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Knee Arthrocentesis in Adults
Published on: February 25, 2022
Knee septic arthritis caused by α-hemolytic Streptococcus in a patient with a recent history of knee arthroscopy: a
Giovanni Balato1, Tiziana Ascione2, Paolino Iorio3
1Unit of Orthopaedic Surgery, Department of Public Health, School of Medicine, Federico II University, Naples, Italy. giovannibalato@gmail.com.
Background:
Arthroscopic partial meniscectomy is a common procedure in orthopedic practice. Infections are uncommon complications of this procedure with an incidence rate of 0,01% - 3,4%. Staphylococcus spp are the predominant causative agents in such cases. We present a case of knee septic arthritis caused by α-hemolytic Streptococcus.
Case Presentation:
A 22-year-old woman diagnosed with obesity (body mass index [BMI] 35 kg/m2) but with no other major comorbidities underwent an arthroscopic selective meniscectomy with administration of intravenous cefazolin for antibiotic prophylaxis. After an uneventful period of 2 months, the patient returned with pain, fever and a discharging sinus at the site of anterolateral arthroscopic portal. Blood tests and magnetic resonance imaging revealed osteomyelitis involving the tibial plate. Cultures of synovial fluid obtained from the knee and a pharyngeal swab yielded α-hemolytic Streptococcus. Five days later, the patient underwent arthroscopic debridement with partial synovectomy. Intraoperative specimens yielded α-hemolytic Streptococcus. The patient received intravenous piperacillin/tazobactam, followed by an associative regimen of amoxicillin and clindamycin with clinical, laboratory and instrumental evidence of symptom resolution.
Conclusion:
The incidence of knee septic arthritis after arthroscopic partial meniscectomy is 0.01-3.4%. This infection is usually caused by Staphylococcus spp. and in rare cases by commensal bacteria, such as α-hemolytic streptococci, secondary to transient bacteremia. Screening of the colonized area is important to prevent possible transient bacteremia. Diagnosis is based on isolation of the causative organisms from synovial fluid cultures, and treatment comprises arthroscopic debridement with individualized systemic antibiotic therapy based on the results of an antibiogram.
Insights
Septic arthritis after arthroscopic partial meniscectomy is rare, typically caused by Staphylococcus. This case highlights a rare instance of knee infection by alpha-hemolytic Streptococcus, emphasizing the need for screening to prevent transient bacteremia.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Microbiology
Background:
- Arthroscopic partial meniscectomy is a common orthopedic procedure.
- Infections following this surgery are uncommon, with an incidence ranging from 0.01% to 3.4%.
- Staphylococcus species are the most frequent pathogens, but other bacteria can cause infection.
Observation:
- A 22-year-old obese woman developed knee septic arthritis two months after arthroscopic partial meniscectomy.
- Symptoms included pain, fever, and a discharging sinus, with imaging revealing osteomyelitis.
- Cultures of synovial fluid and a pharyngeal swab identified alpha-hemolytic Streptococcus as the causative agent.
Findings:
- Alpha-hemolytic Streptococcus, a commensal bacterium, can cause knee septic arthritis secondary to transient bacteremia.
- Diagnosis relies on isolating the organism from synovial fluid cultures.
- Treatment involves arthroscopic debridement and targeted antibiotic therapy based on antibiogram results.
Implications:
- Screening for potential bacterial colonization in patients undergoing meniscectomy may help prevent rare infections.
- This case expands the understanding of causative agents in post-arthroscopic knee infections.
- Individualized antibiotic treatment is crucial for successful management of septic arthritis.
