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

This code indicates a structural disruption or dysfunction of the medial meniscus in an unspecified knee, resulting from a prior injury or tear. The term "derangement" implies an internal mechanical issue, such as a displaced fragment or abnormal movement, rather than an acute tear.

Apply this code when documentation specifies a chronic or old medial meniscal derangement in a knee, without laterality specified. This is appropriate when the patient presents with symptoms related to a previously sustained meniscal injury, such as locking, catching, or instability.

• Requires documentation of "old tear" or "old injury" to differentiate from acute meniscal tears.
• Avoid if laterality (left or right knee) is documented; use a more specific code.
• Often used as a secondary diagnosis when the primary reason for the encounter is related to the chronic meniscal issue.