction. No studies have examined the safety and efficacy of intra-articular corticosteroid injections following TKA. This study aims to examine the safety and efficacy of corticosteroids in intra-articular multimodal analgesic injections.

Materials and methods

This was a historically controlled study conducted at a single academic institution. Before May 2019, patients received an intra-articular cocktail injection without corticosteroids during surgery, referred to as the non-corticosteroid (NC) group. After June 2019, intraoperatively, patients received an intra-articular cocktail injection containing corticosteroids, referred to as the corticosteroid (C) group. Finally, 738 patients were evaluated, 370 in the C cohort and 368 in the NC cohort. The mean follow-up duration was 30.4 months for the C group and 48.4 months for the NC group.

Results

The mean VAS scores at rest on postoperative day (POD) 1 (2.35) and POD3 (3.88) were significantly lower in the C group than those in the NC group, which were 2.86 (POD1) and 5.26 (POD3) (p < 0.05). Walking pain in the C group (4.42) was also significantly lower than that (5.96) in the NC group on POD3 (p < 0.05). Patients in the C group had a significantly higher mean range of motion (ROM) (92.55) on POD3 than that (86.38) in the NC group. The mean time to straight leg raise for group C (2.77) was significantly shorter than that (3.61) for the NC group (p < 0.05). The C group also had significantly fewer rescue morphine (1.9) and metoclopramide (0.21) uses per patient than the NC group, which were 3.1 and 0.24, respectively. No significant differences in fever or vomiting rates between groups were found. Patients in neither group developed periprosthetic joint infections or skin necrosis. One patient in the C group suffered from wound dehiscence, and the wound healed well after debridement. No patient died or had a re-operation in either group.

Conclusions

This pilot trial found that intra-articular injection of multimodal analgesia (including corticosteroids) reduced initial postoperative pain, increased ROM in the early postoperative days (up to POD3), and did not increase wound complications or infection rates in approximately 30 months of follow-up.

Examining cefazolin utilization and perioperative anaphylaxis in patients with and without a penicillin allergy label: A cross-sectional study

STUDY OBJECTIVE

To compare the occurrence of cefazolin perioperative anaphylaxis (POA) in patients with and without a penicillin allergy label (PAL) to determine whether the prevalence of cefazolin POA differs based on the presence of a PAL.

DESIGN

Cross-sectional study.

SETTING

A large U.S. healthcare system in the Baltimore-D.C. region, July 2017 to July 2020.

PATIENTS

112,817 surgical encounters across inpatient and outpatient settings in various specialties, involving 90,089 patients. Of these, 4876 (4.3%) encounters had a PAL.

INTERVENTIONS

Perioperative cefazolin administration within 4 h before surgery to 4 h after the procedure began.

MEASUREMENTS

The primary outcome was cefazolin POA in patients with and without PALs. Potential POA cases were identified based on tryptase orders or diphenhydramine administrations within the initial cefazolin administration to 6 h postoperatively. Verification included two validation steps. The first checked for hypersensitivity reaction (HSR) documentation, and the second, led by Allergy specialists, identified POA and the probable culprit. The secondary outcome looked at cefazolin use trends in patients with a PAL, stratified by setting and specialty.

MAIN RESULTS

Of 112,817 encounters, 1421 (1.3%) had possible cefazolin HSRs. Of these, 22 (1.5%) had POA, resulting in a 0.02% prevalence. Of these, 13 (59.1%) were linked to cefazolin and 9 (40.9%) attributed to other drugs. Only one cefazolin POA case had a PAL, indicating no significant difference in cefazolin POA prevalence between patients with and without PALs (p = 0.437). Perioperative cefazolin use in patients with PALs steadily increased from 2.6% to 6.0% between 2017 and 2020, specifically in academic settings.

CONCLUSIONS

The prevalence of cefazolin POA does not exhibit significant differences between patients with and without PALs, and notably, the incidence remains remarkably low. Based on these findings, it is advisable to view cefazolin as an acceptable choice for prophylaxis in patients carrying a PAL.

Is Penicillin Allergy a Clinical Problem? A Systematic Review of Total Joint Arthroplasty Procedures With Implications for Patient Safety and Antibiotic Stewardship

BACKGROUND

Patients undergoing total joint arthroplasty (TJA) who report penicillin allergy (PA) are frequently administered second-line antibiotics, although recent evidence suggests that this may be unnecessary and could increase infection risk. Many institutions have aimed to improve antibiotic deployment via allergy testing and screening; however, there is little standardization to this process. This review aimed to evaluate (1) antibiotic selection in patients who report PA and assess the impact of screening and testing interventions, (2) rates of allergic reactions in patients who report PA, and (3) the association between reported PA and screening or testing programs and odds of surgical site infection or periprosthetic joint infection.

METHODS

PubMed, EBSCOhost, and Google Scholar electronic databases were searched on February 4, 2023 to identify all studies published since January 1, 2000 that evaluated the impact of PA on patients undergoing TJA (PROSPERO study protocol registration: CRD42023394031). Articles were included if full-text manuscripts in English were available, and the study analyzed the impact of PA and related interventions on TJA patients. There were 11 studies evaluating 1,276,663 patients included. Interventions were compared via presentation of key findings regarding rates of clinically relevant or high-risk PA reported upon screenings or testings, cephalosporin utilizations, allergic reactions, and postoperative infections (surgical site infection and periprosthetic joint infection).

RESULTS

All 6 studies found that PA screening and testing markedly increase the use of first-line antibiotics. Testing showed low rates of true allergy (0.7 to 3%) and allergic reaction frequency for patients who have reported PA receiving cephalosporins was between 0% and 2%. Although there were mixed findings across studies, there was a trend toward second-line antibiotic prophylaxis being associated with a slightly higher rate of infection in PA patients.

CONCLUSIONS

Using PA screening and testing can promote antibiotic stewardship by safely increasing the use of first-line antibiotics in patients who have a reported PA.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

Addition of vancomycin to cefazolin is often unnecessary for preoperative antibiotic prophylaxis during total joint arthroplasties

PURPOSE

The gold standard to decrease total joint arthroplasty (TJA) periprosthetic joint infection (PJI) is preoperative antibiotic prophylaxis. Despite substantial prevention efforts, rates of PJIs are increasing. While cefazolin is the drug of choice for preoperative prophylaxis, adjunctive vancomycin therapy has been used in methicillin-resistant Staphylococcus aureus (MRSA) endemic areas. However, studies examining these combinations are lacking. Therefore, we sought to examine complications among vancomycin plus cefazolin and cefazolin-only recipients prior to primary TJA in a single institutional sample and specifically assessed: (1) microbiological aspects, including periprosthetic joint and surgical site infections, microbes cultured from the infection, and frequency of microbes cultured from nasal swab screening; (2) 30-day emergency department (ED) visits and re-admissions; as well as (3) associated risk factors for infection.

METHODS

A total of 2,907 patients (1,437 receiving both cefazolin and vancomycin and 1,470 given cefazolin only) who underwent primary TJA between 1 January 2014 and 31 May 2021 were identified. SSI and PJI as well as rates of cultured microbes rates were obtained through one year, those with prior nasal swab screening and 30-day re-admission were identified. Subsequently, multiple regression analyses were performed to investigate potential independent risk factors for PJIs.

RESULTS

There was no significant difference in the rates of SSI (P = 0.089) and PJI (P = 0.279) between the groups at one year after operation. Commonly identified organisms included Staphylococcus and Streptococcus species. The VC cohort did have a greater reduction of MRSA in the previously nasal swab-screened subset of patients. Multiple regression analyses demonstrated emergency as well as inpatient admissions as risk factors for PJI.

CONCLUSIONS

Adjunctive vancomycin therapy offers increased protection against MRSA in previously screened individuals. However, those negative for MRSA screening do not require vancomycin and have similar protection to infection compared to recipients of cefazolin only in a high-powered single institution analysis in an MRSA endemic area.

Second-Line Antibiotic Agents in Patient-Reported Penicillin or Cephalosporin Allergy Have No Negative Impact on Antibiotic Resistance After Hip and Knee Arthroplasty

BACKGROUND

The aim of the present study was to compare causative bacteria and their antibiotic resistance profiles in patients developing a periprosthetic joint infection (PJI) based on preoperative prophylactic antibiotic regimens in primary total hip (THA) and primary total and unicompartmental knee arthroplasty (TKA/UKA).

METHODS

We reviewed all cases of PJI occurring after primary THA and primary TKA/UKA, between 2011 and 2020 in a tertiary referral hospital. The standard preoperative prophylactic antibiotic for primary joint arthroplasty was cefuroxime and recommended second-line agent was clindamycin. Patients were divided by the replaced joint and analyzed independently.

RESULTS

In the THA group, culture-positive PJI was detected in 61 of 3,123 (2.0%) cefuroxime-administered cases and 6 of 206 (2.9%) noncefuroxime-administered cases. In the TKA/UKA group, culture positive PJI was identified in 21 of 2,455 (0.9%) cefuroxime-administered cases and in 3 of 211 (1.4%) noncefuroxime administered cases. The most commonly isolated bacteria in both groups were coagulase negative staphylococci (CNS). There were no statistically significant differences of pathogen spectrum depending on the preoperative antibiotic regimen detected. Antibiotic resistance of isolated bacteria was significantly different in 4 of 27 (14.8%) analyzed antibiotics in THA and in 3 of 22 (13.6%) analyzed antibiotics in TKA/UKA. In all cohorts, a high occurrence of oxacillin-resistant CNS (50.0 to 100.0%) and clindamycin-resistant CNS (56.3 to 100.0%) has been observed.

CONCLUSION

The use of the second-line antibiotic did not influence the pathogen spectrum or antibiotic resistance. However, an alarmingly high proportion of CNS strains was resistant to clindamycin.

Are self-reported anthropometric data reliable enough to meet antibiotic prophylaxis guidelines in orthopedic surgery?

BACKGROUND

Surgical site infection is a serious complication in orthopedic surgery. The use of antibiotic prophylaxis (AP) combined with other prevention strategies has been shown to reduce this risk to 1% for hip arthroplasty and 2% for knee arthroplasty. The French Society of Anesthesia and Intensive Care Medicine (SFAR) recommends doubling the dose when the patient's weight is greater than or equal to 100 kg, and the body mass index (BMI) is greater than or equal to 35 kg/m2. Similarly, patients with a BMIgreater than40 kg/m2 orlesser than18 kg/m2 are ineligible for surgery in our hospital. Self-reported anthropometric measurements are commonly used in clinical practice to calculate BMI, but their validity has not been assessed in the orthopedic literature. Therefore, we conducted a study comparing self-reported with systematically measured values and observed the impact these differences may have on perioperative AP regimens and contra-indications to surgery.

HYPOTHESIS

The hypothesis of our study was that self-reported anthropometric values differed from those measured during preoperative orthopedic consultations.

MATERIALS AND METHODS

This single-center retrospective study with prospective data collection was conducted between October and November 2018. The patient-reported anthropometric data were first collected and then directly measured by an orthopedic nurse. Weight was measured with a precision of 500 g and height was measured with a precision of 1 cm.

RESULTS

A total of 370 patients (259 women and 111 men) with a median age of 67 years (17-90) were enrolled. The data analysis found significant differences between the self-reported and measured height [166 cm (147-191) vs. 164 cm (141-191) (p<0.0001)], weight [72.9 kg (38-149) vs. 73.1 kg (36-140) (p<0.0005)] and BMI [26.3 (16.2-46.4) vs. 27 (16-48.2) (p<0.0001)]. Of these patients, 119 (32%) reported an accurate height, 137 (37%) an accurate weight, and 54 (15%) an accurate BMI. None of the patients had two accurate measurements. The maximum underestimation was 18 kg for weight, 9 cm for height, and 6.15 kg/m2 for BMI. The maximum overestimation was 28 kg for weight, 10 cm for height, and 7.2 kg/m2 for BMI. The verification of the anthropometric measurements identified another 17 patients who had contra-indications to surgery (12 with a BMI>40 kg/m2 and 5 with a BMI<18 kg/m2) and who would not have been detected based on the self-reported values.

CONCLUSIONS

Although patients underestimated their weight and overestimated their height in our study, these had no impact on the perioperative AP regimens. However, this misreporting failed to detect potential contraindications to surgery.

LEVEL OF EVIDENCE

IV; retrospective study with prospective data collection and no control group.

Complications of Hip Hemiarthroplasty

Hip hemiarthroplasty is a commonly performed orthopedic surgery, used to treat proximal femur fractures in the elderly population. Although hip hemiarthroplasty is frequently successful in addressing these injuries, complications can occur. Commonly seen complications include dislocation, periprosthetic fracture, acetabular erosion, and leg-length inequality. Less frequently seen complications include neurovascular injury and capsular interposition. This article presents a comprehensive review of the complications associated with the management of hip hemiarthroplasty. [Orthopedics. 2023;46(4):e199-e209.].

Diagnostic Performance of Metagenomic Next⁃Generation Sequencing in the Diagnosis of Prosthetic Joint Infection Using Tissue Specimens

Purpose

The purpose of this study was to evaluate the ability of metagenomic next-generation sequencing (mNGS) diagnosing prosthetic joint infection (PJI) using tissue from hip/knee rapidly and precisely, especially in patients who had received antibiotic treatment within the preceding two weeks.

Methods

From May 2020 to March 2022, 52 cases with suspected PJI were enrolled. mNGS was performed on surgical tissue samples. The sensitivity and specificity of mNGS in diagnosis was evaluated using culture in conjunction with MSIS criteria. This study also looked at how antibiotic use affected culture and mNGS efficacy.

Results

According to MSIS criteria, 31 of the 44 cases had PJI, and 13 were classified in the aseptic loosening group. Sensitivity, specificity, positive/negative predictive value (PPV/NPV), positive/negative likelihood ratio (PLR/NLR), and area under the curve (AUC) of mNGS assay were 80.6% (71.9-91.8%), 84.6 (73.7-97.9%), 92.6 (84.2-98.7%), 64.7 (58.6-74.7%), 5.241 (4.081-6.693), 0.229 (0.108-0.482) and 0.826 (0.786-0.967), respectively, with MSIS as a reference. When MSIS was used as a reference, the results of culture assay were 45.2% (40.8-51.5%), 100 (100.0-100.0%), 100 (100.0-100.0%), 43.3 (39.1-49.5%), +∞, 0.548 (0.396-0.617) and 0.726 (0.621-0.864), respectively. The AUC values for mNGS and culture were 0.826 and 0.731, respectively, and the differences were insignificant. mNGS demonstrated higher sensitivity than culture in PJI subjects who had previously received antibiotic treatment within 2 weeks (69.5% vs 23.1%, P = 0.03).

Conclusion

In our series, mNGS yield a higher sensitivity for diagnosis and pathogen detection of PJI compared to microbiological culture. Additionally, mNGS is less affected by prior antibiotic exposure.

The Impact of Patient-Reported Penicillin or Cephalosporin Allergy on the Occurrence of the Periprosthetic Joint Infection in Primary Knee and Hip Arthroplasty

Reducing the risk of periprosthetic joint infections (PJI) requires a multi-pronged strategy including usage of a prophylactic antibiotic. A history of penicillin or cephalosporin allergy often leads to a change in prophylactic antibiotic regimen to avoid serious side effects. The purpose of the present retrospective study was to determine incidence of PJI based on perioperative antibiotic regimen in total hip arthroplasty (THA), total knee arthroplasty (TKA) or unicompartmental knee arthroplasty (UKA). A review of all primary THAs, primary TKAs and primary UKAs, undertaken between 2011 and 2020 in a tertiary referral hospital, was performed. The standard perioperative antibiotic for joint arthroplasty (JA) in the analyzed tertiary hospital is cefuroxime. There were no differences in prophylactic antibiotic regimen over time. In 7.9% (211 of 2666) of knee arthroplasties and in 6.0% (206 of 3419) of total hip arthroplasties, a second-line prophylactic antibiotic was used. There was no statistically significant higher occurrence of PJI between the first-line and second-line prophylactic antibiotic in knee arthroplasties (p = 0.403) as well as in total hip arthroplasties (p = 0.309). No relevant differences in age, American Society of Anesthesiologists (ASA) score and body mass index (BMI) between the groups were observed.

A New Dressing System Reduces the Number of Dressing Changes in the Primary Total Knee Arthroplasty: A Randomized Controlled Trial

Purpose

We devised a novel dressing system to accelerate the recovery after total knee arthroplasty (TKA). The purpose of this study was to assess the clinical outcomes and economic expenses of the new dressing system.

Methods

In this randomized and controlled trial, we enrolled 98 patients who underwent the first unilateral TKA between September 2020 and June 2021. The patients were randomly assigned to one of two groups: the intervention (the new dressing system group) or the control (the traditional gauze dressing) group. We gathered and evaluated patient data including age, gender, body mass index, surgical side, number of dressing changes, post-operative hospital stay, dressing-related expense, satisfaction, pain and function scores, wound scores and wound-related complications.

Results

The number of dressing changes and post-operative hospital stay in the intervention group were significantly less than in the control group (p = 0.000, p = 0.002). Satisfaction in the intervention group was significantly higher than in the control group's (p = 0.000). There were no significant differences between the two groups in dressing-related expense, pain and function scores. During the one month follow-up, the intervention group's Stony Brook Scar Evaluation Scale (SBSES) was considerably higher than the control group's (p = 0.012).

Conclusion

The new dressing system can reduce the number of dressing changes and post-operative hospital stays while increasing patient satisfaction with no difference in medical costs in TKA. This wound dressing system has potential for application in TKA.

Clinical Trial Registration

https://clinicaltrials.gov, identifier ChiCTR2000033814.

Hold the Antibiotics: Are Preoperative Antibiotics Unnecessary in the Treatment of Pediatric Supracondylar Humerus Fractures?

BACKGROUND

Supracondylar humerus (SCH) fracture is the most common elbow injury in children and often treated with closed reduction and percutaneous pinning (CRPP). There is little published evidence supporting or refuting the use of perioperative prophylactic antibiotics for SCH CRPP in the pediatric population. The purpose of this study is to evaluate the rate of surgical site infection for patients with and without preoperative antibiotics.

METHODS

A retrospective chart review was conducted of patients less than or equal to 16 years from 2012 to 2018 who underwent primary CRPP. Open fractures, multilimbed polytraumas, and immunodeficient patients were excluded. Infection rates were compared using a noninferiority test assuming a 3% infection rate and a predefined noninferiority margin of 4%. A total of 255 patients were needed to adequately power the study.

RESULTS

Of the 1253 cases identified, 845 met eligibility criteria. A total of 337 received antibiotics, and 508 did not. Preoperative nerve injury (P=0.0244) and sterilization technique (P<0.0001) were associated with antibiotic use: 4 patients developed an infection; there were successfully treated superficial infections, and 1 was a deep infection requiring a formal debridement. There were 8 patients that had a recorded mal-union, and 6 patients required additional procedures; 1 patient had a postoperative compartment syndrome on postoperation day 1. The infection rates among patients treated with and without antibiotics were 0.60% and 0.40%, respectively. The absence of antibiotics was not clinically inferior to using antibiotics (P=0.003).

CONCLUSIONS

Infection remains a rare complication following CRPP of SCH fractures. According to our current data, not giving perioperative antibiotics was not inferior to using perioperative antibiotics for preventing superficial or deep infection in patients undergoing CRPP of SCH fractures. With the increase in attention to antibiotic stewardship, it is important to eliminate unnecessary antibiotic use while continuing to maintain a low rate of surgical site infection.

LEVEL OF EVIDENCE

Level IV-case series. This is a therapeutic study that investigates the results from a case series.

Outcomes of Hardware Removal Surgery for Children

Hardware removal is among the most common orthopedic procedures performed in the United States. The goal of this study was to report the outcomes of deep hardware removal for children. This study received institutional review board approval. Patients younger than 18 years who underwent deep hardware removal between 2007 and 2017 were studied. We reviewed 227 procedures involving 132 boys and 95 girls. Mean follow-up was 25 months (range, 14-36 months). Mean age at the time of surgery was 12.8 years (range, 2-17 years). Mean time from initial surgery to hardware removal was 8.4 months (range, 1-72 months). Of the 227 cases, 75 used a tourniquet. Mean tourniquet time was 30.1 minutes (range, 1-118 minutes). Mean length of surgery was 44.0 minutes (range, 4-173 minutes). Mean resident level performing the surgery was postgraduate year 3 (range, postgraduate year 2 to fellow). There were 3 complications. Locations of the implanted hardware included: femur, 85; humerus, 49; tibia, 46; hip/pelvis, 17; ulna, 11; miscellaneous foot, 10; radius, 6; and fibula, 3. Indications for surgery included surgeon recommendations in 122 cases; symptomatic hardware in 68 cases, and parent wishes in 37 cases. Hardware removal for children was safe, and the outcomes were excellent. Complications of hardware removal at a teaching hospital can be minimized when a more senior resident is the primary surgeon. Despite the challenging and historically troublesome nature of deep hardware removal, the current study shows that hardware removal for children is safe and effective. [Orthopedics. 2022;45(2):e91-e95.].

The Effect of Pharmacist-Led Intervention on Surgical Antibacterial Prophylaxis (SAP) at an Orthopedic Unit

Perioperative antibiotic use is a common reason for antibiotic misuse. Evidence suggests that adherence to SAP guidelines may improve outcomes. The purpose of this study was to analyze the impact of pharmacist-led antibiotic stewardship interventions on SAP guideline compliance. The study was conducted at an Orthopedic Department of a tertiary care medical center. SAP compliance and antibiotic exposure in the pre-intervention and intervention period was compared using chi-square, Fisher exact, and Mann-Whitney tests, as appropriate. Prophylactic antibiotic use in orthopedic joint arthroplasties (overall guideline adherence: agent, dose, frequency, duration), clinical outcomes (length of stay-LOS, number of surgical site infections-SSIs), antibiotic exposure and direct antibiotic costs were compared between pre-intervention and intervention periods. Significant improvement in mean SAP duration (by 42.9%, 4.08 ± 2.08 vs. 2.08 ± 1.90 days, p ˂ 0.001), and overall guideline adherence regarding antibiotic use (by 56.2%, from 2% to 58.2%, p ˂ 0.001) were observed. A significant decrease was observed in antibiotic exposure in SAP (by 41%, from 6.07 ± 0.05 to 3.58 ± 4.33 DDD/patient, p ˂ 0.001), average prophylactic antibiotic cost (by 54.8%, 9278.79 ± 6094.29 vs. 3598.16 ± 3354.55 HUF/patient), and mean LOS (by 37.2%, from 11.22 ± 6.96 to 7.62 ± 3.02 days, p < 0.001); and a slight decrease in the number of confirmed SSIs was found between the two periods (by 1.8%, from 3% to 1.2%, p = 0.21). Continuous presence of the clinical pharmacist led to significant improvement in SAP guideline adherence, which was accompanied by decreased antibiotic exposure and cost.

Aspect ratio of nano/microstructures determines Staphylococcus aureus adhesion on PET and titanium surfaces

AIMS

Joint infections cause premature implant failure. The avoidance of bacterial colonization of implant materials by modification of the material surface is therefore the focus of current research. In this in vitro study the complex interaction of periodic structures on PET and titanium surfaces on the adhesion of Staphylococcus aureus is analysed.

METHODS AND RESULTS

Using direct laser interference patterning as well as roll-to-roll hot embossing methods, structured periodic textures of different spatial distance were produced on surfaces and S. aureus were cultured for 24 h on these. The amount of adhering bacteria was quantified using fluorescence microscopy and the local adhesion behaviour was investigated using scanning electron microscopy. For PET structures, minimal bacterial adhesion was identified for an aspect ratio of about 0·02. On titanium structures, S. aureus adhesion was significantly decreased for profile heights of < 200 nm. Our results show a significantly decreased bacterial adhesion for structures with an aspect ratio range of 0·02 to 0·05.

CONCLUSIONS

We show that structuring on surfaces can decrease the amount of S. aureus on titanium and PET as common implant materials.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study highlights the immense potential of applying specific structures to implant materials to prevent implant colonization with pathogen bacteria.

A comparative study of 5 different antibiotic prophylaxis regimes in 4500 total knee replacements

AIM

To compare the incidence of surgical site infection with different antibiotic regimes in elective total knee arthroplasty. We hypothesise that a single high dose of Teicoplanin and Gentamicin is as effective as other regimes.

METHODS

A retrospective study of prospectively collected data on a total of 4500 elective knee replacements over a 9-year period was conducted in a district general hospital. Data were collected on antibiotic regime, patient characteristics, infection (treatment, infective agents, sensitivities) and complications.

RESULTS

Five different antibiotic regimes that have been used in elective knee arthroplasty were identified in our institution. 40 patients in total were identified who had a deep infection. Rates of deep surgical site infection were not significantly different between the five groups (p = 0.83).

CONCLUSION

A single pre-operative dose of Teicoplanin and Gentamicin has similar efficacy of prophylaxis to other regimes for patients undergoing primary elective total knee replacements. We recommend the choice of prophylaxis regimen is made locally based on pathogen virulence, drug resistance and cost.

Disruption of the Gut Microbiome Increases the Risk of Periprosthetic Joint Infection in Mice

BACKGROUND

Periprosthetic joint infection (PJI) is one of the most devastating complications of total joint arthroplasty. Given the mortality and morbidity associated with PJI and the challenges in treating it, there has been increased interest in risk factors that can be modified before surgery. In this study, we used a novel mouse model to consider the role of the gut microbiome as a risk factor for PJI.

QUESTIONS/PURPOSES

(1) Does the state of the gut microbiota before surgery influence the likelihood of developing an established infection in a mouse model of PJI? (2) How does the state of the gut microbiota before surgery influence the local and systemic response to the presence of an established infection in a mouse model of PJI?

METHODS

Male C57Bl/6 mice were divided into two groups: those with modified microbiome [INCREMENT]microbiome (n = 40) and untreated mice (n = 42). In [INCREMENT]microbiome mice, the gut flora were modified using oral neomycin and ampicillin from 4 weeks to 16 weeks of age. Mice received a titanium tibial implant to mimic a joint implant and a local inoculation of Staphylococcus aureus in the synovial space (10 colony forming units [CFUs]). The proportion of animals developing an established infection in each group was determined by CFU count. The local and systemic response to established infection was determined using CFU counts in surrounding joint tissues, analysis of gait, radiographs, body weight, serum markers of inflammation, and immune cell profiles and was compared with animals that received the inoculation but resisted infection.

RESULTS

A greater proportion of animals with disrupted gut microbiota had infection (29 of 40 [73%]) than did untreated animals (21 of 42 [50%]; odds ratio, 2.63, 95% CI, 1.04-6.61; p = 0.035). The immune response to established infection in mice with altered microbiota was muted; serum amyloid A, a marker of systemic infection in mice, was greater than in mice with disrupted gut microbiota with infection (689 µg/dL; range, 68-2437 µg/dL, p < 0.05); infection associated increases in monocytes and neutrophils in the spleen and local lymph node in untreated mice but not were not observed in mice with disrupted gut microbiota.

CONCLUSIONS

The findings from this in vivo mouse model suggest that the gut microbiota may influence susceptibility to PJI.

CLINICAL RELEVANCE

These preclinical findings support the idea that the state of the gut microbiome before surgery may influence the development of PJI and justify further preclinical and clinical studies to develop appropriate microbiome-based interventions.

Despite the Safety of Preoperative Cefazolin for Patients With Non-anaphylactic Penicillin Allergy, 20% of Practitioners Avoid Its Use

Cefazolin is commonly used for surgical site infection prophylaxis due to its low cost and effective coverage. However, it is controversial to use cefazolin in patients with a penicillin allergy despite the cross-reactivity between cefazolin and penicillin being only 1%. Ample literature shows that it is safe to use cefazolin in patients with non-anaphylactic penicillin allergies. However, there is often hesitation by anesthesiologists or orthopedists when prescribing this medication in this population. The current authors sent a 16-question survey to all the residency programs in the United States in anesthesiology and orthopedics asking physicians affiliated with these programs to answer a series of questions about their demographics, prescribing patterns, and knowledge of the cross-reactivity between penicillin and cefazolin. A total of 146 responses in each group, with 82.9% (n=121) of orthopedists and 78.8% (n=115) of anesthesiologists preferring cefazolin for patients with non-anaphylactic penicillin allergies. However, only 57.5% of anesthesiologists and 41.1% of orthopedists knew the correct cross-reactivity between cephalosporins and penicillin. If a provider knew the correct cross-reactivity between cefazolin and penicillin, he or she had an increased odds of prescribing cefazolin to patients with nonanaphylactic penicillin allergies (orthopedics odds ratio [OR], 4.77, P<.01; anesthesiologists OR, 3.59, P<.01). Therefore, this study supports that further education of orthopedic and anesthesia providers about the cross-reactivity between cefazolin and penicillin would lead to more evidence-based, cost-effective care. [Orthopedics. 2019; 42(5):e437-e442.].

Improving in vitro and in vivo antibacterial functionality of Mg alloys through micro-alloying with Sr and Ga

Despite of technical advancements in design and development of new biomaterials, device-related infections continue to occur and can be life-threatening. Differing from existing research work pertaining to introducing antibacterial function upon device surface, this study attempts to address such germ-infection issues through controlled release of antibacterial species from bulk gallium (Ga) and strontium (Sr) containing magnesium (Mg) alloys. To validate such a conceptual framework, Mg alloys containing micro-level concentrations of Ga and/or Sr (0.1 wt%) are employed as model materials, along with commercially pure Mg and titanium (Ti) as control groups. Biodegradation progress of such metal specimens is examined through pH and mass loss measurements, and inductively coupled plasma - atomic emission spectrometry (ICP-AES) as a function of immersion time in Trypticase Soy Broth (TSB) solution under physiological conditions. In vitro biocompatibility and antibacterial performance are characterised through MTT proliferation assay with human mesenchymal stem cells (hMSCs) and the spread plate method with three representative bacterial strains, i.e. S. aureus (ATCC 43300), E. coli (ATCC 25922), and S. epidermidis (ATCC 35984). Animal tests are performed through implanting target metal rods into femurs of Sprague Dawley rats, accompanied with injection of S. aureus to build a model of osteomyelitis. Results demonstrate that such lean additions of Ga and/or Sr reduce the degradation kinetics of Mg matrix, and the release of Ga³⁺ ions plays a crucial role in disabling the viability of all selected bacterial strains. The histological tests confirm that the growth of fibrous tissue has been accelerated in the vicinity of Mg-based implants, in comparison to that of blank and c.p. Ti controls. It is also striking that the smallest number density of S. aureus bacteria on the surface of the retrieved Ga-containing Mg rod implants. Such a proof-of-concept study provides a new and feasible strategy to address the notorious device-infection issues associated with biomedical implants for bone fracture management.

Value of antibiotic prophylaxis in routine knee arthroscopy : A retrospective study

OBJECTIVE

Prophylactic antibiotic use prior to routine knee arthroscopy remains controversial. It is important to know whether antibiotics help decrease the surgical site infection (SSI) rate. Our aims were to assess the efficacy of antibiotic prophylaxis in preventing SSI and to identify risk factors for SSI following routine knee arthroscopy without an implant.

METHODS

A retrospective study was conducted using the electronic medical records at the authors' hospital to identify patients that underwent routine knee arthroscopy without an implant between October 2010 and October 2016. Data on demographics, clinical characteristics and antibiotic administration were extracted. Arthroscopic diagnosis, debridement, partial or complete meniscectomy, arthroscopic shaving and microfracture, removal of loose bodies, synovectomy and lateral retinacular release were included. Complex knee arthroscopy with an implant was excluded. Patients were divided into evaluation (with prophylactic antibiotics) and control (no antibiotic treatment) groups. Continuous variables between groups were compared using the Student's t-test. Data were analyzed using the Chi-squared test for percentages between groups. Multivariate logistic regression was used to identify independent risk factors of SSI.

RESULTS

Of 1326 patients, 614 (46.3%) received prophylactic antibiotics, while 712 (53.7%) did not. There were seven (0.53%) SSIs. The SSI rate did not differ significantly between patients receiving antibiotics (0.49%, three) and those not (0.56%, four). Five patients (0.37%) had superficial infections, two (0.33%) were in the prophylactic antibiotic group and three (0.42%) were in the other group. Deep infections occurred in two patients (0.15%), one (0.16%) in the prophylactic antibiotic group and one (0.14%) in the other group. The difference between the two groups was not statistically significant (P = 1.0). Age over 50 years was associated with an increased risk of SSI (relative ratio [RR] = 1.469, 95% confidence interval [CI] 1.09-2.13, P = 0.009).

CONCLUSIONS

Prophylactic antibiotic use in routine knee arthroscopy without an implant may not be necessary. Age over 50 years was associated with an increased risk of SSI.

Wound closure and follow-up after total knee arthroplasty - Do they affect the rate of antibiotic prescription?

BACKGROUND

This study aimed to evaluate risk factors for oral antibiotic prescription in the first six weeks after primary TKA, particularly whether the wound closure method (staples or sutures) and two-week follow-up clinician (surgeon or general practitioner (GP)) altered antibiotic use.

METHODS

Four thousand eight hundred forty-six TKAs from January 2013 to December 2016 at three tertiary hospitals in Auckland, New Zealand were analysed by manual review of patient electronic records and a national prescription database. Surgeon preference dictates the method of wound closure and whether wound review is followed up by the operating surgeon or by the patient's GP. Univariate and multivariate analysis was carried out to identify significant patient and surgical risk factors for oral antibiotic prescribing.

RESULTS

Oral antibiotics were prescribed in 24% of patients following primary TKA. Twenty-six percent of patients closed with staples were prescribed oral antibiotics versus 19% with sutures (adjusted OR = 1.4, p < 0.004). Excluding re-presentations and readmissions, GPs prescribed oral antibiotics in 22% of patients compared to seven percent of patients seen by surgeons (adjusted OR = 2.8, p < 0.001). Other risk factors for antibiotic prescription included increasing age, BMI and ASA score.

CONCLUSION

Oral antibiotic prescribing rates are higher if the wound was closed with staples and if a GP performed the two-week follow-up. Improved communication between surgeons and GPs are required to ensure adequate follow-up following TKA and appropriate oral antibiotic use.

Surgical site infection following elective nonspinal paediatric orthopaedic surgery: a prospective review

The aim of this study was to determine the rate of surgical site infection (SSI) and the factors that predispose to it in children undergoing nonspinal orthopaedic surgery. Over a 6-month period, 326 children who underwent 334 nonspinal elective orthopaedic surgical procedures were prospectively reviewed for the development of surgical site infections. A total of 14 sites became infected, with an overall infection rate of 4.19%. All the infections were superficial, and the only causative organism detected was Staphylococcus aureus. Operating times longer than 1 h and surgical wounds greater than 10 cm in length were positively associated with SSIs. Although there were differences between male and females, type of admission, the use of prophylactic antibiotics, degree of wound contamination and the grades of surgeons, these differences were not statistically significant. The results of this prospective study provide valuable information that was not previously available to the practicing paediatric orthopaedic surgeon.

Control Strategies for Infection Prevention in Total Joint Arthroplasty

Despite the development of newer preventative measures, the rate of infection continues to be approximately 1% for patients undergoing total joint arthroplasty (TJA). The extent of the infection can range from a mild superficial infection to a more serious periprosthetic joint infection (PJI). PJIs not only play a significant role in the clinical well-being of the TJA patient population, but also have substantial economic implications on the health care system. Several approaches are currently being used to mitigate the risk of PJI after TJA. The variety of prophylactic measures to prevent infection after TJA must be thoroughly discussed and evaluated.

Cefazolin Prophylaxis for Total Joint Arthroplasty: Obese Patients Are Frequently Underdosed and at Increased Risk of Periprosthetic Joint Infection

BACKGROUND

One of the most effective prophylactic strategies against periprosthetic joint infection (PJI) is administration of perioperative antibiotics. Many orthopedic surgeons are unaware of the weight-based dosing protocol for cefazolin. This study aimed at elucidating what proportion of patients receiving cefazolin prophylaxis are underdosed and whether this increases the risk of PJI.

METHODS

A retrospective study of 17,393 primary total joint arthroplasties receiving cefazolin as perioperative prophylaxis from 2005 to 2017 was performed. Patients were stratified into 2 groups (underdosed and adequately dosed) based on patient weight and antibiotic dosage. Patients who developed PJI within 1 year following index procedure were identified. A bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify risk factors for PJI.

RESULTS

The majority of patients weighing greater than 120 kg (95.9%, 944/984) were underdosed. Underdosed patients had a higher rate of PJI at 1 year compared with adequately dosed patients (1.51% vs 0.86%, P = .002). Patients weighing greater than 120 kg had higher 1-year PJI rate than patients weighing less than 120 kg (3.25% vs 0.83%, P < .001). Patients who were underdosed (odds ratio, 1.665; P = .006) with greater comorbidities (odds ratio, 1.259; P < .001) were more likely to develop PJI at 1 year.

CONCLUSION

Cefazolin underdosing is common, especially for patients weighing more than 120 kg. Our study reports that underdosed patients were more likely to develop PJI. Orthopedic surgeons should pay attention to the weight-based dosing of antibiotics in the perioperative period to avoid increasing risk of PJI.

Bacterial Extracellular DNA Production Is Associated with Outcome of Prosthetic Joint Infections

In a retrospective study the association of the production of extracellular DNA (eDNA) in biofilms of clinical staphylococcal isolates from 60 patients with prosthetic joint infection (PJI) and the clinical outcome were investigated. Data from a previous study on eDNA production determined in 24-hour biofilms of staphylococcal isolates (Staphylococcus aureus n=30, Staphylococcus epidermidis n=30) was correlated with the patients' clinical outcome after 3 and 12 months. Statistical analysis was performed using either the Spearman's rank correlations test or the t-test. eDNA production of S. epidermidis in 24-hour biofilms correlated with the patients' outcome ‘not cured‘ after 12 months. For S. aureus no such correlation was detected. Thus, eDNA may be a virulence factor of S. epidermidis. Quantification of eDNA production as a surrogate marker for biofilm formation might be a potential predictive marker for the management of PJI.

Prevention and detection of prosthetic temporomandibular joint infections-update

Prosthetic joint infections are not only distressing complications for patients and surgeons, but also have an enormous financial impact on healthcare systems. The reported incidence of prosthetic joint infection is likely underestimated due to difficulties in their diagnosis. This unfortunate complication has challenged joint replacement surgeons for years, despite all the advances made in this surgical discipline. Since eradication of these infections can be very difficult, prevention remains the primary objective. Identifying recipient risk factors, adopting a proper surgical technique, appropriate wound care, optimizing the operating room environment, and appropriate postoperative care have become some of the core elements that can help to minimize the overall incidence of this complication. The purpose of this article is to provide the temporomandibular joint replacement surgeon with an update on the prevention and detection of prosthetic joint infections based on a review of the most recent information published in the orthopedic and surgical literature.

Periprosthetic bacterial biofilm and quorum sensing

Periprosthetic joint infection (PJI) is a common complication after total joint arthroplasty leading to severe morbidity and mortality. With an aging population and increasing prevalence of total joint replacement procedures, the burden of PJI will be felt not only by individual patients, but in increased healthcare costs. Current treatment of PJI is inadequate resulting in incredibly high failure rates. This is believed to be largely mediated by the presence of bacterial biofilms. These polymicrobial bacterial colonies form within secreted extracellular matrices, adhering to the implant surface and local tissue. The biofilm architecture is believed to play a complex and critical role in a variety of bacterial processes including nutrient supplementation, metabolism, waste management, and antibiotic and immune resistance. The establishment of these biofilms relies heavily on the quorum sensing communication systems utilized by bacteria. Early stage research into disrupting bacterial communication by targeting quorum sensing show promise for future clinical applications. However, prevention of the biofilm formation via early forced induction of the biofilm forming process remains yet unexplored. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2331-2339, 2018.

Prophylactic antibiotics in soft-tissue procedures in children with cerebral palsy

PURPOSE

Data on the benefits of perioperative prophylactic antibiotics in the paediatric population are lacking. In this study, we aimed to assess the rate of infection after isolated soft-tissue procedures in patients with cerebral palsy with and without preoperative prophylactic antibiotics between 2009 and 2015.

METHODS

We reviewed the records of all children with cerebral palsy who underwent isolated soft-tissue procedures (on the upper and lower limb) at our hospital between 2009 and 2015. Children with at least 30-day postoperative follow-up were included. Children who had groin incisions were excluded.

RESULTS

Two groups were identified: the antibiotic group (77 children with 203 incisions and 343 procedures) had one surgical site infection; the no-antibiotic group (48 children with 102 incisions and 177 procedures) had no surgical site infections.

CONCLUSION

These results suggest that the use of preoperative antibiotics does not change the rate of postoperative surgical site infections.

LEVEL OF EVIDENCE

Level III therapeutic study.

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.

The effect of wound dressings on infection following total joint arthroplasty

Background

The use of perioperative surgical wound dressings is an important factor in the mitigation of infection following total joint arthroplasty (TJA). Few studies have been published comparing wound dressings and infection rates after TJA.

Methods

MEDLINE, PubMed, and EMBASE were searched for studies published between 2006 and 2016 reporting infection rates in patients using various wound dressings after undergoing TJA. All studies comparing Hydrofibre dressings to Standard dressings or Absorbent dressings were included in this meta-analysis. Studies looking at TJA secondary to trauma were excluded. Two individuals independently extracted data, and study results were divided based on type of treatment. The primary outcome was to compare the infection rate of Hydrofibre dressings to that of both Standard Dressings and Absorbent dressings.

Results

Of a total of 3721 participants, 1483 were treated with Standard dressings (non-impregnated gauze), 1911 with Hydrofibre dressings, and 327 with Absorbent dressings. The risk ratio for infection comparing Standard with Hydrofibre was 4.16 (95% confidence interval, 1.71-10.16) as compared to 2.60 (95% confidence interval, 0.66-10.27) when comparing Absorbent with Hydrofibre dressings.

Conclusions

Our analysis suggests that Hydrofibre dressings may be significantly better than Standard and Absorbent dressings with respect to reducing infection. However, given the observed heterogeneity and small number of studies included, more comparative studies are needed to definitively recommend superiority among dressings following TJA.

Level of Evidence

Level 1.

Post-operative fever in orthopaedic surgery: How effective is the 'fever workup?'

BACKGROUND

Defining the appropriate threshold at which to initiate a fever workup is imperative to promote patient safety, appropriate resource utilization, and antibiotic stewardship. Our group performed a systematic review of the available literature on perioperative fever (POF) workups in orthopaedic patients to evaluate the frequency, timing and utility of blood cultures (BC) and other investigations in the POF workup, to determine the clinical relevance of any infections and to evaluate their cost effectiveness.

METHODS

Studies were identified by searching MEDLINE, EMBASE, Pubmed, Cochrane and Google Scholar for articles through September 2016. Forty-nine articles were retrieved and 22 articles met the pre-determined inclusion criteria. Proportions of positive studies were noted and averaged using random effects analysis.

RESULTS

Post-operative pyrexia ranged in prevalence between 8.1% and 87.3%. The studies routinely performed during a fever workup had wide ranges of diagnostic yield, including chest X-rays from 0% to 40%, urinalyses from 8.2% to 38.7%, urine cultures from 0% to 22.4% and BC from 0% to 13.3%. Only two patients with positive BC developed clinical sepsis. Cost per fever evaluation ranged from $350 to $950.

CONCLUSION

The findings of this review suggest that early post-operative fever is an expected event following orthopaedic surgery. Based on the available literature, any kind of workup in the absence of localizing symptoms in the third post-operative day or before is unwarranted and is an inappropriate use of hospital resources.

Peri-operative antibiotic treatment of bacteriuria reduces early deep surgical site infections in geriatric patients with proximal femur fracture

PURPOSE

The aim of this study was to conduct a re-evaluation of current strategies for peri-operative prophylaxis of infections in orthopaedic surgery of geriatric patients (≥65 years) with proximal femoral fractures (PFF).

METHODS

Between 01/2010 and 08/2014 all post-operative infections after stabilization of PFF of 1,089 geriatric patients were recorded retrospectively. All patients pre-operatively received a single dose of 1.5 g cefuroxime (group 1). These were compared to prospectively determined post-operative rates of surgical site infection (SSI) of 441 geriatric patients, which were operated on between 09/2014 and 03/2017 due to PFF. In this second group we investigated the urinary tract on admission. Bacteriuria was treated with the pre-operative single dose of 1.5 g cefuroxime along with ciprofloxacin for five days, beginning on admission. Level of significance was set to p < 0.05.

RESULTS

A total of 141 patients of group 2 had a bacteriuria. Seventy-seven of these patients revealed biochemical signs of manifest urinary tract infection. Multi-resistant pathogens were found in 15 patients and pathogens were cefuroxime-resistant in 37. The differences of SSI after at least three months were 2.1% in group 1 and 0.45% in group 2 for all patients with surgery of PFF (p < 0.02) and for those with arthroplasty (p < 0.037) significant.

CONCLUSIONS

The immediate antibiotic therapy of a prevalent bacteriuria for five days decreases the risk of SSI after surgery of PFF. Our single-centre study can only point out the problem of prevalent reservoirs of pathogens and the need for treatment. Evidence-based therapy concepts (indications of antibiotics, classes, duration) have to be developed in multi-centric and prospective studies.

Higher risk of revision for infection using systemic clindamycin prophylaxis than with cloxacillin

Background and purpose - Clindamycin has not been compared with other antibiotics for prophylaxis in arthroplasty. Since 2009, the Swedish Knee Arthroplasty Register (SKAR) has been collecting information on the prophylactic antibiotic regime used at every individual operation. In Sweden, when there is allergy to penicillin, clindamycin has been the recommended alternative. We examined whether there were differences in the rate of revision due to infection depending on which antibiotic was used as systemic prophylaxis. Patients and methods - Patients who had a total knee arthroplasty (TKA) performed due to osteoarthritis (OA) during the years 2009-2015 were included in the study. Information on which antibiotic was used was available for 80,018 operations (55,530 patients). Survival statistics were used to calculate the rate of revision due to infection until the end of 2015, comparing the group of patients who received cloxacillin with those who received clindamycin as systemic prophylaxis. Results - Cloxacillin was used in 90% of the cases, clindamycin in 7%, and cephalosporins in 2%. The risk of being revised due to infection was higher when clindamycin was used than when cloxacillin was used (RR =1.5, 95% CI: 1.2-2.0; p = 0.001). There was no significant difference in the revision rate for other causes (p = 0.2). Interpretation - We advise that patients reporting allergic reaction to penicillin should have their allergic history explored. In the absence of a clear history of type-I allergic reaction (e.g. urticaria, anaphylaxis, or bronchospasm), we suggest the use of a third-generation cephalosporin instead of clindamycin as perioperative prophylaxis when undergoing a TKR. No recommendation can be given regarding patients with type-1 allergy.

Prosthetic joint infection-a devastating complication of hemiarthroplasty for hip fracture

Background and purpose - Hemiarthroplasty is the most common treatment in elderly patients with displaced femoral neck fracture. Prosthetic joint infection (PJI) is a feared complication. The infection rate varies in the literature, and there are limited descriptive data available. We investigated the characteristics and outcome of PJI following hemiarthroplasty over a 15-year period. Patients and methods - Patients with PJI were identified among 519 patients treated with hemiarthroplasty for a femoral neck fracture at Oslo University Hospital between 1998 and 2012. We used prospectively registered data from previous studies, and recorded additional data from the patients' charts when needed. Results - Of the 519 patients, we identified 37 patients (6%) with early PJI. 20 of these 37 patients became free of infection. Soft tissue debridement and retention of implant was performed in 35 patients, 15 of whom became free of infection with an intact arthroplasty. The 1-year mortality rate was 15/37. We found an association between 1-year mortality and treatment failure (p = 0.001). Staphylococcus aureus and polymicrobial infection were the most common microbiological findings, each accounting for 14 of the 37 infections. Enterococcus spp. was found in 9 infections, 8 of which were polymicrobial. There was an association between polymicrobial infection and treatment failure, and between polymicrobial infection and 1-year mortality. Interpretation - PJI following hemiarthroplasty due to femoral neck fracture is a devastating complication in the elderly. We found a high rate of polymicrobial PJIs frequently including Enterococcus spp, which is different from what is common in PJI after elective total hip arthroplasty.

Increased Resistance of Skin Flora to Antimicrobial Prophylaxis in Patients Undergoing Hip Revision Arthroplasty

BACKGROUND/AIM

Prosthetic joint infection (PJI) remains a major complication after total joint replacement and is the primary indication for revision arthroplasty. Specifically, coagulase-negative Staphylococci (CNS) can cause low-grade infections. Despite the use of cephalosporin-based antimicrobial prophylaxis (AMP) and antiseptic treatment at the surgical site, evidence suggests that a significant number of cases of dermal CNS results in low-grade PJI. Thus, this study examined the bacterial colonization and resistance patterns at the surgical site. We hypothesized that the bacteria developed resistance to antibiotics that are frequently used in primary and revision total hip arthroplasty (THA) procedures.

PATIENTS AND METHODS

Ninety patients, including 63 primary and 27 revision THA patients, were enrolled in this study. For each patient, a single swab of the skin at the surgical site was subjected to clinical microbiology to assess bacterial colonization. Furthermore, resistance to a sentinel panel of antibiotics (benzylpenicillin, erythromycin, tetracycline, oxacillin, fusidic acid, clindamycin, gentamicin, levofloxacin/moxifloxacin, rifampicin, linezolid and vancomycin) was tested.

RESULTS

In 96.7% of the patients, at least one bacterial strain was identified at the surgical site, with CNS strains comprising 93.1% of the total. The sentinel panel showed that 30.7% of the CNS strains exhibited maximal resistance to oxacillin, a commonly used cephalosporin. Additionally, oxacillin resistance increased 1.9-fold (p=0.042) between primary and revision THA. Notably, 8.1% of the CNS stains found on patients undergoing primary THA were resistant to gentamicin, an aminoglycoside, and this rate increased 4.7-fold (p=0.001) for patients undergoing revision THA.

CONCLUSION

CNS strains have significant resistance to standard AMP, particularly in individuals undergoing revision THA.

Biotransformation of Silver Released from Nanoparticle Coated Titanium Implants Revealed in Regenerating Bone

Antimicrobial silver nanoparticle coatings have attracted interest for reducing prosthetic joint infection. However, few studies report in vivo investigations of the biotransformation of silver nanoparticles within the regenerating tissue and its impact on bone formation. We present a longitudinal investigation of the osseointegration of silver nanoparticle-coated additive manufactured titanium implants in rat tibial defects. Correlative imaging at different time points using nanoscale secondary ion mass spectrometry, transmission electron microscopy (TEM), histomorphometry, and 3D X-ray microcomputed tomography provided quantitative insight from the nano- to macroscales. The quality and quantity of newly formed bone is comparable between the uncoated and silver coated implants. The newly formed bone demonstrates a trabecular morphology with bone being located at the implant surface, and at a distance, at two weeks. Nanoscale elemental mapping of the bone-implant interface showed that silver was present primarily in the osseous tissue and colocalized with sulfur. TEM revealed silver sulfide nanoparticles in the newly regenerated bone, presenting strong evidence that the previously in vitro observed biotransformation of silver to silver sulfide occurs in vivo.

Predicting lower limb periprosthetic joint infections: A review of risk factors and their classification

AIM

To undertook a systematic review to determine factors that increase a patient's risk of developing lower limb periprosthetic joint infections (PJI).

METHODS

This systematic review included full-text studies that reviewed risk factors of developing either a hip or knee PJI following a primary arthroplasty published from January 1998 to November 2016. A variety of keywords were used to identify studies through international databases referencing hip arthroplasty, knee arthroplasty, infection, and risk factors. Studies were only included if they included greater than 20 patients in their study cohort, and there was clear documentation of the statistical parameter used; specifically P-value, hazard ratio, relative risk, or/and odds ratio (OR). Furthermore a quality assessment criteria for the individual studies was undertaken to evaluate the presence of record and reporting bias.

RESULTS

Twenty-seven original studies reviewing risk factors relating to primary total hip and knee arthroplasty infections were included. Four studies (14.8%) reviewed PJI of the hip, 3 (11.21%) of the knee, and 20 (74.1%) reviewed both joints. Nineteen studies (70.4%) were retrospective and 8 (29.6%) prospective. Record bias was identified in the majority of studies (66.7%). The definition of PJI varied amongst the studies but there was a general consensus to define infection by previously validated methods. The most significant risks were the use of preoperative high dose steroids (OR = 21.0, 95%CI: 3.5-127.2, P < 0.001), a BMI above 50 (OR = 18.3, P < 0.001), tobacco use (OR = 12.76, 95%CI: 2.47-66.16, P = 0.017), body mass index below 20 (OR = 6.00, 95%CI: 1.2-30.9, P = 0.033), diabetes (OR = 5.47, 95%CI: 1.77-16.97, P = 0.003), and coronary artery disease (OR = 5.10, 95%CI: 1.3-19.8, P = 0.017).

CONCLUSION

We have highlighted the need for the provider to optimise modifiable risk factors, and develop strategies to limit the impact of non-modifiable factors.

Should Preoperative Antibiotics Be Tailored According to Patient's Comorbidities and Susceptibility to Organisms?

BACKGROUND

Preoperative antibiotic prophylaxis remains one of the most important strategies for preventing periprosthetic joint infection (PJI). Current guidelines recommend giving universal antibiotic prophylaxis to all total joint arthroplasty patients regardless of their medical conditions or immune status; however, no studies have evaluated the individualizing of antibiotics. The aims of this study were (1) to determine if comorbidities influence the organism profile of PJIs, and (2) to investigate if the efficacy of two different perioperative antibiotics (cefazolin or vancomycin) for preventing PJI is affected by patient's comorbidities.

METHODS

Using an institutional database of 1022 PJIs, the influence of different patient's comorbidities on the organism profile was evaluated. To investigate the influence of perioperative antibiotics (cefazolin or vancomycin monotherapy) on PJI rate, 8575 primary total joint arthroplasties were identified, crossmatched for PJI, and analyzed based on the comorbidities of the cohort. The PJI rate of each antibiotic within each comorbidity was compared.

RESULTS

Although no comorbidities were associated with an increased rate of Gram-positive infections or Gram-negative infections, metastatic disease (odds ratio [OR] 5.71, P = .018), congestive heart failure (OR 2.2, P = .010), chronic pulmonary disease (OR 1.76, P = .015), and diabetes mellitus (OR 1.66, P = .019) were associated with antibiotic resistant organisms. However, there was no difference in the PJI rate between cefazolin and vancomycin monotherapy when stratifying for diabetes mellitus, rheumatoid arthritis, liver disease, and hypothyroidism.

CONCLUSION

The results of the present study support the current recommendations of a universal antibiotic prophylaxis protocol rather than an antibiotic regimen individualized to a patient's comorbidities.

Single-stage osseointegrated reconstruction and rehabilitation of lower limb amputees: the Osseointegration Group of Australia Accelerated Protocol-2 (OGAAP-2) for a prospective cohort study

INTRODUCTION

Lower limb amputations have detrimental influences on the quality of life, function and body image of the affected patients. Following amputation, prolonged rehabilitation is required for patients to be fitted with traditional socket prostheses, and many patients experience symptomatic socket-residuum interface problems which lead to reduced prosthetic use and quality of life. Osseointegration has recently emerged as a novel approach for the reconstruction of amputated limbs, which overcomes many of the socket-related problems by directly attaching the prosthesis to the skeletal residuum. To date, the vast majority of osseointegration procedures worldwide have been performed in 2 stages, which require at least 4 months and up to 18 months for the completion of reconstruction and rehabilitation from the time of the initial surgery. The current prospective cohort study evaluates the safety and efficacy of a single-stage osseointegration procedure performed under the Osseointegration Group of Australia Accelerated Protocol-2 (OGAAP-2), which dramatically reduces the time of recovery to ∼3-6 weeks.

METHODS AND ANALYSIS

The inclusion criteria for osseointegrated reconstruction under the OGAAP-2 procedure are age over 18 years, unilateral transfemoral amputation and experiencing problems or difficulties in using socket prostheses. All patients receive osseointegrated implants which are press-fitted into the residual bone. Functional and quality-of-life outcome measures are recorded preoperatively and at defined postoperative follow-up intervals up to 2 years. Postoperative adverse events are also recorded. The preoperative and postoperative values are compared for each outcome measure, and the benefits and harms of the single-stage OGAAP-2 procedure will be compared with the results obtained using a previously employed 2-stage procedure.

ETHICS AND DISSEMINATION

This study has received ethics approval from the University of Notre Dame, Sydney, Australia (014153S). The study outcomes will be disseminated by publications in peer-reviewed academic journals and presentations at relevant clinical and orthopaedic conferences.

Reducing surgical site infections following total hip and knee arthroplasty: an Israeli experience

PURPOSE

To assess the changes observed in surgical site infection (SSI) rates following total joint arthroplasty (TJA) after the introduction of an infection control programme and evaluate the risk factors for the development of these infections.

DESIGN

Prospective cohort study.

SETTING

Large tertiary medical centre in Israel.

METHODS

Data about SSIs and potential prophylaxis-, patient-, and procedure-related risk factors were collected for all patients who underwent elective total hip and total knee arthroplasty during the study period. Multivariant analyses were conducted to determine which significant covariates affected the outcome.

RESULTS

During the 76-month study period, SSIs (superficial and deep) occurred in 64 (4.4%) of 1554 patients. As compared with the 34 (7.7%) SSIs that occurred in the first 25 months, there were 23 (4.7%) SSIs in the following 25 months, and only 7 (1.3%) SSIs in the last third of the study (p = 0.058 and <0.001, respectively). A multiple logistic regression model indicated that risk factors for prosthetic joint infection were a National Nosocomial Infections Surveillance (NNIS) System surgical patient risk index score of 1 (OR 1.8; 95% CI 1.1-3.1) or 2 (OR 2.8; 95% CI 1.2-11.8). The incidence of SSI was not correlated with the timing, nor the duration of antibiotic prophylaxis.

CONCLUSIONS

The introduction of preventive measures and surveillance coincided with a significant reduction in SSIs following TJA in our institution. The risk of infection correlated with higher scores in the NNIS System surgical patient risk.

Role of prophylactic antibiotics in lesser toe fusion surgery: A prospective randomised controlled trial

BACKGROUND

This prospective randomised controlled trial was performed to determine whether the incidence of local infection is reduced in patients who are administered prophylactic antibiotics for lesser toe fusion surgery.

METHODS

100 adult patients undergoing toe fusion surgery that required K-wires to be left in situ for 4-6 weeks were randomly allocated into those who received prophylactic antibiotics (Group 1, n=48) and those who did not (Group 2, n=52). Patients were followed up regularly and during each visit K-wire insertion sites were assessed for signs of pin tract infection.

RESULTS

The mean age of Group 1 was 58.0 (SD 17.5) and Group 2 was 62.7 years (SD 14.7). The overall infection rate was 4%. Three patients (6.2%) in Group 1 and one patient (1.9%) in Group 2 developed signs of infection, which required treatment by oral antibiotics. All infections were low grade. There were no features suggestive of osteomyelitis in any of the patients.

CONCLUSION

The overall infection rate in lesser toe fusion surgery is low and that using prophylactic antibiotics does not reduce the incidence. Inappropriate use of antibiotics, however, may contribute to the development of antibiotic resistance and adds to healthcare costs.

Antibiotic prophylaxis in orthopaedic surgery: difficult decisions in an era of evolving antibiotic resistance

Prophylactic antibiotics can decrease the risk of wound infection and have been routinely employed in orthopaedic surgery for decades. Despite their widespread use, questions still surround the selection of antibiotics for prophylaxis, timing and duration of administration. The health economic costs associated with wound infections are significant, and the judicious but appropriate use of antibiotics can reduce this risk. This review examines the evidence behind commonly debated topics in antibiotic prophylaxis and highlights the uses and advantages of some commonly used antibiotics. Cite this article: Bone Joint J 2016;98-B:1014-19.

Biofilm and the Role of Antibiotics in the Treatment of Periprosthetic Hip and Knee Joint Infections

An increasing demand for lower limb arthroplasty will lead to a proportionate increase in the need for revision surgery. A notable proportion of revision surgery is secondary to periprosthetic joint infections (PJI). Diagnosing and eradicating PJI can form a very difficult challenge. An important cause of PJI is the formation of a bacterial biofilm on the implant surface. Our review article seeks to describe biofilms; their definitions and formation, common causative bacteria, prophylactic and therapeutic antibiotic therapy.