An extracorporeally length-adjustable
implant system comprises – an
implant component (1) for an
implantable prosthesis, which is embodied to be fastened to a bone (90) to be lengthened and which comprises an adjustment device (2) with two fastening parts (21, 22) that are displaceable relative to one another, each of which is intended for arrangement at a part of the bone (90) to be lengthened, wherein the adjustment device (2) is embodied to distract the two fastening parts (21, 22) that are displaceable relative to one another and comprises a drive element (3) with a permanent
magnet arranged in rotationally movable fashion and a mechanism (4) which converts a rotational movement of the permanent
magnet into a distracting longitudinal movement of the adjustment device (2); and – an
extracorporeal drive unit (7, 7', 7") for the drive element of the
implant component (1). The
extracorporeal drive unit (7, 7', 7") comprises a rotatably mounted
extracorporeal magnetic ring (8) with an interior (80) embodied to receive the bone (90) to be lengthened with the adjustment device (2), and an actuation device (75) which is embodied to rotate the extracorporeal magnetic ring (8) in the
ring plane thereof, wherein the extracorporeal magnetic ring (8) is embodied as a permanent
magnet structure and has a directed static
magnetic field which is stationary with respect to the ring in its interior, and the extracorporeal magnetic ring (8) is mechanically rotated by the actuation device (75). Thus, the invention attains an increase in the adjustment reliability while simplifying the drive unit at the same time, and hence it is rendered suitable for laymen and patients.