Description

All steps in the protocol will be completed under the standard of care for our hospital's orthopedic joints and trauma surgeons. All patients identified under the inclusion criteria will undergo preoperative imaging. In accordance with current standards of care, patients with periprosthetic fractures (PPFs) around the hip will receive three views of X-rays of the hip and femur as well as the anterior-posterior view of the pelvis. Likewise, patients with PPFs around the knee will undergo X-rays that include the knee and femur. No advanced imaging (Computed Tomography, Magnetic Resonance Imaging, etc.) will be obtained for the purpose of this study.

Preoperative laboratory analysis will include C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) as inflammatory markers. Intraoperative synovial fluid analysis will be performed using synovial white blood cell (WBC) count and polymorphonuclear (PMN) percentage. Three cultures will be obtained from the involved joint fluid and tissue, and incubated for 14 days for analysis of aerobic, anaerobic bacterial cultures, fungal and acid-fast bacilli (AFB) analysis. The cultures will be collected from synovial fluid, peri-implant femoral synovium/periosteum, peri-implant tibial or acetabular synovium/periosteum. These laboratory tests and cultures are part of the standard protocol our surgeons have determined for their patient care.

Based on the Musculoskeletal Infection Society (MSIS) criteria for positive histology intraoperative histology will be performed utilizing frozen section analysis. These slides will be isolated from synovium, peri-implant femoral synovium/periosteum, and peri-implant tibial or acetabular synovium/periosteum. Additional cultures may be sent at discretion of surgeon but would not be included in analysis.

Per institutional protocol, preoperative cefazolin and vancomycin will be administered intravenously and continued for 24 hours perioperatively. Patients who are allergic to vancomycin will receive daptomycin, and those who are allergic to beta-lactam drugs including cephalosporins will be given gentamicin. No intra-articular antibiotics will be routinely administered.

All cultures will be followed until final. If cultures become positive, our institutional infectious disease (ID) department will be consulted for further recommendations and consideration for treatment.