Fig. 2

 A 41-year-old male in the intraoperative ultrasound group. a Top view image of the right elbow joint with the patient in the supine position. A linear probe is held to view the radial nerve. A pilot needle is slowly inserted inside the anterolateral elbow joint. b The real-time ultrasound image of the radial nerve (black arrow) and pilot needle (white arrow). The needle is inserted into the anterolateral elbow joint. c Corresponding arthroscopic image obtained from the direct lateral viewing portal, showing insertion of the pilot needle (white arrow) into the anterolateral elbow joint