ICD-10-CM > M00-M99 > M65-M67 > M67 > M67.2 > M67.23 M67.23 Synovial hypertrophy, not elsewhere classified, forearm Non-Billable/Non-Specific Codes M67.231Synovial hypertrophy, not elsewhere classified, right forearmM67.232Synovial hypertrophy, not elsewhere classified, left forearmM67.239Synovial hypertrophy, not elsewhere classified, unspecified forearm