baker's cyst

Baker’s cyst


Pathophysiology:

Posterior herniation of capsule of the knee joint leads to escape of synovial fluid into one of the posterior bursae, Baker's cysts arise between the tendons of the medial head of the gastrocnemius and the semimembranosus muscles. They are posterior to the medial femoral condyle.
When this bulge becomes large enough, it becomes palpable and cystic. Most Baker's cysts maintain this direct communication with the synovial cavity of the knee, but sometimes, the new cyst pinches off.
A Baker's cyst can rupture if patient is mobile, particularly on standing up quickly or climbing stairs. Fluid escapes into the soft tissue of the popliteal fossa and upper calf, causing sudden and severe pain, swelling and tenderness of the upper calf. Dependent oedema of the ankle develops, and the knee effusion reduces dramatically in size and maybe undetectable.

Investigations:

Ultrasound
Positive patellar tap sign


D/dx:

DVT(may co-exist)

Treatment:

Baker's cysts usually require no treatment unless they are symptomatic. Often rest and leg elevation are all that is needed. If necessary, the cyst can be aspirated to reduce its size, then injected with a corticosteroid to reduce inflammation. Surgical excision is reserved for cysts that cause a great amount of discomfort to the patient.
A ruptured cyst is treated with rest, leg elevation, and injection of a corticosteroid into the knee, patient maybe given analgesics or NSAIDS for pain relief and swelling.

Management:

Many activities can put strain on the knee, and cause pain in the case of Baker's cyst. Avoiding activities such as squatting, kneeling, heavy lifting, climbing, and even running can help prevent pain. Despite this, some exercises can help relieve pain, and a physiotherapist may instruct on stretching and strengthening the quadriceps