PMC5828490_01
Preoperative radiograph showing end-stage osteoarthritis of the hip joints associated with large femoral heads.
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Radiographs showed multiple changes of the skeleton, including end-stage osteoarthritis of the hip joints (Figure 1) and knee joints and hyperlordosis of the lumbar spine.
Axial CT image of the hip joints, demonstrating significant retroversion of the acetabulum.
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The computed tomography (CT) images of the hip joints revealed significant retroversion of the acetabulum (Figure 2).
Preoperative three-dimensional motion analysis demonstrates fixed anterior tilting of the pelvis, limited mobility of the lumbar spine, and anterior deviation of the center of gravity.
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Therefore, it was possible to identify that hip dysfunction had a major impact on gait disturbance (Figure 3).
Full-scale three-dimensional plaster models of the pelvis, showing the aspherical acetabular cavity and the thin acetabular wall.
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The acetabular cavity was aspherical, and the wall was thin even in the safe zone (Figure 4). To fill the vault, the diameter of the acetabular component needs to be more than 66 millimeters.
Setting a 68-millimeter diameter hemisphere at 0  of anteversion on the plaster model. This demonstrates that its posterior part projects backward from the acetabulum and its anterior part is deep in the bony wall. To avoid bony impingement, a significant amount of the bone needs to be removed.
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When a 68-millimeter diameter hemisphere was set at 0  of anteversion, its posterior part projected backward from the acetabulum, and its anterior part was deep in the bony wall (Figure 5).
Simulation of surgery, using a 68-millimeter diameter acetabular shell, a tapered wedge stem, and a 44-millimeter femoral head. Bony impingement occurs between the anterior and anteroinferior acetabulum and the proximal femur.
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Thus, the plan was to fix a 68- or 70-millimeter diameter acetabular shell at 40  of abduction and 0  of anteversion in terms of the anatomical measurements, remove a significant amount of the bone from the anterior and anteroinferior parts of the acetabulum, use a 44-millimeter head, and fix the stem at 30  of anteversion (Figure 6).
Postoperative radiograph of the hip joints, taken 1.5 years after the last surgery, demonstrating well-fixed components.
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Radiographs demonstrated stable components (Figure 7).
Postoperative three-dimensional motion analysis demonstrates that the patient's gait pattern has improved significantly.
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Three-dimensional motion analysis demonstrated that her center of gravity had shifted posteriorly because of the improvement of the flexion contractures of bilateral hip joints and that her gait pattern improved significantly (Figure 8).