Hip replacement surgery, or total hip arthroplasty, involves replacing a damaged hip joint with an artificial implant. The most serious potential complication is a prosthetic joint infection (PJI), which occurs when bacteria colonize the implant surface. Because the body’s immune system struggles to clear these bacteria, PJI often requires complex treatment, including long courses of antibiotics or additional surgery. To mitigate this risk, patients are sometimes prescribed preventative antibiotics before medical or dental procedures that could introduce bacteria into the bloodstream.
Why Preventative Antibiotics Are Considered
The primary concern that drives the need for preventative antibiotics is a temporary condition called bacteremia, which is the presence of bacteria in the bloodstream. Invasive procedures, such as those involving tissue manipulation, can momentarily push bacteria from the procedure site into the circulation. If these bacteria travel through the bloodstream, they can settle, or “seed,” the surface of the non-living hip implant.
The artificial joint lacks a natural blood supply, making it difficult for immune cells and antibiotics to eliminate adhering bacteria. Once a bacterial colony forms a protective layer, called a biofilm, the infection becomes established. Prophylaxis—the use of antibiotics before a procedure—is intended to eliminate transient bacteria in the blood before they can colonize the implant.
The risk of this type of hematogenous infection is highest in the immediate post-operative period, generally considered to be the first three to six months following surgery. However, some orthopedic surgeons may recommend increased caution and prophylaxis for up to two years after the procedure. Patients with compromised immune systems, such as those with poorly controlled diabetes, inflammatory arthritis, or prior history of joint infection, may remain at an elevated risk for the rest of their lives.
Dental Procedures and Current Antibiotic Recommendations
Dental procedures are the most common reason patients with hip replacements are advised to consider antibiotic prophylaxis. Historically, it was standard practice for nearly all patients to take antibiotics before any dental work, but this recommendation has significantly changed. Major organizations, including the American Dental Association (ADA) and the American Academy of Orthopaedic Surgeons (AAOS), now recognize that the risk of PJI following most routine dental procedures is very low.
Current consensus guidelines state that prophylactic antibiotics are generally not recommended for most patients with prosthetic joints undergoing common dental procedures. This shift in guidance is partly due to the growing concern over the potential harms of widespread antibiotic use, such as the development of antibiotic-resistant bacteria and serious infections like Clostridium difficile. The risk of a severe allergic reaction to the antibiotic is often considered to outweigh the minimal risk of joint infection from a simple dental procedure.
However, antibiotics are still often considered necessary for high-risk dental procedures that involve significant manipulation of the gum tissue or breaking the oral mucosal barrier. These procedures include:
- Tooth extractions
- Periodontal surgery
- Dental implant placement
- Root canal surgery that involves an incision
The decision to prescribe antibiotics for these procedures should be made collaboratively between the patient’s dentist and orthopedic surgeon, especially if the patient has a weakened immune system or other risk factors.
Poor oral hygiene is a continuous source of low-level bacteremia, which poses a greater long-term risk than a single dental procedure. Therefore, maintaining excellent daily oral health is more beneficial than relying on occasional prophylactic antibiotics. The patient’s orthopedic surgeon should always be consulted before scheduling any invasive dental work, regardless of the procedure’s perceived risk level.
Non-Dental Medical Procedures Requiring Prophylaxis
Beyond dental work, a limited number of non-dental medical procedures may also necessitate antibiotic prophylaxis, particularly those that involve sites already known to be contaminated or infected. The general principle is to prevent bacteria from a localized infection from reaching the prosthetic joint via the bloodstream.
Procedures involving the genitourinary (GU) tract, such as cystoscopy, may require antibiotics if a urinary tract infection is present. Routine screening procedures involving the gastrointestinal (GI) tract, such as colonoscopy or upper endoscopy, generally do not require prophylaxis. However, if the GI procedure is more invasive or involves a known infection, prophylactic antibiotics may be warranted.
Incision and drainage of an abscess, such as a boil or deep tissue infection, is another scenario where antibiotics are often required. Draining the abscess can push a large concentration of bacteria into the bloodstream, making it a high-risk event for the hip implant. Before undergoing any invasive medical procedure, the patient must inform the treating physician about their hip replacement so the need for prophylaxis can be properly assessed.