A reinforcing implant anchors shafts of two prostheses which are arranged opposite each other on an elongated bone, in particular a femur. The implant has a generally elongated shaft-like shape and a receiving sleeve at both ends for a respective anchoring shaft and a disconnectable coupling piece lying between the receiving sleeves for a rigid connection. In this manner, a force bridge is formed between the two anchoring shafts so that the bone is no longer subjected to the force transmission in particular in the sensitive intermediate region between the two anchoring shafts.
