X-rays are still the number one tool physicians rely on to make an accurate diagnosis of osteoarthritis (OA). The radiograph shows changes that can’t be seen with a clinical exam. For example, narrowing of the joint space and bone spurs associated with OA are easily seen on X-rays.
Other changes common with OA that can be observed with X-rays include changes at the joint margins and subchondral bone. Subchondral bone refers to the first layer of bone underneath cartilage. Once the joint cartilage is destroyed by the OA process, the subchondral bone can be affected, too.
Without X-rays, there are some clinical tests that can be helpful in diagnosing hip OA. Hip range-of-motion (quantity and quality) is a key factor. A quick and easy screening test for the hip is to try assuming a squat position. If this position aggravates the symptoms (or you cannot do it because of hip pain), the hip is involved in some way.
The examiner looks for a specific pattern of motion typical with OA. Loss of hip internal rotation is a positive sign of OA. The examiner also relies on how the joint feels during testing motions. There should be a smooth, easy give through the full arc of motion. The examiner feels for a slight spring at the end of the motion. Any blocks or resistance to movement caused by pain or a bone-on-bone sensation may be an indication of degenerative joint disease.
X-rays may still be needed if all these tests are positive. But if they are negative, it may rule out OA and X-rays can be avoided. It’s likely that your physician found enough suspicious test results to suggest further testing with X-ray imaging. Don’t be afraid to ask your doctor about her findings so far and express your concerns about radiation exposure.