Periprosthetic joint infection (PJI) can be devastating to patients and their families. This complication remains relatively rare, with a reported incidence of 1% to 2% for primary hip and knee arthroplasty.1 When an infection occurs, many medical disciplines are involved in management, including orthopaedics, infectious disease (ID), anesthesiology, and internal medicine as well as ancillary services such as nutrition, physical therapy, pharmacy, nursing, and care coordination. Management of these efforts is similar to the treatment provided by centers that specialize in oncology, bariatric surgery, and cardiac care, which typically use established care pathways. Multidisciplinary care of complex oncology patients improves the speed and accuracy of diagnosis, improves outcomes, and decreases litigation.2,3 Comparing management of PJI to that of cancer is not that far off the mark, especially given that the mortality rates associated with two-stage exchange for PJI (ie, the management method most commonly used in the United States) approach 25% to 33% at 5 years postoperatively.4-6 Ninety-day mortality following management of chronic PJI is significantly higher than that associated with aseptic revision.7
Several studies have demonstrated that primary total joint arthroplasty performed in a high-volume setting may be associated with better outcomes.8,9 Cram et al10 compared the number of adverse outcomes following total hip and knee arthroplasty performed at specialty hospitals and general hospitals. The authors reported fewer adverse outcomes following total hip and knee arthroplasties performed at specialty hospitals. A study of 3,800 hospitals found that adverse outcomes (ie, death, infection, deep vein thrombosis and/or pulmonary embolism, myocardial infarction, bleeding) decreased with specialization of the hospital center.11 These Centers of Excellence and specialty hospitals use a care pathway that aids the multidisciplinary team in the decision-making process. Clinical care pathways have been shown to improve adverse outcome rates, decrease the length of hospital stay, and improve patient and caretaker satisfaction.12,13 Similar findings have been noted in patients undergoing oncologic care and care following complex revision arthroplasty. Mankin et al14 reported that outcomes improved and complications decreased when orthopaedic oncology patients received all of their care at one institution. Similarly, in a study of patients treated with two-stage exchange for PJI, outcomes improved and treatment times decreased when care was provided at one institution.15 Dy et al16 reviewed revision total joint arthroplasty in patients listed in statewide databases in New York and California. The authors found an increase in complication rates when patients changed hospitals for a revision arthroplasty. Although this study did not specifically examine PJI, an increase in complications was evident when patients transferred their care to a smaller hospital. The use of a care pathway at a Center of Excellence for the prevention and management of PJI may be beneficial.
Here, we summarize work at the recent Musculoskeletal Infection symposium with regard to best practices for prevention and treatment of PJI within the context of a Center of Excellence. We also evaluate the goals of medical optimization, including assessment of nonmodifiable risk factors; a systematic approach to infection management; and the importance of registries to help create and maintain care pathways.
Center of Excellence
Ideally, Centers of Excellence provide better overall outcomes at lower financial, physical, and emotional costs to the patient, thus providing a greater value by decreasing variability in treatment pathways and incorporating best practices based on evidence. Total joint arthroplasty is generally regarded as a good area of focus for a Center of Excellence because of the high reproducibility of good results, low complication rates, and predictable expense. The process of being designated as a Center of Excellence typically includes the use of multidisciplinary care pathways and teams and evaluation of surgeons’ credentials, hospital volume, electronic medical records, patient data management and/or tracking, and process metrics.17 A full description of this process is beyond the scope of this review.
Standardization of the preoperative clearance process provides a guideline for most patients undergoing primary total joint arthroplasty. This eliminates the variability in what is thought to be important by primary care physicians or other medical providers in the preoperative assessment of patients. It also provides an opportunity for surgeons and medical providers to address any modifiable risk factors. Preoperative evaluations can include, but are not limited to, complete blood count; renal panel; albumin, prealbumin, hemoglobin A1c, and cotinine levels; nasal swab screenings for Staphylococcus aureus; and preoperative washes. Plans for perioperative intravenous antibiotics are developed at this time, as well. Optimization before a revision arthroplasty, especially revision for PJI, can be difficult because of the time constraints that are often involved.
Patients with immunosuppressed status, a body mass index (BMI) >40 kg/m2, end-stage renal disease on dialysis, liver disease, and/or prior joint infection have a high risk of infection or other complications and may require adjusted protocols that can include a prolonged course of mupirocin or chlorhexidine decolonization. Administration of nasal mupirocin and vancomycin should also be considered for select patients, and withholding or delay of antibiotics before revision total joint arthroplasty should be avoided. Withholding antibiotics before revision surgery should be considered only in cases of clinical infection in which a pathogen has not yet been identified.18 Preoperative consultation with an appropriate specialist should also be considered for patients with HIV/AIDS, joint infection, poor dentition, open skin lesions, or an elevated hemoglobin A1c level. Appropriate preoperative screening should be viewed as a timeout for high-risk patients and should occur weeks before the elective surgery, similar to the timeout performed in the operating room before surgery.19
Management of hyperglycemia is crucial to the perioperative care of patients treated with total joint arthroplasty. Hyperglycemia has been associated with increased morbidity, mortality, hospital costs, and length of hospital stay.20,21 Of note, 48% of patients with hyperglycemia do not have a diagnosis of diabetes mellitus.22 Hyperglycemia should be addressed regardless whether the patient has a diagnosis of diabetes mellitus because a growing body of research on patients who undergo orthopaedic surgical procedures has demonstrated that hyperglycemia independent of a diagnosis of diabetes mellitus is associated with increased infections and complications such as deep vein thrombosis.23-26 Therefore, preoperative diagnosis of hyperglycemia and treatment and follow-up of patients with newly discovered hyperglycemia is critical. Treatment typically requires a multidisciplinary effort by nurses, educators or dieticians, and clinical support staff, with the goal of achieving an adjusted normoglycemic level (70 to 110 mg/dL) in nondiabetics and euglycemia (110 to 180 mg/dL) in diabetics with standardized glucose monitoring, insulin protocols, diet, and hypoglycemia management.22 The team can also help coordinate care, communicate with primary care physicians, and educate patients regarding survival skills when dealing with hyperglycemia and diabetes mellitus.27
Attendees of the Musculoskeletal Infection symposium delineated modifiable and nonmodifiable risk factors for PJI. Although these factors are not absolute contraindications to surgery, they provide a framework for determining when surgery is not the best management option. In some patients, the nonmodifiable risk factors are too numerous and outweigh the possible benefit of surgery. Patients with a BMI >50 kg/m2, compromised skin, poor dentition, active infection, or poorly controlled HIV/AIDS (CD4 ≤200 cells/mm3)28 and those who are awaiting an organ transplant are poor candidates for surgery. Patients considered at risk of complications are those with a BMI of 40 to 50 kg/m2, history of cardiac disease, diabetes mellitus (A1c level >7% or blood glucose level >130 mg/dL), malnutrition, or obstructive sleep apnea, and those who smoke.29 The STOP BANG checklist can be used to screen patients for obstructive sleep apnea (Figure 1). Preoperative medical evaluation is particularly important to assess and treat patients with known coagulopathy. Patients with these risk factors should be referred to appropriate providers to help manage the medical conditions to achieve optimization before surgery. Interventions might include systematic weight loss programs, cardiology consultation, management of diabetes mellitus, nutrition/dietary consultation, and smoking cessation programs.
Data collection, analysis, and feedback are a key aspect of integrated care. These steps require surgeons to remain fully engaged and typically involve an interdisciplinary approach to design and implementation of risk-reduction protocols and processes. Implementation of these protocols leads to increased patient safety and reductions in preventable complications, length of hospital stay, and same-day surgery cancellations.30 A shift in culture is created when we are not solely focused on the survivability of an elective surgery, but rather on developing a plan for optimal outcome, which coincides with an increased focus on the development of the perioperative medicine subspecialty. This subspecialty focuses not only on the survivability or inherent risk of a surgery but also on identifying comorbidities and actively managing them to improve outcomes. Care pathways also allow for the critical assessment of performance and research.
Systematic Approach to Infection Management
Few medical centers in the United States or Europe have established multidisciplinary approaches along with outpatient parenteral antimicrobial therapy (OPAT) for treatment of orthopaedic infections. Representatives from Oxford University in England and Oregon Health and Science University (OHSU) in the United States described models of multidisciplinary care of orthopaedic infections that have been developed and successfully implemented.31,32
Management of musculoskeletal infection is challenging. It is a serious disease process that can be life-threatening and is progressive without treatment and often painful; it also may be systemic, resulting in multiple medical conditions that may require complex medical and surgical interventions. Musculoskeletal infection can create functional or psychological issues (eg, role limitations, depression, inability to work).33 The presentation and clinical scenarios surrounding PJIs are so varied that the current evidence base for diagnostic and treatment strategies is imperfect. With musculoskeletal infections, there is always the possibility that treatment may fail or that the disease may recur.
To address these challenges, a multidisciplinary team can improve diagnosis and treatment protocols, better manage comorbidities, and align patient goals of care with the available surgical and antibiotic options. This can result in a direct decrease in length of stay and reduced readmission rates associated with complications from antibiotics or infection. At OHSU, readmission from outpatient intravenous antibiotic complications decreased over a 5-year period, and a substantial number of inpatient days were saved annually by early discharges through preoperative planning for OPAT.34 The multidisciplinary group, which is often led by ID specialists and orthopaedic surgeons, can monitor antibiotic use and recommend prudent use of antimicrobials for better infection control.
Combining orthopaedic and ID (and potentially plastic surgery) consultations makes clinic visits much more convenient for patients. This was especially important at Oxford University and OHSU, which are tertiary referral centers, with patients travelling hundreds of miles for consultation and care. There are also educational benefits in the interdisciplinary education of orthopaedic residents and ID fellows as well as research opportunities to further understand orthopaedic infections.
Models for the Multidisciplinary Team Approach
The bone infection unit at Oxford University in England has a dedicated inpatient ward for patients with orthopaedic infections. In this setting, the ID team assumes primary responsibility for inpatient care, and orthopaedic surgeons are consultants. There are combined orthopaedic-ID ward rounds and radiology and pathology meetings. This arrangement allows the ID team to function as the hospitalists. It also allows the team to optimize the patient’s medical comorbidities perioperatively and manage antibiotic therapy. Outpatient care is provided in a combined clinic similar to that at OHSU.
The OHSU model is centered on the OPAT service, which is staffed by ID specialists with a special interest in orthopaedic infections. Most surgical and antibiotic plans are developed at the outpatient clinic by the ID specialist, pharmacist, orthopaedic surgeon, and patient. This plan includes care for patients with chronic infection and for patients without infection who have a high risk of postoperative infection. For patients who present with emergent orthopaedic infections, the OHSU inpatient ID team performs the inpatient consultation to guide initial antibiotic selection and then refers patients to the OPAT team for further management. Discussions about prognosis and future surgery usually occur in an outpatient, multidisciplinary setting, even for emergency patients. The multidisciplinary team monitors patients with infections throughout the OPAT course as they continue oral antibiotic suppression therapy and undergo reconstructive surgery, if necessary.
In addition to the specialists on the orthopaedic infection teams in the Oxford University and OSHU models, the infection team could include a dietician at the combined clinic visit to provide preoperative and postoperative nutrition advice and improved diabetic care. Combined visits with oncology would be appropriate for the patient with an orthopaedic infection who also requires chemotherapy for cancer and ready access to palliative care.
The Role of Registries in Centers of Excellence for PJI
Most national registries serve as a repository for data across a population of patients who have undergone total joint arthroplasty. In many instances, registries can serve as an early warning system for implants with high failure rates. Registries also report on the type of implants used, the etiology of failure, and survivorship. Registries show that PJI remains one of the most common causes of failure following total hip and knee arthroplasty.35 However, the use of registries to evaluate management of PJI is limited. Much of the current literature reports results from single institutions, with various numbers of patients, different surgical techniques, and variable results. For example, the success of irrigation and débridement with polyethylene exchange for acute PJI ranges from 30% to 85%.36-38
The United States has lagged behind other countries in establishing a nationwide registry. To address this, the American Joint Replacement Registry (AJRR) started in 2010 as a pilot program with 10 hospitals. Currently, the AJRR has enrolled and is receiving data from 430 hospitals.39 Its goal is to “foster a national center for data collection and research on total hip and knee arthroplasty with far-reaching benefits to society including reduced morbidity and mortality, improved patient safety, improved quality of care and medical decision-making, reduced medical spending, and advances in orthopaedic science and bioengineering.”39 Currently, level I and II data are being collected from all participating hospitals, with pilot programs already underway at several hospitals for collection of level III and IV data (Table 1).35 The addition of these patient-reported outcome measures is intended to distinguish AJRR from other registries.
The true power of a registry lies in its ability to report on a larger sample size across a population. Symposium attendees noted that consideration should be given to the creation of a subsection of the registry that solely focuses on PJI. This subsection could have far-reaching implications with regard to the true incidence of PJI as well as its etiology, patient comorbidities, and treatment outcomes. More importantly, this subsection of the registry could allow for evaluation and potential standardization of treatment regimens for PJI. In addition, the financial implications of PJI treatment could be better evaluated. This type of information would have a significant impact on the creation of Centers of Excellence in PJI. As we move toward specialized centers for management of PJI, outcomes data from a large registry can show the benefits of care pathways and Centers of Excellence.
Limitations to Establishing a Center of Excellence for PJI
Although many feel that patients with PJI would be better served at one institution or a designated Center of Excellence, there may be some reluctance on the part of surgeons and hospitals to take on the care of these patients. One reason for this reluctance is that there would be a higher risk of reportable new infections in the setting of a complex revision or a previous infection. In an era in which healthcare value and outcomes are more closely scrutinized by private and government payers, reported rates of infection will become more important because they could be associated with reimbursement rates. Complex revision and infection often require longer hospital stays than those associated with primary total joint arthroplasty. Kapadia et al40 compared infected and uninfected total knee arthroplasties and found that patients with PJI had significantly longer hospitalizations (5.3 days versus 3 days), more readmissions (3.6 versus 0.1), and more clinic visits (6.5 versus 1.3). The mean annual cost was also significantly higher in the infected group ($116,383 [range, $44,416 to $269,914]) than in the matched control group ($28,249 [range, $20,454 to 47,957]).
There is a financial disincentive for hospitals and healthcare systems to take on the additional financial and system burdens associated with PJI. The development of a viable business model to sustain a Center of Excellence that treats orthopaedic infections is challenging. The ideal model would pay for activity or treatment, create incentives to excel at the provider and system level, and ensure access to care for patients in a timely manner. Creation of a tiered insurance product may encourage patients to preferentially seek care at Centers of Excellence and provide a cost benefit to insurance carriers in terms of improved quality and efficiency of care.
Continued evaluation of care pathways and creation of Centers of Excellence that can best prevent and treat PJI are of the utmost importance, especially with the increasing burden of infection and the growing demand for total joint arthroplasty.1 The decreased complications and improvements in care at tertiary centers are likely multifactorial but stem from a centralization of care, with improved communication among teams of specialists and the use of defined care pathways for treating patients. Although not every institution that manages orthopaedic infections can establish a Center of Excellence, the care pathways and models described here provide a framework to help prevent infection and improve the care of patients with these infections.
Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 6, 19, 23, and 24 are level II studies. References 4, 5, 11, 12, 13, 15, 17, 25, 30, 33, 36, and 40 are level III studies. References 2 and 7 are level IV studies. References 26, and 27 are level V expert opinion.
References printed in bold type are those published within the past 5 years.
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