Prevention of periprosthetic joint infection—have we been barking up the wrong tree?

The impact of patient risk factors

There is a wide range of host- or patient-related risk factors which may need to be considered before TJA. These range from behavioral factors such as smoking and alcohol use to metabolic conditions, chronic disease, immunological factors, nutrient deficiencies, or dermatological issues. At the recent 3rd ICM, evidence was presented showing that 80% of patients undergoing TJA have at least one modifiable risk factor for infection [6]. Indeed, research showed that there were 25 modifiable risk factors found to be associated with an increased risk of PJI [6]. As noted above, smoking, obesity, diabetes, anemia, and malnutrition were found to be the most common modifiable risk factors with other factors shown to be contributory to the risk of infection [6]. In some cases, guidance has been issued on whether TJA is appropriate in some patients—for example, undiagnosed hyperglycemia can be an issue, with TJA being advised against in those patients with elevated HbA1c (> 7%; indicating hyperglycemia, or poor glycemic control in a diabetic patient) [5]. Further, emerging research has shown that some of these patient-related risk factors such as obesity, inflammatory bowel disease, diabetes, as well as Clostridium difficile infection are linked to gut dysbiosis—discussed in Part 3  of this series—which makes patients more prone to infection. There are strategies which can be considered before TJA, such as smoking cessation, weight loss, optimization of vitamin D levels, management of immunosuppression, of malnutrition, or of anemia, which attempt to modify some of these patient risk factors. 

Skin decontamination reduces microbial load

As any orthopedic surgeon knows, it has become standard to preoperatively prepare the skin to reduce the bacterial load before surgery [4, 5]. For preparation before TJA, effective strategies are in place which include using 2.0–2.5% chlorhexidine in alcohol or povidone-iodine on the surgical site as preoperative preparation [5]. Further, in the days prior to surgery the use of antiseptic soap is also recommended [4]. Other preoperative preparations such as hair removal at the surgical site are common; however, care should be taken because—as with vigorous application of antiseptics—hair removal can potentially increase the occurrence of infection through damage to the skin surface [4, 5].

Also to be considered is nasal colonization by Staphylococcus aureus. Although the available evidence is limited, research indicates that eradication of S aureus may reduce infection rates; however, the optimal method for achieving this remains a matter of ongoing discussion. The value of a standardized questionnaire to preoperatively screen for and assess the risk of methicillin-resistant S aureus (MRSA) infection has been evaluated [7], showing that it may be valuable in identifying high-risk patients. To decolonize the nose, 2% mupirocin ointment has been advised, yet at the 3rd ICM it was discussed that although mupirocin remains the recommended standard, there are concerns over resistance, cost, and efficacy. Thus, povidone-iodine could be used as a cost-effective alternative with comparable outcomes in reducing both colonization and surgical-site infection rates (strength of recommendation: moderate) [8]. 

Bioburden reduction (step two) is closely tied to step eight, which is the use of an antiseptic solution for irrigation during surgery to ensure effective debridement of tissues [4]. Recommendations include the use of povidone-iodine solution to irrigate the deep and subcutaneous tissues [4], with a 0.5% povidone-iodine solution commonly used for this purpose [4]. For removal of biofilms on orthopedic surfaces, a recent study [9] showed that 10% povidone-iodine solution with or without hydrogen peroxide consistently removed methicillin-sensitive S aureus and Escherichia coli biofilms in vitro and could be considered for clinical use [9]. Not only does povidone-iodine have broad-spectrum antimicrobial properties, it is effective in both chemical and mechanical decontamination, whilst remaining nontoxic to human tissues, and in particular, fibroblasts [4].

Although povidone-iodine is well known for its antimicrobial and cleansing properties, it is not used during revision procedures at either Citak’s or Abedi’s departments. According to Citak, 'at Helios ENDO-Klinik where he practices, saline (NaCl) is used for standard irrigation and polyhexanide solution for septic cases.' Nonetheless, its potential role in future protocols warrants further investigation.

Antibiotic prophylaxis is a well-established method to prevent infection

Perioperative antibiotic prophylaxis is a standard and proven way to prevent infection during major orthopedic surgery. Commonly, first- or second-generation cephalosporins are used as a primary method of prophylaxis [4], and it is recommended that a single weight-adjusted dose of antibiotic prophylaxis should be given 30–60 minutes before incision. Citak comments, “In our clinic every patient receives a weight-adjusted single shot of antibiotics intravenously before surgery. If a patient weighs more than 120 kg, then it is recommended to use 3 g rather than 2 g cephalosporin.” Indeed, at the 3rd ICM, it was recommended that administration of all prophylactic antibiotics need to be weight based (level of evidence: strong) [10]. In addition, alternative routes of antibiotic administration are under investigation, including intrawound vancomycin powder, diluted povidone-iodine lavage, and intraarticular administration of vancomycin and tobramycin after TJA [3]; however, further studies are needed before their role in clinical practice can be defined.

Regarding postoperative antibiotic prophylaxis, while there is clear consensus on the perioperative use of antibiotics to prevent PJI, there is no consistency in the literature for continuing antibiotic prophylaxis after total hip arthroplasty (THA) [11].

Being mindful of best practices in the operating room

As outlined in the ten steps for PJI prevention (Table 1), what happens in the operating room is an important component of infection prevention. Regarding soft tissues (see Table 1, Step 4), here the focus is on using instruments in a proper fashion and not handling tissues by hand which may lead to contamination through potentially contaminated gloves. Moreover, the operating surgeon should be aware of skin tension, incision size, and minimizing the use of nonabsorbable sutures or electrocautery which have been associated with an increased risk in infection [4]. Further, it has been shown that for every 60 minutes of surgery the likelihood of surgical site infection increases by 37% [4].