Moldable bone implants for use in a bone defect or wound include a plurality of biocompatible granules and a biocompatible polymer that together form an implant mass. The polymer is softened with a plasticizer to make the implant mass moldable. The plasticizer can dissipate or be extracted to cause the implant mass to harden. The implant mass can be shaped in-situ or ex-situ. Implants formed in-situ are shaped by the bone defect or wound. The implant becomes hard through contact with body fluids, which extracts the plasticizer from the implant mass. Bone implants formed ex-situ, such as in a mold, are shaped by a mold, for example, and then hardened by placing the implant mass in contact with a hardening agent, such as water, which extracts the plasticizer from the implant mass. The shaped, hardened implant can be placed into a bone defect of corresponding size and shape.