73521

Radiologic examination, hips, bilateral, with pelvis when performed; 2 views

CPT code 73521 is a diagnostic imaging procedure used to evaluate the bilateral hip joints and, if necessary, the pelvis, using radiographic (X-ray) technology. This specific code is designated for a study that consists of exactly two views. In clinical practice, this often involves an Anteroposterior (AP) view of the pelvis, which captures both hip joints simultaneously, and a second view, which is typically a lateral or frog-leg lateral projection of both hips. The primary objective of this procedure is to provide a comparative assessment of the left and right hip structures. The bilateral nature of the exam is critical for identifying pathologies that may be subtle or bilateral, such as osteoarthritis, developmental dysplasia, or systemic inflammatory conditions. During the procedure, the patient is positioned in a manner that allows the X-ray beam to penetrate the pelvic and femoral anatomy, projecting the image onto a digital sensor or film. The resulting images allow the radiologist to inspect the femoral heads, the acetabulum (hip socket), the joint space, and the surrounding pelvic bones. This imaging is often the first line of defense in diagnosing hip pain, assessing traumatic injuries, or monitoring the progression of chronic degenerative diseases. Because the code description includes the pelvis 'when performed,' any pelvic imaging captured during these two views is bundled into this code and cannot be reported separately. This code ensures that physicians have a baseline for comparison, which is the gold standard for many orthopedic and rheumatologic evaluations.

Clinical Indications

  • Bilateral hip pain or stiffness
  • Evaluation for bilateral hip osteoarthritis (primary or secondary)
  • Suspected occult fractures of the femoral neck or pelvis
  • Assessment of developmental dysplasia of the hip (DDH) in adults or children
  • Post-operative follow-up for bilateral total hip arthroplasty (THA)
  • Evaluation for Legg-Calve-Perthes disease or Slipped Capital Femoral Epiphysis (SCFE)
  • Bilateral hip trauma
  • Avascular necrosis of the femoral head
  • Rheumatoid arthritis involving the hips
  • Unexplained gait abnormalities or limping

Procedure Steps

  1. Verify the patient's identity and confirm the order for bilateral hip X-rays.
  2. Instruct the patient to remove any radiopaque objects such as belts, jewelry, or zippers, and provide a clinical gown.
  3. Position the patient supine on the radiographic table for the Anteroposterior (AP) pelvis/hip view.
  4. Align the patient's lower extremities, typically rotating the feet internally 15-20 degrees to better visualize the femoral necks.
  5. Center the X-ray beam midway between the anterior superior iliac spine (ASIS) and the symphysis pubis.
  6. Execute the first exposure while the patient remains motionless to capture the AP view of the pelvis and bilateral hips.
  7. Reposition the patient for the second view, typically the 'frog-leg' lateral position, by flexing the knees and abducting the thighs.
  8. Ensure proper collimation to include the relevant anatomy and minimize radiation exposure.
  9. Execute the second exposure to capture the lateral/frog-leg view of the bilateral femoral heads and acetabula.
  10. Review the acquired images for technical quality, including proper exposure, positioning, and inclusion of all necessary landmarks.
  11. Send the images to the PACS system for interpretation by a radiologist.

Coding Guidelines

  • CPT 73521 is specific to 2 views total for a bilateral hip examination.
  • If only 1 view is performed for bilateral hips, this code is not applicable; consult current HCPCS or payer-specific guidelines for single-view bilateral hip studies.
  • If 3 or 4 views are performed, use CPT code 73522.
  • If 5 or more views are performed, use CPT code 73523.
  • The code description explicitly states 'bilateral,' therefore, modifier 50 (bilateral procedure) should not be used.
  • The pelvic examination is included in 73521 when performed; do not report 72170 (Radiologic examination, pelvis; 1 or 2 views) in addition to 73521.
  • If imaging is performed on only one hip (unilateral), use codes 73501, 73502, or 73503 depending on the number of views.
  • Use modifier 26 for the professional component (interpretation) and modifier TC for the technical component if billing for a non-facility setting.

Associated ICD-10 Codes