Derangement of unsp meniscus due to old tear/inj, unsp knee

This code signifies an internal derangement of a knee meniscus resulting from a prior injury or tear that has since healed or become chronic. It indicates a mechanical dysfunction or instability within the knee joint attributed to the long-standing meniscal damage. The specific meniscus involved (medial or lateral) and the affected knee (right or left) are not specified.

Use this code when documentation confirms a meniscal derangement secondary to an old, rather than acute, tear or injury, and the specific meniscus or knee laterality is not documented. This is appropriate for patients presenting with chronic knee pain, locking, or instability where imaging or clinical findings point to a pre-existing meniscal lesion. Documentation should clearly state "old tear," "chronic injury," or similar terminology.

• Avoid using this code if the laterality (right/left) or the specific meniscus (medial/lateral) is documented; more specific codes are available.
• Do not use for acute meniscal tears; those are classified under different codes.
• Ensure the documentation explicitly links the derangement to an "old" or "chronic" injury, not a recent event.