ICD-10-CM > S00-T88 > S80-S89 > S83 > S83.1 > S83.12 > S83.123 S83.123 Posterior subluxation of proximal end of tibia, unspecified knee Non-Billable/Non-Specific Codes S83.123A..., initial encounterS83.123D..., subsequent encounterS83.123S..., sequela