case_images: PMC5458690_01
case_images: Anterior posterior pelvic radiograph taken prior to the first surgery.
case_images: JOCR-7-20-g001.jpg
case_images: PMC5458690_01_JOCR-7-20-g001.jpg
case_images: F1
case_images: Radiographs showed a lateral center-edge angle of 36  and an alpha angle of 83  on the anterior-posterior (AP) and 72  on the frog view (Fig. 1 and 2).
case_images: Frog view radiograph taken prior to the first surgery.
case_images: JOCR-7-20-g002.jpg
case_images: PMC5458690_01_JOCR-7-20-g002.jpg
case_images: F2
case_images: Radiographs showed a lateral center-edge angle of 36  and an alpha angle of 83  on the anterior-posterior (AP) and 72  on the frog view (Fig. 1 and 2).
case_images: Follow-up anterior posterior pelvic radiograph taken 3 months after the left hip arthroscopy demonstrating Grade 3 heterotopic ossification on the left side.
case_images: JOCR-7-20-g003.jpg
case_images: PMC5458690_01_JOCR-7-20-g003.jpg
case_images: F3
case_images: Follow-up radiographs at 3 months after the left hip arthroscopy showed Grade 3 HO on the left side (Fig. 3 and 4).
case_images: Follow-up frog view radiograph taken 3 months after the left hip arthroscopy demonstrating Grade 3 heterotopic ossification on the left side.
case_images: JOCR-7-20-g004.jpg
case_images: PMC5458690_01_JOCR-7-20-g004.jpg
case_images: F4
case_images: Follow-up radiographs at 3 months after the left hip arthroscopy showed Grade 3 HO on the left side (Fig. 3 and 4).
case_images: Follow-up radiographs taken 3 months after the right hip arthroscopy showed no heterotopic ossification (Grade 0).
case_images: JOCR-7-20-g005.jpg
case_images: PMC5458690_01_JOCR-7-20-g005.jpg
case_images: F5
case_images: Follow-up radiographs at 3 months after the right hip arthroscopy showed no HO (Grade 0) (Figure 5).