Commonly a cyst: This can be from many things but if you have an internal knee problem like a meniscus tear or wear on your cartilage, you joint can make extra fluid and this can escape out the back of the knee joint and create a space filled with joint fluid called a poplital (or baker's) cyst. Get evaluated by your doctor first and get a diagnosis.
Answered 2/24/2018
5.7k views
2 doctors weighed in across 2 answers
A doctor has provided 1 answer
A doctor has provided 1 answer
2 doctors weighed in across 2 answers
90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more.
Ask your question