Derang of medial meniscus due to old tear/inj, unsp knee

This diagnosis code signifies an internal derangement of the medial meniscus in the knee, specifically attributed to a prior tear or injury that has since become chronic. It indicates a structural disruption within the knee joint affecting the medial meniscal cartilage, resulting from an older, unspecified traumatic event.

Use this code when documentation clearly states a chronic or old tear of the medial meniscus, without specifying the exact nature of the derangement (e.g., bucket handle, flap). This code is appropriate when the laterality of the knee (left or right) is not documented. Supporting documentation would include physician notes detailing a history of a medial meniscal injury and current symptoms consistent with chronic meniscal pathology.

• Ensure documentation specifies "old tear" or "chronic injury" to differentiate from acute tears.
• Do not use if the laterality of the knee (left or right) is documented; instead, select a more specific code from the M23.23- subcategory.
• Avoid using if the specific type of meniscal derangement (e.g., bucket handle, complex) is known; choose a more precise code from M23.2- if available.