Oral infections can harbor bacteria and serve as a source of hematogenous infection [2]. That is why active oral infections should be treated before joint replacement, and oral health should be maintained indefinitely. Because of this recognition, some authors propose routine dental screening before an arthroplasty to decrease the risk of bacteremia from the oral cavity. Some investigators have questioned the cost effectiveness of routine dental screening [3]. However, dental pathogens or procedures are responsible for only a small percentage of joint infections [4]. Barrington et al. [5] found that routine preoperative dental clearance revealed 23 % incidence of pathology, and none of these patients with pathology developed subsequent PJI. In addition, there is no official recommendation from the American Academy of Orthopedic Surgeons (AAOS) regarding dental clearance prior to TJA to prevent PJI [6].

Therefore, some authors advocated selective dental clearance prior to TJA based on patient profile. The risk factors that are associated with dental pathology are tobacco use, poor flossing habits, history of tooth extraction, older age, narcotic use, and lack of a dentist visit within 12 months [7]. As a result, surgeons must exercise their own clinical judgement in determining whether or not a dental clearance is necessary regarding the risk factors.

Studies have shown that the anterior nares are the most consistent site of reservoir for Staphylococcus aureus and high-level nasal carriage of S. aureus is an important risk factor for subsequent surgical site infection (SSI) [8]. Studies have attempted to identify risk factors associated with nasal carriage of S. aureus. Male gender, obesity, a history of a cerebrovascular accident, multiple hospital admissions, and having a pet at home have all been identified as predisposing factor for S. aureus nasal carriage [9].

Three types of patient population with regard to S. aureus nasal carriage have been identified: persistent carriers, intermittent carriers, and non-carriers. Between 10 and 35 % of healthy individuals are thought to be persistent carriers as one or more strains of S. aureus are isolated from their nares [10]. Persistent nasal carriers are in particular risk of subsequent SSI [11].

Current literature supports the practice of screening for nasal carriers of S. aureus followed by decolonization with intranasal mupirocin and chlorhexidine gluconate (CHG) baths which has been shown to be associated with a decreased incidence of MRSA colonization and disease [12, 13]. There are, however, some logistic issues associated with this practice. The Center for Disease Control, in their revision of the SSI guidelines decided to table the issue of MRSA screening and decolonization because of the current issues surrounding this practice. One of the issues relates to the emergence of resistance to mupirocin that appears to be on the rise. Another issue relates to the recurrence or persistence of S. aureus in patients who have undergone decolonization [14]. The International Consensus group on PJI did also recognize the fact that screening and decolonization for MRSA leads to a lowering of SSI but did not endorse universal practice of screening in patients undergoing TJA because of the issues that have been highlighted previously.

Smoking is considered as one of the important modifiable risk factors for SSI. Smoking impairs the oxygenation of the surgical site due to nicotine-induced vasoconstriction, shift of oxyhemoglobin dissociation curve, and microthrombus formation by abnormal platelet aggregation.

Smoking is associated with postoperative morbidity and mortality. An effective smoking cessation program led to a fewer wound healing complications and postoperative morbidity [15, 16]. Although current smokers are under a higher risk, any history of smoking increases the risk of overall postoperative complications [16]. In a review that included total of 21 studies comparing nonsmokers to current smokers and former smokers found 24 % and 32 % higher risk of any postoperative complication in smokers after TKA or THA, respectively [17].

It is therefore paramount to encourage patients to halt smoking prior to undergoing TJA. The optimal time for cessation of smoking is not known but recommended to be at least 4–8 weeks prior to surgery. But each additional week of smoking cessation before the operation has a significant impact on the reduction of postoperative complications [18]. Also there is no consensus as to what constitutes as heavy smoking. It is, however, known that smoking more than one pack per day is significantly associated with PJI and other postoperative complications [19]. Thus, all efforts should be made to have all heavy smokers evaluated well in advance of TJA and cessation of smoking exercised at least 4–6 weeks prior to elective arthroplasty [20, 21].

An increased risk of postoperative complications, such as delirium, pneumonia, cognitive decline, and death has been linked to alcohol consumption [22, 23]. It was also shown that patients who discontinue drinking for 4 weeks prior to surgery have substantially reduced risk of postoperative complications [24]. Thus alcohol cessation before elective arthroplasty needs to be in place. If patients cannot stop alcohol consumption prior to surgery, a reduction in alcohol consumption should be attempted [25].

Patients with diagnosis of diabetes mellitus (DM) are at an increased risk of adverse perioperative outcomes following total joint arthroplasty [26]. In addition, strict glycemic control (HbA1C levels <7 %) is associated with a decrease in infectious complications across a variety of surgical procedures [27].

As conflicting results are presented regarding the effect of the type of DM (IDDM vs NIDDM) in the surgical outcome [26, 28], additional studies are necessary to evaluate the effect of diabetes type on perioperative morbidity in patients managed with arthroplasty. Regardless of the diabetes type, patients with uncontrolled DM exhibit significantly increased odds of surgical and systemic complications, higher mortality, and increased length of hospital stay following lower extremity total joint arthroplasty [26]. Thus, preoperative optimization of patients with uncontrolled diabetes and strict glycemic control after arthroplasty are extremely important in minimizing the postoperative complications in general and PJI in particular.

Although the increased prevalence of adverse perioperative outcomes in patients with diagnosis of DM have been demonstrated indefinitely, the risk of uncontrolled or poorly controlled hyperglycemia in previously non-DM patients undergoing total joint arthroplasty has been unappreciated and underestimated. Stress-induced hyperglycemia is activated by the hypothalamic–pituitary axis in patients without a diagnosis of DM after major surgery and trauma. Hyperglycemia occurs in up to two thirds of surgical patients who are not known to have diabetes [29, 30]. And as glycemic control appears to be critical in patients undergoing total joint arthroplasty, a special attention should also be paid to non-DM patients for better control of postoperative glucose [31, 32]. Frisch et al. [33] found even an increased risk of 30-day mortality associated with hyperglycemia in non-DM patients when compared with those with well-controlled diabetes [30].

Patients with chronic liver failure undergoing major orthopedic procedures including hip surgery, spine fusions, and operations for long bone fractures have been shown to have a substantially higher incidence of perioperative complications and in particular infection [34].

The pathogenesis of increased incidence of infection in patients with chronic liver disease is likely multifactorial and related to:

Beside the increased risk for infection, the success of surgical treatment of PJI in patients with chronic liver failure is reported to be poor. Hsieh et al. [37] reported a very high failure of two-stage exchange arthroplasty in ten patients with infection after THA. The authors recommended that the very high failure rate in these patients needs to be borne in mind when counseling these patients [37].

The mortality of patients with chronic liver failure is also reported to be high in patients undergoing non-hepatic surgery [38] including THA [39]. In a study by Cohen et al. the postoperative mortality was reported to be 15.8 % in patients with chronic liver failure who underwent THA.

The extent of hepatic dysfunction was the most important factor contributing to the development of infection in cirrhotic patients [40]. The risk of increased mortality was to a large extent determined by the preoperative Child-Turcotte-Pugh score [39, 41] (Table 12.2). Patients with Child’s B and C class were found to have a significantly higher incidence of postoperative complications at 52.9 % compared to 10.2 % in patients with Child’s A disease [39]. In addition, international normalized ratio (INR) greater than 1.6, presence of encephalopathy and prolonged prothrombin time were reported as poor prognostic factors [32, 36]. Because of these discoveries, some authors recommend aggressive correction of prolonged prothrombin time before surgery in order to avoid excessive bleeding [37].

The number of cirrhotic patients who need total joint arthroplasty will increase with improvement in the medical care of these patients in future [37]. The surgeons should be aware of the increased complications in these patients. The orthopedic surgeons should seek contact with the hepatologist caring for these patients prior to arthroplasty in an attempt to optimize their medical condition as much as possible. Patients should also be carefully monitored in the postoperative period with focus on minimizing complications such as infection, bleeding, and hepatic decompensation [39]. Patients with a higher Child-Turcotte-Pugh score should in particular be watched vigilantly and perhaps not subjected to elective arthroplasty if at all avoidable [42].

Patients with chronic renal failure (CRF) are also at risk of increased postoperative complications. Although there are some encouraging reports [43–47] patients with CRF who are on dialysis or received renal transplant undergoing THA had a relatively higher overall risk of developing early and late postoperative infection compared to patients without CRF. The risk of infection is particularly high in patients receiving hemodialysis [47–51]. Most of the CRF patients may also be carriers of MRSA and should receive an additional perioperative antibiotic, such as vancomycin, with activity against MRSA [46].

The exact reason for the increased risk of postoperative complications and in particular infection in patients with CRF remains unknown but attributed to a variety of factors, most of which relate to having a chronic disease state. For example, patients with CRF are usually anemic and may be in need of blood transfusion that by itself, and through immunomodulation, increases the risk of postoperative infection [46, 52, 53]. Patients with CRF also have a compromised immune system with impaired neutrophil function that can place them at higher risk of infection. Because of the higher risk of infection in patients with CRF, some authorities have advocated that femoral component fixation should be performed with antibiotic impregnated cement. Current literature does not, however, prove superiority for one mode of implant fixation in these patients [46, 53, 54].

THA in CFR patients can be considered a reliable surgical option with the awareness of the relatively high rates of early and late complications. Thus, elective arthroplasty must be performed within the framework of careful multidisciplinary patient management.

This group includes patients with rheumatoid arthritis (RA), juvenile inflammatory arthritis, and spondyloarthritis such as ankylosing spondylitis and psoriatic arthritis (PA). This patient population have been identified to have a higher baseline risk of infection compared with the general population [55].

In addition to the immune modulating effect of the disease itself, most of these patients who are on disease-modifying anti-rheumatic drugs (DMARDs) may be at added risk of infection [56]. The most commonly used medications are synthetic DMARDs such as methotrexate, hydroxychloroquine, and leflunomide; corticosteroids; and biologic agents, including the TNF blocking agents. As a general rule, disease-modifying agents should be stopped before the elective TJA. The cessation of these drugs should be performed in consultation of rheumatologist that can be arranged based on the specific medication and the individual patient. The International Consensus Group of PJI has proposed a drug cessation protocol based on the half-life of these biological drugs.

The incidence of preoperative anemia in patients undergoing elective orthopedic procedures is reported to be as high as 35 % [64]. Preoperative anemia has also been shown to be an independent risk factor for PJI [65]. Patients who are anemic preoperatively are expected to experience worsening of their anemia in the postoperative period due to surgical blood loss. Thus efforts should be made to treat preoperative anemia, if possible, that can then reduce the need for postoperative blood transfusion [66]. However, the first step in patients without an obvious cause for anemia should be the investigation for a possible primary etiology.

There are some treatment options for anemia such as autologous blood donation, iron replacement, and administration of erythropoietin (epoetin alfa). Autologous blood donation has well-known disadvantages including storage problems, increasing postoperative anemia and transfusion [67], transfusion reactions and, last but not least, contamination of the donated blood with blood-borne pathogens, either bacterial or viral [68]. Iron and erythropoietin treatments are safer strategies. The treatment of preoperative anemia with iron, with or without erythropoietin, was found to reduce the risk of transfusion in patients undergoing TJA [69].

Although malnutrition has been understood as inadequate nutrition, according to the definition of the World Health Organization, under-nutrition, obesity, micronutrient deficiency are all different forms of malnutrition [70].

Malnutrition was found to be another common risk factor for SSI. Previous studies have found a close association between malnutrition and PJI [71, 72]. Malnutrition is defined as a serum total lymphocyte count <1500 cells/mm³, a serum albumin concentration of <3.5 g/dl, low serum prealbumin and serum transferrin levels <200 mg/dl [72–74].

Malnutrition is thought to predispose patients to SSI by impairing wound healing, persistent wound drainage, inability to eradicate microorganisms and prolonging inflammation via several mechanisms, decreasing lymphocyte count, including impaired fibroblast proliferation and collagen synthesis [72, 75–77].

Thus screening patients contemplating elective arthroplasty may be a worthwhile endeavor. Patients with obesity, history of extreme weight loss, poor nutritional habits are in particular risk of malnutrition. The workup for malnutrition involves obtaining preoperative biochemical profile of the blood and complete blood counts with differential. Additional blood tests such as transferrin can also be ordered. Patients with malnutrition should be seen by nutrition specialists for possible nutritional optimization. As the malnutrition is a correctable risk factor, postponing the elective surgeries is strongly recommended until the patient’s malnutrition has been corrected.

Obesity is a different form of malnutrition that affects more people compared to other forms of nutritional problems in developed countries. Approximately one-third of patients undergoing THA are obese [78, 79]. These patients must be aware of the higher complication rates before undergoing TJA. Patients with a BMI≥50.0 kg/m² reportedly have an 18.3 times higher odds of infection compared with non-obese [20].

The reason for increased risk may be related to an increase in operative time, greater need for allogeneic blood transfusion, presence of other comorbidities, traumatic tissue retraction, and increased risk of poor wound healing in the obese patients [18, 23]. Elective arthroplasty in morbidly obese patients with BMI≥40.0 kg/m² also significantly increases the risk of infection [80].

In some recent studies, the safety of weight loss is questioned which raise concerns for preoperative malnutrition as discussed later in this chapter [71, 81]. In the study of Inacio et al. patients who lost weight before a total hip replacement and kept it off post-operatively had a 3.77 times greater likelihood of deep SSIs compared with the reference group [81]. These findings emphasize the critical importance in respecting the balance between malnutrition and weight loss.

Another issue about obese patients is the preoperative dose adjustment of prophylactic antibiotics. Because of the relative unpredictability of pharmacokinetics in obese individuals, some antibiotics require adjustment based on patient weight in order to avoid under dosing of the preoperative prophylactic antibiotics [82–84]. The AAOS recommends to double the dose of cefazolin for patients >80 kg in IV antibiotic prophylaxis in primary TJA to optimize the efficacy of the therapy of antibiotic administration [85].

The airborne transmission of bacteria within the operating room (OR) environment is perhaps the major cause of contamination of the wound during total joint arthroplasty and subsequent SSI [99]. There are mainly two routes of airborne bacteria. First is the direct contamination of the wound that occurs when airborne particles directly drop into the wound. Second is the indirect contamination, in which the airborne bacteria settle on sterile surfaces around the wound and then transferred into the wound via the surgeon’s hands or the surgical instruments [100]. A study demonstrated that 70 % of contaminations are as a result of indirect fall out and 30 % from direct contamination by the way of the hands and instruments that are placed into the wound [101].

The number of airborne bacteria around the wound is correlated with the incidence of subsequent PJI [100]. The air quality is also affected by the traffic in the OR, as described in the next section of this chapter. In recent years many attempts have been made aimed at improving the air quality of the OR environment. Laminar flow is one of the most popular methods that aims to accomplish this objective. The efficacy and importance of laminar flow has been recently questioned. In fact the evidence seems to point to the contrary. A study using the New Zealand registry data has shown that the incidence of PJI was higher after THA that were performed in a laminar flow room [102]. At this point the efficacy and importance of laminar air flow in reducing SSI and PJI remains unproven.

Another strategy to improve the air quality in the OR related to the use of ultraviolet lighting. The rates of SSIs were reduced with the use of ultraviolet lighting in the operating rooms [103]. There is a major issue with the use of UV lighting in the OR, the most important of which relates to the hazard that UV may impart on the personnel present. In one study the exposure to ultraviolet lighting in the operating room was found to be 6–28 times greater than the recommended limits [104]. Another study demonstrated that 36 % of orthopedic operating-room personnel exposed to ultraviolet light reported eye and skin related symptoms due to the excessive exposure. Because of the safety concerns, the U.S. Centers for Disease Control and Prevention recommended against the routine use of ultraviolet lights in the operating rooms [105–107].

An ongoing debate currently relates to the optimal surgical attire of the surgeon and the scrubbed personnel. In orthopedic surgery space suits have been used for many years. There is no conclusive evidence that proves the efficacy of the space suits in reducing SSI [108]. One study analyzing the 10-year results of 88,311 THAs or TKAs from the New Zealand Joint Registry demonstrated that the rate of revision for early deep infection has not been reduced by the use of laminar flow operating rooms and the space suits [109]. A recent study by Kapadia et al., in fact detected a higher infection rate with the use of laminar-flow operating rooms and body exhaust suits [110]. Also Hooper et al. [109] studying the rate of early infection identified an increased rate of early infection with the use of space suits both in conventional and in laminar flow theaters.

Another ongoing debate relates to what constitutes the most optimal antiseptic agent for skin preparation and hand washing prior to TJA. In a Cochrane Database review by Tanner et al. there was no significant difference among various antiseptic agents for hand scrub. Another issue relates to the optimal time for hand washing and skin preparation. Currently hand washing with a soap and antiseptic agent for a minimum of 2 min prior to surgery has been recommended [63].

The hospital and surgeon volume is also considered an important factor in influencing SSI rates. There is a reverse relationship between the rate of complications and the surgical volume. The reason for this finding may relate to the fact that high volume surgeons may have an efficient protocol in place that minimized the risk of SSI and may be more expedient in executing the surgery [111]. No significant association was found between hospital volume and the rate of revisions of THAs. But the type of hospital was found to be associated with revision rates, non-teaching hospitals tended to have a higher revision risk, while nonprofit hospitals tended to be associated with a lower revision [112].

The personnel are the major sources of bacteria in the OR. The amount of bacteria falling into the open wound is increased as the number of people in the room increases and the longer the wound is open [101]. It has been shown that an individual emits a few hundred-thousands of airborne particles carrying bacteria while wearing sterilized clothing in the operating room [113]. Also opening and closing of the OR doors can generate significantly marked air currents and subsequently reduces the quality of the OR air. Beside the traffic and the number of people present in the OR, a further finding suggests that there is a direct correlation between the activity level of OR personnel and the bacterial counts in the OR air [114, 115].

Thus, every effort should be made to minimize the number of personnel in the operating room and strictly control the OR traffic. In addition to limiting the OR traffic consideration should be given to the use of a sub-sterile hallway for entry and exit from the OR that helps improve the quality of room air. One strategy that helps reduce the OR traffic involves storage of implants and commonly used instruments inside the operating room. In addition the education of the personnel regarding the importance of keeping the traffic to a minimum is likely to help reduce bacterial counts in the OR environment.

Clipping, as opposed to shaving, should be the preferred method for hair removal, when needed. Using razor may cause superficial skin abrasions or irritation and expose the bacteria from the deeper layers leading to a potential infection. A recent systematic review of randomized and quasi-randomized controlled trials showed that hair clipping lowered the rate of SSI when compared to shaving [116].

There is currently no evidence in the literature that shows the most appropriate setting and time in which to remove hair from the surgical site. Given the overall lack of research specific to the environment in which preoperative hair removal should take place, we recommend that hair removal be performed in the hospital as close to the time of surgery as possible by either the surgical team or the trained nursing staff. Most surgeons prefer to perform hair removal prior to arrival of the patient in the OR to avoid having hair clipping around the surgical site.