7 Management of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) continues to be a devastating problem in the field of total joint arthroplasty. There are a number of surgical options to decide from and management decisions are based upon the interplay between host, pathogen, and surgeon characteristics. The goal of management is to maximize function, prevent systemic complications, and eradicate infection. Throughout this chapter we will discuss the most relevant recent literature and guiding theories to assist the treating orthopaedic surgeon in the surgical decision-making process.

10 Graft Infections

Ligament reconstructions are one of the most frequently performed orthopaedic procedures. Postoperative graft infection, although a rare complication, is one of the most serious complications of ligament reconstructions. Graft infections represent a uniquely challenging situation with the goal of maintaining joint stability while eradicating the infectious process. Intra-articular infections occur following 0.05 to 1.9% of anterior cruciate ligament (ACL) reconstructions and 0.5% of posterior cruciate ligament (PCL) reconstructions, and gram-positive bacteria are typically responsible for infection. Patients typically present with signs and symptoms of septic arthritis during the acute (<2 weeks) period postoperatively, but graft infections have been reported for up to 15 months after ACL reconstructions. Risks for infection following ACL reconstruction include hamstring autograft usage, prior knee surgery, and hemarthrosis. Graft infections typically require multiple surgical debridements and prolonged antibiotic management, adding to the overall healthcare cost. Non-operative and operative measures that preserve the graft tissue have been successful, but removal of the graft and subsequent reimplantation are sometimes necessary. Additionally, the situation of intraoperative graft contamination during ACL reconstruction is discussed and whether a contaminated graft can be safely implanted. This chapter reviews multiple aspects of graft infections including demographics, risk factors, diagnosis, management, complications, and prevention.

1 Detection of Microbes in Orthopaedic Infections

A very broad range of microorganisms cause orthopaedic infections. Modern diagnosis depends on traditional culture techniques, which remain in common use, and on molecular testing, which is advancing rapidly as a field. Advances in culture-based techniques include modifications in specimen collection, incubation, and identification. Identification of pathogens through detection and analysis of microbial nucleic acids, without culturing the organism, is the focus of molecular microbiologic diagnostics. A variety of polymerase chain reaction (PCR) tests can identify single or multiple pathogens in a single PCR reaction. 16S PCR uses conserved DNA sequences to identify a very broad array of pathogens. Newer techniques (next-generation sequencing) avoid the limitations of PCR and can detect an even broader, theoretically unlimited range of pathogens by sequencing all of the nucleic acids in entire samples. The place for these technologies in orthopaedics is evolving. While anecdotal reports and some studies show molecular diagnostics’ advantages over culture, traditional cultures still remain the most accessible, affordable, and reliable in most clinical scenarios. However, further improvements are likely to alter the landscape of microbial diagnosis of orthopaedic infections.

2 Antibiotics for Orthopaedic Infections

Antibiotics play a critical role in the treatment of bone and joint infections. In clinical practice, antibiotics may be delivered intravenously, orally, or topically, alone or as part of a delivery mechanism. This chapter will discuss the most commonly used oral and intravenous antibiotics in orthopaedic infections, their efficacy and bioavailability, and important considerations when using these antibiotics for patient care. This chapter will additionally focus on the use of topical antibiotics and nondegradable/biodegradable carriers for antibiotic delivery, such as the use of heat-stable antibiotics in cement spacers. The information presented here is designed for use as a clinical reference to provide guidance on the care of patients with orthopaedic infections including osteomyelitis, septic joints, and periprosthetic joint infections.

4 Surgical Wound Dressings after Treating Orthopaedic Infections

The postoperative dressing functions as an important barrier to prevent orthopaedic infections and reinfections. Preoperative assessment of patient factors and intraoperative evaluation of the soft tissue and wound serve as key elements to determining the right dressing for individual patients when treating orthopaedic infections. This chapter explores characteristics of the ideal dressing and fundamental features of different dressing options available to surgeons, including standard nonocclusive dressings, occlusive dressings with or without antimicrobial impregnated materials, negative pressure wound therapy, and closed incision negative pressure wound therapy. Advantages and disadvantages of each dressing type are discussed with literature evidence. Finally, this chapter provides surgeons with an algorithmic approach to dressing selection for patients undergoing treatment for orthopaedic infections.

8 Infection after Fracture Fixation and Infected Nonunions

Infection after fracture surgery is a challenging entity. Prompt diagnosis and treatment is of paramount importance. Successful treatment includes culture-specific antibiotic therapy in collaboration with the infectious disease team.

6 Treatment of the Septic Native Joint

A septic native joint can be a debilitating condition that is associated with significant morbidity and mortality. Traditionally, a septic native joint was considered one of the few surgical emergencies in orthopaedics, as a delay in diagnosis and treatment can result in joint destruction and loss of joint mobility and even mortality. While prompt diagnosis is crucial, diagnosis can be challenging, as it can be difficult to differentiate between a septic native joint from crystalline arthropathy, and rheumatological and osteoarthritis flares. Diagnosis of a septic joint relies on clinical findings, serological test, synovial aspiration, and culture results. Traditionally, a synovial fluid white blood cell cutoff of 50,000 cells/mm3 is often used; however, it is important to note that infectious arthritis may frequently occur in patients with lower cell counts who are immunosuppressed or are infected with a less virulent organism. The mainstay of treatment for a septic joint is appropriate antibiotic therapy and surgical treatment. This chapter will focus only on native septic joint rather than periprosthetic joint infection, or a joint infection in the presence of a prostheses.

3 Irrigation Solutions for Orthopaedic Infections

This chapter will provide an overview of antiseptic agents used to irrigate wounds for the prevention or treatment of orthopaedic infections, including their mechanism of action, spectrum of microbicidal activity, safety including potential adverse effects, efficacy in eliminating infective pathogens, and efficacy against established biofilm. Some of the common irrigation solutions include acetic acid, bacitracin and polymyxin, chlorhexidine, dilute povidone-iodine (PI), sodium hypochlorite, and hydrogen peroxide. The current guidelines for prevention of surgical site infection (SSI) from the Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), and International Consensus Meeting (ICM) on orthopaedic infections only recognize sterile dilute PI as the most optimal irrigation solution. PI, sodium hypochlorite, and hydrogen peroxide provide the broadest range of antimicrobial coverage. Chlorhexidine, PI, and hydrogen peroxide may be useful in eradicating biofilm. The addition of antibiotics to irrigation solutions is not recommended as it does not confer any benefit and may further contribute to emergence of antibiotic resistant pathogens. While severe adverse effects are uncommon, cases of anaphylaxis with chlorhexidine and oxygen emboli with the use of hydrogen peroxide have been reported.

5 Osteomyelitis

Osteomyelitis is a fascinating condition that can affect all parts of the human skeleton. It presents in several distinct ways, but all have varying degrees of inflammation, systemic ill health, bone death, and soft-tissue compromise. Understanding the components of the disease and the interplay between bacteria, biofilm formation, and the host response is critical to successful treatment. Recent advances in diagnostic methods, imaging, local delivery of antimicrobials, and bone reconstruction have greatly improved the outcome for many patients. Surgery remains central to the effective treatment of chronic osteomyelitis and many acute cases. Eradication of infection is largely dependent on the skill of the surgeon in identifying the areas of dead bone and removing them during surgery. Osteomyelitis is challenging and rewarding to treat, and most patients should enjoy prolonged disease-free periods or cure. Holistic care of the patient requires close collaborative working in a multidisciplinary team including physicians, surgeons, nurses, and therapists to achieve the best outcomes.