Baker's cyst

baker's cyst or popliteal cyst

1. Popliteal Cyst (Baker’s Cyst) Siwaporn Khureerung

2. What is a Baker's cyst? Popliteal cyst is a distend bursa or herniation of synovial membrane through the posterior part of capsule of the knee or escape of fluid through normal communication of bursa with the knee. It is filled with synovial inside the knee joint. (semimembranosus or medial gastrocnemius bursa)  most common in children aged 4 to 7 years and in adults aged 35 to 70 years.  more common in adults than in children.

3. Causes of a Baker's cyst A primary Baker's cyst  idiopathic Baker's cyst. It usually develops in younger people and children. A secondary Baker's cyst  most common type. Develop if there is underlying problem within the knee, such as arthritis (osteoarthritis and rheumatoid arthritis), or a tear in the meniscal cartilage that lines the inside of the knee joint. or an infection within the knee joint.

4. Symptoms Some people do not have any symptoms. Symptoms can include pain, swelling and tightness behind the knee especially when standing up. Larger the Baker's cyst, the more likely it is to produce symptoms symptoms related to underlying knee problem such as arthritis  ‘knee pain’ Less commonly, you may feel a sensation of clicking or locking of your knee.

5. Physical Examination The popliteal fossa (area behind the knee) may be swollen Translumination test :: Positive If the lump grows quickly or have night pain ,severe pain ,fever need more test to make sure other type of tumors

6. Differencial diagnosis Thrombophlebitis ,thrombosis Benign soft tissue tumor peripheral nerve sheath tumor ( neurolemmoma ) Lopoma , malignancy , vascular mass

7. Ultrasound scan good investigation to show a Baker's cyst and to help to exclude a DVT

8. MRI SCAN used to confirm the diagnosis. Appears as a high signal intensity homogenous cystic mass

9. Arthroscopy

10. Management N o specific treatment is needed . Treatment of any underlying knee problem Treatment to help relieve symptoms  Support stockings   NSAIDs    Physiotherapy  ICE    Fluid drainage    Crutches  Cortisone (steroid) injection   Surgery

11. Complications Rupture (split open). Deep vein thrombosis even if the cyst does not rupture. I nfected . Posterior compartment syndrome Common peroneal nerve and tibial nerve compression

12. Home care R.I.C.E - R est your leg - I ce the inflamed area - C ompress your knee - E levate your leg ,especially at night