Editorial Commentary: Ultrasound-Guided Diagnostic Injections and Arthroscopic Iliopsoas Fractional Lengthening May Alleviate Post-Total Hip Arthroplasty Pain, Avoid Unnecessary Revision Arthroplasty, and Improve Patients' Prognosis.

Identifying the cause of pain after total hip arthroplasty (THA) may be one of the more challenging tasks in orthopaedic surgery. Causes of symptoms after surgery may include infection, periarticular pain (including iliopsoas impingement/tendonitis), referred pain, polyethylene liner wear, component loosening, trunnionosis or metallosis, instability, component misplacement, or idiopathic pain. Psoas impingement, which is reported in up to 8% of patients after THA, may be caused by anatomic, technical, and prosthetic factors. A malpositioned or oversized acetabular component is the most common cause of mechanical irritation of the tendon. Ultrasound-guided diagnostic injections have become an important in-office tool to confirm the diagnosis, and if conservative measures fail, arthroscopic iliopsoas fractional lengthening shows excellent outcomes, with no loss of flexion strength or range of motion. Accurate diagnosis and a minimally invasive, cost-effective arthroscopic solution with excellent postoperative results can avoid the need for revision THA.