Can carbon fiber implants substitute for collateral ligament?

The biomechanic and histologic changes following replacement of the medial collateral digit of the knee with carbon fiber filament prostheses of varying diameters were studied in young rabbits. Biomechanic testing showed changes with time in the mode of failure and force to failure of the replacements, but the initial differences in the force to failure of the three diameter groups diminished over the 12-week experimental period. Histologic studies with both light and electron microscopy revealed resorption of the carbon fibers and replacement by fibrosed ligaments. There was a correlation between the change in mode of failure and force to failure and increased production, orientation, and organization of new collagen fibrils, as well as simultaneous fragmentation of the carbon fibers.