Dealing with prosthetic joint infections

At VA morning report today we had a great discussion lead by Dr. Cutrell regarding management of prosthetic joint infections. He referenced a NEJM review article written by Dr Zimmerli. Here are some highlights from the article as well as the link!

– Due to the use of peri-operative antibiotics and laminar airflow surgical environment, intra-operative infection rates are <2%
– There are currently no uniform criteria that establish the diagnosis
– Most common organisms are coag negative staph (30-40%), staph aureus (12-20%), mixed flora (10%), streptococci (10%), GNR (~5%), enterococci (~5%) and anaerobes (~5%)
– Infections of prosthetic joints are classified into early (<3 months), delayed (3-24 months) and late (<24 months)
– Early infections have classic presentation of acute onset joint pain, effusion, erythema, fever and have more virulent organisms including staph aureus
– Delayed infections are more subtle and symptoms can include implant loosening, persistent joint pain and involve less virulent organisms such as coag neg staph
– Early and delayed infections are generally acquired during implantation whereas late infections are generally due to hematogenous seeding
– WBC count in the serum and CRP are less discriminative, however a synovial fluid neutrophil percent >65% has 97% sensitive and 98% specific for joint infection in patients without underlying inflammatory joint disease
– The article includes a great table of antibiotic choice based on culture data – example includes Nafcillin + Rifampin for MSSA or Vancomycin + Rifampin for MRSA. Both can be transitioned to Cipro + Rifampin orally for outpatient regimen after first 2 weeks
– Remember that Rifampin can be added for staph organisms (however cannot be used as monotherapy due to the high rate of developing resistance) and that Floroquinolones have great bone penetration
– Surgical management can include a staged process with wash out before resection arthroplasty +/- re-implantation as well as the use of anti-microbial spacer or cement

Also check out the IDSA guidelines: joint infection%22