What is a Joint Replacement Infection?
A very small percentage of patients (less than 1%) who undergo hip replacement may develop an infection around the hip joint following surgery. This infection is called a periprosthetic hip infection.
How do Joint Replacement Infections Occur?
Your immune system is usually able to protect your body from bacteria or other infectious organisms by attacking it through the lymph system or blood stream. However, your hip or knee prosthesis, which is made of metal or plastic, does not have any blood vessels or lymphatic drainage, making it difficult for the immune system to gain access to and destroy these organisms. The organisms can attach themselves to the metal and form a barrier around them that antibiotics cannot reach. The bacteria can then multiply and cause the failure of the hip or knee prosthesis.
Causes of Joint Replacement Infections
Joint replacement infections may occur immediately after the surgery or even many years later. The most common way bacteria or any other infectious organism reaches the hip joint is through:
- Breaks in the skin
- Dental procedures such as tooth extraction
- Other surgeries
Risk factors for Joint Replacement Infections
Factors that increase your risk of developing a periprosthetic hip infection are:
- Immunodeficiency disorders (e.g., HIV or lymphoma)
- Peripheral vascular disease
- Immunosuppressive treatments
Symptoms of Joint Replacement Infections
You may have developed a joint replacement infection if you notice the following signs and symptoms around your hip joint:
- Drastic increase in pain and stiffness without injury
- Redness and warmth
- Drastic increase in swelling
- Fever and chills
Diagnosis of Joint Replacement Infections
Your doctor will discuss your symptoms, ask about your medical history, and perform a physical examination. Imagining studies such as X-rays and laboratory tests to identify the infection may also be ordered. Your doctor may also draw out fluid from your hip for a microscopic examination.
Treatment of Joint Replacement Infections
The various treatment options for periprosthetic hip infections include:
Nonsurgical Treatment of Periprosthetic Hip Infections
If only the skin and the underlying soft tissue is infected, oral or intravenous antibiotics may be enough to treat the condition.
Surgical Treatment of Periprosthetic Hip Infections
If the infection has penetrated to the deeper tissues around the hip joint, surgical treatment is necessary. The various surgical treatment options include:
Debridement for Periprosthetic Hip Infection
When a deep infection is diagnosed early, a surgical washout and debridement (removal of infected debris and dead tissue) may be all that is required to treat the condition. The hip implant is thoroughly cleaned during this procedure and any plastic liners or spacers may be replaced.
Staged-surgery for Periprosthetic Hip Infection
If the periprosthetic infection is diagnosed at a later stage, a 2-staged surgery may be performed. The first stage involves removal of the hip implant, washout of the hip joint, placement of an antibiotic spacer, which maintains the integrity of the joint, and the administration of intravenous antibiotics. The second stage, which occurs a few weeks later, is the placement of the new hip prosthesis after the removal of the antibiotic spacer and performing a surgical washout of the hip.
Single-Stage Surgery for Periprosthetic Hip Infection
During this procedure, the infected hip implant is removed, the hip joint is washed out, and the new hip implant is placed within the hip. This relatively new method of treating a periprosthetic hip infection is slowly gaining popularity.
Prognosis Periprosthetic Hip Infection
The prognosis for conservative treatment of periprosthetic hip infection is good if the infection is identified early and treated promptly. In case the infection has been present for some time, revision surgery and replacement of the hip prosthesis is usually necessary.