Abstract:
Introduction: The removal of orthopedic prosthetic implants fixed with bone cement during revision surgery can be difficult. The use of high-speed burrs or revision instruments can cause considerable debris, bone loss, and increased operative times which results increased infections rates. The use of a noninvasive AC electro-magnetic-field (EMF) that is applied externally to the cemented prosthetic implant and renders the bone cement plastic state may facilitate easier revisions with cemented prosthesis.
Methods; Prosthetic femoral components for total knees and hips were cemented into “Saw Bones” proximal and distal femurs with radiopaque bone cement. The components were made of cobalt-chromium alloys and zirconium oxide. The experiment was performed by hand to simulate surgical revision processes. The embedded implant was exposed to a 30-100kHz frequency EMF. The implant was placed under tension and removed from the bone cement coating using approximately 40lbs of force No increase in temperature was detected at the exterior surface of the bone cement. In a separate experiment, pliers were used, and the bone cement was easily removed from the prosthetic implant using approximately 5lbs of torque.
Results:The bond between the bone cement and the implant appeared to be disrupted by the heat and the bone cement became more ductile. Plastic deformation easily occurred as a result of the applied tension and the bone cement underwent a ductile rupture, as opposed to a brittle fracture. This behavior was also seen when the 5lbs of torque was applied.
Discussion:The invention represents a significant time-saving and safety improvement for revisions of cemented implants that are required to be removed. The procedure mitigates damage to tissue and bone, probably will reduced infection rates, and reduces effort by the surgical team.
Biography:
Gerhard E. Maale has accumulated extensive years of postgraduate education across various fields, including biomedical engineering, molecular biology, DNA and RNA biochemistry, clinical chemistry, biofilm engineering, pharmacology, orthopedic oncology, and pathology. In the realm of rapid molecular diagnostics, he served as the Chief Medical Officer (CMO) at Abbott, overseeing rapid bacteria identification for orthopedic platforms through 16S DNA deep sequencing using IBIS technology (electrospray double mass spectrometry). His professional journey includes roles such as Associate Professor in the Department of Orthopedic Surgery at Texas Tech University School of Medicine (1984-2000), Clinical Associate Professor in Orthopedic Surgery at UT Southwestern (1988-1996), and Consultant to William Beaumont Army Hospital Orthopedics (1988-2002). He also held positions as Clinical Associate Professor of Orthopedics at Texas Tech in Lubbock and El Paso (1988 2002) and Associate Professor in the Department of Pathology at Texas Tech University School of Medicine (1984-2000). Gerhard E. Maale directed Orthopedic Oncology and completed a Fellowship at the University of Texas Southwestern Medical School (1990 2001). He served as a Consultant for the Montana State University Center for Biofilm Engineering from 2000 to 2010. Throughout his career, he has received several honors, including a medical student research award from the University of Florida College of Medicine for 1975 and 1976, the Journal of Trauma Residents' Award for the Northeast Regional Competition (1983-1984 NIH and NCI sponsored for Oncology Fellowship), and Teaching Excellence Awards for Southwestern Orthopedic Residents in 1990 and 1992. Currently, Gerhard E. Maale is involved in various roles and projects, including working as a consultant for Neuro Resource Group, serving as a Lead Investigator for research at Montana State University and Rapid Molecular Diagnostics LLC. He is also a Clinical Professor of Orthopedic Surgery at Baylor Regional Medical Center at Plano, Director of Orthopedic Oncology at Medical City Hospital Plano, CMO at Zyvex Labs Lab, Inc., and Professor of Orthopedic Surgery at Oklahoma State University since 2020. His work spans topics such as orthopedic applications of a cutaneous handheld neurostimulator, inhibition of biofilm formation, antibiotic-loaded pellets, and local elution levels in patients with periprosthetic joint infections.
