Reconstruction after Pelvic Bone Massive Resection: Evolution and Actuality of 3D-Printing Technology.

PURPOSE OF THE STUDY: Pelvic reconstructions after massive bone resections are among the most challenging practices in orthopedic surgery. Whether the bone gap results after a trauma, a tumor resection, or it is due to a prosthetic revision, it is mandatory to reconstruct pelvic bone continuity and rebuild the functional thread that connects spine and hip joint. Several different approaches have been described in literature through the decades to achieve those goals. MATERIAL AND METHODS: To this date, 3D-printed implants represent one of the most promising surgical technologies in orthopedic oncology and complex reconstructive surgery. We present our experience with 3D-printed custom-made pelvic prostheses to fulfi ll bone gaps resulting from massive bone loss due to tumor resections. We retrospectively evaluated 17 cases treated with pelvic bone reconstruction using 3D-printed prostheses. Cases were evaluated in terms of both oncological and functional outcomes. RESULTS: At the last follow-up, local complications were found in 6 cases (36%): in 4 (23.5%) of them the cause was a local recurrence of the disease, whereas only 2 (12.5%) had non-oncologic issues. The mean MSTS score in our population increased from 8.2 before surgery to 22.3 at the latest clinical control after surgery. DISCUSSION: 3D-printing technology, used to produce cutting jigs and prosthetic implants, can lead to good clinical and functional outcomes. These encouraging results are comparable with the ones obtained with other more frequently used reconstructive approaches and support custom-made implants as a promising reconstructive approach. CONCLUSIONS: Our data confi rm 3D-printing and custom-made implants as promising technologies that could shape the next future of orthopedic oncology and reconstructive surgery. KEY WORDS: custom made prosthesis, pelvic reconstruction, orthopedic oncology, cutting jigs, 3D-printing.

Total hip replacement: a retrospective multicentric analysis on re-intervention rate after single component revision.

Total hip arthroplasty (THA) revision is a procedure consisting in the replacement of a single or multiple implant components and could take place once or more times (re-revision). The aim of this multicentre study is to evaluate the benefits of single component revision in respect of the principles that define implant stability. Two hundred and forty-two patients underwent THA revision at Orthopaedic Clinic of Pisa and Versilia (ITA) from January 2007 to December 2016. We have systematically excluded revisions due to septic or traumatic prosthesis loosening, revisions of both implant components (cotyle and stem) and replacement alone. To evaluate implant stability, we used preoperative X ray and intra-operative mechanical stress tests, applying accredited criteria. Two hundred and twenty-six patients (93%) underwent a single procedure of THA revision: 193 had cotyle replacement and 33 had femoral stem replacement. The remaining 16 (7 %) underwent at least two procedures: 10 of them had consecutive failure of the same component, while the other 6 had revision of the other component after the first procedure. Considering our cases series, we can assert that single component revision is the best choice when no signs of loosening are present on the remaining component. Nevertheless, an accurate evaluation with unanimous radiological criteria and intraoperative testing is essential for the surgeon to choose the most suitable treatment.