OF THE MUSCULOSKELETAL TUMOR SOCIETY AND THE INTERNATIONAL SOCIETY OF LIMB SALVAGE LUMiC 1 Endoprosthetic Reconstruction After Periacetabular Tumor Resection : Short-term Results

Background Reconstruction of periacetabular defects after pelvic tumor resection ranks among the most challenging procedures in orthopaedic oncology, and reconstructive techniques are generally associated with dissatisfying mechanical and nonmechanical complication rates. In an attempt to reduce the risk of dislocation, aseptic loosening, and infection, we introduced the LUMiC prosthesis (implantcast, Buxtehude, Germany) in 2008. The LUMiC prosthesis is a modular device, built of a separate stem (hydroxyapatite-coated uncemented or cemented) and acetabular cup. The stem and cup are available in different sizes (the latter of which is also available with silver coating for infection prevention) and are equipped with sawteeth at the junction to allow for rotational adjustment of cup position after implantation of the stem. Whether this implant indeed is durable at short-term followup has not been evaluated. Questions/purposes (1) What proportion of patients experience mechanical complications and what are the associated risk factors of periacetabular reconstruction with the LUMiC after pelvic tumor resection? (2) What proportion of patients experience nonmechanical complications and what are the associated risk factors of periacetabular reconstruction with the LUMiC after pelvic tumor resection? (3) What is the cumulative incidence of implant failure at 2 and 5 years and what are the mechanisms of reconstruction failure? (4) What is the functional outcome as assessed by Musculoskeletal Tumor Society (MSTS) score at final followup? Methods We performed a retrospective chart review of every patient in whom a LUMiC prosthesis was used to reconstruct a periacetabular defect after internal hemipelvectomy for a pelvic tumor from July 2008 to June 2014 in eight centers of orthopaedic oncology with a minimum followup of 24 months. Forty-seven patients (26 men [55%]) with a mean age of 50 years (range, 12–78 years) were included. At review, 32 patients (68%) were The institution of one or more of the authors (MPAB, MAJvdS, PDSD) has received, during the study period, funding from Implantcast GmbH, Buxtehude, Germany. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. Each author certifies that his or her institution approved or waived approval for the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research. Clinical Orthopaedics and Related Research neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. This work was performed at the Leiden University Medical Center, Leiden, The Netherlands. M. P. A. Bus (&), M. A. J. van de Sande, P. D. S. Dijkstra Department of Orthopaedic Surgery, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands e-mail: m.p.a.bus@lumc.nl A. Szafranski Institute of Mother & Child, Warsaw, Poland S. Sellevold Oslo University Hospital, Oslo, Norway T. Goryn Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland P. C. Jutte University Medical Center Groningen, Groningen, The Netherlands J. A. M. Bramer Academic Medical Center, Amsterdam, The Netherlands 123 Clin Orthop Relat Res (2017) 475:686–695 DOI 10.1007/s11999-016-4805-4 Clinical Orthopaedics and Related Research® A Publication of The Association of Bone and Joint Surgeons®