Derang of ant horn of medial mensc d/t old tear/inj, l knee

This code describes a chronic internal derangement affecting the anterior portion of the medial meniscus in the left knee, resulting from a prior tear or injury. This condition typically involves mechanical symptoms such as locking, catching, or instability due to the displaced meniscal tissue. It indicates a persistent issue rather than an acute injury.

Use this code for patients presenting with symptoms attributable to an old, unrepaired tear of the anterior horn of the medial meniscus in the left knee. Documentation should clearly state "old tear," "chronic tear," or "due to old injury" and specify the anterior horn and medial meniscus. Imaging reports (e.g., MRI) confirming an old tear in this specific location are crucial for accurate coding.

• Ensure documentation specifies "old tear" or "chronic injury" to differentiate from acute tears.
• Verify the specific location: anterior horn of the medial meniscus.
• Laterality is critical; this code is specific to the left knee.