Introduction:
Between 2003 and 2013, about 620,400 total hip arthroplasties (THAs) were performed in the United Kingdom (UK). At the moment, 80,000 THAs are performed annually on average. These numbers demonstrate how popular this procedure is becoming more and more. Still, there is a risk associated with this increase in numbers. A deep periprosthetic joint infection is one of the more serious surgical consequences that might occur (PJI). Even though there is a very low chance of infection, the effects and long-term consequences can be disastrous.
Without a doubt, PJI causes severe patient morbidity and presents orthopedic institutions with a challenging clinical and financial burden. It is evident that the patient and the medical facility both benefit from the early diagnosis and treatment of PJI. Therefore, this article compiles the most recent data and provides a contemporary PJI diagnosis and treatment algorithm.
What Is the Pathophysiology Of Infection?
Any type of prosthetic material infection in the body gives microbes a way around the host's immune system. Bacteria form formations along the surface of the prosthetic material called biofilms when they infect prosthetic joints. These biofilms, which cling to a prosthesis' surface like "slime," are made of highly hydrated extracellular matrix generated by bacteria. The bacteria go into a very sluggish "sessile" growth phase inside the slime due to the accumulation of waste products and the depletion of metabolic resources. The bacteria are 1000 times more resistant to growth-dependent antibiotics in this condition. The bacteria arrange themselves within the biofilm in a heterogeneous structural and functional pattern.
Sometimes, during the prosthesis implantation, microbes penetrate the joint cavity (direct inoculation). For others, the bloodstream is how the germs "seed" the joint (hematogenous dissemination). Hematogenous spread can occur via a quiescent bacteremia or a clinically severe bacteremia (for example, 34 percent of staphylococcal bacteremia result in PJI). The mouth cavity is a major source of microorganisms, especially in people who have dental illness. Certain organisms, including coagulase-negative staphylococci, have very low pathogenicity in specific situations. Biofilm and prosthetic material are the only things that allow these creatures to survive. Persistent low-grade infection with a few systemic symptoms is typically caused by low-pathogenicity pathogens.
Septicemia and bacterial endocarditis can result from infections caused by high-virulence organisms (Staphylococcus aureus is a common example of such an organism).
The germs that cause problems most frequently are Staphylococci species. About 10 % of cases are caused by streptococci, 10 percent by enterococci, and 8 percent by Gram-negative bacteria.
How To Diagnosis?
After THA, the diagnosis of PJI can provide a difficult clinical conundrum. One should keep a high index of suspicion for infection in the setting of a painful postoperative total hip arthroplasty. It is critical to have a good working definition in order to identify and treat PJI accurately. There has been a great deal of variance in the definition of PJI throughout history.
There is not a single test that can consistently and accurately diagnose infection. This obscures the reality that the PJI definition necessitates the fulfillment of certain requirements. Consequently, it is best to use a mix of biochemical tests, diagnostic imaging, and clinical assessment.
Clinical Evaluation:
It is important to get a complete history from the patient. Particular attention should be paid to any postoperative problems, such as discomfort and delayed wound healing from superficial wound infections. Examining the patient's comorbidities is also crucial. It has been demonstrated that a number of diseases are associated with a higher risk of infection. These include HIV infection, hypothyroidism, immunosuppression, morbid obesity, smoking, renal illness, diabetes mellitus, and uncontrolled hyperglycemia.
Lab Research:
Important tests that should always be examined in the evaluation process for PJI are the serum CRP and ESR. However, aging and medical comorbidities may have an impact on these parameters. A CRP >10 mg/L and an ESR >30 mm/h have been demonstrated to indicate elevated levels. Thirteen There is a great deal of variation in the literature on the sensitivity and specificity of ESR and CRP.
Aspiration and Synovial Fluid Analysis in Unification:
The research unequivocally supports the long-standing belief that joint aspiration is a crucial technique in the diagnosis of pressure injuries (PJI). According to the data, antibiotics ought to be avoided for at least two weeks before aspiration. Synovial WBC and synovial PMN% are commonly tested in synovial fluid. A synovial WBC of 20,000 cells/ml and a synovial PMN% of 89% are regarded as threshold values in acute infections. In the context of chronic infection, these numbers do vary, though. The aspirate should be sent for enriched cultures and antimicrobial sensitivity. Analyzing synovial fluid using leukocyte esterase (LER) colorimetric testing has also been described.
Pathology:
Histology can be a helpful diagnostic method for Parkinson's disease. Neutrophils in periprosthetic tissue are indicative of pressure sore inflammation (PJI). The MSIS consensus group advises the histopathologist to exclude neutrophils attached to endothelium or tiny veins, as well as those trapped in superficial fibrin when looking for neutrophils.
Plain X-ray Radiographs:
Radiographs in cases of acute PJI are frequently unimpressive. However, radiographic alterations could take place in the setting of persistent PJI. Osteolysis and gradual loosening are two of these. Radiographs ought to be a regular component of the imaging workup, even though loosening might not always be the result of an underlying illness.
What Is the Treatment Plan?
After talking with the patient, determining the treatment's objective is crucial for treating PJI. The goal may be the control of infection for some patients and the eradication of infection for others. Patients should be encouraged to determine the main objectives of their care, whether it is to reduce pain, enhance limb function, or prevent a potentially fatal infection. A multidisciplinary team must be included to facilitate collaborative decision-making about the optimal course of action. Specialists in orthopedics, plastic surgery, infectious diseases, microbiology, and radiology should be on this team.
Suppression of Antibiotics
Long-term oral antibiotic suppressive therapy is recommended for patients with medical comorbidities who cannot undergo revision surgery. Here, keeping the patient in a functional state is more important than necessarily curing the infection clinically. Even though studies on suppression therapy have been done, it is difficult to measure its effectiveness. Sixty percent of patients receiving suppressive medication in one trial reported no significant incidents throughout their two-year follow-up. An event was defined as an ongoing or recurring infection, treatment stopping due to serious side effects, and both connected and unrelated deaths. Aspiration of the hip is essential to try to identify the causative organism when thinking about suppressive treatment. Before pursuing this option, it is important to consider the significant risk of life-threatening septicemia associated with some virulent organisms, such as S. aureus or Group A streptococci, if the suppression technique fails.
Conclusion:
Revision surgery for an infected arthroplasty yields good results when provided by specialized multidisciplinary care. In patients treated for acute infections within the first three weeks of treatment, or for chronic infections treated with direct exchange or two-stage exchange, the rate of control of infection is approximately 85 percent.
Eighty percent of patients who have acute postoperative infections respond well to further surgery that involves the removal of infected soft tissues and cleaning of the prosthesis within the first three weeks. Patients who are examined within three weeks of the infection's beginning should have the same approach for acute infections associated with secondary contamination of the prosthesis after several years of normal performance.
