ICD-10-CM > M00-M99 > M05-M14 > M06 > M06.0 > M06.06 M06.06 Rheumatoid arthritis without rheumatoid factor, knee Non-Billable/Non-Specific Codes M06.061Rheumatoid arthritis without rheumatoid factor, right kneeM06.062Rheumatoid arthritis without rheumatoid factor, left kneeM06.069Rheumatoid arthritis without rheumatoid factor, unspecified knee