Derang of ant horn of lat mensc due to old tear/inj, l knee

This diagnosis code signifies a structural disruption of the anterior portion of the lateral meniscus in the left knee, specifically caused by a previously sustained tear or injury that has since become chronic. This derangement can lead to symptoms such as pain, clicking, locking, or instability in the knee joint.

Use this code when documentation clearly indicates a chronic or old tear of the anterior horn of the left lateral meniscus, resulting in ongoing derangement. This is typically supported by imaging reports (e.g., MRI) showing an old meniscal tear and clinical notes describing persistent symptoms attributable to this chronic injury.

• Ensure the documentation specifies "anterior horn" and "lateral meniscus" for accurate coding.
• Confirm the injury is explicitly described as "old," "chronic," or "due to old tear/injury" to differentiate from acute tears.
• Laterality (left knee) is crucial; do not use for the right knee or unspecified side.