An implant system, in particular a modular implant system, such as a spinal implant system, comprising an implant part, for example a (spinal) plate, and at least one fastener, wherein the implant part has, for the fastener, a fastener receiving opening. The system also comprises thermoplastic material, the thermoplastic material being equipped for being liquefied by mechanical vibration, especially ultrasonic vibration energy. The fastener receiving opening and the fastener can be shaped so that the fastener can be inserted relative to the implant part at a variable angle. The fastener, the plate and the thermoplastic material are equipped for the thermoplastic material, after re-solidification, to secure the fastener against at least one of an axial (back-out) movement of the fastener, a rotation of the fastener relative to the implant part, a variation of the angle of the fastener relative to the implant part.
