Common sonographic findings in the painful hip after hip arthroplasty.

Diagnosing the cause of hip pain in patients with hip arthroplasty can be challenging because of the numerous possible causes of pain and artifacts caused by the prosthetic components on computed tomography and magnetic resonance imaging. Sonography plays an important role in the diagnosis and management of these patients because the soft tissues surrounding the prosthetic joint are not obscured by artifacts and because sonography enables hands-on examination of the painful site, dynamic evaluation of moving structures, and comparison with the opposite side. Another advantage of sonography is the ability to perform sonographically guided diagnostic and therapeutic procedures. In this pictorial essay, we highlight commonly encountered sonographic findings in patients with hip pain after hip arthroplasty.