Approach to Decrease Infection Following Total Joint Arthroplasty




Surgical site infection in total joint arthroplasty is a challenging complication that warrants discussion with regard to prevention and management. Limiting postoperative infection rate is a paramount quest in the orthopedic community. Several preoperative risk factors have been identified in orthopedic literature with regards to likelihood of developing postoperative infection. This article evaluates several factors that predispose total joint arthroplasty patients to infection. Methods of patient surgical preparation designed to decrease postoperative infection, decreasing intraoperative traffic during procedural settings, and elaborate intraoperative prophylactic advancements are assessed. Approaches to decrease postoperative infection by discussing means of lowering rates of postoperative transfusion, wound drainage, and hematoma formation are analyzed.


Key points








  • Surgical site infections are a debilitating and costly adverse outcome following total joint replacement that is minimized with proper preoperative, intraoperative, and postoperative screening.



  • The most effective means of preventing surgical site infections is through the preoperative optimization of all total joint surgical candidates.



  • New pharmacologic and intraoperative technologies are allowing orthopedic surgeons to better prevent and if needed combat surgical site infections.






Introduction


Degenerative joint osteoarthritis is a debilitating disease, profoundly altering a patient’s functional capacity and quality of life. Advancements in total joint arthroplasty (TJA) have allowed for excellent pain relief and restoration of biomechanical function. By the year 2030, demand for TJA in the United States is expected to exceed 4 million TJA procedures a year. One of the most concerning and serious complications of any TJA is deep infection. However, periprosthetic joint infections (PJI) have a reasonably low reported incidence at 0.5% to 3%. As such, PJIs remain one of the most challenging orthopedic complications in terms of prevention and treatment. Unsuccessful treatment can result in devastating morbidity including several reoperations; overall loss of function; and significant cost to patient, caregivers, and the health care system. Estimated cost of a single PJI has been reported at approximately $50,000, increasing to greater than $100,000 for resistant organisms. Reported cost of revisions because of infection in 2009 was $566 million and projected to reach up to $4 billion by 2030. A better understanding of successful approaches to prevent periprosthetic infections will allow orthopedic surgeons to better optimize their patients preoperatively, intraoperatively, and postoperatively, improving patient outcomes.


Although eradicating periprosthetic infection may seem daunting, a methodical approach minimizes operative risks while improving outcomes. The development of PJI can result from several perioperative factors. Preoperative patient selection and optimization, intraoperative emphasis on sterility, and postoperative antibiotics and wound care play a pivotal role in avoiding the dreaded complications of infection. This article discusses current measures and concepts to decrease risks for deep infections in TJA.




Introduction


Degenerative joint osteoarthritis is a debilitating disease, profoundly altering a patient’s functional capacity and quality of life. Advancements in total joint arthroplasty (TJA) have allowed for excellent pain relief and restoration of biomechanical function. By the year 2030, demand for TJA in the United States is expected to exceed 4 million TJA procedures a year. One of the most concerning and serious complications of any TJA is deep infection. However, periprosthetic joint infections (PJI) have a reasonably low reported incidence at 0.5% to 3%. As such, PJIs remain one of the most challenging orthopedic complications in terms of prevention and treatment. Unsuccessful treatment can result in devastating morbidity including several reoperations; overall loss of function; and significant cost to patient, caregivers, and the health care system. Estimated cost of a single PJI has been reported at approximately $50,000, increasing to greater than $100,000 for resistant organisms. Reported cost of revisions because of infection in 2009 was $566 million and projected to reach up to $4 billion by 2030. A better understanding of successful approaches to prevent periprosthetic infections will allow orthopedic surgeons to better optimize their patients preoperatively, intraoperatively, and postoperatively, improving patient outcomes.


Although eradicating periprosthetic infection may seem daunting, a methodical approach minimizes operative risks while improving outcomes. The development of PJI can result from several perioperative factors. Preoperative patient selection and optimization, intraoperative emphasis on sterility, and postoperative antibiotics and wound care play a pivotal role in avoiding the dreaded complications of infection. This article discusses current measures and concepts to decrease risks for deep infections in TJA.




Preoperative measures


Optimizing the Patient


Assessment of the general medical health of each patient with a thorough history and physical examination is an important precursor for infection prevention. Several medical comorbidities have been shown to generate a significant propensity for infection, most notably diabetes, rheumatoid arthritis, obesity, and immunosuppression (including chronic steroid use). The combination of these comorbidities is demonstrated to significantly increase the overall risk for infection. Special care should be taken in selecting patients with manageable medical comorbidities and optimizing all current medical issues before proceeding with TJA.


Diabetes


Several studies have reported diabetes as an integral contributor to the development of infections. Diabetes combined with any other comorbidity has been shown to significantly increase infection rates. Hemoglobin A 1C is a frequently ordered outpatient blood test representative of glucose control over the past 3 months. Marchant and colleagues reported that patients with moderately elevated hemoglobin A 1C are two to four times as likely to develop PJI. However, other studies have suggested that the risk for PJI is more closely associated with the patient’s current glycemic status rather than the patient’s long-term glycemic control. Mraovic and colleagues reported patients with blood glucose levels greater than 200 mg/dL on postoperative Day 1 are twice as likely to have a PJI, compared with patients with well-controlled glucose levels. Surgical procedures, such as TJA, can result in stress-induced hyperglycemia postoperatively. Patients with diabetes have increased variability in perioperative glycemic levels, increasing the propensity for PJI. Thus, orthopedic surgeons must be cognizant of the long-term and perioperative effects of poor glycemic control in all TJA candidates, but particularly those with diabetes mellitus.


Obesity


Although an area of controversy, recent literature supports the correlation between obesity and morbid obesity with PJI. Dowsey and Choong prospectively examined 1214 consecutive primary total knee arthroplasties (TKA) comparing deep infection rates of morbidly obese and obese patients with nonobese control subjects. The results indicated morbidly obese patients (body mass index >40) were nearly at nine times higher risk of developing deep infection. No infections were recorded in nonobese patients. Furthermore, obese patients (body mass index <40) did not demonstrate an increased risk for periprosthetic knee infections when compared with the nonobese control subjects. A similar study in total hip arthroplasty (THA) patients evaluating obese and morbidly obese patients indicated increased risk for PJI in both cohorts. Namba and colleagues evaluated deep infections in obese patients with THA and TKA, concluding that obese patients had a 6.7- and 4.2-fold increased risk of developing deep infection following TKA and THA, respectively. In addition, the combination of obesity with diabetes revealed a nearly seven-fold increase in periprosthetic knee infections when compared with obese patients without diabetes.


Other comorbidities


Comorbidities, such as cardiovascular disease, chronic anemia, rheumatoid arthritis, and chronic immunosuppression, have demonstrated increased rates of PJI. In a study evaluating greater than 56,000 TKAs, patients with an American Society of Anesthesiologists score greater than three demonstrated a statistically significant increased infection rate of 53.3% compared with 38.2%. Males are twice as likely to have PJI, than their female counterparts. Patients with the human immunodeficiency virus, hemophilia, and those with CD4 counts of less than or equal to 200/mm 3 are at increased risk for PJI because of their immunocompromised status. Hence, patients with high-risk comorbidities should be counseled extensively and medically optimized before elective surgical intervention.


Nutritional status


Nutritional status is predictive of infection and postoperative wound healing. Malnutrition is most commonly delineated with a series of serologic tests including serum transferrin less than 200 mg/dL, serum albumin less than 3.5 g/dL, and a total lymphocyte count less than 1500/mm 3 . Poor nutritional status is most frequently cited in the elderly, bariatric patients, and the morbidly obese. Jaberi and colleagues prospectively examined 10,325 patients following TJA with 300 developing persistent wound drainage greater than 48 hours. In their study, they concluded that malnourished patients had a higher rate of PJI. Greene and colleagues similarly assessed the impact of surgery on the nutritional status of 217 patients with TJA. Postoperatively, patients’ total lymphocyte counts had dropped 57% and serum albumin had dropped 72% from preoperative values. By postoperative Day 10, no patient had returned to preoperative levels. Lavernia and colleagues reported the effect of poor nutrition on length of stay following TKA. They prospectively examined 119 and found that patients with albumin levels less than 3.4 g/dL had a 32.7% higher hospital charge and longer length of stay (3.4 days). Zorilla and colleagues examined serum zinc levels as a predictor of postoperative outcomes. They prospectively examined 97 patients who underwent hemiarthroplasty for acute hip fracture and found an 11.8-fold increased risk for delayed wound healing. Prolonged wound healing greater than 5 days has been shown to increase the likelihood of PJI by 12.5-fold. Because of its prevalence among patients with TJA, it is crucial to optimize the nutritional status before surgical intervention.


Smoking


The detrimental effects of smoking tobacco on wound healing and all-cause complications are well documented in patients with TJA. In one large retrospective study smokers were 32% more likely to suffer from postoperative complications including mortality. Furthermore, there was an association between the number and severity of systemic complications and the number of pack-years smoked. Peersman and colleagues study demonstrated smokers were at a statistically significant risk for PJI when compared with nonsmokers. Clinicians should inform their patients about the various medical risks associated with smoking tobacco, and encourage them to quit smoking at least 6 to 8 weeks before surgery.


Infection Starts with the Host


Surgical site infection (SSI) and wound drainage greater than 48 hours has been correlated to the development of PJI. In addition to optimizing the patient’s ability to heal postoperatively, prevention of SSI involves minimizing risk from superficial bacterial sources. A study by von Eiff and colleagues used the bacterial genotype to demonstrate that 80% of nosocomial SSIs originated from native endogenous Staphylococcus aureus . The prevalence of colonization with S aureus has been dropped from 32.4% to 28.6% of infections, whereas the prevalence of methicillin-resistance S aureus (MRSA) has increased from 0.8% to 1.5%. Both S aureus and MRSA colonization have been associated with a significant increase in risk for SSI. In a study by Yano and colleagues preoperative screening for nasal colonization of MRSA in orthopedic patients revealed that 4% of patients had MRSA-positive nasal cultures of which 26% developed MRSA wound infections. Conversely, of the patients with negative nasal colonization, only 1.3% developed SSI.


However, whether SSIs result from exogenous bacterial contamination or endogenous self-inoculation and colonization is still controversial. Although intranasal S aureus colonization is a risk factor for orthopedic SSI, most postoperative bacterial strains recovered from the surgical suites were different strains than those identified in preoperative nasal samples. Despite the uncertainty of the origin, several studies have shown the effectiveness of implementation of prehospital screening and decolonization protocols in decreasing SSI. Decolonization protocols started 5 days before surgery include combination of nasal mupirocin ointment, chlorhexidine total body wash, and chlorhexidine mouth rinse and have been demonstrated to reduce postoperative infections. Buehlmann and colleagues revealed that such preadmission protocols were 98% effective in preventing PJI and decolonizing the nares and groin. In contrast, Wendt and colleagues compared decolonization protocols with a placebo group in various regions of the body and reported that preadmission decolonization protocols were only successful in eradicating MRSA from the groin, but not the nares, throat, or perineum.




Intraoperative measures


The surgeon has control over several factors within the operating room that may decrease the risk of PJI. Intraoperative considerations include use of effective skin preparations, control over sterile operative and facility environments, perioperative prophylactic antibiotics, and wound management. It is also important for the surgeon to have a team that is cohesive and aware of TJA protocols designed to increase sterility, and maximize operating room efficiency.


Skin Preparation


It is beneficial to thoroughly examine the patient’s skin in the office and in the preoperative area. Detection of abrasions, bruising, ulcers, pet scratches, psoriatic patches, or cellulitis should be routine practice and may reduce the risk for wound infections. It is important to appreciate existing incisional scars. Incorporating previous incisions into the new incision decreases the risk for devascularized skin bridges, postoperative skin necrosis, and subsequent wound infection. Removal of hair around the incision site has become a routine part of the preoperative preparation. There are limited data to support hair removal in prevention of SSI. A Cochrane review article showed no statistical difference between hair removal and decrease in SSI. In fact, SSI statistically increased when hair was removed with a razor as compared with clippers. Alcohol or aqueous skin preparations have been shown to have a skin penetration of only 300 μm. This leaves viable bacteria deep inside hair follicles and skin recolonization may occur in 30 minutes. Although, hair removal does not reduce the risk for SSI, it does improve surgical site visibility. When implemented, it is recommended that hair be removed immediately before surgery with an electric clipper, minimizing bacterial recolonization and epidermal abrasions.


Several preoperative skin preparations are currently available; however, no one agent has superiority over the other. Investigators have compared the use of preparation regimens containing DuraPrep (3M Company, St. Paul MN) solution and a povidone-iodine scrub before TJA. Both methods were found to be equivalent in reducing the frequency of SSIs and PJIs. The addition of alcohol to aqueous skin preparations, such as chlorhexidine, has been shown to be beneficial, but has the disadvantage of drying out the skin’s top layer. Disruption of the most superficial skin layers aids bacterial proliferation. The use of skin preparation agents, such as Avagard (3M Company), moisturizes the skin preventing its drying.


Draping out the prepared surgical area is an important step in conserving sterility and decreasing the risk for infection. Care must be taken to only isolate skin that has been adequately sterilized. Plastic adhesive drapes have shown decreased rates of contamination when compared with traditional cloth drapes. Use of an iodine-impregnated drape, such as Ioban (3M Company), may theoretically decrease PJI. A Cochrane article reviewed more than 3000 patients in five different studies and found no significant decrease in PJI with antimicrobial-incorporated adhesive drapes. Appropriate draping including a water-tight seal around nonsterilized skin and use of adhesive drapes over the incision site is imperative to maintain sterility and decrease infection rates.


Prophylactic Antibiotics


Systemic prophylactic antibiotic use before TJA has been shown in several studies to reduce the rate of infection. In a recent meta-analysis of seven studies, antibiotic prophylaxis reduced the absolute risk of SSI in TJA by 8% and the relative risk by 81% compared with no antibiotic prophylaxis. Antibiotics need to be effective against organisms responsible for postoperative infections, such as S aureus , Staphylococcus epidermidis , Escherichia coli , and Proteus . Currently, the American Academy of Orthopedic Surgeons recommends antibiotics for prophylaxis with a first- or second-line cephalosporin, most commonly cefazolin and cefuroxime, in the absence of a β-lactam allergy. Clindamycin, vancomycin, or teicoplanin can be used in the presence of a documented cephalosporin allergy or known antibiotic-resistant organism, such as MRSA. Given the increasing prevalence of MRSA, it is important to recognize patients who are at higher risk of being colonized. Risk factors for MRSA include recent antibiotic use, hospitalization, female sex, diabetes, age greater than 65 years, human immunodeficiency virus, or health care workers. Those patients should have their prophylactic antibiotics adjusted accordingly.


Fulkerson and colleagues examined bacterial cultures from infected TJA and susceptibilities to prophylactic antibiotics. They found that only 61% of bacterial isolates were sensitive to cefazolin. In patients previously treated with antibiotics, the vancomycin sensitivity was only 78%, and cefazolin sensitivity was 0%. Sewick and colleagues examined the use of a dual antibiotic prophylaxis with preoperative cefazolin and vancomycin on 1828 TJAs. They found no statistical difference in SSI when compared with cefazolin alone. The use of vancomycin as a primary prophylactic antibiotic is controversial and current literature supports primary prophylaxis with a first- or second-line cephalosporin when applicable.


To reach minimal inhibitory concentration, prophylactic antibiotics should be initiated within 1 hour of start of the procedure. Several studies confirm that 24 hours of antibiotics is as effective as 48 or 72 hours. Current recommendations include one intraoperative dose of antibiotics followed by one or two additional perioperative doses. A second additional dose of antibiotics may be administered during prolonged surgical duration beyond the half-life of the antibiotic (typically 4 hours) or when blood loss exceeds 1000 mL.


Our Own Worst Enemy


A potential source for intraoperative wound contamination includes airborne bacteria. These bacteria almost commonly originate from operating room staff. Bacterial shedding from one operating room staff member can be 10,000 bacteria per minute. When compared with a completely empty operating room, the addition of five personnel increases the airborne microbial count 15-fold. This source of contamination has been well documented over the years. In fact, Charnley is credited with saying, “The living body of personnel in an operating room is by far the most important source of pathogenic organisms.” Several techniques have been implemented to minimize the circulating airborne bacterial load and promote a “clean air” environment.


Traffic Control


Ambient airborne particulate and bacteria counts increase because of bacterial shedding from operating room personnel and air exchange between the sterile operating room and nonsterile hallways. The repeated opening and closing of operating room doors has been shown to be a predictor of the number of airborne particulates in an operating room. In the modern operating room, restricting presence to only scrubbed sterile personnel is not practical because most operating room staff must regularly travel between operating rooms. To combat airborne contamination, clean air enclosures have been established within the operating room. This allows anesthesia and other unscrubbed personnel to remain physically separate from the sterile surgical field. Currently, there are little data to support the use of clean air enclosures within the operating room. Although some amount of foot traffic within the operating room is to be expected, excessive use of the operating room doors and increased number of personnel should be discouraged.


Space Suits and Laminar Flow Systems


Lidwell and colleagues first examined the use of ultraclean laminar air flow (LAF) systems in the operating room for control of airborne contamination compared with typical turbulent flow rooms. They examined greater than 8000 operating rooms and found a 75% decrease in SSI with LAF compared with a control room. Historically, use of LAF without the use of preoperative antibiotics was shown to decrease the prevalence of SSI from 3.4% to 1.2%. Vertical LAF units have demonstrated 80% to 93% reduction in environmental and surface contamination. The accepted airborne bacterial counts for ultraclean LAF is less than or equal to 10 cfu/m 3 . When combined with the use of body exhaust systems (BES), operating room bacterial counts decrease to 1 cfu/m 3 . Ritter and colleagues showed that BESs reduce airborne contamination by 38% when compared with sterile gowns and up to 69% when compared with plain surgical scrubs. Despite several studies showing the significant decrease in airborne contamination with the combination of LAF and BES, the efficacy of these methods at decreasing infection rates is still controversial. Hooper and colleagues analyzed greater than 51,000 primary THAs and greater than 36,000 TKAs assessing LAF and BES use and the rate of revision for early deep infection. Their data failed to demonstrate any decrease in the rate of infection in either modality. Similarly, Ahl and colleagues showed no statistical difference in deep infection rate when examining greater than 8000 TKAs with laminar flow rooms and body suits. Whyte and colleagues revealed that air contamination does not significantly reflect surface contamination, and proposed surface bacteria as a more substantial risk factor for SSI. Ultraclean laminar flow systems and BES remain extremely popular in TJA despite debate over their efficacy.


An alternative to using LAF systems to reduce the number of airborne bacterial and particulate load in addition to decreasing surface contaminates involves directly killing bacteria using ultraviolet lighting (UVL). UVL at 290 μW/cm 2 has been shown to decrease surface bacterial counts more than with LAF alone. Ritter and colleagues prospectively examined 5890 TJA with and without UVL and revealed a 3.1 times decrease in SSI, solely by using UVL. Although effective in preventing SSI, there exist safety concerns for patient and personnel because of the carcinogenic properties of UVL. Currently, the Centers for Disease Control and Prevention and National Institutes of Health recommend against the use of UVL, citing significant safety hazards. The use of UVL seems to be an effective adjunct to ultraclean air operating room environment and with proper operating room staff and patient protective equipment, could be a cost-effective addition or alternative to LAF.


Intraoperative Anesthesia Measures


The anesthesia team plays an important intraoperative role in the prevention of postoperative wound complications and deep infections. During the procedure, the anesthesia team is responsible for implementing protocols to optimize postoperative healing. This includes an appropriate timing of perioperative antibiotics, intraoperative monitoring of blood glucose, and temperature controls.


Because of the increase in physiologic stress during the operation, insulin requirements are typically elevated. This is especially important with patients with decreased insulin response, such as type 1 and 2 diabetes. An estimated 8% of all TJAs are performed on patients with diabetes. Frequent intraoperative blood glucose monitoring is also encouraged and is of particular importance in patients with type 1 diabetes. Continual postoperative glycemic checks are required because insulin requirements may fluctuate as the patients metabolic needs readjust.


Mild hypothermia during a major operation is a common event. This has been shown to trigger thermoregulatory vasoconstriction and decrease subcutaneous perfusion and oxygen tension and promote postoperative wound infection. Reduction of oxygen tension may also impair the oxidative mechanism of neutrophils, decreasing the tissues ability to immunogenic and anabolic activity. Hypothermia also directly impairs function of the patient’s natural overall immune function. A multicenter, randomized controlled trial assessing intraoperative warming in colorectal patients demonstrated that patients with normothermia had a significantly lower risk of developing postoperative infections than their hypothermic counterparts (6% vs 19%, respectively). Hence, intraoperative normothermia is likely to decrease SSI in patients undergoing major TJA and should be implemented by the anesthesia team.


Antibiotic Bone Cement


Prevention of infection in TJA may be augmented with the use of antibiotic-impregnated cement. The addition of heat-resistant antibiotics to bone cement allows for the direct delivery of antimicrobials to the area with the greatest concern. Antibiotic-impregnated cement has been demonstrated to have bactericidal activity for at least 7 to 10 days following implantation and up to 10 years in some studies. Antibiotic-loaded bone cement (ALBC) allows for the delivery of high antibiotic concentrations at the operative site, reducing the adverse systemic effects while increasing antibiotic concentration at the surgical site. The use of ALBC in conjunction with systemic antibiotics has been shown to decrease wound infection and PJI revision rates. A randomized prospective study by Chiang and Chiu examined the prophylactic use of ALBC in primary TKAs and compared their outcomes with standard polymethyl methacrylate bone cement. In the cohort receiving ALBC, no infections were reported, whereas the standard polymethyl methacrylate cohort had a 3.1% infection rate.


Despite the promising data, the use of ALBC continues to be controversial. Concerns regarding routine use of ALBC in primary TJA include decreasing bone cement strength, development of antibiotic resistance, hypersensitivity reactions, and increased cost. Although the addition of large amounts of antibiotics to bone cement can alter cement properties, the use of lower doses has been shown to have negligible mechanical effects. The increased cost associated with the use of ALBC can adversely affect the use of TJA. To offset increased cost of approximately $60,000 per 100 patients undergoing TJA, the decrease in infection incidence needs to be greater than 1.2%. However, the use of prophylactic ALBC in high-risk patients with a history of bacterial infections or immunocompromised status is generally well accepted. Although still controversial, the use of prophylactic ALBC has been demonstrated to be effective and beneficial in properly selected patients with TJA.

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Feb 23, 2017 | Posted by in ORTHOPEDIC | Comments Off on Approach to Decrease Infection Following Total Joint Arthroplasty
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