Baker’s cyst is a fluid-filled popliteal bursa located along the medial border of the popliteal fossa. It is an extension of the semimembranosus bursa posteriorly.
- Symptoms associated with associated joint pathology (knee swelling or stiffness)
- Pain in the popliteal space
- Leg edema
- Prominence of the popliteal fossa
- Decreased range of motion of the knee
- Locking of the knee
- Foucher’s sign: the cyst becomes hard with knee extension and soft with knee flexion.
- Neuropathic lancinating pains radiating from the knee down the back of the leg
- Pain or discomfort with prolonged standing and hyperflexion of the knee
- Presence of associated DVT
_ Believed to be fluid distention of bursal sac separating semimembranous tendon from medial head of gastrocnemius.
_ In children, popliteal cysts are usually a primary process arising from the gastrocnemius-semimembranosus bursa without direct communication with the joint space.
_ In adults, Baker’s cysts are usually associated with pathologic changes of the knee joint, such as the following:
- Rheumatoid arthritis (RA)
- Osteoarthritis of the knee
- Meniscal tears
- Patellofemoral chondromalacia
- Infection (tuberculosis)
Baker’s cyst frequently mimics DVT and is sometimes referred to as pseudothrombophlebitis syndrome.
_ Plain radiographs (AP and lateral views)
- Strenuous activity avoidance
- Knee immobilization sometimes necessary
_ NSAIDs can be used to treat underlying joint pathology (RA, gout, and pseudogout).
_ Arthrocentesis with intraarticular injection or injection of the cyst with corticosteroids (triamcinolone acetonide 40 mg).
_ Arthroscopic surgery to remove loose cartilaginous fragment
_ Partial or total meniscectomy
_ Open excision of the cyst