2.1. Study Design

We carried out a retrospective, monocentric, continuous study that comprised all of the patients treated between 2005 and 2017 in the orthopedic surgery department at Nantes University Hospital after a malignant pelvic bone tumor resection. All of the patients who met the Musculoskeletal Infection Society (MSIS) criteria in the first year following surgery were included and were considered to be infected with an SSI [21].

The patients had to be over 16 years of age and operated for a curative procedure for a primary malignant bone affecting the iliac bone or the sacrum. The exclusion criteria comprised soft tissue sarcomas, a proximal femur tumor without acetabular involvement, tumors of the lumbar spine, and revision surgeries for pelvic tumors considered to be local recurrences. Of the 114 patients who met the inclusion criteria, 22 cases involving bone metastasis, 6 involving a hematologic malignancy, and 31 involving non-curative surgeries were excluded. For the remaining surgical cohort, the 29 patients considered to be infected one year postoperatively based on the MSIS criteria constituted our cohort of interest.

All of the infected patients received only 24 h of antibiotic prophylaxis, dispensed in the hour before the incision, so as to be as effective as possible [22]. From 2005 to 2012, patients received a 24 h single antibiotic prophylaxis comprising 1GC (cefazoline 2 g IV). Since 2012, they received a dual antibiotic prophylaxis combining 1GC with a nitroimidazole drug (metronidazole 1 g IV). After the initial dose, reinjections were performed at half the dose, for 24 h, every two antibiotic half-lives. If the surgery took more than 4 h, 1 g of cefazoline was reinjected once at H4, and then 1 g was administrated every 8 h (along with metronidazole 500 mg, since 2012). If the patient’s weight was more than 100 kg and their BMI >35 kg/m², the dose was doubled in order to attain a sufficiently bactericidal concentration at the surgical site [23]. In case of allergies, we used clindamycin, vancomycin, or cotrimoxazole.

Before a pelvic bone tumor resection, a preoperative skin preparation was performed using povidone–iodine liquid soap, and no specific bowel preparation was done.