Hand-Modelled Composite Prostheses after Resection of Peri-Acetabular Bone Malignancies

PURPOSE To improve function after pelvic resection involving the acetabulum, using an anatomic composite implant built with screws and cement. MATERIAL AND METHOD Since 1990, 66 patients with peri-acetabular bone malignancies have been treated by extensive resection followed by hand-modelled innominate prosthesis with partially constrained total hip prosthesis. The hand-modelled innominate prosthesis was made of a titanium cup, a set of long titanium screws and two or three packs of gentamycine-loaded cement. RESULTS Many postoperative complications were observed: deep infection (14%), hip prosthesis dislocation (25%) and local recurrence (15%). Sixteen patients (25%) had to be reoperated. Nevertheless, at last follow-up, 62 patients still had composite prosthesis. The mean functional result, rated according to a modified Enneking's staging system, was 80% with unlimited walking without support, average hip flexion 100 degrees , length discrepancy less than 1 cm. DISCUSSION These results were similar to those described in the literature for custom-made innominate prostheses and much better than those of alternative reconstructive procedures. Hand-modelled composite prostheses are cheaper, easier, more adaptable and enables better anchorage than custom-made prostheses. Such a procedure can be used even after total iliac wing resection. CONCLUSION The advantages of such a procedure plead for its extensive use after acetabular resection. But long-term follow-up is necessary to validate indications.