ABSTRACT
In a rabbit model of a weight bearing, articulating prosthetic joint we repeatedly injected submicron particles of Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) produced in a hip simulator. The contralateral knee with the same prosthesis was injected with carrier (NaCl) without UHMWPE. Histomorphometrical studies on undecalcified cut and ground sections at 26 and 42 weeks involved quantifications of the entire bone to metal contact and the bone area around each implant. We found no statistically significant differences between test and control groups, and the UHMWPE debris did not induce any significant osteolysis, indicating that an osseointegrated implant with a sealed interface may not be affected by UHMWPE debris or progress to aseptic loosening.
Subject(s)
Knee Prosthesis , Osteolysis/etiology , Polyethylenes/pharmacology , Humans , Prosthesis FailureABSTRACT
The addition of sodium fluoride to poly (methyl-methacrylate) (PMMA) bone cement may theoretically improve the fixation of joint replacement. This hypothesis was tested in an animal model using nine mature healthy lop-eared rabbits. A femoral prosthesis was inserted in both knees to resurface the patellofemoral articulation. The same acrylic cement, with and without sodium fluoride, was randomised between the two sides for prosthetic fixation. Two screw shaped implants machined from cured rods of either cement were also inserted bilaterally into the proximal tibia. Qualitative and quantitative histomorphometry of the bone tissue response surrounding the cement in the femur and the intact tibial implants revealed similar results regardless of sodium fluoride addition. Six weeks after surgery removal, torque did not significantly differ between the two sides. Our findings indicate that addition of sodium fluoride to PMMA has little effect on implant stability and bone remodeling in rabbits in the short-term.
