Derang of ant horn of lat mensc d/t old tear/inj, unsp knee

This code indicates a structural disruption of the front part of the lateral meniscus in the knee, specifically attributed to a prior injury or tear that has since become chronic. This derangement can lead to symptoms such as pain, clicking, or instability within the knee joint.

Apply this code when documentation specifies a chronic derangement of the anterior horn of the lateral meniscus, clearly linked to an old tear or injury, and the specific knee (right or left) is not documented. Supporting documentation would include imaging reports (e.g., MRI) confirming the chronic nature and location of the meniscal derangement, along with a history of a previous knee injury.

• Ensure the documentation explicitly states "old tear" or "old injury" to differentiate from acute meniscal derangements.
• If the specific knee (right or left) is documented, use the more specific codes M23.241 (right) or M23.242 (left).
• Do not use this code for acute meniscal tears; refer to codes in the S83.2- category for acute injuries.