PMC5643084_01
Plain radiographic, contrast-enhanced computed tomographic, and magnetic resonance images of the hip. Anteroposterior view on plain radiography shows no abnormal findings around the left hip (a). Axial view on contrast-enhanced computed tomography reveals a cystic lesion at the anterior aspect of the left hip compressing the left femoral vessels (white arrow, (b)). Magnetic resonance imaging reveals a cystic lesion extending from the anterior aspect of the left hip to the intrapelvic region. The mass has iso-high intensity on a T1-weighted axial image (c) and high intensity on a T2-weighted coronal image (d).
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fig1
There was no evidence of stem loosening, subsidence, or osteolysis around the stem and cup on plain radiography (Figure 1(a)). Contrast-enhanced computed tomography revealed a large cystic lesion extending from the anterior aspect of the left hip to the intrapelvic region and compressing the left femoral artery and vein (Figure 1(b)). Magnetic resonance imaging (MRI) also showed a well-defined cystic lesion (Figures 1(c) and 1(d)).
(a) Photograph of the resected pseudotumor. (b) Intraoperative photograph of the stem trunnion showing corrosion of the head-neck junction with black debris adhered to the trunnion (white arrow).
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First, we made an incision via an ilioinguinal approach and resected the pseudotumor enveloped in the iliac muscle (Figure 2(a)). However, corrosion of the head-neck junction with black metal debris was detected around the trunnion (Figure 2(b)).
(a) Preoperative photograph showing left leg swelling and redness. (b) Photograph taken 3 weeks after revision surgery showing almost complete resolution of inflammatory changes in the left leg.
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fig3
The left leg swelling and redness improved immediately after surgery and the inflammatory changes were almost resolved at 3 weeks postoperatively (Figure 3).