The invention concerns a prosthesis comprising: a stem part comprising: a rod, configured for being inserted into a medullary cavity of a diaphyseal fragment of a fractured long bone, for securing the stem part to the diaphyseal fragment, and an epiphyseal end, fixedly secured to the rod by means of at least one linker leg of the stem part, so that a gap is formed between the epiphyseal end and the rod along said at least one linker leg； and an implant distinct from the stem part and comprising: an internal part located at least partially within the gap, and at least one fastener for fastening epiphyseal fragments of the fractured long bone to the stem part, said at least one fastener being secured to the internal part.
