M23: Internal derangement of knee
M23.0: Cystic meniscus
Cystic meniscus, or M23.0, is a condition that affects the soft, c-shaped discs of cartilage (menisci) in your knee joint. These menisci function as shock absorbers between your thigh bone and shin bone. In a cystic meniscus, a small fluid-filled sac, or cyst, develops within the cartilage. This may be due to wear and tear, overuse, or a knee injury, causing the fluid to build up. This condition may not always produce noticeable symptoms, but when it does, it can cause pain, swelling in the knee, stiffness, or a sense of instability. Occasionally, a cystic meniscus may lead to a locked knee, where you are unable to fully straighten the knee. Despite its name, this condition actually relates to fluid accumulation rather than true cyst formation.
Patient Disclaimer
The information provided on this page is for general educational purposes only. It is not intended for self-diagnosis and does not replace professional medical advice. Always consult your doctor or a qualified healthcare provider with any questions or concerns about your health.
If you see an ICD diagnosis code (e.g., on a medical report), be aware that doctors may also include additional indicators to express diagnostic certainty. Only a healthcare professional can interpret these codes accurately in the context of your individual case.
For a complete understanding of your condition and what the diagnosis means for you, please speak directly with your doctor.