The goal of joint replacement surgery, which is a popular orthopaedic procedure, is to use prosthetics to reduce pain and restore function to injured joints.
The knee and hip joints are the ones that are replaced the most frequently. Osteoarthritis, rheumatoid arthritis, and traumatic joint injuries are all conditions that can require joint replacement.
One of the most dreaded outcomes of joint replacement surgery is prosthetic joint infection (PJI). It can happen in as many as 1% of patients, which is not unusual.
Long-term antibiotic medication, surgical revision, prosthesis replacement, and physical therapy are frequently needed for PJI. Collaboration between the orthopaedics, rheumatology and infectious disease departments is necessary for diagnosis and therapy.
What is a Prosthetic joint infection (PJI)?
One of the unusual but significant side effects of having a prosthetic joint placed is prosthetic joint infection (PJI).
Bacterial development and infection around the artificial joint are to blame. Damage to joints and tissues results, as well as pain and a reduction in joint function. Numerous variables can affect the severity and rate of incidence of the symptoms.
Prosthetic joint infections are thought to occur in 0.8–1.9% of knee replacements and 0.3–1.7% of hip replacements.
Infections in prosthetic joints can be categorized based on when they developed with the original surgery:
- Early: within the first three months following joint replacement
- Delayed: between two months and two years following a joint replacement
- Late: happens more than two years following a joint replacement
Symptoms of Prosthetic Joint Infection:
One of the initial symptoms of an infection in a prosthetic joint is typically fever. Other signs can include:
- Pain at the incision site
- Redness and warmth at the incision site
- Swelling of the joint or limb
- Drainage from the incision site
- After a period of being pain-free, the joint may experience discomfort or stiffness.
- Chills or night sweats
- Fatigue
Causes of Prosthetic Joint Infection:
Bacterial invasion of the implant and consequent damage to the surrounding tissue resulting in septic endoprosthetic infections. The bacteria could enter the joint by one of two routes:
- Direct invasion: Early infections typically develop through this pathway within the first three months following joint replacement. An infection may happen if microorganisms manage to contaminate the prosthesis during surgery (due to a lack of sterility). In contrast, improper wound care throughout the healing process might result in an infection that, if left untreated, can spread to your joint. This occurs when a hollow passageway known as a sinus tract develops between the skin on the outside and the inside of your joint.
- Hematogenous spread: This occurs when bacteria enter your body through an unrelated organ (such as your gallbladder), travel through the circulation, and then infect your prosthetic joint. Additionally, after oral surgery, bacteria may enter your circulation and travel to a joint. After blood invasion, prosthetic joints are typically not spared because they are attractive to germs. In late-onset prosthetic joint infections, hematogenous dissemination is typically the route of infection (more than 2 years after surgery).
Infections in prosthetic joints can be brought on by a wide variety of microorganisms. The most frequently isolated bacteria, Staphylococcus aureus, is responsible for up to 44% of endoprosthetic infections. E. Coli and Klebsiella, enteric gram-negative bacilli, are second with 25%.
Diagnosing Prosthetic Joint Infections:
A physical examination and review of your symptoms are typically the first steps in making the diagnosis of prosthetic joint infection. Your doctor may also issue the following orders if a PJI is suspected:
- Blood tests: Blood samples will be collected to check for signs of inflammation in the body, such as elevated white blood cell counts, which can indicate infection.
- Blood culture: To identify the infectious agent, a blood sample is kept in a setting that promotes bacterial development.
- Needle aspiration: A sample of synovial fluid, the lubricant found in joints, is taken from the joint for microscopic examination.
- Bone scan: A little amount of radioactive material is used in this imaging test to highlight a contaminated area on the computer screen.
- Computed tomography (CT) scan: X-ray and computer technologies are used in a CT scan to provide fine-grained cross-sectional images of tissue, bone, and blood vessels.
- Magnetic resonance imaging (MRI): Images used for screening and diagnostics are produced using magnets and pulsed radio frequency.
- Tissue biopsy: It is possible to examine a little bit of tissue to see if any microorganisms are present. Typically, this is administered during surgery to replace the worn-out prosthetic.
Risk Factors:
The following conditions increase a person’s chance of getting an infection in a prosthetic joint:
- Diabetes
- Smoking
- Obesity
- Rheumatoid arthritis
- Weakened immune system
- when the surgery is done, there is an active infection somewhere else in the body.
- Repeat joint replacement
- Malignant (cancerous) or benign (non-cancerous) tumors
Treatment:
Infected prosthetic joints require complicated medical care. Since the appropriate therapy differs significantly from case to case, there are no set rules for treatment. Surgery is almost always necessary for treatment, which always involves long-term antibiotic therapy.
Antibiotic Treatment
Whether or not surgery is undertaken, they are the cornerstone of care and are always recommended to treat infections of prosthetic joints. The type of microorganism, the degree of infection, the planned surgery, and the patient’s response all affect how long the therapy will last.
The minimum duration of antibiotic medication is two weeks, and it may last up to six months or longer. In non-acute instances with few symptoms, antibiotic treatment may be postponed until the bacteria responsible is found (through intra-operative specimen collection or pre-operative joint fluid aspiration).
Initially administered intravenously, antibiotic therapy can frequently be switched to oral administration once the organism has been identified.
The following patients may benefit from using only antibiotic therapy without surgery:
- Refuse surgery
- Are poor candidates for surgery
Surgery:
Surgery for revision is recommended in the majority of cases of prosthetic joint infection. The decision to have surgery is influenced by many variables, including the condition of the joint, when the infection first appeared, and the patient’s preferences. The potential methods are as follows:
- Debridement without prosthetic joint removal: There are only a few situations in which this tactic is appropriate. In early cases (30 days after the initial operation) if the prosthetic joint is still in good shape, your surgeon may decide to clean the joint without removing the prosthesis. The infective organism must be responsive to accessible long-term antibiotic therapy for this technique to work.
- Multi-stage revision: In the initial stage of surgery, the joint is removed. The duration of the antibiotic course is at least six weeks. To install a brand-new prosthetic joint, multiple procedures are carried out.
- Resection arthroplasty: This occurs when the artificial joint is taken out without being replaced. The old joint is fused in its place (arthrodesis). Patients who have undergone repeated PJI therapies and have not improved are treated with this procedure because they lack the mechanical and biological prerequisites for additional surgery.
- Amputation: Amputation is the last resort for patients who have not improved despite receiving all available treatments and who still have an active infection. For patients who are already confined to beds and are unable to move around, this may be a more practical choice.
Preventing Prosthetic Joint Infections:
By doing these easy steps, you can help prevent PJIs:
- Quit smoking.
- Manage your blood sugar well.
- Maintain good oral hygiene.
- Before having dental work done, take antibiotics to stop bacteria from getting into your bloodstream through your gums.
- Before upper endoscopy or similar operations, take antibiotics to stop bacteria from getting into your bloodstream through a tiny lesion.