This photo is from a patient on chemotherapy who developed septic arthritis due to Haemophilus influenza infection.
Notice the extracellurar rods and the very rare intracellular rods present in this smear (see arrows). The dificulty in observing these organisms shows the importance of not ony a good stain but a well distributed cytospin.
Joint fluids are more viscous than other fluids and making a good smear can be dificult. Sometimes making the smear from a saline dilution of the fluid works better.