I’ve just been told I have acetabular cysts. This is what’s causing so much hip and groin pain. What causes the cysts? I do have ovarian cysts. Are the two related?

The term ‘cyst’ refers to any sac that contains fluid or a semisolid material of some kind. Cysts usually occur in soft tissues like the ovaries, bladder, skin, or digestive tract. There can be cysts in the knee and shoulder, too.

Cysts can occur in bone just under the layer of cartilage that attaches to the bone. These are called subchondral bone cysts. A subchondral bone cyst in the hip socket is an acetabular cyst. Acetabulum is another word for the socket or cup-shaped part of the hip joint.

Doctors aren’t exactly sure what causes acetabular cysts. One idea is that thinning of the layer of cartilage occurs with aging. Then tiny cracks form in the cartilage leading to the development of cysts. This theory suggests the cysts are brought on by mechanical stress.

Another idea is that a labral tear occurs forcing fluid into the acetabulum through the tear. The labrum is a rim of cartelage around the acetabulum that helps hold the head of the femur (thighbone) in the socket. Once synovial fluid enter the acetabulum, a bone cysts forms.

There’s no known link between ovarian cysts and acetabular cysts. It’s may be just a coincidence that you have two different kinds of cysts in your body.