Page 218 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

Chapter 11
between the anterior and posterior cortices10, 74, 77. In a number of these stemmed implants, the stem is tapered, which causes the implant to anchor itself as a result of axial loading along the weight-bearing axis10, 40. Theoretically, this type of xation should not only reduce the risk of iliac fractures and cranial migration, but also of aseptic loosening40.
It is for these reasons that additively manufactured (3D-printed) pelvic prostheses, in our opinion, should be met with caution. Although these hemipelvic implants are superior for restoring iliac crest anatomy, they typically lack adequate xation in the weight-bearing axis. Mechanical complications, including loosening, cranial migration and component breakage, can therefore be expected; in that regard, custom hemipelvic implants are much like hemipelvic allografts.
1.4 Infection
Pelvic tumor resections are notorious for the high risk of postoperative infection (18-32%), irrespective of the reconstructive technique used14, 23, 50, 75, 78, 79. Deep infections can be devastating, necessitating multiple surgical debridements, removal of implants or even – although rarely – hindquarter amputation14. The high risk of infection can be attributed to the length and complexity of the surgical procedure, creating a large dead space and leaving large soft tissue defects, and the immunocompromised status of patients, due to co-treatment with chemotherapy38, 80-82. A validated deep infection risk score for endoprosthetic reconstructions is currently lacking, and should be developed in future research to allow surgeons to better identify patients at risk for developing surgical site infection. Given the in uence of operative time on the risk of infection, we feel that further centralization of care for patients with pelvic bone tumors should be considered.
Numerous precautions have been taken in an attempt to reduce the rate of infection, including the administration of prophylactic antibiotics – which are given for a duration of up to ve days postoperatively82. To date, solid evidence to support the use of a speci c antibiotic protocol is lacking. Currently, there is an international randomized controlled study (the PARITY trial) ongoing to determine the optimal antibiotic regimen (one or ve days) following endoprosthetic reconstruction for bone tumor resection83.
Other strategies to reduce the risk of deep infection focus on implant surface modi cations to minimize adhesion of bacteria, inhibit the formation of a bio lm, and provide bactericidal action84. In recent years, silver coating of endoprostheses
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