Callus distraction is an enrichment of the surgical orthopaedic way of reconstructing bone defects, but it is also an effective method of lengthening limbs. The biological facts correspond to our knowledge about fracture healing. Concerning apparatures, further development is needed. In certain cases the ring fixator is the method of choice, but in most indications it is not necessary. Every effort should be made to adapt modern technologies, including fully implantable systems, to the "biological method" of callus distraction, whenever possible.