Cystic meniscus, posterior horn of lat mensc, unsp knee

This code describes a fluid-filled sac (cyst) located within the posterior aspect of the lateral meniscus in an unspecified knee. This condition can cause pain, swelling, and mechanical symptoms such as clicking or locking of the knee joint. It often arises from meniscal tears or degeneration.

Use this code when documentation specifies a cystic lesion originating from the posterior horn of the lateral meniscus, and the laterality of the knee (right or left) is not recorded. This diagnosis is typically confirmed by imaging studies such as MRI.

• Ensure documentation explicitly states "posterior horn" and "lateral meniscus."
• If the laterality of the knee is known, a more specific code (M23.051 or M23.052) should be used.
• Do not confuse with meniscal tears without cyst formation (M23.2- series) or other types of knee cysts (e.g., Baker's cyst, M71.2-).