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

This code signifies a chronic internal derangement of an unspecified meniscus in the right knee, stemming from a prior tear or injury. It indicates ongoing mechanical symptoms or instability attributed to a historical meniscal insult, rather than an acute event.

Apply this code when documentation specifies a right knee meniscal derangement due to an old or chronic tear/injury, without further specification of the particular meniscus (medial or lateral). This is appropriate for patients presenting with persistent knee pain, locking, or catching, where imaging or history confirms a past meniscal injury.

• Ensure the documentation explicitly states "old tear" or "chronic injury" to differentiate from acute meniscal tears.
• Avoid using this code if the specific meniscus (medial or lateral) is identified; instead, use the more precise M23.21- or M23.22- codes.
• Always specify laterality (right, left, or bilateral) as indicated in the clinical record.