Fig. 1

Measurement of intra-articular pressure and surgical operation. A Measurement of intra-articular pressure. B Bony landmarks and approaches of the hip joint (A/B/C/D symbol indicate the anterolateral approach, the anterior approach, the puncture point of intra-articular pressure measurement and the approach of core decompression, respectively. The black arrow indicates the anterior superior spine, the white arrow indicates the greater trochanter, and the white pentacle indicates the route of femoral vascular and nerve). C AI-4423 pressure sensor and IntelliVue MP50 pressure recorder. (The red arrow is a pressure sensor connected to the pressure detector.) D Establishment of the anterolateral approach for hip arthroscopy. E Incised lateral joint capsule outside the joint capsule through the view of the anterolateral approach. (The black pentacle shows the open joint capsule viewed from the outside, the black arrow represents the labrum, and the white arrow represents the femoral head.) F Incised lateral joint capsule inside the joint capsule through the view of the anterior approach. (The black pentacle shows the open joint capsule viewed from the inside, the black arrow represents the labrum, and the white arrow represents the femoral head.) G, H Intraoperative X-ray fluoroscopy of core decompression in the positive and frog positions