Page 59 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

The implant consists of a hemispherical acetabular component and a porous-
coated, one-size titanium 70 mm stem, with an 11-mm maximum core diameter.
The stem is ribbed and carries two 5 mm wings to secure rotational stability. A
cylindrical segment (available in 0 mm, 10 mm and 20 mm lengths) connects
the acetabular component with the stem. A standard polyethylene liner was
used. Triplanar CT images were obtained for pre-operative templating ( gure 2). Computer-navigated techniques were not routinely used. 3
Cephalosporins were given intravenously prior to surgery and were usually continued for ve days postoperatively. Patients were placed in the lateral decubitus position which allowed them to be rotated almost prone or supine. The incision started posteriorly and was extended superiorly across the iliac crest to the anterior superior iliac spine and then angled distally along the line of the femoral artery, to a point approximately 10 cm distal to the greater trochanter. After en bloc tumor resection, a Kirschner (K-) wire was inserted in the medial part of the remaining ilium, adjacent to the sacroiliac joint, to guide implantation of the stem. This part of the ilium (part 1A according to a modi ed version of Enneking’s classi cation)8, ( gure 3) allows a prosthesis to be seated well between the anterior and posterior cortices because of its shape.
Figure 2A. Figure 2B. Figure 2C.
Figures 2A-C. Clinical images taken 3.5 years post-operatively of patient 3. Figure 2a – anteroposterior radiograph showing the position of the pedestal cup in the ilium. Figure 2b and 2c – CT images in the frontal plane, (b) through the pedestal cup and (c) in the sagittal plane, through the pedestal cup.
The ilium was prepared by drilling over the K-wire and this was followed by gradual reaming. Two grooves were created for the anti-rotation wings and a trial stem was introduced. After checking anteversion and inclination, the de nitive stem was implanted with its tip close to the sacroiliac joint. When necessary, a
Pedestal cup endoprosthesis
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