An instrument (500) for use in applying a biological compound (24) to the porous surface of a prosthetic implant (10) to be implanted on to a surface of a bone includes a vessel (566) for containing the biological compound and a fixture (554,560) for surrounding the component. The fixture has a surface (562) for closely conforming to a portion of the surface (18) of said prosthetic implant having a porous structure, an inlet (576) and an opposed outlet. The instrument includes a first device (582) for advancing the biological compound from the vessel, into the inlet of the fixture and out of the outlet of the fixture.
