case_images: PMC8102130_01
case_images: PMC8102130_02
case_images: Severe hip dysplasia. Preoperative X-ray images of the patient at 7 years old. Image (a) depicts the pelvis on an anteroposterior X-ray projection. The acetabular angle (AC angle) is 26  and 35  on the left and right, respectively. The lateral center-edge angle (LCE angle) is 14  on the left hip and 8  on the right. Image (b) shows Rippstein's projection of the patient's pelvis.
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case_images: fig1
case_images: At 6 years old, hip dysplasia was diagnosed on both sides, which was indicated by an increasingly abnormal gait pattern (Figure 1).
case_images: Postoperative result after Salter's triple osteotomy and VDRO on both sides. Image (a) shows the direct postoperative situation after surgery. Image (b) shows a consolidation of the osteotomies 6 weeks after surgery, prior to the removal of the k-wires.
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case_images: PMC8102130_02_CRIOR2021-5584408.002.jpg
case_images: fig2
case_images: Salter innominate osteotomy and a varus derotation osteotomy (VDRO) were performed on both sides with subsequent improvement of symptoms (Figure 2). Surgery was performed in the pediatric department of a university hospital.
case_images: Result of the Salter osteotomy and VDRO at 8 years old. One year after bilateral surgery to remove the femoral implants. The AC angle is 16  on the left side and 20  on the right side. The LCE angle is 34  on the left hip and 30  on the right side.
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case_images: fig3
case_images: On the right hip, the LCE was 30 , and AC was 20  after surgery (Figure 3).
case_images: PMC8102130_03
case_images: PMC8102130_04
case_images: MRI of the right hip at the age of 22 years. The left image depicts the femoral head on the axial plane in a fat-saturated sequence. Edema can be observed in the femoral head. The right image shows the hip in coronal plane in a T1 sequence after application of contrast medium (gadolinium). The femur head has been deformed into a sickle-like shape.
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case_images: fig4
case_images: The MRI showed advanced ONFH (Figure 4).
case_images: Advanced femoral head necrosis on both sides. The anteroposterior projection of the pelvis was made for planning the THA. Because of increasing pain on the right side, correlating with advanced femoral head necrosis, the patient requested THA surgery on the right hip.
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case_images: PMC8102130_04_CRIOR2021-5584408.005.jpg
case_images: fig5
case_images: An anteroposterior X-ray of the pelvis gave indicated advanced ONFH in both hips (Figure 5).
case_images: Intraoperative picture of the dysmorphic femoral head. The hip joint was approached from the posterior. After incision of the hip joint's capsule, the femoral head was luxated out of the acetabulum.
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case_images: fig6
case_images: During surgery, the whole dimension of ONFH became obvious (Figure 6).
case_images: Postoperative image with periprosthetic fracture. This X-ray was taken in the postoperative care unit while the patient was lying in bed. A Vancouver type B1 fracture can be detected on the image. Hence, revision surgery was planned.
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case_images: fig7
case_images: A Vancouver type B1 periprosthetic fracture was diagnosed (Figure 7).
case_images: Osteosynthesis of the periprosthetic fracture. X-ray on the day of hospital discharge. The anteroposterior pelvic projections show the THA and osteosyntheses. The fracture has been reduced and fixed with four cable cerclages. The patient was restricted to 20 kg weight-bearing on the left leg for 6 weeks.
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case_images: PMC8102130_04_CRIOR2021-5584408.008.jpg
case_images: fig8
case_images: The femoral shaft was supported by four 1.8 mm cerclages (Cable-Ready, Zimmer, Hamburg, Germany) (Figure 8).