ICD-10-CM > M00-M99 > M20-M25 > M23 > M23.6 > M23.63 M23.63 Other spontaneous disruption of medial collateral ligament of knee Non-Billable/Non-Specific Codes M23.631Other spontaneous disruption of medial collateral ligament of right kneeM23.632Other spontaneous disruption of medial collateral ligament of left kneeM23.639Other spontaneous disruption of medial collateral ligament of unspecified knee