Drug-Eluting Orthopedic Implants

Abstract

Drug-eluting orthopedic implants address the two complications that have defined orthopedic surgery's limitations for decades: periprosthetic infection and aseptic loosening. Both complications originate at the implant-bone interface, both produce substantial patient morbidity and healthcare cost, and both have historically been addressed through systemic pharmacological approaches whose concentration at the implant surface is orders of magnitude below what local delivery can achieve. The convergence of controlled-release coating technology, bioactive surface engineering, and improved pharmacokinetic understanding has produced a generation of drug-eluting orthopedic implants that deliver antibiotics, osteoinductive factors, or antiresorptive agents directly to the implant-bone interface over periods of days to months. This study presents the Drug-Eluting Orthopedic Implant Assessment Framework (DEOIAF), evaluating five drug-eluting implant platform types -- antibiotic-loaded bone cement and surface coatings (ABC-SC), PLGA microsphere-incorporated surface coatings (PLGA-SC), bioactive ceramic coatings with controlled drug release (BCC-CDR), bone morphogenetic protein-loaded scaffold platforms (BMP-SP), and hybrid drug-nanomaterial surface architectures (DNM-SA) -- across four orthopedic clinical contexts: primary total joint arthroplasty, revision arthroplasty for aseptic loosening, septic revision arthroplasty, and spinal fusion and trauma fixation. Performance was scored using the Orthopedic Drug-Elution Effectiveness Score (ODEES), a weighted composite of clinical efficacy (0.30), release profile control (0.20), mechanical integration (0.20), safety profile (0.15), and manufacturing feasibility (0.15). Antibiotic-loaded bone cement and surface coatings achieved the highest ODEES (0.887), driven by the strongest clinical evidence base in orthopedic infection prevention (0.920) and manufacturing feasibility (0.920). BMP-loaded scaffold platforms ranked second (0.874) with the best clinical efficacy in spinal fusion contexts (0.940). PLGA microsphere-incorporated coatings (0.863) achieved the best release profile control (0.920). Bioactive ceramic coatings (0.858) and hybrid nanomaterial architectures (0.831) showed strong technical performance but face manufacturing and regulatory translation challenges.