case_images: PMC9909124_01
case_images: PMC9909124_02
case_images: Ultrasonographic images of (A) Case 1 in September 2019 before albutrepenonacog alfa (rFIX-FP) treatment; image shows the left ankle joint, where liquid storage (arrow) and osteochondral damage (arrowheads) are observed and (B) in April 2020 while receiving rFIX-FP 3500 units (60.3 IU/kg) once weekly.
case_images: cureus-0015-00000033573-i01.jpg
case_images: PMC9909124_02_cureus-0015-00000033573-i01.jpg
case_images: FIG1
case_images: Joint ultrasonography showed bleeding in the joint (Figure 1) and joint X-ray showed advanced-stage arthropathy (Figure 2).
case_images: Joint X-ray images of Case 1 (A) left ankle joint showing advanced stage arthropathy (arrow) and (B) right ankle joint in September 2019 before albutrepenonacog alfa (rFIX-FP) treatment.
case_images: cureus-0015-00000033573-i02.jpg
case_images: PMC9909124_02_cureus-0015-00000033573-i02.jpg
case_images: FIG2
case_images: Joint ultrasonography showed bleeding in the joint (Figure 1) and joint X-ray showed advanced-stage arthropathy (Figure 2).
case_images: PMC9909124_03
case_images: PMC9909124_04
case_images: PMC9909124_05
case_images: PMC9909124_06
case_images: Ultrasonographic image of the right knee joint of Case 3 (A) showing bleeding (arrow) in September 2019 while receiving albutrepenonacog alfa (rFIX-FP) with 4000 units (59.7 IU/kg) once every two weeks, and (B) disappearance of bleeding (arrow) in May 2020 while receiving rFIX-FP with 4000 units (59.7 IU/kg) once weekly.
case_images: cureus-0015-00000033573-i03.jpg
case_images: PMC9909124_06_cureus-0015-00000033573-i03.jpg
case_images: FIG3
case_images: IU/kg), the dosing schedule was changed. In May 2020, ultrasonography showed the disappearance of bleeding in the right knee joint (Figure 3).