Meniscal cyst is a fluid–filled cavity in the thickness of the meniscus. It proceeds chronically. The main complaint of patients with meniscal cyst is pain that occurs and increases with movements in the joint. On examination, a swelling is found on the lateral surface of the knee. The final diagnosis is made according to arthroscopy, ultrasound or MRI of the knee joint. Treatment consists in dissection of the cyst or complete removal of the altered meniscus. Operations are usually performed using arthroscopic equipment.
M23.0 Cystic meniscus
The disease develops more often in young and middle age. It is generally believed that the cause of cystic degeneration of the menisci is a constant increased load on the knee joint (with heavy physical work or sports). The external meniscus is more often affected, less often the internal one (ratio 5:1).
The patient has pain in the area of the articular gap, which increases with the load on the knee joint and disappears at rest. When examined by an orthopedic traumatologist, a dense, painful swelling with a size of 0.5 to 3 cm on the lateral surface of the joint is revealed. Small meniscal cysts are located at the level of the articular gap, disappear when flexing and reappear when extending the knee, sometimes they are not palpable. As the meniscal cyst increases, the tumor-like formation extends beyond the joint and spreads along the path of least resistance.
The cyst of the external meniscus usually occurs in the middle third of the outer part of the meniscus, less often in the area of the anterior or posterior horn. The cyst of the menisci does not connect with the capsule of the joint, which is gradually thinning under the pressure of a growing tumor-like formation. As a rule, the protrusion is located behind the external lateral ligament. The cyst of the inner meniscus protrudes from behind or in front of the inner lateral ligament, less often protrudes through the thickness of the ligament. A long-existing meniscal cyst causes degenerative changes in bone tissue and leads to the development of deforming arthrosis.
In traumatology and orthopedics, the diagnosis of meniscal cysts is made based on the clinical picture, the results of knee ultrasound, arthroscopy or MRI. With the development of deforming osteoarthritis of the tibial condyle, characteristic changes are detected on radiographs (Rauber-Tkachenko symptom).
The patient is recommended to reduce the load on the knee joint. With severe pain syndrome, painkillers and nonsteroidal anti-inflammatory drugs are prescribed. The final cure of the meniscal cyst is impossible without surgery, however, the complete removal of the cystically altered meniscus leads to the rapid development of deforming arthrosis. Therefore, surgical intervention should be as gentle as possible. The preferred option is the removal of the meniscus by endoscopic arthroscopy, which reduces the traumatic nature of the operation and reduces the likelihood of complications. Depending on the location and size of the meniscal cyst, the cyst is dissected or the damaged part of the meniscus is removed.