What to do if you are unable to aspirate any joint fluid?
It is crucial to establish the diagnosis of septic joint in a timely fashion because studies have shown that cartilage destruction can occur 1 to 2 days after the onset of symptoms. If the needle is in the appropriate position within the joint but fluid cannot be aspirated (i.e., a dry tap), a lavage with nonbacteriostatic saline can be performed. The lavage sample may be sent to microbiology for culture and gram stain, but not cell count. One study found that hip joint lavage in the setting of an initial dry tap for suspected septic hip resulted in an increased positive diagnostic yield of 29%.