Sports injuries or trauma may move the ball too much one way or another causing small pieces of bone or cartilage to shear off.
These small pieces are called “loose bodies.”, and it is appropriate to think of these bodies as debris in the joint.
These loose bodies may also be caused by degeneration to the hip joint as happens in many forms of arthritis. These loose bodies may stay in one place or may migrate within the joint.
They can often cause pain and stiffness when they are pinched or caught between two moving structures.
This pain or motion loss is seen in the groin where the true hip joint lies. Often, they may spontaneously move causing relief from the pain. However, as they are often constantly in motion, they may move to again cause pain in the same area or another area of the hip.