ICD-10-CM > S00-T88 > T20-T25 > T24 > T24.4 > T24.42 T24.42 Corrosion of unspecified degree of knee Non-Billable/Non-Specific Codes T24.421Corrosion of unspecified degree of right kneeT24.421A..., initial encounterT24.421D..., subsequent encounterT24.421S..., sequelaT24.422Corrosion of unspecified degree of left kneeT24.422A..., initial encounterT24.422D..., subsequent encounterT24.422S..., sequelaT24.429Corrosion of unspecified degree of unspecified kneeT24.429A..., initial encounterT24.429D..., subsequent encounterT24.429S..., sequela