The hip is described as a ball and socket joint. The ball of the femur sits deep inside the socket of the pelvic bone called the acetabulum. Several structures including the capsule, ligaments, and tendons hold these bones together. 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.
Diagnosis
The diagnosis of loose bodies follows a particular pattern once the patient is seen in the Sports Medicine physician’s office. A detailed history is obtained in order to determine the cause of the loose bodies. A physical examination is performed to determine possible motion loss or loss of strength. The exam may also determine what motions of the hip are most painful for the patient. Plain x-rays of the hip and pelvis may show the loose bodies. An MRI (Magnetic Resonance Imaging) or MRA (Magnetic Resonance Arthogram), which is an MRI using dye injected into the joint, can be used also to find positioning of the loose bodies within the joint. A CT (Computed Tonography) may also be used less frequently to see where the bodies are sitting within the hip joint.
