Septic Arthritis Treatment & Management

Medical management of infective arthritis focuses on adequate and timely drainage of the infected synovial fluid, administration of appropriate antimicrobial therapy, and immobilization of the joint to control pain.

Acute prosthetic joint infection (PJI) (< 3 wk in duration) can be cured medically if it is of the early type or secondary to hematogenous spread without any evidence of periarticular soft-tissue involvement or joint instability.^[6]

Overall, the mean length of hospitalization for septic arthritis is 11.5 days. However, outpatient antibiotic therapy in stable patients can significantly reduce hospital stays.

Consultations

In general, obtain a consultation with an orthopedic surgeon or rheumatologist. If the initial treatment response is poor or the etiology of the synovitis remains unknown, consult with an infectious disease specialist.

In native joint infections, antibiotics usually need to be administered parenterally for at least 2 weeks. However, each case must be evaluated independently. Infection with either methicillin-resistant S aureus (MRSA) or methicillin-susceptible S aureus (MSSA) requires at least 4 full weeks of intravenous antibiotic therapy. Orally administered antimicrobial agents are almost never indicated in the treatment of S aureus infections.

Gram-negative native joint infections with a pathogen that is sensitive to quinolones can be treated with oral ciprofloxacin for the final 1-2 weeks of treatment. As a rule, a 2-week course of intravenous antibiotics is sufficient to treat gonococcal arthritis.^[23]

Antibiotic selection

Initial antibiotic choices must be empirical, based on the sensitivity pattern of the pathogens of the community. Consider the rise of resistance among potential bacteria when choosing an initial antibiotic regimen. If local incidence of MRSA is high (in particular, marked increase in the resistance of the pneumococcus), prescribe alternate antibiotics initially. Because many isolates of group B streptococci have become tolerant of penicillin, use a combination of penicillin and gentamicin or a later-generation cephalosporin. MRSA is becoming established outside of the hospital setting. Enterobacteriaceae and P aeruginosa are becoming more resistant to multiple antibiotics. Knowing the resistance patterns in the community, as well as in the hospital, is most important.

Preferably, the antibiotic should be bactericidal with some effect against the slow-growing organisms that are protected within a biofilm (eg, coagulase-negative S aureus [CONS]). Rifampin fulfills these requirements; however, this agent should never be used alone because of the rapid development of bacterial resistance to the drug.

If, after 5 days of therapy, the joint shows some degree of improvement, consider an empirical trial of an anti-inflammatory agent. If the joint fails to respond after 5 days of appropriate antibiotic therapy (eg, presence of clinically significant fever, continued synovial purulence, persistently positive findings on culture), reassess the therapeutic approach, as follows:

• Reculture the fluid and reexamine for crystals
• Perform appropriate serologies for diagnosis of Lyme disease; if these are positive, treat per current guidelines
• If fungal or mycobacterial infection is possible, consider obtaining a synovial biopsy
• Consider the possibility of reactive arthritis; nonsteroidal inflammatory agents (NSAIDs) are the primary therapeutic agents for reactive arthritis
• Perform imaging studies, either radiographs or magnetic resonance imaging (MRI), to rule out periarticular osteomyelitis.

Antibiotics have a role in suppressing associated chronic osteomyelitis and chronically infected prosthetic material that cannot be removed for various reasons.

The use of fluoroquinolones for an extended period should be considered when the removal of an infected prosthesis is not possible. Cure rates as high as 62% have been documented in relatively small series. Generally, such prolonged therapy is seen as suppressive and not curative.^[24]

Oral antibiotics are usually used in treating gonococcal joint infections.

Usually, immobilization of the infected joint to control pain is not necessary after the first few days. If the patient's condition responds adequately after 5 days of treatment, begin gentle mobilization of the infected joint. Most patients require aggressive physical therapy to allow maximum postinfection functioning of the joint.

Initial physical therapy consists of maintaining the joint in its functional position and providing passive range-of-motion exercises. The joint should bear no weight until the clinical signs and symptoms of synovitis have resolved. Aggressive physical therapy is often required to achieve maximum therapy benefit.

The choice of the type of drainage, whether percutaneous or surgical, has not been resolved completely.^{[19, 25]} In general, use a needle aspirate initially, repeating joint taps frequently enough to prevent significant reaccumulation of fluid. Aspirating the joint 2-3 times a day may be necessary during the first few days. If frequent drainage is necessary, surgical drainage becomes more attractive.

Gonococcal-infected joints rarely require surgical drainage.

Surgical drainage is indicated when one or more of the following occur:

• The appropriate choice of antibiotic and vigorous percutaneous drainage fails to clear the infection after 5-7 days
• The infected joints are difficult to aspirate (eg, hip)
• Adjacent soft tissue is infected

Routine arthroscopic lavage is rarely indicated. However, drainage through the arthroscope is replacing open surgical drainage. With arthroscopic drainage, the operator can visualize the interior of the joint and can drain pus, debride, and lyse adhesions.

In cases of prosthetic joint infection (PJI) that require surgery for cure, successful treatment requires appropriate antibiotic therapy combined with removal of the hardware. Despite appropriate antibiotic use, the success rate has been only about 20% if the prosthesis is left in place. In recent years, evidence has shown that debridement alone could yield a cure rate of 74.5% of patients with a prosthetic joint infection and a C-reactive protein (CRP) level of 15 mg/dL or less who are treated with a fluoroquinolone.^[26] For the time being, a 2-stage approach should be regarded as the most effective technique.

First, remove the prosthesis and follow with 6 weeks of antibiotic therapy. Then, place the new joint, impregnating the methylmethacrylate cement with an anti-infective agent (ie, gentamicin, tobramycin). Antibiotic diffusion into the surrounding tissues is the goal. The success rate for this approach is approximately 95% for both hip and knee joints.

An intermediate method is to exchange the new joint for the infected joint in a 1-stage surgical procedure with concomitant antibiotic therapy. This method, with concurrent use of antibiotic cement, succeeds in 70-90% of cases.

Strictly adhere to sterile procedures whenever the joint space is invaded (eg, in aspiration or arthroscopic procedures).

Antibiotic prophylaxis with an antistaphylococcal antibiotic has been demonstrated to reduce wound infections in joint replacement surgery. Polymethylmethacrylate cement impregnated with antibiotics may decrease perioperative infections.

Using antibiotic prophylaxis on the same theoretic basis as that for cardiac valvular disease has been advocated. Whenever a sustained bacteremia may be encountered, be aware of the possibility of joint involvement, especially for prosthetic joints. Consideration should be given to more prolonged treatment of the bacteremia to cover the possibility of very early joint infection (secondary prophylaxis). The implanted hardware most likely is at greatest risk of bacteremia infection within a few months of placement. The risk probably decreases as a pseudocapsule evolves. During this time, prophylaxis is probably most beneficial. A recent well-designed study refutes the recommendation that all joint replacement patients require antibiotic prophylaxis prior to dental procedures.^[27]

Treat any infection promptly to lessen the chance of bloodstream invasion. In addition, decreasing the incidence of underlying infections best prevents reactive arthritis.

Patient education

Instruct patients with a prosthetic joint in place to recognize early signs of joint infection and, more importantly, to recognize bacterial infections in other parts of their bodies to prevent associated bacteremias.

For patient education information, see Arthritis Center as well as Knee Pain and Ticks.