Treatment of Joint Replacement Infections

How Infections of Joint Replacements are Treated

Joint replacement surgery, including hip replacement surgery and knee replacement surgery, is very successful.  In fact, most studies show that about 90% of patients have good or excellent results after having this type of surgery.  However, not everyone does perfectly, and there are some serious complications that can occur after a joint replacement.  One of the most concerning complications is an infection of the replaced joint.

Risks of Joint Replacement

As stated, most patients do very well after joint replacement, but there are possible risks of surgery.  Infection is one of the most serious complications of a joint replacement.  The chance of developing an infection is small, but not zero.  About 1-3% of patients will develop an infection after joint replacement.  Some of the risk factors for developing a joint replacement infection include:

  • Diabetes
  • Malnutrition
  • Smoking
  • Obesity
  • Steroid use
  • Alcoholism
  • Rheumatoid Arthritis

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Preventing Surgical Infections

The ultimate goal of your surgeon, and the entire healthcare team, is to prevent the possibility of infection.  There are some steps that can be taken to lower the chance of infection.  At the time of surgery, the primary goal is to ensure sterility of the patient (both the skin and the surgical wound), and the operating environment.  Giving antibiotics intravenously at the time of surgery is also helpful. 

After surgery, patients should prevent infection from entering their blood stream by treating all infections (for example, urinary tract infections, pneumonia, etc) appropriately.  There has also been debate about treatment with antibiotics before undergoing dental work, although this is no longer recommended for routine treatment.

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Superficial Infection

A superficial infection, also called a skin infection or suture abscess, is an infection limited to the upper layer of the surgical wound, and does not extend down to the joint replacement implant.  Superficial infections can often be manged non-surgically, but should be brought to your surgeon's attention as they can turn into a more significant problem. 

If the infection spreads into the deeper part of the surgical wound, it becomes a more significant problem that may require surgery.  In addition, some deeper infections may masquerade as a superficial infection.   If this is not recognized, the deeper infection may worsen and not be diagnosed until a later stage.  Therefore, any concern for infection should be evaluated by your surgeon.

Early Joint Infections

Most surgeons categorize infections of the joint replacement implants as early infections or late infections.  Early infections occur within 6 weeks of the initial surgery, and are thought to be a result of bacterial contamination at the time of surgery.  Early infections are almost always treated with surgery to clean the implants, followed by several weeks or months of IV antibiotic treatment.  Additional surgery may be necessary to completely clean the implants, and if the infection cannot be cured the implants may need to be removed and replaced.

Late Joint Infections

Late infections typically occur more than 6 weeks after surgery, and can occur months or years after having undergone joint replacement.  Late infections are a more worrisome problem, because the infection has typically been around the implanted joint for a long time.  This can cause the implants to become loose and it also makes the infection difficult to eradicate.  In order to cure the infection, the implants almost always have to be removed in a surgery called a revision joint replacement.

One-Stage Revision Replacement

A one-stage revision replacement is performed to remove joint replacement implants, and replace them with new implants at that time of surgery.  A one-stage revision is commonly performed for implants that have loosened, but less commonly performed for implants that are infected.  When infection occurs, the implants need to be removed to cure the infection, but the bone and soft-tissue also has to be treated for infection.  Therefore, most surgeons use a two-stage revision surgery, where the implants are removed during one surgery, then the infection is treated with antibiotics, and then a second surgery is done to implant a new joint prosthesis.

Two-Stage Revision

A two-stage revision is the usual treatment for a late infection of a joint replacement.  At the time of the first surgery, the infected implants are removed and the joint is thoroughly cleaned.  Often a temporary spacer is placed in the joint to prevent excessive scarring and contracting of the tissues.  These spacers can be impregnated with antibiotics to treat the infection as well.  Following the first surgery, several weeks or months of antibiotic treatment is given to eradicate the infection.  Finally, a second surgery is done once the infection is cured to place a new joint replacement.

Success of Treatment

There have been many studies on the results of treatment of infection of joint replacement.  The good news is, that most joint replacement infections can be cured.  This may require multiple surgeries and months of antibiotic treatment, but the infection most often resolves.

The bad news is that patients who have had infections tend not to do as well functionally, compared to patients who didn't have an infection.  Patients often have more weakness, stiffness, or limp after having been treated for a joint replacement infection.

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