Only a medical professional can diagnose hip impingement. A doctor can make this diagnosis after conducting a physical exam, ordering medical imaging (such as x-rays), and ruling out other problems.
Patient Interview and Physical Exam
During the patient interview, the patient should be ready to answer questions about past injuries, surgeries, and symptoms, including when symptoms began and what movements cause pain.
During a physical exam, the doctor will try to trigger the hip pain as well as observe limitations in the hip’s range of motion. This may include active motion tests, during which the patient is asked to perform specific movements, and passive motion tests, during with the patient relaxes and the doctor moves the patient’s affected leg.
The FADIR (flexion, adduction, and internal rotation) test is a passive motion test to help diagnose hip impingement. The patient lies on his or her back, with the legs straight and relaxed, then:
- The doctor raises the affected leg so that the knee and hip are bent at 90 degrees.
- Supporting the knee and ankle, the doctor gently pushes the entire leg across the midline of the patient’s body (adduction).
- While keeping the knee in position, the doctor moves the foot and lower calf away from the body (abduction).
People who have hip impingement typically feel pain during step three. Some people who do not have hip impingement also experience pain during this test, so the doctor may examine the unaffected hip for comparison.
Doctors may also perform the FABER (flexion, abduction, and external rotation) test. The FABER test is similar to the FADIR test, but the doctor rotates the knee outward and the foot and lower calf inward. Pain during the FABER test can indicate hip impingement or another condition, such as a problem with the sacroiliac joint of the lower back.
A case of hip impingement cannot be definitively diagnosed without medical imaging, such as x-rays and/or an MRI.
The bony growths that cause hip impingement can often be seen on an x-ray. In addition, small bone defects called herniation pits can show up as 3 to 15 mm wide1 dark spots on X-rays. A person who has hip impingement is more likely to have herniation pits on the neck of the femur.1,2 These pits are not a cause for alarm and are not treated.
MRI and MRI arthrogram
An MRI shows a detailed view of the hip joint and surrounding tissue, providing the doctor details about if and where impingement is occurring. When arthrography is used, contrast material is injected directly into the hip, providing to a clearer, more detailed MRI.
An MRI can also help detect injuries related to the impingement, including:
- Injuries to the hip’s labrum
- Damage to the hip’s articular cartilage
MRIs are expensive and time consuming, so an MRI is not always ordered during the initial diagnosis. For example, if the physical exam and x-ray suggest hip impingement, a doctor may prescribe physical therapy without ordering an MRI. An MRI is ordered when it is necessary to rule out other diagnoses and before surgery is considered.
A doctor may suggest injecting cortisone directly into the hip’s joint capsule to help confirm a diagnosis. If the injection decreases the patient’s pain, it suggests the pain is caused by a problem inside the hip capsule, such as impingement, and not outside the hip capsule, such as piriformis syndrome. Cortisone injections are not a long-term treatment for hip impingement.
The Challenge of Diagnosing Hip Impingement
An x-ray or MRI may show bone abnormalities that are indicative of hip impingement but, for reasons that are not well understood, those changes do not cause impingement during movement.2-4 So it is possible for medical images to show signs of hip impingement even though the patient’s hip pain is caused by another problem. A physician will consider all possible diagnoses.
Other Possible Diagnoses
There are many conditions that can cause hip pain. In addition to hip impingement, these conditions include—but are not limited to—hip osteoarthritis, muscle strains, hip bursitis, and joint infection, as well as pelvic conditions and back problems that can cause referred hip pain.