Cystic meniscus, unspecified meniscus, left knee

This code signifies the presence of a cystic lesion within an unspecified meniscus of the left knee. A meniscal cyst is a fluid-filled sac that forms adjacent to or within the meniscus, often associated with a meniscal tear. It can cause pain, swelling, and mechanical symptoms in the knee joint.

This code is appropriate when documentation clearly indicates a meniscal cyst in the left knee, but the specific meniscus (medial or lateral) is not identified. It is used for diagnostic purposes following imaging studies such as MRI or ultrasound that confirm the presence of the cyst.

• Ensure documentation specifies "left knee" and "unspecified meniscus" for accurate code assignment.
• If the specific meniscus (medial or lateral) is identified, a more specific code from the M23.0 series should be used.
• Always code any associated meniscal tear or other knee pathologies separately if documented.