Gateshead rods are tiny carbon fibre rods used in the 1980s, and which were inserted into drill holes on damaged joint cartilage to encourage the passage of repair cells from the underlying bone marrow.
Evaluation of Gateshead carbon fibre rod as an implant material for repair of osteochondral defects: a morphological and mechanical study in the rabbit knee. Qiu YS, Shahgaldi BF, Revell WJ and Heatley FW. Biomaterials. 2002 Oct;23(19):3943-55.