BackgroundReconstruction 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?MethodsWe 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 alive. The reverse Kaplan-Meier method was used to calculate median followup, which was equal to 3.9 years (95% confidence interval [CI], 3.4–4.3). During the period under study, our general indications for using this implant were reconstruction of periacetabular defects after pelvic tumor resections in which the medial ilium adjacent to the sacroiliac joint was preserved; alternative treatments included hip transposition and saddle or custom-made prostheses in some of the contributing centers; these were generally used when the medial ilium was involved in the tumorous process or if the LUMiC® was not yet available in the specific country at that time. Conventional chondrosarcoma was the predominant diagnosis (n = 22 [47%]); five patients (11%) had osseous metastases of a distant carcinoma and three (6%) had multiple myeloma. Uncemented fixation (n = 43 [91%]) was preferred. Dual-mobility cups (n = 24 [51%]) were mainly used in case of a higher presumed risk of dislocation in the early period of our study; later, dual-mobility cups became the standard for the majo...

The low curative response to current treatment regimens for most soft tissue sarcomas indicates a strong need for alternative treatment strategies and predictive markers for treatment outcome. PCI (photochemical internalization) is a novel treatment strategy to translocate drugs into cytosol that otherwise would have been degraded in lysosomes. Two highly geno-and phenotypically different uterine and vulvar leiomyosarcoma cell lines, MES-SA and SK-LMS-1, were treated with bleomycin (BLM) activated by PCI (PCI). The MES-SA cells were much more sensitive to PCI than the SK-LMS-1 cells and the treatment induced a 7-8 fold higher increase in DNA double-strand breaks at the same dose of light as measure by γH2AX staining. A 3-fold higher induction of apoptosis and stronger activation of Bax and p21 was also measured in the P53WT MES-SA cells, compared to the P53mut SK-LMS-1 cells. The basal formation of reactive oxygen species (ROS) was 3-fold higher in SK-LMS-1 cells than in the MES-SA cells and SK-LMS-1 cells expressed glutathione peroxidase 1 (GPx1) and more superoxide dismutase 2 (SOD2) than the MES-SA cells. Glutathione depletion with the glutathione synthetase inhibitor buthionine sulfoximine increased the cytotoxic effect of the photochemical treatment (PDT) most strongly in the SK-LMS-1 cells, and reduced PCI-induced H2AX activation in the MES-SA cells, but not in the SK-LMS-1 cells. The results indicate PCI as a potential novel treatment strategy for soft tissue sarcomas, with antioxidant enzymes, in particular GPx1, and the P53 status as potential predictive markers for response to PCI.

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