Abstract
Ten to 15% of the pelvic girdle tumors are primary malignant bone tumors, while about 80% are osseous metastases. Due to improved function, enhanced quality of life, and acceptable local recurrence rates, limb salvage surgery has replaced external hemipelvectomies in many cases of primary malignancies. However, large segmental bony defects and poor bone quality due to the disease process itself and subsequent treatment (i.e. chemotherapy and radiation) can make stable implant fixation difficult when performing a total hip arthroplasty (THA) for oncologic periacetabular lesions with concurrent fractures. Various methods are available to reconstruct the hemipelvis, and include large structural allografts, allograft-prosthetic composites (APCs), custom-made endoprostheses, modular saddle prostheses, and modular hemipelvis endoprostheses. However, short- and mid-term results from our institution indicate that tantalum reconstructions with adjuvant screw fixation and supplemental reinforcement cages provide reasonable improvement in clinical outcomes and stable fixation in situations with massive bone loss and compromised bone quality. On the femoral side, cemented fixation remains a viable option (including proximal femoral replacements), but uncemented distal fixation with extensively-porous coated cylindrical stems or modular fluted tapered stems can be considered if the disease process (or subsequent treatment) primarily affects the proximal femur. In addition to long-term fixation, post-operative dislocations remain a significant concern given the often compromised abductor mechanism.
