An implantable modular spacer device to treat an infected articular seat includes a stem element, a head or ball element, and coupling elements between the stem element and the head that include a plurality of elongated teeth, placed at pre-established distances from each other, and a plurality of housing seats for the teeth. An implantable spacer device to treat a bone seat or joint seat or for the two-step treatment of infections of joint prostheses includes a joint component adapted to be inserted in an articular zone of the patient and having an external surface, a stem component adapted to be implanted in a bone or in a residual bone bed of a preceding joint prosthesis, and adjustable connection elements, wherein at least part of the external surface of the first portion of the stem component and at least part of the external surface of the joint component define a contact surface with the bone tissue or adapted for coupling with the bone tissue. The connection elements are placed between the joint component and the stem component to adjust the distance thereof, and the contact surface in the joint component and/or in the stem component has a plurality of recesses or housing a filling material that includes a pharmaceutical or medical substance, wherein the plurality of recesses affects or is substantially placed along the entire contact surface or in proximity thereto.