For decades, external fixation was the best option for limb lengthening. Recent advances have resulted in alternatives that decrease complications associated with external fixation and show improved results. Internal limb lengthening uses the PRECICE system for limb lengthening of the femur and tibia. This system uses the principles of bone regeneration (distraction osteogenesis) to pull segments of the bone apart and stimulate new bone formation. Once the system has been placed, gradual limb lengthening with internal fixation uses a non-invasive method to lengthen the nails. This type of limb lengthening is associated with less pain and more comfort for patients.