Remarkable advances in the field of periprosthetic joint infection (PJI) have occurred during the past decade, as a multitude of studies have evaluated the prevention, diagnosis, and treatment of PJI. In addition, the AAOS clinical practice guideline (CPG) on the diagnosis of PJI of the hip and knee has provided a framework for appropriate tests to aid with diagnosis. The Musculoskeletal Infection Society (MSIS) and the International Consensus Meeting then standardized the definition of PJI to provide diagnostic criteria for the orthopaedic community. Although the diagnostic criteria have been used uniformly globally, prevention and treatment of PJI vary throughout the world.
During the 2018 MSIS Annual Meeting, an international panel of expert surgeons and basic scientists discussed the various aspects of PJI management. Moderated by then MSIS President Antonia F. Chen, MD, MBA, the panelists included Claudio Diaz-Ledezma, MD (Chile); Yixin Zhou, MD, PhD (China); Salvador Rivero-Boschert, MD (Mexico); Kelly Vince, MD (New Zealand); Rihard Trebše, MD (Slovenia); Richard Kyte, MD (South Africa); Yuhan Chang, MD, PhD (Taiwan); and Noreen Hickok, PhD (United States).
Preoperative risk factors for PJI
The panel first discussed preoperative risk factors for PJI, including obesity, diabetes, smoking, intra-articular injections, and previous septic arthritis. A debate regarding obesity focused on the American Association of Hip and Knee Surgeons recommendation to not perform elective surgeries in patients with a body mass index (BMI) > 40 kg/m2, which the majority of surgeons on the panel follow. However, the panel noted that other factors, including malnutrition and soft-tissue distribution, may play a larger role in development of PJI than obesity alone. The role of bariatric surgery for weight loss prior to elective arthroplasty also was discussed; the literature recommends that patients wait at least one year after bariatric surgery before undergoing joint replacement surgery. In Asian countries, the panelists noted, few patients have high BMI, but they added that underweight patients (BMI < 18 kg/m2) may have a greater risk of PJI than patients of normal weight.
Diabetes is a common medical condition worldwide, particularly in obese patients, and a broad range of glucose and hemoglobin A1C (HgbA1C) cutoffs prior to joint arthroplasty is used throughout the world. Fasting glucose cutoffs, the surgeons on the panel explained, range from 135 mg/dL
to 200 mg/dL, and HgbA1C cutoffs range from 6 percent to 8.5 percent. Perioperative glucose control was discussed as the next frontier of postoperative PJI prevention.
With respect to smoking, all panelists agreed on the risks related to tobacco use prior to elective joint replacement. All advocated for three to six weeks of preoperative smoking cessation to improve postoperative wound healing and reduce the risk of PJI. They recommended laboratory tests for nicotine and cotinine to detect preoperative smoking, although surgeons noted that both tests are not available in every institution or country. Additionally, international surgeons noted that, due to cultural norms, it is difficult to implement smoking cessation in their patients and that patients smoke in the immediate postoperative period, even while in the hospital.
All surgeons on the panel agreed that intra-articular injections within three months prior to surgery increase the risk of PJI, although the literature has mixed results. Similarly, all panelists agreed that patients who present with previous septic arthritis should get a full infection workup prior to total joint arthroplasty, including serum erythrocyte sedimentation rate and C-reactive protein. If the levels are elevated, then the joint should be aspirated and sent for white blood cell count, polymorphonucleocyte percentage, culture, and crystals. One surgeon said he measures serum ferritin divided by serum iron to aid with the diagnosis of PJI; a level greater than eight is indicative of PJI. If a patient is negative for PJI, the surgeons wait six to 12 months from the index septic arthritis before performing elective arthroplasty and use antibiotic cement, if possible. If a patient presents with a septic joint and concomitant arthritis, then surgeons place an antibiotic-loaded spacer and treat the patient like a two-stage exchange arthroplasty patient.
With regard to treatment of PJI, most centers around the world perform surgery in two stages depending on the timing of infection. The definition of acute versus chronic PJI was hotly debated, as the timelines can guide surgical management. A discussion of biofilm formation and treatment ensued, garnering panelist and audience participation. Because biofilms form rapidly following surgery by attaching to implants or aggregating in the synovial fluid, removal of the prosthesis through one or two stages potentially decreases the likelihood of PJI recurrence.
Additionally, antibiofilm antimicrobials such as rifampin can aid in the treatment of Staphylococcus aureus PJI, but the regimen is not used universally. However, surgical management with débridement, antibiotics, and implant retention is a viable option if performed with agents that disrupt biofilm, which involves a combination of chemical and mechanical disruption. All panelists agreed that thorough débridement is necessary to control PJI and that toluidine blue dye can be applied intra-articularly to identify devitalized tissue. Finally, treating PJI patients in musculoskeletal infection centers with multidisciplinary management was considered ideal.
Antonia F. Chen, MD, MBA, is an orthopaedic surgeon at Brigham and Women’s Hospital at Harvard Medical School. She is the director of research, arthroplasty services, and the first past-president of MSIS.
Claudio Diaz-Ledezma, MD, is an adult reconstruction surgeon at Clinica Red Salud Santiago in Chile. He is a member of the AAOS Adult Reconstruction Knee Program Committee.