Popliteal Fossa Swellings

Question 1

What are some differentials of a popliteal fossa swelling

Answer 1

Skin and subcut tissue - lipoma, sebaceous cyst
Artery - popliteal artery aneurysm
Vein - saphena varix (at the saphenopopliteal junction), DVT
Nerve - neuroma (eg. tibial nerve)
Enlarged bursae
Cysts - Baker’s cyst, popliteal cyst

Question 2

What is a Baker’s cyst

Answer 2

A posterior herniation of the capsule of the knee joint causing synovial fluid to leak into one of the posterior bursae
Associated with degenerative changes in the knee joint

Question 3

How do you diagnose a Baker’s cyst

Answer 3

Ultrasound - fluid between the semimembranosus and medial gastrocnemius tendons

Question 4

How can you treat a Baker’s cyst

Answer 4

Aspiration - however recurrence is common

Question 5

What is a popliteal cyst

Answer 5

Usually located on the medial side of the popliteal fossa, under the medial head of gastrocnemius
Found in children and young adults

Question 6

What would you expect to see on examination of a popliteal cyst

Answer 6

More common in boys than girls
Usually unilateral
More prominent when knee extended and disappears in flexion
Firm
Transilluminated