The performance of carbon fiber-reinforced ultra-high molecular weight
polyethylene was compared with that of plain (non-reinforced) polyethylene
on the basis of the damage that was observed on the articulating surfaces
of retrieved tibial components of total knee prostheses. Established
microscopy techniques for subjectively grading the presence and extent of
surface damage and the histological structure of the surrounding tissues
were used to evaluate twenty-six carbon fiber-reinforced and twenty plain
polyethylene components that had been retrieved after an average of
twenty-one months of implantation. All of the tibial components were from
the same design of total knee replacement. The two groups of patients from
whom the components were retrieved did not differ with regard to weight,
the length of time that the component had been implanted, the radiographic
position and angular alignment of the component, the original diagnosis, or
the reason for removal of the component. The amounts and types of damage
that were observed did not differ for the two materials. For both
materials, the amount of damage was directly related to the length of time
that the component had been implanted. The histological appearance of
tissues from the area around the component did not differ for the two
materials, except for the presence of fragments of carbon fiber in many of
the samples from the areas around carbon fiber-reinforced components.