What are common risk factors for periprosthetic joint infection?

• A. Diabetes, obesity, smoking, immune suppression, previous infection, prolonged operative time, malnutrition.
• B. Running, high salt intake, allergies.
• C. Vitamin C deficiency, cold weather.
• D. Increased calcium intake, fiber.

Answer: (A)

The main idea is identifying factors that weaken the body's ability to fight infection around an implant and/or increase exposure to bacteria during or after surgery. The strongest, well-established risk factors include conditions that impair immune function, wound healing, or tissue perfusion, as well as aspects of the surgery itself that raise contamination risk.

Diabetes is a major risk because high blood sugar can impair neutrophil function and wound healing, and poor glycemic control is consistently linked with higher infection rates after joint replacement. Obesity increases risk through poorer tissue perfusion and healing, more challenging surgery, and greater technical complexity, all of which raise the chance of infection. Smoking reduces blood flow and oxygen delivery to tissues, slowing healing and defense mechanisms. Immune suppression—whether from medications, diseases, or therapies—directly lowers the body’s ability to fight off pathogens. A history of prior infection around the joint or nearby sites increases the likelihood of residual organisms seeding a new prosthesis. Prolonged operative time exposes tissues longer to potential contamination and causes more tissue trauma, both of which elevate infection risk. Malnutrition impairs immune response and collagen synthesis, hindering healing and infection control.

The other options don’t describe factors with established, direct links to higher PJI risk. Activities like running, or dietary items such as high salt, calcium, or fiber, or conditions like vitamin C deficiency or cold weather, are not recognized as common risk factors for periprosthetic joint infection in the way that the factors listed above are.