How do you monitor for infections after hip replacement?

From the Guidelines

Monitoring for infections after hip replacement involves watching for specific symptoms, such as increasing pain, redness, warmth, swelling, or drainage around the surgical site, as well as fever over 101°F, chills, or increasing fatigue, and following your surgeon's recommendations for follow-up care, including imaging studies like radiography, CT, or MRI, and laboratory tests like joint aspiration with synovial fluid analysis, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) 1. To monitor for infections after hip replacement, patients should:

• Look for signs of infection, such as increasing pain, redness, warmth, swelling, or drainage around the surgical site
• Monitor for systemic symptoms, such as fever over 101°F, chills, or increasing fatigue
• Keep the incision clean and dry, following the surgeon's instructions for wound care
• Attend all scheduled follow-up appointments, which typically occur at 2-6 weeks, 3 months, 6 months, and annually thereafter
• Undergo imaging studies, such as radiography, CT, or MRI, as recommended by the surgeon to evaluate the hip prosthesis and surrounding tissue
• Have laboratory tests, such as joint aspiration with synovial fluid analysis, CRP, and ESR, to check for inflammation and infection 1
• Take all prescribed antibiotics completely, even if they feel better, to prevent the infection from reaching the prosthesis Infections after hip replacement can occur early (within 3 months) or later, and prompt treatment is essential to prevent the infection from reaching the prosthesis, which may require additional surgery and prolonged antibiotic treatment 1. Some key points to consider when monitoring for infections after hip replacement include:
• Joint aspiration with synovial fluid analysis is a useful test for confirming the presence or absence of infection and identifying the causative organism 1
• Imaging studies, such as radiography, CT, or MRI, can help evaluate the hip prosthesis and surrounding tissue for signs of infection or other complications 1
• Laboratory tests, such as CRP and ESR, can help check for inflammation and infection 1
• Prompt treatment of infections is essential to prevent the infection from reaching the prosthesis and to improve outcomes 1

From the Research

Monitoring for Infections after Hip Replacement

To monitor for infections after hip replacement, several methods and criteria are used, including:

• Statistical process control methods, such as the cumulative summation test (CUSUM test), to continuously monitor the postoperative infection rate 2
• Blood tests, such as C-reactive protein (CRP) levels, to screen for possible contraindications for arthroplasty, such as an acute infection 3
• Perioperative testing, including white blood-cell count and percentage of polymorphonuclear cells of intraoperatively aspirated hip synovial fluid, to determine the presence of periprosthetic infection 4
• A standardized protocol to assess and grade periprosthetic infection, which can guide treatment decisions, such as single-stage or two-stage revision arthroplasty 5
• Diagnostic parameters, including technetium-99m labeled hydroxymethylene diphosphonate and technetium-99m hexamethylpropyleneamine oxide-labeled granulocyte scintigraphy, histology of peri-implant tissues, laboratory tests for inflammation, and microbiology, to assess infection before revision surgery 6

Diagnostic Criteria

The diagnostic criteria for periprosthetic joint infections (PJIs) include:

• Positive intraoperative culture
• Gross purulence at the time of reoperation
• Positive histopathological findings
• Elevated erythrocyte sedimentation rate and C-reactive protein level
• Synovial fluid cell count of >3000 white blood cells/mL 4
• The Musculoskeletal Infection Society (MSIS) proposed criteria, which include major and minor criteria, such as sinus tract, purulence, and positive culture results 3

Treatment and Outcomes

The treatment of periprosthetic infection can include single-stage or two-stage revision arthroplasty, and the outcomes can vary depending on the treatment approach and the severity of the infection 5. Early diagnosis and treatment of infection are crucial to prevent long-term complications and improve patient outcomes.