Ortho 711.89 inf arthritis nec-mult secondary. what does this mean?

Diagnosis code: Insurance companies require a "code" on the bill, instead of the actual name of the diagnosis. The code you list is for "arthritis in more than one joint due to undefined infectious or parasitic disease."

See details: 711.89 is the diagnostic code for infection of multiple joints. It does specific the exact organism causing the infection.