A radiological and histological analysis of five knee joints after a minimum of 15 years following the implanting of carbon fibre which had been used as a treatment for knee instability was undertaken. All patients underwent Total Knee replacement for secondary osteoarthritis. Histological analysis demonstrated a variable amount of macroscopically visible carbon particles in the synovium, hyaline cartilage and menisci showed . At microscopy these particles were found enveloped by giant cells and lying quiescent with no active inflammatory changes. No intact carbon fibre ligament was noted within the joint, small portion of the old ligament were covered with a thin fibrous layer but there was no evidence of any structure resembling neo-ligament.

Extra articularly the carbon fibre was covered with a thick fibrous sheath with no active inflammatory changes inflammation. In the bone tunnels the carbon fibre- bone interface showed an apposition of the bone to the carbon fibre without any interposing fibrous sheath.

The histology suggests that carbon fibre bonds directly with the bone without fibrous interposition and that there is no evidence of synovitis changes related to the carbon fibre material.

The study suggest that although carbon fibre failed structurally as a ligament replacement it did not cause any significant long term inflammatory pathology.