A method of manufacturing a surgical instrument or prosthesis and a surgical instrument or prosthesis so manufactured are described. A first material is injected into a first mould to form an interim component. Portions of the interim component define at least one channel. The maximum wall thickness of the interim component is less than a first threshold determined by the injection moulding properties of the first material. The maximum width of the at least one channel is less than a second threshold determined by the injection moulding properties of a second material. The second material is injected into a second mould containing at least part of the channel of the interim component so that the channel is at least partially filled with the second material.
