Intraosseous concentration and inhibitory effect of different intravenous cefazolin doses used in preoperative prophylaxis of total knee arthroplasty

Preoperative, Intraoperative & Postoperative Concepts to Prevent Infection for Unicompartmental Knee Arthroplasty

Periprosthetic joint infection (PJI) is a complication that occurs in less than 1% of patients after unicompartmental knee arthroplasty (UKA). Though infrequent, it may potentially lead to revision while placing a significant financial burden on the healthcare system. Pre-operative, intra-operative, and postoperative strategies should be implemented to minimize the risk of PJI. Patient optimization prior to surgery can help to identify patients at risk for PJI and also maximize the health of the patient prior to surgery. Intraoperative and postoperative strategies can also mitigate the risk of postoperative infection. This article will summarize the evidence for preoperative, intra-operative, and postoperative strategies to prevent PJI in UKA. This will include topics on malnutrition and obesity, staphylococcus aureus, smoking, human immunodeficiency virus, rheumatoid arthritis, as well as skin preparation, laminar air flow, preoperative antibiotic administration anti-microbial incision drapes, pulsatile lavage, vancomycin powder, wound closure method, thromboprophylactic agents, and closed incisional negative pressure wound therapy dressings.

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.

A novel method for quantification of cefazolin local tissue concentration in blood, fat, synovium, and bone marrow using liquid chromatography - mass spectrometry

To be effective, the concentration of antibiotic used must exceed the minimum inhibitory concentration (MIC) against infecting organisms at and in the surgical site. Few studies follow antibiotic levels for tissues that are manipulated during surgery. The aim of this work was to develop and validate a novel LC-MS method as well as an efficient extraction technique for the quantification of cefazolin in local tissues and whole blood. This method uses the same efficient extraction method across multiple tissue types affected by orthopedic surgery: blood, fat, synovium, and bone marrow. The ability to quantify cefazolin in these tissues will help identify surgical techniques and antibiotic dosing protocols that better protect patients from infection. The internal standard, 13C2,15N-cefazolin, co-elutes with cefazolin, and was used in calibration curves and tissue extracts as well as for cefazolin recovery and matrix effects. The protocol was rigorously tested, including measurements of reproducibility and calibration curve quality. The recovery of the extraction method ranges from 94% to 113% across all sample types. There is little to no matrix effect on cefazolin signal (98-120%). The developed method was used to determine cefazolin concentrations in tissues of 10 patients undergoing a total knee replacement. Cefazolin blood concentrations were approximately 500 times higher than in adipose, synovium, and bone marrow tissues. This clinical data shows that although the minimum inhibitory concentration is largely surpassed in blood, the concentration of cefazolin in fat, synovium, and bone marrow could be insufficient during a knee replacement. This method of cefazolin quantification will help surgeons optimize antibiotic concentrations in the local tissues during knee replacement surgery and potentially reduce serious post-surgical infections.

Local tissue concentrations of cefazolin during total joint arthroplasty: a systematic review

BACKGROUND

Periprosthetic joint infections (PJI) following joint arthroplasty are now the leading cause of reoperation and are associated with serious morbidity to the patient, often requiring several staged operations and a prolonged course of parenteral antibiotics. Prophylactic administration of intravenous antibiotics before skin incision is arguably the most important measure to prevent PJI; however, the dose effectiveness of cefazolin in target tissue is not well known. We aimed to identify parameters affecting local tissue concentration (LTC) of cefazolin.

METHODS

We performed a literature search using the following keywords: "orthopaedics," "orthopedic," "arthroplasty" and "cefazolin." We included studies that measured LTC of cefazolin from samples obtained during either a total knee or total hip arthroplasty.

RESULTS

Of the 332 records screened, we included 10 studies that described LTC of cefazolin. The included studies evaluated dosing (n = 7), procedure type (n = 3), body mass index (n = 1) and tourniquet utilization (n = 1).

CONCLUSION

Few studies have measured LTC levels of antibiotics (or levels of cefazolin) to validate current recommendations for antibiotic prophylaxis in orthopedic surgery. With infection as the leading reason for early reoperation or revision surgery, the parameters affecting LTC during orthopedic procedures need to be further assessed.

Comparison of 2g vs 1 g of Prophylactic Cefazolin in Surgical Site Infections in Trauma Surgery Below the Knee

BACKGROUND

The rate of surgical site infections (SSIs) after foot or ankle surgery remains high, despite the implementation of antibiotic prophylaxis. Recently, guidelines suggest a single dose of 2 g instead of 1 g of cefazolin for implant surgery; this decision is largely based on pharmacokinetic studies. However, the clinical effect of this higher dose has never been investigated in foot and ankle surgery. This retrospective cohort study investigated the effect of 2 g compared with 1 g of prophylactic cefazolin on the incidence of SSIs in foot and ankle surgery.

METHODS

All patients undergoing trauma-related surgery of the foot, ankle, or lower leg between September 2015 and March 2019 were included. The primary outcome was the incidence of an SSI. SSIs were compared between patients receiving 1 g and 2 g of cefazolin as surgical prophylaxis, using a propensity score to correct for possible confounders.

RESULTS

A total of 293 patients received 1 g and 126 patients received 2 g of cefazolin. The overall number of SSIs was 19 (6.5%) in the 1-g group and 6 (4.8%) in the 2-g group. Corrected for possible confounders, this was not statistically significant (OR, 0.770; P = .608).

CONCLUSION

Even though the decrease in SSI rate from 6.5% to 4.8% was found not to be statistically significant, it might be clinically relevant considering the reduction in morbidity, mortality, and healthcare costs. Research linking pharmacokinetic and clinical results of prophylactic cefazolin is needed to establish whether or not the current recommendations and guidelines are sufficient for preventing SSIs in foot and ankle surgery.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Target site antibiotic concentrations in orthopedic/trauma extremity surgery: is prophylactic cefazolin adequately dosed? A systematic review and meta-analysis

Background and purpose - The incidence of surgical site infections (SSIs) in trauma/orthopedic surgery varies between different body parts. Antibiotic prophylaxis (e.g., with cefazolin) lowers infection rates in closed fracture surgery and in primary arthroplasty. For prophylactic antibiotics to prevent infections, sufficient concentrations at the target site (location of surgery) are required. However, dosage recommendations and the corresponding efficacy are unclear. This review assesses target site cefazolin concentrations and the effect of variation in dose and location of target site during orthopedic extremity surgery. Methods - For this meta-analysis and systematic review, the literature was searched using the following keywords: "cephalosporins," "orthopedic," "extremity," "surgical procedures," and "pharmacokinetics". Trials measuring target site antibiotic concentrations (bone, soft tissue, synovia) during orthopedic surgery after a single dose of cefazolin were included. Results - The search identified 14 studies reporting on concentrations in the shoulder (n = 1), hip (n = 8), knee (n = 8), or foot (n = 1). A large variation was seen between studies, but the pooled results of 4 studies showed higher concentrations in hip than in knee (mean difference: 4 ug/g, 95% CI 0.8-7). Articles comparing different doses of cefazolin reported higher bone concentrations after 2 g than before, but pooling results did not lead to a statistically significant difference. Interpretation - Although not all results could be pooled, this study shows that cefazolin concentrations are higher in the hip than in the knee. These findings suggest that the dose of prophylactic cefazolin might not be sufficient in distal parts of the extremity. Further research should investigate whether a higher dose of cefazolin can lead to higher concentrations and fewer SSIs.