Method of attaching a modular femoral head to the neck of a hip stem prosthesis for the preventation of corrosion therebetween

摘要

The method includes the steps of providing a thin layer of a thermoplastic polymer on the outer mating surface of the femoral neck 8. To assemble the femoral head 12 and neck 8, the head 12 is placed onto the neck 8 and the assembly is heated to a temperature of approximately 800 degrees Fahrenheit. At this temperature, the thermoplastic polymer becomes molten and exhibits exceptional adhesive characteristics. Once the thermoplastic is in its molten state, the femoral head 12 is impacted onto the neck by known instrumentation. Impacting provides a tight mechanical connection between the mating parts. Once impacted, the assembly is permitted to cool to ambient temperature which transforms the thermoplastic polymer into its solid state. The thermoplastic polymer chemically bonds the mating parts together and exhibits a strength at the junction around 10 ksi.;The use of the thin layer of thermoplastic polymer also forms a uniform contact surface between the mating parts to allow for stress transfer across the entire mating surface and thereby reduces the overall transfer of stress per unit area. The bond created between the mating parts further forms a barrier to moisture to prevent corrosion or fretting between the mating surfaces.