The hip is a fairly complex joint. Problems that often seem like they are in the hip really originate from the low back, sacroiliac joint, and even the knee. True hip pain usually occurs in the groin and front of the thigh. But even knowing the problem is in the hip doesn’t identify the true cause. It could be the soft tissues in and around the joint, the articular cartilage inside the joint, or the rim of cartilage around the rim of the hip socket called the labrum.
When the labrum is tored, frayed, or damaged in some way, it can get pinched between the head of the femur and the acetabulum (hip socket). This pinching or impingement is what causes the groin pain, loss of hip motion, and sometimes grinding, catching, or locking sensation with certain hip motions.
Labral tears can be especially difficult to diagnose because there are often other changes going on in the hip at the same time. The physician relies on a standard physical exam, history, and then special tests to sort it all out. Joint range-of-motion, strength, and a postural assessment provide helpful information. The patient’s report of what makes it better and what makes it worse is also very useful.
There is also a pain test that can be done. The surgeon injects a numbing agent similar to novocaine into the hip joint. If the pain goes away, it’s an indiction that the source of the pain is coming from inside the joint. If the pain doesn’t go away, it could still be something around or just outside the joint.
But X-rays and sometimes MRIs are often needed to confirm the presence of a torn labrum. And even then, it isn’t until the surgeon performs an arthroscopic exam that the true extent (and possibly cause) of the problem are uncovered.