{"code":"M05.66","type":"code","title":"Rheumatoid arthritis of knee with involvement of other organs and systems","codeAlso":[],"includes":[],"modern_v":"official26","codeFirst":[],"excludes1":["rheumatic fever (I00)","juvenile rheumatoid arthritis (M08.-)","rheumatoid arthritis of spine (M45.-)"],"excludes2":[],"isBillable":false,"fyEffectivity":{"fy2026":true,"fy2027":true,"billableFy2026":false,"billableFy2027":false},"sibling_codes":["M05.661","M05.662","M05.669"],"inclusionTerms":[],"sibling_titles":{"code":"M05.669","title":"Rheumatoid arthritis of unspecified knee with involvement of other organs and systems","isBillable":true},"useAdditionalCode":[],"clinicalDefinition":"Rheumatoid arthritis of knee with involvement of other organs and systems is a non-billable ICD-10-CM category code (M05.66). A more specific billable subcode must be selected for claims submission. Excludes1 (not coded here): rheumatic fever (I00); juvenile rheumatoid arthritis (M08.-); rheumatoid arthritis of spine (M45.-).","officialDefinition":"Rheumatoid arthritis of knee with involvement of other organs and systems is a non-billable ICD-10-CM category code (M05.66). A more specific billable subcode must be selected for claims submission. Excludes1 (not coded here): rheumatic fever (I00); juvenile rheumatoid arthritis (M08.-); rheumatoid arthritis of spine (M45.-).","seventhCharacterInstructions":[],"workflowProtocols":[],"guidelines":{"whenToUse":[],"whenNotToUse":[],"commonBillingMistakes":[],"codeComparisons":[],"documentationChecklist":[]},"domainLandscape":{"summary":"Primary diagnostic domain and clinical landscape evaluation.","keyCategories":[],"diagnosticContinuum":"Progression continuum from acute presentation to resolution."},"children":[],"hierarchy":[],"relatedCodes":[],"relevantCPTCodes":[],"documentationTips":[],"caseStudies":[],"description":"","overview":"","noteProvenance":{"rheumatic fever (I00)":"M05","juvenile rheumatoid arthritis (M08.-)":"M05","rheumatoid arthritis of spine (M45.-)":"M05"},"hcc":{"mapped":false,"model":"CMS-HCC V28","paymentYear":"2026","categories":[],"otherModels":[]}}