Pes anserine bursitis is a cause of knee pain. The pes anserine bursa is a bursa that sits just inferior and medial to the knee joint. You have 160 bursa scattered throughout your body. Basically, the bursa are like bubble wrapping in packages. The bursa are fluid-filled sacs that are there in order to give you cushioning so that as you go through life and you’re bumping, moving, and doing normal stuff you don’t end up with a lot of bruises because those bursae have provided some cushioning to the normal wear and tear of life. Sometimes those bursa become inflamed, and –itis is the latin suffix for inflammation, so bursitis is just inflammation of the bursa.
The pes anserine bursa is the place where these three hamstring tendons come together and attach into the lower leg. Sometimes that bursa can become inflamed. There are two general ways that one develops pes anserine bursitis. One is a direct trauma to the pes anserine bursa, like you got hit in the knee or you banged your knee against something. That’s relatively uncommon, but it certainly can happen.
More typically, pes anserine bursitis is a symptom of an underlying problem, often either an underlying biomechanical problem such as tight hamstrings, or it can also very commonly go along with knee osteoarthritis or another problem within the knee that then affects the gait and you end up with more stresses going through the hamstring tendons and you end up with this bursitis. One of the ways that pes anserine bursitis is addressed biomechanically is by doing hamstring stretching and closed-chain quadriceps strengthening exercise. It’s really important to make sure that when someone has pes anserine bursitis that the underlying cause is identified so that it can be appropriately addressed.