The invention relates to a connection device for connecting an implant system anchored in bone with an external prosthesis component, such as a limb prosthesis, prosthetic knee elbow or finger. The connection device includes a main housing, a first attachment portion arranged for attachment to the implant system and a second attachment portion arranged for attachment to the prosthesis component. It further includes a safety mechanism to protect the implant system from high mechanical forces, including rotational forces and or bending forces. According to one aspect of the invention the safety mechanism includes a rotational force release mechanism. This includes a first component including a ring unit having an inner surface with at least one depression and a second component includes at least one plunge unit urged into contact with said the depression by said spring means. According to another aspect the safety mechanism includes a bending force release mechanism with the second attachment portion being pivotable and having a spring loaded cam unit acting on a cam surface of the main hosing. According to a further aspect the safety mechanism is arranged to limit rotating forces as well as bending forces.