Jumbo cup in hip joint renovation may cause the center of rotation to increase

Figure 3 The X-ray photogrammetry used to determine relative center elevation and upper cup position of the hip joint is shown[11]. TL: Teardrop line; a’: Center height of hip joint of jumbo cup; a: Center height of hip joint offside; b’: Horizontal distance between teardrop and teardrop line and center line of jumbo cup hip; b: Horizontal distance between vertical line crossed teardrop and center of contralateral hip joint; c: The amount of elevation of center of hip joint (a’-a); d: The amount of elevation of center of hip joint due to the upper acetabular cup.