ICD-10-CM > S00-T88 > S80-S89 > S83 > S83.4 > S83.40 S83.40 Sprain of unspecified collateral ligament of knee Non-Billable/Non-Specific Codes S83.401Sprain of unspecified collateral ligament of right kneeS83.401A..., initial encounterS83.401D..., subsequent encounterS83.401S..., sequelaS83.402Sprain of unspecified collateral ligament of left kneeS83.402A..., initial encounterS83.402D..., subsequent encounterS83.402S..., sequelaS83.409Sprain of unspecified collateral ligament of unspecified kneeS83.409A..., initial encounterS83.409D..., subsequent encounterS83.409S..., sequela