Treatment of Septic Arthritis

Septic arthritis requires immediate surgical debridement combined with appropriate antibiotic therapy for 3-4 weeks in uncomplicated cases. 1, 2

Diagnosis and Initial Assessment

Septic arthritis is an orthopedic emergency requiring prompt diagnosis to prevent permanent joint dysfunction 1
Joint aspiration is the definitive diagnostic procedure with synovial fluid white blood cell count ≥50,000 cells/mm³ suggestive of septic arthritis 1
Synovial fluid culture is positive in approximately 80% of non-gonococcal septic arthritis cases 1
Imaging with ultrasound and MRI helps detect joint effusions, soft tissue involvement, and concomitant osteomyelitis 2
Negative joint aspirate culture does not rule out infection; consider percutaneous bone biopsy if clinical suspicion remains high 1, 2

Immediate surgical debridement is essential, with arthrotomy, irrigation, and debridement being the standard surgical interventions 1
Surgical drainage is indicated in all cases of septic arthritis 1
For prosthetic joint infections, device removal is recommended 1
If a prosthetic device cannot be removed, chronic suppression with fluconazole 400 mg daily (if the isolate is susceptible) is recommended 1

Empiric broad-spectrum antibiotic therapy should be initiated after obtaining cultures 1
IV vancomycin is recommended as first-line therapy for adults with septic arthritis, particularly when MRSA is a concern 1, 2
IV vancomycin is recommended for MRSA coverage in children, with clindamycin 10-13 mg/kg/dose IV every 6-8 hours as an alternative if clindamycin resistance is low 1, 2

For MRSA infections, adding rifampin to the regimen may be beneficial due to its excellent penetration into bone and biofilm 1, 2
For methicillin-sensitive Staphylococcus aureus (MSSA), switch to nafcillin, oxacillin, or cefazolin 2
In cases of polymicrobial infection, dual antibiotic coverage is necessary 1, 2
In children <4 years, Kingella kingae should be considered as a potential causative organism 1, 3
In patients with sickle cell disease, Salmonella species should be considered 1, 3
For Candida septic arthritis, fluconazole 400 mg daily for 6 weeks OR an echinocandin for 2 weeks followed by fluconazole 400 mg daily for at least 4 weeks is recommended 1

Duration of antibiotic therapy is typically 3-4 weeks for uncomplicated septic arthritis 1, 2
For prosthetic joint infections, longer antibiotic courses (12 weeks) show better outcomes than shorter courses (6 weeks) 1, 2
Concomitant osteomyelitis occurs in up to 30% of children with septic arthritis and requires longer treatment 1, 2

For persistent or recurrent joint swelling after a course of oral antibiotics, re-treatment with another 4-week course of oral antibiotics or 2-4 weeks of IV ceftriaxone is recommended 1, 2
Arthroscopic synovectomy may reduce the duration of joint inflammation in cases of persistent synovitis with significant pain or functional limitation 1, 2
Follow CRP and ESR to monitor treatment response 2

Oral antibiotics can be given in most cases as they are not inferior to intravenous therapy after initial stabilization 4
Poor functional outcomes occur in approximately 24% to 33% of patients with septic arthritis 5
The 90-day mortality rate of knee septic arthritis is 7% in patients 79 years and younger and from 22% to 69% in patients older than 79 years 5
All patients with candidemia should have a dilated retinal examination within the first week of therapy to establish if endophthalmitis is present 1
Be vigilant for drug interactions and adverse effects from antibiotics in elderly patients 2