2019 John Charnley Award: Increased risk of prosthetic joint infection following primary total knee and hip arthroplasty with the use of alternative antibiotics to cefazolin: the value of allergy testing for antibiotic prophylaxis

Perioperative Cefazolin for Total Joint Arthroplasty Patients Who Have a Penicillin Allergy: Is It Safe?

BACKGROUND

Cefazolin is the standard of care for perioperative antibiotic prophylaxis in total joint arthroplasty (TJA) in the United States. The potential allergic cross-reactivity between cefazolin and penicillin causes uncertainty regarding optimal antibiotic choice in patients who have a reported penicillin allergy (rPCNA). The purpose of this study was to determine the safety of perioperative cefazolin in PCNA patients undergoing primary TJA.

METHODS

We identified all patients (n = 49,842) undergoing primary total hip arthroplasty (n = 25,659) or total knee arthroplasty (n = 24,183) from 2016 to 2022 who received perioperative intravenous antibiotic prophylaxis. Patients who had an rPCNA (n = 5,508) who received cefazolin (n = 4,938, 89.7%) were compared to rPCNA patients who did not (n = 570, 10.3%), and to patients who did not have an rPCNA (n = 43,359). The primary outcome was the rate of allergic reactions within 72 hours postoperatively. Secondary outcomes included the rates of superficial infections, deep infections, and Clostridioides difficile infections within 90 days.

RESULTS

The rate of allergic reactions was 0.1% (n = 5) in rPCNA patients who received cefazolin, compared to 0.2% (n = 1) in rPCNA patients who did not (P = .48) and 0.02% (n = 11) in patients who have no rPCNA (P = .02). Allergic reactions were mild in all 5 rPCNA patients who received cefazolin and were characterized by cutaneous symptoms (n = 4) or dyspnea in the absence of respiratory distress (n = 1) that resolved promptly with antibiotic discontinuation and administration of antihistamines and/or corticosteroids. We observed no differences in the rates of superficial infections (0.1 versus 0.2%, P = .58), deep infections (0.3 versus 0.4%, P = .68), or C difficile infections (0.04% versus 0%, P = .99) within 90 days in rPCNA patients who received cefazolin versus alternative perioperative antibiotics.

CONCLUSIONS

In this series of more than 5,500 patients who had an rPCNA undergoing primary TJA, perioperative prophylaxis with cefazolin resulted in a 0.1% incidence of allergic reactions that were clinically indolent. Cefazolin can be safely administered to most patients, independent of rPCNA severity.

LEVEL OF EVIDENCE

III.

Oral Postoperative Antibiotic Prophylaxis for Outpatient Total Hip and Knee Arthroplasty: Describing Current Practices

BACKGROUND

Despite an increase in outpatient total hip arthroplasty (THA) and total knee arthroplasty (TKA), large-scale data are lacking on current practice for antibiotic prophylaxis prescribing. We aimed to describe current oral antibiotic prophylaxis practices nationally for outpatient THA and TKA.

METHODS

This nationwide retrospective cohort study included primary outpatient THA or TKA procedures in patients aged 18 to 64 years from 2018 to 2021 using a national claims database. Oral antibiotic prescriptions filled perioperatively (defined as 5 days before to 3 days after surgery) were extracted; these were categorized and assumed to represent postoperative prophylaxis. Multivariable logistic regression measured associations between patient and surgery characteristics and perioperative oral antibiotic prophylaxis. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) are reported.

RESULTS

Oral antibiotic prescriptions were filled in 16.5% of 73,015 outpatient THA and TKA (18.4% of 24,857 THAs, 15.5% of 48,158 TKAs) procedures. Prescriptions were most often for cephalosporins (74.3%), with cephalexin (52.8%), and cefadroxil (19.1%) being the most common. Non-cephalosporin antibiotics prescribed were mainly clindamycin (6.8%), sulfamethoxazole-trimethoprim (6.7%), and doxycycline (6.2%). The odds of receiving oral antibiotic prophylaxis were higher for THA compared to TKA (OR 1.13, 95% CI 1.09 to 1.18, P < .001) and in the presence of obesity, diabetes, and autoimmune conditions (OR 1.08 to 1.13, P < .001 to .01). Ambulatory surgery center procedures also had significantly increased odds of prophylaxis compared to hospital-based outpatient surgeries (OR 2.62, 95% CI 2.51 to 2.73, P < .001). Additionally, regional and time-based variations were noted.

CONCLUSIONS

Perioperative oral antibiotic prophylaxis prescriptions were filled in only 16.5% of outpatient THA and TKA cases, with variation in the type of antibiotic prescribed. The receipt of any prophylaxis and specific medications was associated with demographic, clinical, and procedure-related characteristics. Follow-up research will evaluate associations with infection risk reduction.

Can ChatGPT Answer Patient Questions Regarding Total Knee Arthroplasty?

The internet has introduced many resources frequently accessed by patients prior to orthopaedic visits. Recently, Chat Generative Pre-Trained Transformer, an artificial intelligence-based chat application, has become publicly and freely available. The interface uses deep learning technology to mimic human interaction and provide convincing answers to questions posed by users. With its rapidly expanding usership, it is reasonable to assume that patients will soon use this technology for preoperative education. Therefore, we sought to determine the accuracy of answers to frequently asked questions (FAQs) pertaining to total knee arthroplasty (TKA).Ten FAQs were posed to the chatbot during a single online interaction with no follow-up questions or repetition. All 10 FAQs were analyzed for accuracy using an evidence-based approach. Answers were then rated as "excellent response not requiring clarification," "satisfactory requiring minimal clarification," satisfactory requiring moderate clarification," or "unsatisfactory requiring substantial clarification."Of the 10 answers given by the chatbot, none received an "unsatisfactory" rating with the majority either requiring minimal (5) or moderate (4) clarification. While many answers required nuanced clarification, overall, answers tended to be unbiased and evidence-based, even when presented with controversial subjects.The chatbot does an excellent job of providing basic, evidence-based answers to patient FAQs prior to TKA. These data were presented in a manner that will be easily comprehendible by most patients and may serve as a useful clinical adjunct in the future.

Surgical prophylaxis in pediatric orthopedic patients with penicillin allergy: a multicentered retrospective prognostic study

Up to 20% of orthopedic surgeons still avoid the use of cephalosporins in patients with penicillin allergies despite its reported safety in the adult and general surgery pediatric population. The primary objective is to determine the incidence of adverse effects and allergic reactions when using cephalosporins in pediatric orthopedic patients labeled as penicillin-allergic as compared to those without previously reported penicillin allergy. A multicenter retrospective chart review was performed across three level 1 trauma centers from January 2013 to February 2020 to identify penicillin-allergic as well as non-penicillin-allergic pediatric patients treated for orthopedic injuries. Data were collected regarding patient demographics, antibiotic administered, timing of antibiotic administration, reported drug allergy, and described allergic reaction. Postoperative or intraoperative allergic reactions to antibiotics, surgical site infections, and complications were recorded. A total of 2289 surgeries performed by four fellowship-trained surgeons were evaluated. Eighty-five patients diagnosed with penicillin allergy were identified and underwent 95 surgeries and 95 patients without previously reported penicillin allergy underwent 95 surgeries. One patient, with a documented history of anaphylaxis to cefazolin, sustained an anaphylactic reaction intraoperatively to cefazolin. There were no other reported reactions, surgical site infections, or complications. There was no statistically significant difference in rate of allergic reaction in patients with previously reported penicillin allergy treated with cefazolin and those with no previous reported reaction ( P > 0.05). Prophylaxis with cephalosporins is not associated with increased risk for allergic reaction. Cephalosporins can be safely administered to pediatric patients with penicillin allergy undergoing orthopedic intervention. Level of evidence: Level II, Multicenter Retrospective Prognostic Study.

Additional doses of prophylactic antibiotics post-arthroplasty: Are there any benefits?

Guidelines for prophylactic antibiotic administration in total joint replacement vary considerably in terms of drug, dosage, route of administration and duration of cover. Despite the range of treatment options available, infection remains the most common reason for arthroplasty failure in the decades following a procedure, simultaneously increasing health care costs and lowering patient satisfaction considerably. This work aims to evaluate whether there are benefits to administering further doses of antibiotic post-arthroplasty, in addition to the recommendations of current protocols. We present a review of evidence surrounding infection rates in a variety of prophylactic regimens, and weigh this against further considerations such as cost to the patient and risks of nephrotoxicity. In summary, the available evidence does not suggest a benefit to administering additional doses post-arthroplasty in most cases. However, further doses may benefit those deemed at high risk of infection, or those in areas of high methicillin-resistant Staphylococcus aureus prevalence.

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.

After primary shoulder arthroplasty appropriate vancomycin antibiotic prophylaxis does not lead to increased infectious complications when compared to cefazolin

BACKGROUND

In primary shoulder arthroplasty (SA), intravenous (IV) cefazolin has demonstrated lower rates of infectious complications when compared to IV vancomycin. However, previous analyses included SA cohorts with both complete and incomplete vancomycin administration. Therefore, it is currently unclear whether cefazolin still maintains a prophylactic advantage to vancomycin when it is appropriately indicated and sufficiently administered at the time of surgical incision. This study evaluated the comparative efficacy of cefazolin and complete vancomycin administration for surgical prophylaxis in primary shoulder arthroplasty with respect to infectious complications.

METHODS

A retrospective cohort study was conducted utilizing a single institution total joint registry database, where all primary SA types (hemiarthroplasty, anatomic total shoulder arthroplasty, and reverse shoulder arthroplasty) performed between 2000 to 2019 for elective and trauma indications using IV cefazolin or complete vancomycin administration as the primary antibiotic prophylaxis were identified. Vancomycin was primarily indicated for patients with a severe self-reported penicillin or cephalosporin allergy and/or MRSA colonization. Complete administration was defined as at least 30 minutes of antibiotic infusion prior to incision. All included SA had at least 2 years of clinical follow-up. Multivariable Cox proportional hazard regression was used to evaluate all-cause infectious complications including survival free of prosthetic joint infection (PJI).

RESULTS

The final cohort included 7177 primary SA, 6879 (95.8%) received IV cefazolin and 298 (4.2%) received complete vancomycin administration. Infectious complications occurred in 120 (1.7%) SA leading to 81 (1.1%) infectious reoperations. Of the infectious complications, 41 (0.6%) were superficial infections and 79 were (1.1%) PJIs. When categorized by administered antibiotics, there were no differences in rates of all infectious complications (1.6% vs. 2.3%; P = .352), superficial complications (0.5% vs. 1.3%; P = .071), PJI (1.1% vs. 1.0%; P = .874), or infectious reoperations (1.1% vs. 1.0%; P = .839). On multivariable analyses, complete vancomycin infusion demonstrated no difference in rates of infectious complications compared to cefazolin administration (hazard ratio [HR], 1.50 [95% confidence interval (CI), 0.70 to 3.25]; P = .297), even when other independent predictors of PJI (male sex, prior surgery, and Methicillin-resistant Staphylococcus aureus colonization) were considered.

CONCLUSIONS

In comparison to cefazolin, complete administration of vancomycin (infusion to incision time greater than 30 minutes) as the primary prophylactic agent does not adversely increase the rates of infectious complications and PJI. Prophylaxis protocols should promote appropriate indications for the use of cefazolin or vancomycin, and when necessary, ensure complete administration of vancomycin to mitigate additional infectious risks after primary SA.

Patient-reported allergies are associated with increased rate of postoperative stiffness after arthroscopic rotator cuff repair

BACKGROUND

Several risk factors have been identified for the development of postoperative shoulder stiffness, and there has been increasing interest in orthopedic literature regarding patient-reported allergy (PRA) as an identifiable risk factor for adverse outcomes. The purpose of this study is to determine whether PRAs are associated with subsequent rates of diagnosis of adhesive capsulitis (AC) or return to the operating room for postoperative shoulder stiffness within 2 years after arthroscopic rotator cuff repair (ARCR).

METHODS

Current Procedural Terminology surgical billing codes were used to retrospectively identify patients who underwent ARCR at a single urban academic institution from January 2012 to December 2020 with minimum 2-year follow-up. Lysis of adhesions (LOA), manipulation under anesthesia (MUA), and AC of the shoulder were further queried within 2 years postoperatively for the ipsilateral shoulder. Patients were excluded if they had undergone ipsilateral MUA/LOA or received a diagnosis of AC before the index procedure. Demographic characteristics and medical comorbidities (hypertension, diabetes, hyperlipidemia, and hypothyroidism) were extracted from electronic medical records. Baseline characteristics were compared between patients with and without PRAs. Multivariate logistic regression analyses were performed to determine the association of the presence of PRAs overall, as well as the presence of 1, 2, or 3 or more PRAs, with subsequent MUA/LOA or diagnosis of AC within 2 years postoperatively.

RESULTS

Of 7057 patients identified in the study period, 6583 were eligible for the final analysis. The mean age was 56.6 ± 11.7 years, and the mean body mass index was 29.1 ± 5.6. Overall, 19.3% of patients (n = 1271) reported at least 1 allergy, and 7.1% (n = 469) had >1 PRA. A total of 44 patients (0.7%) underwent subsequent ipsilateral MUA/LOA within 2 years postoperatively, whereas 93 patients (1.4%) received a diagnosis of ipsilateral AC in the same time frame. PRAs were significantly associated with subsequent diagnosis of AC (odds ratio [OR]: 2.39; 95% confidence interval [CI]: 1.45-3.92; P < .001), but not MUA/LOA (OR: 1.97, 95% CI: 1.26-3.61; P = .133). Patients with 2 PRAs had greater odds of being diagnosed with AC than patients with 1 PRA (OR: 2.74; 95% CI: 1.14-5.99; P = .012). Although this association was nonsignificant for MUA/LOA, patients with 2 PRAs (OR: 2.67; 95% CI: 0.96-8.80; P = .059) demonstrated a similar statistical trend.

CONCLUSION

PRAs are associated with increased odds of receiving a diagnosis of AC within 2 years after ARCR but were not found to be associated with return to the operating room for postoperative stiffness.

Exacerbation of Osteoarthritic Joint Pain by Lyme Disease

Lyme disease progresses through three distinct clinical phases: early localized, early disseminated, and late disseminated. Lyme arthritis is characterized by attacks of joint swelling lasting for weeks to months, potentially causing permanent joint damage in late disseminated disease. Our case focuses on a 63-year-old, obese, type 2 diabetic, wheelchair-bound, Caucasian male with severe bilateral knee pain. Our patient had previously undergone bilateral knee arthroscopies for meniscal tears and also had knee injections performed previously without the desired level of pain alleviation. He indicated a recent cough that was treated with erythromycin and noted his knees felt better during the course of the antibiotic. The patient recreationally enjoyed hunting and mentioned that his dog had Lyme Disease. Laboratory confirmation of Lyme disease prompted our patient to be treated with doxycycline. Upon completion of doxycycline therapy, our patient noted significant improvement in his knee pain. The improvement was significant enough that the patient canceled a planned bilateral knee replacement with his orthopedic surgeon, and no longer required the use of a wheelchair as he was able to return to ambulating independently. The patient's quality of life improved significantly, and he could also return to work. Lyme disease should be a consideration in the differential diagnosis of patients in areas endemic to the disease, and patients who tend to have outdoor lifestyles.

Dyslipidaemia is associated with Cutibacterium acnes hip and knee prosthetic joint infection

PURPOSE

Optimization of medical factors including diabetes and obesity is a cornerstone in the prevention of prosthetic joint infection (PJI). Dyslipidaemia is another component of metabolic syndrome which has not been thoroughly investigated as an individual, modifiable risk factor. This study examined the association of dyslipidaemia with PJI caused by the lipophilic microbe Cutibacterium acnes (C. acnes).

METHODS

A retrospective chart review examined patients with positive C. acnes culture at hip or knee arthroplasty explantation. A control group with methicillin-sensitive Staphylococcus aureus (MSSA) positive cultures at explantation was matched for age, sex, and surgical site, as well as a second control group with no infection. A total of 80 patients were included, 16 with C. acnes, 32 with MSSA, and 32 with no infection. All patients had a lipid panel performed within one year of surgery. Lipid values and categories were compared using multinomial logistic regressions.

RESULTS

High or borderline triglycerides (TG) (relative risk ratio (RRR) = 0.13; P = 0.013) and low high-density lipoprotein (HDL) (RRR = 0.13; P = 0.025) were significantly associated with C. acnes PJI compared to MSSA-PJI. High or borderline TG (RRR = 0.21; P = 0.041) and low HDL (RRR = 0.17; P = 0.043) were also associated with a greater probability of C. acnes infection compared to no infection.

CONCLUSIONS

The presence of elevated TG and low HDL were both associated at a statistically significant level with C. acnes hip or knee PJI compared to controls with either MSSA PJI or no infection. This may represent a specific risk factor for C. acnes PJI that is modifiable.

Non-cefazolin antibiotic prophylaxis is associated with higher rates of elbow periprosthetic joint infection

BACKGROUND

Periprosthetic joint infection (PJI) is a common source of failure following elbow arthroplasty. Perioperative prophylactic antibiotics are considered standard of care. However, there are no data regarding the comparative efficacy of various antibiotics in the prevention of PJI for elbow arthroplasty. Previous studies in shoulder, hip, and knee arthroplasty have demonstrated higher rates of PJI with administration of non-cefazolin antibiotics. The elbow has higher rates of PJI than other joints. Therefore, this study evaluated whether perioperative antibiotic choice affects rates of PJI in elbow arthroplasty.

MATERIALS AND METHODS

A single-institution, prospectively collected total joint registry database was queried to identify patients who underwent primary elbow arthroplasty between 2003 and 2021. Elbows with known infection prior to arthroplasty (25) and procedures with incomplete perioperative antibiotic data (7) were excluded, for a final sample size of 603 total elbow arthroplasties and 19 distal humerus hemiarthroplasties. Cefazolin was administered in 561 elbows (90%) and non-cefazolin antibiotics including vancomycin (32 elbows, 5%), clindamycin (27 elbows, 4%), and piperacillin/tazobactam (2 elbows, 0.3%) were administered in the remaining 61 elbows (10%). Univariate and multivariate analyses were conducted to determine the association between the antibiotic administered and the development of PJI. Infection-free survivorship was estimated using the Kaplan-Meier method.

RESULTS

Deep infection occurred in 47 elbows (7.5%), and 16 elbows (2.5%) were diagnosed with superficial infections. Univariate analysis demonstrated that patients receiving non-cefazolin alternatives were at significantly higher risk for any infection (hazard ratio [HR] 2.6, 95% confidence interval [CI] 1.4-5.0; P < .01) and deep infection (HR 2.7, 95% CI 1.3-5.5; P < .01) compared with cefazolin administration. Multivariable analysis, controlling for several independent predictors of PJI (tobacco use, male sex, surgical indication other than osteoarthritis, and American Society of Anesthesiologists score), showed that non-cefazolin administration had a higher risk for any infection (HR 2.8, 95% CI 1.4-5.3; P < .01) and deep infection (HR 2.9, 95% CI 1.3-6.3; P < .01). Survivorship free of infection was significantly higher at all time points for the cefazolin cohort.

DISCUSSION

In primary elbow arthroplasty, cefazolin administration was associated with significantly lower rates of PJI compared to non-cefazolin antibiotics, even in patients with a greater number of prior surgeries, which is known to increase the risk of PJI. For patients with penicillin or cephalosporin allergies, preoperative allergy testing or a cefazolin test dose should be considered before administering non-cefazolin alternatives.

Management of Penicillin Allergy in the Perioperative Setting

The selection of perioperative antibiotic prophylaxis is challenging in patients with a history of penicillin allergy; as such, we present a literature review exploring current best practices and the associated supporting evidence, as well as areas for future research. Guidelines recommend the use of alternative agents in patients with an IgE-mediated hypersensitivity reaction, but those alternative agents are associated with worse outcomes, including an increased risk of surgical site infection, and higher cost. More recent data suggest that the risk of cross-reactivity between penicillins and cephalosporins, particularly cefazolin, is extremely low, and that cefazolin can be used safely in most penicillin-allergic patients. Studies have therefore explored how best to implement first-line cefazolin use in patients with a penicillin allergy label. A variety of interventions, including preoperative allergy de-labeling with incorporation of penicillin skin testing, use of patient risk-stratification questionnaires, and utilization of clinician algorithms to guide antibiotic selection intraoperatively, have all been shown to significantly increase cefazolin utilization without a corresponding increase in adverse events. Further studies are needed to clarify the most effective interventions and implementation strategies, as well as to evaluate whether patients with severe delayed hypersensitivity reactions to penicillin should continue to be excluded from receipt of other beta-lactams.

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.

Rat model of recalcitrant prosthetic joint infection using biofilm inocula

Prosthetic joint infection (PJI) is a rare but devastating complication of joint arthroplasty. Biofilm formation around the prosthesis confers tolerance to antibiotics so that treatment is challenging. Most animal models of PJI use planktonic bacteria to establish the infection which fails to reproduce the pathology of chronic infection. We aimed to establish a rat model of Staphylococcus aureus PJI in male Sprague-Dawley rats using biofilm inocula and demonstrate its tolerance to frontline antibiotics. Pilot studies indicated that infection could be introduced to the knee joint by a biofilm-coated pin but that handling the prosthetic without disturbing the biofilm was difficult. We, therefore, developed a pin with a slotted end and used a miniature-biofilm reactor to develop mature biofilm in this niche. These biofilm-laden pins consistently produced infection of the bone and joint space. Treatment with high dose cefazolin, 250 mg/kg, starting the day of surgery reduced or cleared pin-adherent bioburden within 7 days, however when escalation from 25 to 250 mg/kg cefazolin treatment was delayed for 48 h, rats were unable to clear the infection. To track infections, we used bioluminescent bacteria, however, the bioluminescent signal did not accurately track the degree of infection in the bone and joint space as the signal did not penetrate the bone. In conclusion, we demonstrate that using a custom prosthetic pin, we can generate biofilm in a specific niche using a novel bioreactor setup and initiate a rat PJI that rapidly develops tolerance to supra-clinical doses of cefazolin.

Intraosseous regional prophylaxis in total knee arthroplasty

Prophylactic antibiotics are important in reducing the risk of periprosthetic joint infection (PJI) following total knee arthroplasty. Their effectiveness depends on the choice of antibiotic and the optimum timing of their administration, to ensure adequate tissue concentrations. Cephalosporins are typically used, but an increasing number of resistant organisms are causing PJI, leading to the additional use of vancomycin. There are difficulties, however, with the systemic administration of vancomycin including its optimal timing, due to the need for prolonged administration, and potential adverse reactions. Intraosseous regional administration distal to a tourniquet is an alternative and attractive mode of delivery due to the ease of obtaining intraosseous access. Many authors have reported the effectiveness of intraosseous prophylaxis in achieving higher concentrations of antibiotic in the tissues compared with intravenous administration, providing equal or enhanced prophylaxis while minimizing adverse effects. This annotation describes the technique of intraosseous administration of antibiotics and summarizes the relevant clinical literature to date.

Assessing ChatGPT Responses to Common Patient Questions Regarding Total Hip Arthroplasty

BACKGROUND

The contemporary patient has access to numerous resources on common orthopaedic procedures before ever presenting for a clinical evaluation. Recently, artificial intelligence (AI)-driven chatbots have become mainstream, allowing patients to engage with interfaces that supply convincing, human-like responses to prompts. ChatGPT (OpenAI), a recently developed AI-based chat technology, is one such application that has garnered rapid growth in popularity. Given the likelihood that patients may soon call on this technology for preoperative education, we sought to determine whether ChatGPT could appropriately answer frequently asked questions regarding total hip arthroplasty (THA).

METHODS

Ten frequently asked questions regarding total hip arthroplasty were posed to the chatbot during a conversation thread, with no follow-up questions or repetition. Each response was analyzed for accuracy with use of an evidence-based approach. Responses were rated as "excellent response not requiring clarification," "satisfactory requiring minimal clarification," "satisfactory requiring moderate clarification," or "unsatisfactory requiring substantial clarification."

RESULTS

Of the responses given by the chatbot, only 1 received an "unsatisfactory" rating; 2 did not require any correction, and the majority required either minimal (4 of 10) or moderate (3 of 10) clarification. Although several responses required nuanced clarification, the chatbot's responses were generally unbiased and evidence-based, even for controversial topics.

CONCLUSIONS

The chatbot effectively provided evidence-based responses to questions commonly asked by patients prior to THA. The chatbot presented information in a way that most patients would be able to understand. This resource may serve as a valuable clinical tool for patient education and understanding prior to orthopaedic consultation in the future.

Effect of non-cephalosporin antibiotic prophylaxis on the risk of periprosthetic joint infection after total joint replacement surgery: a retrospective study with a 1-year follow-up

Background

Cephalosporins are recommended as first-line antibiotic prophylaxis in total joint replacement surgery. Studies have shown an increased risk for periprosthetic joint infection (PJI) when non-cephalosporin antibiotics have been used. This study examines the effect of non-cephalosporin antibiotic prophylaxis on the risk for PJI.

Methods

Patients with a primary hip or knee replacement performed from 2012 to 2020 were identified (27 220 joint replacements). The primary outcome was the occurrence of a PJI in a one-year follow-up. The association between perioperative antibiotic prophylaxis and the outcome was examined using logistic regression analysis.

Discussion

Cefuroxime was used as prophylaxis in 26,467 operations (97.2%), clindamycin in 654 (2.4%) and vancomycin in 72 (0.3%). The incidence of PJI was 0.86% (228/26,467) with cefuroxime and 0.80% (6/753) with other prophylactic antibiotics. There was no difference in the risk for PJI with different prophylactic antibiotics in the univariate (OR 1.06, 95% CI 0.47-2.39) or multivariable analysis (OR 1.02, 95% CI 0.45-2.30).

Conclusion

Non-cephalosporin antibiotic prophylaxis in primary total joint replacement surgery was not associated with an increased risk for PJI.

Cefazolin vs Second-line Antibiotics for Surgical Site Infection Prevention After Total Joint Arthroplasty Among Patients With a Beta-lactam Allergy

Background

Cefazolin is a first-line agent for prevention of surgical site infections (SSIs) after total joint arthroplasty. Patients labeled allergic to beta-lactam antibiotics frequently receive clindamycin or vancomycin perioperatively due to the perceived risk of a hypersensitivity reaction after exposure to cefazolin.

Methods

This single-system retrospective review included patients labeled allergic to penicillin or cephalosporin antibiotics who underwent a primary total hip and/or knee arthroplasty between January 2020 and July 2021. A detailed chart review was performed to compare the frequency of SSI within 90 days of surgery and interoperative hypersensitivity reactions (HSRs) between patients receiving cefazolin and patients receiving clindamycin and/or vancomycin.

Results

A total of 1128 hip and/or knee arthroplasties from 1047 patients were included in the analysis (cefazolin n = 809, clindamycin/vancomycin n = 319). More patients in the clindamycin and/or vancomycin group had a history of cephalosporin allergy and allergic reactions with immediate symptoms. There were fewer SSIs in the cefazolin group compared with the clindamycin and/or vancomycin group (0.9% vs 3.8%; P < .001) including fewer prosthetic joint infections (0.1% vs 1.9%). The frequency of interoperative HSRs was not different between groups (cefazolin = 0.2% vs clindamycin/vancomycin = 1.3%; P = .06).

Conclusions

The use of cefazolin as a perioperative antibiotic for infection prophylaxis in total joint arthroplasty in patients labeled beta-lactam allergic is associated with decreased postoperative SSI without an increase in interoperative HSR.

When intravenous vancomycin prophylaxis is needed in shoulder arthroplasty, incomplete administration is associated with increased infectious complications

BACKGROUND

Vancomycin is often used as antimicrobial prophylaxis for shoulder arthroplasty (SA) either when first generation cephalosporins are contraindicated or colonization with resistant bacteria is anticipated. In general, vancomycin necessitates longer infusion times to mitigate potential side effects. When infusion is started too close to the time of the incision, administration may not be complete during surgery. This study evaluated whether incomplete administration of intravenous vancomycin prior to SA affects the rate of infectious complications.

METHODS

Between 2000 and 2019, all primary SA types (hemiarthroplasty, anatomic total SA, reverse SA) performed at a single institution for elective and trauma indications using intravenous vancomycin as the primary antibiotic prophylaxis and a minimum follow-up of 2 yr were identified. The time between the initiation of vancomycin and skin incision was calculated. Complete administration was defined as at least 30 min of infusion prior to incision. Demographic characteristics and infectious complications including survival free of prosthetic joint infection (PJI) were generated. Multivariable analyses were conducted to evaluate the association between vancomycin timing and the development of PJI.

RESULTS

A total of 461 primary SAs were included. Infusion was incomplete (< 30 minutes preoperatively) for 163 [35.4%] SA and complete (> 30 minutes preoperatively) for 298 [64.6%] SAs. The incomplete group demonstrated higher rates of any infectious complication (8% vs. 2.3%; P = .005), PJI (5.5% vs. 1%; P = .004), and reoperation inclusive of revision due to infectious complications (4.9% vs. 1%; P = .009). Survivorship free of PJI was worse in SA with incomplete compared to those with complete vancomycin administration. Survival rates for incomplete and complete administration were 97.6% and 99.3% at 1 mo, 95.7% and 99.0% at 2 yr, 95.1% and 99.0% at 5 yr, and 93.9% and 99.0% at 20 yr, respectively (P = .006). Multivariable analyses confirmed that incomplete vancomycin administration was an independent risk factor for PJI compared with complete administration (hazard ratio, 4.22 [95% confidence interval, 1.12-15.90]; P = .033), even when other independent predictors of PJI (age, male sex, prior surgery, methicillin-resistant Staphylococcus aureus colonization, and follow-up) were considered.

CONCLUSIONS

When vancomycin is the primary prophylactic agent used at the time of primary SA, incomplete administration (infusion to incision time under 30 min) seems to adversely increase the rates of infectious complications and PJI. Prophylaxis protocols should ensure that complete vancomycin administration is achieved to minimize infection after SA.

Dose optimization in surgical prophylaxis: sub-inhibitory dosing of vancomycin increases rates of biofilm formation and the rates of surgical site infection

Antibiotic stewardship is viewed as having great public health benefit with limited direct benefit to the patient at the time of administration. The objective of our study was to determine if inappropriate administration of antibiotics could create conditions that would increase the rates of surgical infection. We hypothesized that sub-MIC levels of vancomycin would increase Staphylococcus aureus growth, biofilm formation, and rates of infection. S. aureus MRSA and MSSA strains were used for all experiments. Bacteria were grown planktonically and monitored using spectrophotometry. Quantitative agar culture was used to measure planktonic and biofilm bacterial burden. A mouse abscess model was used to confirm phenotypes in vivo. In the planktonic growth assay, increases in bacterial burden at ¼ MIC vancomycin were observed in USA300 JE2 by 72 h. Similar findings were observed with ½ MIC in Newman and SH1000. For biofilm formation, USA300 JE2 at ¼ and ½ MIC vancomycin increased biofilm formation by approximately 1.3- and 2.3-fold respectively at 72 h as compared to untreated controls. Similar findings were observed with Newman and SH1000 with a 2.4-fold increase in biofilm formation at ½ MIC vancomycin. In a mouse abscess model, there was a 1.2-fold increase with sub-MIC vancomycin at 3 days post infection. Our study showed that Sub-optimal vancomycin dosing promoted S. aureus planktonic growth and biofilm formation, phenotypic measures of bacterial virulence. This phenotype induced by sub-MIC levels of vancomycin was also observed to increase rates of infection and pathogenesis in our mouse model. Risks of exposure to sub-MIC concentrations with vancomycin in surgical procedures are greater as there is decreased bioavailability in tissue in comparison to other antibiotics. This highlights the importance of proper antibiotic selection, stewardship, and dosing for both surgical prophylaxis and treatment of infection.

Antibiotic Prophylaxis in One-Stage Revision of Septic Total Knee Arthroplasty: A Scoping Review

BACKGROUND

Total knee replacement (TKA) is becoming a routine procedure in orthopedic surgery. One of the possible complications of this surgery is periprosthetic joint infection (PJI). The purpose of this study is to identify, through a literature review, which antibiotic is used as prophylaxis for septic one-stage revision TKA and what is the rationale for its use.

METHODS

We searched: MEDLINE, Embase, PsycINFO on Ovid, the Cochrane Library, and the Google Scholar Database. The searches were limited by date (January 2005 to September 2022) and to the English language. All types of original research were considered, including prospective or retrospective longitudinal studies, cross-sectional studies, and randomized trials. The specific search terms were ((antibiotic [MeSH]) AND (prophylaxis)) and (TKA OR TKR OR "Arthroplasty, Replacement, Knee" [MeSH] OR ((knee) adj2 (replace* OR arthroplasty* OR prosthe*))).

RESULTS

Despite our research efforts, we found no article capable of answering the question of which antibiotic to use as surgical prophylaxis for a septic revision one-stage TKA.

CONCLUSIONS

Although the research results are inconclusive, we would recommend using the same antibiotic prophylaxis as for primary joint replacement, i.e., cefazolin, as it was recommended for its low side effect rate and relative effectiveness.

Impact of Penicillin Allergy-Based Alternative Antibiotics on the Risk of Postoperative Central Nervous System Infection: A Retrospective Cohort Study

BACKGROUND

Central nervous system (CNS) infection is one of the most serious complications after neurosurgery. This study aimed to analyze the effect of penicillin allergy (PA) and alternative prophylactic antibiotics on risk of postoperative CNS infection in patients undergoing neurosurgery.

METHODS

Data of patients who underwent neurosurgical procedures from January 2015 to December 2021 were analyzed retrospectively. Patients with PA were compared with patients without PA in a 1:1 ratio. A multivariate logistic regression model was used to examine whether PA was a risk factor for postoperative CNS infection.

RESULTS

Overall, 15,049 eligible neurosurgical records were reviewed, from which 578 surgical records of 556 patients with PA were matched to 578 records of 570 patients without PA. Patients with PA showed significantly lower probability to receive prophylactic cephalosporins (55.9% vs. 98.8%, P < 0.01), but significantly higher probability to receive clindamycin (41.86% vs. 1.03%, P < 0.01), than patients without PA. Multivariate analysis revealed that patients with PA were more likely to experience postoperative CNS infection than patients without PA (odds ratio = 2.03; 95% confidence interval, 1.15-3.56; P = 0.014). The incidence of postoperative CNS infection returned to a level comparable to that in general population when patients with suspected PA received prophylactic cephalosporins.

CONCLUSIONS

PA is associated with higher risk of postoperative CNS infection in patients undergoing neurosurgery. This may be attributed to the use of alternative prophylactic antibiotics other than cephalosporins, especially clindamycin.

Effects of extended oral antibiotic prophylaxis on surgical site infections after instrumented spinal fusion: a cohort study of 901 patients with a minimum follow-up of 1 year

BACKGROUND AND PURPOSE

We aimed to determine whether an extended oral antibiotic prophylaxis protocol may reduce the rate of surgical site infection (SSI) in patients undergoing instrumented spinal fusion.

PATIENTS AND METHODS

This retrospective cohort study comprise 901 consecutive patients subjected to spinal fusion between September 2011 and December 2018 with a minimum 1-year follow-up. 368 patients operated on between September 2011 and August 2014 were administered standard intravenous prophylaxis. 533 patients operated on between September 2014 and December 2018 were administered an extended protocol with 500 mg of oral cefuroxime axetil every 12 hours (clindamycin or levofloxacin in allergic individuals) until the removal of sutures. SSI was defined following the Centers for Disease Control and Prevention criteria. The association between risk factors and the incidence of SSI was evaluated by odds ratio (OR) with a multiple logistic regression model.

RESULTS

The bivariate analysis showed a statistically significant association between SSI and the type of prophylaxis used ("extended"' = 1.7% vs. "standard" = 6.2%, p= 0.001), with a lower proportion of superficial SSIs with the extended regimen (0.8% vs. 4.1%, p = 0.001). The multiple logistic regression model showed an OR = 0.25 (95% confidence interval [CI] 0.10-0.53) for extended prophylaxis and an OR = 3.5 (CI 1.3-8.1) for non-beta-lactams antibiotics.

CONCLUSION

Extended antibiotic prophylaxis seems to be associated with a reduction in the incidence of superficial SSI in instrumented spine surgery.

Is Topical Vancomycin an Option? A Randomized Controlled Trial to Determine the Safety of the Topical Use of Vancomycin Powder in Preventing Postoperative Infections in Total Knee Arthroplasty, as Compared With Standard Postoperative Antibiotics

BACKGROUND

The demand for total knee arthroplasties (TKAs) is expected to rise in the coming decades, increasing the burden of periprosthetic joint infections (PJIs). The use of intrawound vancomycin powder (VP) has proven to be effective in reducing the incidence of PJIs after spinal surgery. That said, its effectiveness in TKA remains unclear. This trial aims to examine the efficacy of intrawound vancomycin powder first versus standard postoperative antibiotics in preventing PJIs after TKA.

METHODS

This study was a double-blinded, noninferiority, randomized controlled trial. All participants received standard preoperative intravenous (IV) antibiotics (Cefazolin/Vancomycin) within 60 minutes of skin incision. Patients in the treatment group received 1 gram of VP applied intraoperatively by the orthopedic surgeon (500 mg directly on the prosthesis, 500 mg above the closed joint capsule). These patients did not receive postoperative antibiotics. Patients in the control group received standard postoperative IV antibiotics. The primary outcome was the incidence of acute surgical site infection within 42 days of procedure.

RESULTS

There were 80 patients randomized to the treatment group and 85 patients randomized to the control. Groups were matched with respect to baseline characteristics, including average age (66 versus 64), BMI (35.7 versus 33.4), and diabetics (16 versus 13). The trial was halted at 1 year as a significantly greater proportion (P = .03) of patients in the treatment group (n = 3, 3.75%) were diagnosed with PJIs compared to the control (n = 0).

CONCLUSION

Our trial demonstrated the intrawound application of VP to be inferior to standard postoperative IV antibiotics in reducing the incidence of PJIs after TKA.

Does the Prosthetic Phase of Dental Implants Justify the Prescription of Preventive Antibiotics in Healthy Patients? A Systematic Review

Recently published surveys data show that the routine prescription of preventive antibiotics (PA) in the prosthetic phase of dental implants is more common than might be expected. The present study aimed to answer the PICO (population, intervention, comparison, and outcome) question "In healthy patients starting the implant prosthetic phase, does the prescription of PA compared with not prescribing PA decrease the incidence of infectious complications?" by a systematic literature review. A search was performed in 5 databases. The criteria employed were those described in the PRISMA Declaration. Studies included were those that provided information on the need to prescribe PA in the prosthetic phase of implants, that is, in second-stage surgeries, impression-taking, and prosthesis placement. The electronic search identified 3 studies that met the established criteria. The prescription of PA in the prosthetic phase of implants does not show a justified benefit/risk ratio. Preventive antibiotic therapy (PAT) may be indicated in the second stages or in peri-implant plastic surgery procedures lasting more than 2 hours and/or where soft tissue grafts are used extensively. In these cases, given the current lack of evidence, it is recommended to prescribe 2 g of amoxicillin 1 hour before surgery and, in allergic patients, to prescribe 500 mg of azithromycin 1 hour preoperatively.

Preoperative allergy testing for patients reporting penicillin and cephalosporin allergies is economically justified in preventing infection after total shoulder arthroplasty

BACKGROUND

The use of alternative antibiotics to cefazolin has been associated with increased risk of infection after shoulder arthroplasty. Routine preoperative allergy testing in patients reporting penicillin and cephalosporin allergies increases the number able to receive cefazolin and may reduce the occurrence of infection after shoulder arthroplasty, but the financial viability of this practice is unclear. We used break-even modeling to determine the economic viability of routine preoperative allergy testing for infection prevention in total shoulder arthroplasty patients reporting penicillin and cephalosporin allergies.

METHODS

Allergy testing cost ($248.24), infection rates after shoulder arthroplasty following use of noncefazolin antibiotics (3.09%), and infection-related care costs ($55,243) were derived from the literature. A break-even equation using these variables was developed to determine the absolute risk reduction (ARR) in the infection rate that would economically justify the routine implementation of preoperative allergy testing. The number needed to treat was calculated from the ARR.

RESULTS

Preoperative allergy testing is considered economically justified if it prevents at least 1 infection out of 223 shoulder arthroplasties (ARR = 0.45%). These protocols remained economically viable at varying allergy testing costs, initial infection rates, and infection-related care costs.

CONCLUSIONS

Routine preoperative penicillin allergy testing is an economically justified infection prevention strategy among patients reporting penicillin and cephalosporin allergies in the setting of elective shoulder arthroplasty. Widespread implementation of this practice may considerably reduce the economic and societal burden associated with prosthetic infections.

The association between penicillin allergy and surgical site infection after orthopedic surgeries: a retrospective cohort study

Background

Cephalosporins are used as first-line antimicrobial prophylaxis for orthopedics surgeries. However, alternative antibiotics are usually used in the presence of penicillin allergy (PA), which might increase the risk of surgical site infection (SSI). This study aimed to analyze the relationship between SSI after orthopedic surgeries and PA among surgical candidates and related alternative antibiotic use.

Methods

In this single-center retrospective cohort study, we compared inpatients with and without PA from January 2015 to December 2021. The primary outcome was SSI, and the secondary outcomes were SSI sites and perioperative antibiotic use. Moreover, pathogen characteristics of all SSIs were also compared between the two cohorts.

Results

Among the 20,022 inpatient records, 1704 (8.51%) were identified with PA, and a total of 111 (0.55%) SSI incidents were reported. Compared to patients without PA, patients with PA had higher postoperative SSI risk (1.06%, 18/1704 vs. 0.51%, 93/18318), shown both in multivariable regression analysis (odds ratio [OR] 2.11; 95% confidence interval [CI], 1.26-3.50; p= 0.004) and propensity score matching (OR 1.84; 95% CI, 1.05-3.23; p= 0.034). PA was related to elevated deep SSI risk (OR 2.79; 95% CI, 1.47-5.30; p= 0.002) and had no significant impact on superficial SSI (OR 1.39; 95% CI, 0.59-3.29; p= 0.449). The PA group used significantly more alternative antibiotics. Complete mediation effect of alternative antibiotics on SSI among these patients was found in mediation analysis. Pathogen analysis revealed gram-positive cocci as the most common pathogen for SSI in our study cohort, while patients with PA had higher infection rate from gram-positive rods and gram-negative rods than non-PA group.

Conclusion

Compared to patients without PA, patients with PA developed more SSI after orthopedic surgeries, especially deep SSI. The elevated infection rate could be secondary to the use of alternative prophylactic antibiotics.

Does addition of gentamicin for antibiotic prophylaxis in total knee arthroplasty reduce the rate of periprosthetic joint infection?

BACKGROUND

First-generation cephalosporins are used as antibiotic prophylaxis in total joint arthroplasty patients. However, this regimen does not address Gram-negative bacteria causing periprosthetic joint infection (PJI). Previous studies have suggested that the addition of an aminoglycoside as antibiotic prophylaxis in THA reduces surgical site infection (SSI), and less is known on its effect in TKA. This study aimed to investigate if the addition of a single-dose gentamicin, administered pre-operatively, is associated with lower rates of infection in TKA patients.

PATIENTS AND METHODS

This is a retrospective study of patients who underwent primary TKA as treatment for osteoarthritis between January 2011 and April 2021, with a minimum 1-year follow-up. The mean age was 69.9 (± 9.8), the mean BMI was 29.7 (± 5.5), and most patients had American Society of Anaesthesiology (ASA) score of 2-3 (92.9%). Patients were stratified based on the peri-operative antibiotic prophylaxis they received: cefazolin with addition of gentamicin (case group) or cefazolin (control group). Our primary study endpoints were rates of PJI and SSI, which were compared between groups using the chi-square test. Statistical significance was set as p < 0.05.

RESULTS

The final study population consisted of 1590 patients, 1008 (63.4%) in the control group and 582 (36.6%) patients in the case group. The total infection rate for patients that received gentamicin dropped by 34%; however, this finding did not reach statistical significance (1.3% (control) vs. 0.86% (case), p = 0.43). The same drop was seen after subdivision of infections to PJI (0.5% vs. 0.34%, 32% drop, p = 0.66) and SSI (0.8% vs. 0.52%, 35% drop, p = 0.52).

CONCLUSIONS

A single dose of gentamicin administered pre-operatively to a standard antibiotic prophylaxis was not associated with a statistically significant lower rate of PJI. Although the difference in infection rate did not reach statistical significance, the current study noted a drop in the rate of infection by 1/3 in the gentamicin cohort. Further investigation to evaluate the potential benefit of adding gentamicin to a peri-operative antibiotic regimen is warranted.

Increasing patient-reported allergies are not associated with pain, functional outcomes, or satisfaction following medial patellofemoral ligament reconstruction: a retrospective comparative cohort study

Background

Patient-reported allergies (PRAs) are often stigmatized as a potential nonmodifiable risk factor for increased pain and worse functional outcomes following surgery. However, there is a dearth of literature directly assessing the impact of PRAs on outcomes in sport surgeries such as medial patellofemoral ligament reconstruction (MPFLR). The purpose of our study was to determine whether PRAs were associated with worse outcomes following MPFLR.

Methods

We conducted a retrospective review of patients who underwent MPFLR at our institution from 2011 to 2019. Patients were included if they had at least 12 months of follow-up. PRAs were obtained from preoperative medical assessments and categorized by drug class. Demographic and perioperative data were obtained from electronic medical records. Postoperative outcomes were measured using a telephone survey and included recurrent instability, Visual analog scale (VAS) for pain, VAS for sports, Kujala score, MPFL-Return to Sport after Injury (MPFL-RSI) score, and overall satisfaction score. Multiple linear regression was used to determine association between PRAs and outcome measures, and p-values less than 0.05 were considered significant.

Results

The cohort included 141 MPFLR. Most patients were female (98, 70%) with an average age of 25 years (range 12–56 years). Average follow-up time was 47 months. Forty-seven patients (33%) reported at least one PRA. There were no significant differences in postoperative pain, functional outcomes, satisfaction, or return to sport between patients with or without PRAs (all p > 0.05). Absence of antibiotic PRAs was predictive of higher VAS (p < 0.007), but there were no other differences. There were no significant differences in outcomes between patients without PRAs, PRAs without a concomitant psychiatric disorder, or PRAs with a concomitant psychiatric disorder (all p > 0.05).

Conclusions

In conclusion, PRAs with or without concomitant psychiatric diagnoses are not associated with worse postoperative pain, functional outcomes, or satisfaction following MPFLR with allograft, dispelling common misconceptions that increased number of allergies or psychiatric diagnoses lead to inferior surgical outcomes. Presence of antibiotic allergies was associated with lower VAS postoperative pain score. Future research should investigate the relationship between PRAs and other surgeries in the field of sports medicine.

Advances in immunoglobulin E mediated antibiotic allergy

PURPOSE OF REVIEW

The purpose of this review is to identify recent advances in our understanding and management of immunoglobulin E (IgE)-mediated antibiotic allergy.

RECENT FINDINGS

Antibiotics remain a leading cause of fatal anaphylaxis reported to the FDA. However, recent advances have defined the features of adult and pediatric patients without true IgE-mediated allergy or any mechanism of anaphylaxis when tested. This has created opportunities to use direct challenges to disprove these allergies at the point-of-care and improves antibiotic stewardship. Additional advances have highlighted cross-reactive structural considerations within classes of drugs, in particular the R1 side-chain of cephalosporins, that appear to drive true immune-mediated cross-reactivity. Further advances in risk-based approaches to skin testing, phenotyping, and re-exposure challenges are needed to standardize antibiotic allergy evaluation.

SUMMARY

Recent advances in defining true IgE-mediated drug allergy have helped to identify patients unlikely to be skin-test positive. In turn, this has identified patients who can skip skin testing and proceed to direct ingestion challenge using history risk-based approaches. The ability to identify the small number of patients with true IgE-mediated allergy and study their natural history over time, as well as the vast majority without true allergy will facilitate important and novel mechanistic discoveries.

Periprosthetic joint infection: what next?

Periprosthetic joint infection (PJI) remains an extremely challenging complication. We have focused on this issue more over the last decade than previously, but there are still many unanswered questions. We now have a workable definition that everyone should align to, but we need to continue to focus on identifying the organisms involved. Surgical strategies are evolving and care is becoming more patient-centred. There are some good studies under way. There are, however, still numerous problems to resolve, and the challenge of PJI remains a major one for the orthopaedic community. This annotation provides some up-to-date thoughts about where we are, and the way forward. There is still scope for plenty of research in this area.

Cite this article: Bone Joint J 2022;104-B(11):1193–1195.

Techniques for Decreasing Bacterial Load for Open Shoulder Surgery

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Benzoyl peroxide (BPO) 5% has been shown to reduce Cutibacterium acnes load on the skin. BPO 5% with miconazole nitrate (MN) 2% may be beneficial, whereas BPO 5% with clindamycin cream 1% to 1.2% does not seem to have additive effects when compared with BPO 5% alone. Chlorhexidine gluconate solutions reduce the total bacterial load on the skin, but do not seem to have a significant effect on C. acnes.

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ChloraPrep seems to be the best surgical skin preparation to decrease overall positive skin cultures. Preincisional hydrogen peroxide 3% application has been shown to be a cost-effective practice to inhibit growth of C. acnes. Vancomycin powder before deltopectoral interval closure has antimicrobial effects against C. acnes and is a cost-effective practice. Finally, Bactisure surgical lavage is protective against the formation of biofilms.

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IV cefazolin has been shown to be more effective for shoulder arthroplasty infection prophylaxis than antibiotic alternatives such as vancomycin. Thus, patients with a questionable history of penicillin allergy should undergo additional testing.

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For shoulder surgery infection prophylaxis, we recommend the use of BPO 5% cream for 5 days preoperatively with chlorhexidine wipes the night before and the morning of surgery. IV cefazolin should be administered perioperatively, and patients with a questionable history of penicillin allergy should be tested. Surgeons should consider preincisional application of hydrogen peroxide 3% for 5 minutes, followed by standard ChloraPrep preparation. Normal saline should be used for preclosure lavage. Finally, application of vancomycin powder deep to the deltopectoral interval closure should be considered.

Antimicrobial Stewardship in Total Joint Arthroplasty: Outcomes of a Collaborative Program Implementation

INTRODUCTION

Antimicrobial stewardship has been cited as a crucial component of orthopaedic surgical care; however, limited high-quality data exist to guide antibiotic use across the total joint arthroplasty continuum. Antimicrobial stewardship program (ASP) implementation and evaluation is needed in this space.

METHODS

We pursued a prospective, sequential cohort study of an interprofessional ASP for total joint arthroplasty (TJA) formed in late 2017 at the study institution. Twelve total evidence-based recommendations for protocol change were issued, with 11 accepted and implemented across three project phases spanning March 2018 to December 2019. The primary study outcome was the rate of optimal preoperative intravenous antibiotic selection as assessed for Baseline versus Postintervention time periods. Secondary outcomes included individual antibiotic utilization rates. Descriptive statistics were pursued for institutional surgical site infection (SSI) and postoperative acute kidney injury (AKI) rates across the affected time frame. A cost-benefit analysis of the ASP was estimated from the institutional perspective.

RESULTS

The rate of optimal preoperative antibiotic selection increased from 64.9% in the Baseline Period (February 2018, n = 57) to 95.4% in the Postimplementation period (June 2018 to December 2019, n = 1,220) (P < 0.001). The rates of second-line preoperative antibiotics and total perioperative antibiotic exposures decreased. Total SSI and AKI rates in primary elective TJA seemed to decrease from calendar year 2018 to 2019 (deep SSI 1.00% to 0.22%, superficial SSI 0.66% to 0.00%, and AKI 1.97% to 1.03%). The institution realized an estimated $197,050 cost savings per 1000 TJA procedures.

DISCUSSION

A comprehensive ASP for TJA was associated with an increased use of optimal preoperative antibiotic selection, decreased total antibiotic exposures, and cost savings, without apparent detriment to SSI or AKI rates.

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.

The prevalence and risk factors of dislocation after primary total hip arthroplasty

This study aimed to investigate the occurrence of dislocation and risk factors following primary total hip arthroplasty (THA). Retrospective analysis was done on the clinical data of 441patients with primary total hip arthroplasty who were admitted to our hospital between May 2018 and early December 2020. A total of 294 patients without posterior soft tissue repair were included as control group, and a total of 147 patients with repair of the short external rotator muscle and joint capsule were assigned to the repair group. All operated patients were observed to analyze the occurrence and risk of early postoperative dislocation. Within 6 months after hip arthroplasty, the early hip dislocation rate in the repair group was 0.68%, which was significantly lower than that in the control group (4.78%) (P < 0.05). The results of multifactorial analysis showed that age ≥75 years, combined limb or mental illness, artificial femoral head diameter <30 mm, posterolateral approach and prosthesis placement outside the safety zone, and improper handling were risk factors for dislocation (P < 0.05); The incidence of re-dislocation was lower in the targeted intervention group (P < 0.05). The occurrence of dislocation after THA is related to age, gender, and type of orthopedic disease. The risk factors should be explored to develop targeted intervention protocol, decreasing the dislocation rate and improving the prognosis.

Preoperative Prophylactic Antibiotics in Total Hip and Knee Arthroplasty: What, When, and How

Although there are numerous nonpatient-related factors that may help reduce infection risk, the proper use of prophylactic antibiotics is most responsible for reducing infection. The role of prophylactic antibiotics is to reduce early periprosthetic joint replacement, which is accomplished by having adequate antibiotic tissue levels at the time of skin incision. The goal of this section of the symposium is to review current antibiotic recommendations, how to manage patients with a self-reported penicillin allergy, review the use of dual antibiotics, discuss the use of antibiotics in the outpatient total joint setting, as well as very briefly discuss the administration of intraosseous antibiotics in knee arthroplasty.

Extended Oral Antibiotic Prophylaxis After Aseptic Revision TKA: Does It Decrease Infection Risk?

BACKGROUND

Extended oral antibiotic prophylaxis (EOA) has been shown to potentially reduce infection rates after high-risk primary total knee arthroplasties (TKAs) and reimplantations. However, data is limited regarding EOA after aseptic revision TKAs. This study evaluated the impact of EOA on infection-related outcomes after aseptic revision TKAs.

METHODS

904 aseptic revision TKAs from 2014-2019 were retrospectively identified. Patients who received EOA >24 hours perioperatively (n = 267) were compared to those who did not (n = 637) using an inverse probability of treatment weighting model. Mean age was 66 years, mean BMI was 33 kg/m², and 54% were female. Outcomes included cumulative probabilities of any infection, periprosthetic joint infection (PJI), superficial infection, and re-revision or reoperation for infection.

RESULTS

The cumulative probability of any infection after aseptic revision TKA was 1.9% at 90 days, 3.5% at 1 year, and 8.1% at 5 years. Patients without EOA had a higher risk of any infection at 90 days (HR = 7.1; P = .01), but not other time points. The cumulative probability of PJI after aseptic revision TKA was 0.8% at 90 days, 2.3% at 1 year, and 6.5% at 5 years. Patients without EOA did not have an increased risk of PJI. There were no differences in re-revision or reoperation for infection at any time point between groups.

CONCLUSION

Extended oral antibiotics after aseptic revision TKA were associated with a 7-fold decreased risk of any infection at 90 days. The results suggest a potential role for EOA after aseptic revision TKA and warrant additional prospective studies.

LEVEL OF EVIDENCE

Level III.

Antibiotic Prophylaxis with Cefazolin Is Associated with Lower Shoulder Periprosthetic Joint Infection Rates Than Non-Cefazolin Alternatives

BACKGROUND

Although prophylactic antibiotics are considered the standard of care, data with regard to the comparative efficacy of specific antibiotics in the prevention of periprosthetic joint infection (PJI) have remained limited. This study evaluated whether perioperative antibiotic choice affects rates of PJI development in shoulder arthroplasty.

METHODS

From 2000 to 2019, all primary shoulder arthroplasty types (hemiarthroplasty, anatomic total shoulder arthroplasty, reverse shoulder arthroplasty) performed for elective and trauma indications with perioperative antibiotic data and a minimum follow-up of 2 years were identified from a single institution. Demographic characteristics, PJI risk factors, and PJI-free survivorship data were retrieved. Multivariable analyses were conducted to determine the association between the antibiotic administered and the development of PJI.

RESULTS

Of 7,713 shoulder arthroplasties, cefazolin was administered in 6,879 procedures (89.2%) and non-cefazolin antibiotics consisting of vancomycin (465 procedures [6.0%]), clindamycin (345 procedures [4.5%]), and alternative regimens (24 procedures [0.31%]) were administered in 834 procedures (10.8%). PJIs occurred in 101 shoulder arthroplasties (1.3%), with Cutibacterium acnes as the most common pathogen (44 procedures [43.6%]). PJI-free survivorship was greater in shoulder arthroplasties in which cefazolin was administered compared with those in which non-cefazolin antibiotics were administered, with 0.91% greater survival free of PJI at 1 month, 1.4% at 1 year, and 2.7% at 15 years (p < 0.001). Cefazolin administration, compared with non-cefazolin administration, was associated with a 69% reduction in all-cause PJI risk and a 78% reduction in C. acnes PJI risk (p < 0.001). A higher risk of PJI for both groups was observed with vancomycin; the hazard ratio [HR] was 2.32 (95% confidence interval [CI], 1.22 to 4.40; p = 0.010) for all-cause PJI and 2.94 (95% CI, 1.12 to 7.49; p = 0.028) for C. acnes PJI. A higher risk of PJI was also observed for both groups for clindamycin; the HR was 5.07 (95% CI, 2.83 to 9.05; p < 0.001) for all-cause PJI and 8.01 (95% CI, 3.63 to 17.42; p < 0.001) for C. acnes PJI.

CONCLUSIONS

In primary shoulder arthroplasty, cefazolin administration was associated with a significantly lower rate of PJI compared with non-cefazolin alternatives, including both vancomycin and clindamycin. These risk discrepancies were observed across all infectious pathogens and may be considered even greater when C. acnes was the infecting bacterium.

LEVEL OF EVIDENCE

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

Antibiotic prophylaxis in total joint arthroplasty – the usual practice and variability among joint replacement surgeons in Hong Kong

Background

Perioperative antibiotics is a well established measure to prevent periprosthetic joint infection (PJI). However, the usual practice of prescription vary from surgeon to surgeon. This study aims to investigate and compare the usual practice and variability of prescribing antibiotic prophylaxis among different joint replacement surgeons in Hong Kong.

Methods

An online questionnaire was prepared and sent to members of the Adult Joint Reconstruction (AJR) Chapter of the Hong Kong Orthopaedic Association (HKOA). The questionnaire consists of a total of 15 questions in 3 categories: choice of antibiotics, dose of antibiotics and duration of antibiotics prescribed by the surgeon.

Results

A total of 25 responses were received and data collected. Participants were from a diverse background from different hospitals with variable years of experience. Results showed a general consensus on the choice of antibiotics, but also a wide variability on the actual prescription, particularly about the weight-adjusted dose and total duration of antibiotics given.

Conclusion

There is a wide variability among surgeons regarding the actual prescription of antibiotic prophylaxis. Correlation between rate of PJI and specific aspects of antibiotic prescription is needed to give recommendations to surgeons regarding perioperative antibiotic usage in total joint arthroplasties.

Patients Who Do Not Receive Aspirin Because of Allergy Have an Increased Risk of Venous Thromboembolism Following Total Joint Arthroplasty

BACKGROUND

Patient-reported allergies to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) may preclude certain patients from receiving aspirin as venous thromboembolism (VTE) prophylaxis after total joint arthroplasty (TJA). The purpose of the study was to (1) determine whether the use of non-aspirin agents due to a self-reported aspirin or NSAID allergy was associated with a higher incidence of VTE and (2) determine the rate of true allergic reactions in patients who reported an allergy but still received aspirin.

METHODS

Prospectively collected data from 45,171 patients who underwent primary TJA between 2000 and 2019 were reviewed. Patients who reported an allergy to aspirin or NSAIDs were identified (n = 823). Using a validated VTE risk calculator, each patient was assigned a risk score based on 26 comorbidities. Bleeding complications, VTEs that occurred within 90 days postoperatively, and allergic reactions were collected as end points. Multivariable logistic regression was performed to determine the factors associated with VTE.

RESULTS

The overall incidence of aspirin or NSAID allergy was 1.8%. Only 80 of 267 patients (30%) reported an allergy to only aspirin and still received aspirin. Compared with patients who received aspirin without a history of allergy (n = 17,648), patients who received non-aspirin thromboprophylaxis due to allergy (n = 383) had a higher incidence of VTE (2.87% versus 0.24%, p < 0.001). On multivariable regression, these patients had an 8-fold increase in VTE risk (adjusted odds ratio, 7.94; 95% confidence interval, 2.86 to 22.07; p < 0.001). The incidence of true allergic reactions to aspirin among those with a reported allergy was 1.8% (number needed to harm = 55). No patients developed anaphylaxis or severe hypersensitivity reactions.

CONCLUSIONS

Patients with a self-reported allergy to aspirin or NSAIDs were at a significantly increased risk for VTE if they received non-aspirin thromboprophylaxis agents following TJA. Future research should evaluate the usefulness of preoperative allergy testing when selecting a VTE prophylactic agent in patients with self-reported allergies.

LEVEL OF EVIDENCE

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

Are Patient-Reported Drug Allergies Associated With Prosthetic Joint Infections and Functional Outcomes Following Total Hip and Knee Arthroplasty?

BACKGROUND

The purpose of this study is to determine if the number and types of patient-reported drug allergies are associated with prosthetic joint infection (PJI) and functional outcomes following total joint arthroplasty (TJA).

METHODS

This is a retrospective review of all patients who underwent a primary, elective total hip (THA) or knee arthroplasty (TKA) over a 10-year period at a single academic institution. Demographic, clinical information, and number and type of patient-reported drug allergy was collected. Univariate and multivariate logistic regressions were performed to identify risk factors for PJI and risk of PJI based on number of allergies. Univariate analysis was also performed to identify if the number of patient-reported allergies affected functional outcome scores.

RESULTS

Of 31,109 patients analyzed, there were 941 (3%) revisions for infection (491 knees and 450 hips). At least one allergy was reported by 16,435 (52.8%) patients, with a mean of 1.2 ± 1.9. Those who underwent revision for infection had a significantly higher number of reported allergies (1.68 ± 1.9 vs 1.23 ± 1.9, P < .0005, 95% confidence interval -0.58 to 0.33). On univariate regression the number of allergies independently predicted revision TJA for infection (P < .0001) as did age, gender, body mass index, and smoking status. On multivariate regression for each additional patient-reported allergy, risk of PJI increased by 1.11 times (95% confidence interval 1.07-1.14, P < .0001). Number of patient-reported allergies did not predict 3-month or 1-year functional outcome scores.

CONCLUSION

Patients with a higher number of reported allergies may be at increased risk of PJI following TJA.

LEVEL OF EVIDENCE

Prognostic Level II.

Understanding Penicillin Allergy, Cross-reactivity, and Antibiotic Selection in the Preoperative Setting

Penicillin allergies are reported by 8% to 15% of the US population, but up to 95% of these allergies do not correspond to a true allergy when tested. Recent studies have demonstrated that having a penicillin allergy label (PAL) results in a 50% increased odds of surgical site infection among patients reporting a penicillin allergy entirely attributable to the use of a beta-lactam alternative antibiotic (primarily clindamycin or vancomycin). This study provides a review of the prevalence of PAL, the cross-reactivity with cefazolin, immunogenic components of cefazolin and penicillin, and current guidelines for preoperative antibiotic selection in patients with PALs. On understanding these principles, a new set of guidelines and a risk stratification tool are proposed for assessing allergies and determining appropriate antibiotic choice, dosage, and timing in the orthopaedic preoperative setting.

Cefazolin remains the linchpin for preventing acute periprosthetic joint infection following primary total knee arthroplasty

Aims

Despite recent literature questioning their use, vancomycin and clindamycin often substitute cefazolin as the preoperative antibiotic prophylaxis in primary total knee arthroplasty (TKA), especially in the setting of documented allergy to penicillin. Topical povidone-iodine lavage and vancomycin powder (VIP) are adjuncts that may further broaden antimicrobial coverage, and have shown some promise in recent investigations. The purpose of this study, therefore, is to compare the risk of acute periprosthetic joint infection (PJI) in primary TKA patients who received cefazolin and VIP to those who received a non-cephalosporin alternative and VIP.

Methods

This was a retrospective cohort study of 11,550 primary TKAs performed at an orthopaedic hospital between 2013 and 2019. The primary outcome was PJI occurring within 90 days of surgery. Patients were stratified into two groups (cefazolin vs non-cephalosporin) based on their preoperative antibiotic. All patients also received the VIP protocol at wound closure. Bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify the odds ratio of PJI.

Results

In all, 10,484 knees (90.8%) received cefazolin, while 1,066 knees (9.2%) received a non-cephalosporin agent (either vancomycin or clindamycin) as preoperative prophylaxis. The rate of PJI in the cefazolin group (0.5%; 48/10,484) was significantly lower than the rate of PJI in the non-cephalosporin group (1.0%; 11/1,066) (p = 0.012). After controlling for confounding variables, the odds ratio (OR) of developing a PJI was increased in the non-cephalosporin cohort compared to the cefazolin cohort (OR 2.389; 1.2 to 4.6); p = 0.01).

Conclusion

Despite the use of topical irrigant solutions and addition of local antimicrobial agents, the use of a non-cephalosporin perioperative antibiotic continues to be associated with a greater risk of TKA PJI compared to cefazolin. Strategies that increase the proportion of patients receiving cefazolin rather than non-cephalosporin alternatives must be emphasized.

Cite this article: Bone Jt Open 2022;3(1):35–41.