This study was performed to determine the safety and effectiveness of lengthening of the tibia, in patients who have a limb-length discrepancy or a short stature, with use of distraction osteogenesis, a technique based on the principle of distracting the callus that is formed after a subperiosteal osteotomy of the proximal portion of the diaphysis of a long bone. A total of 230 tibial lengthening procedures were done in 150 patients. Seventy procedures were performed because of a limb-length discrepancy, which was secondary to trauma (thirty limbs), congenital fibular hemimelia (twenty-six), poliomyelitis (ten), or infection (four). The remaining 160 procedures were performed because of a short stature, which was secondary to achondroplasia (fifty-eight limbs), Turner syndrome (thirty-four), an idiopathic etiology (twenty-two), hypochondroplasia (twenty), achondroplasia (ten), Ellis-van Creveld syndrome (six), rickets (four), or adrenogenital syndrome, Laron syndrome, or pseudoachondroplasia (two limbs each). The age of the patients at the time of the operation was 18.4+/-6.2 years (average and standard deviation), with a range of six to forty-one years. The procedures were performed according to one of three protocols. In Group A (ninety procedures), an Orthofix telescopic fixator and a variable number of screws were used and the tibiofibular syndesmosis was not stabilized; in Group B (ninety-six procedures), an Orthofix reconstruction system was used, the syndesmosis was stabilized, and a tenotomy of the Achilles tendon was performed; and in Group C (forty-four procedures), an Orthofix Garches lengthening device was used, the syndesmosis was stabilized, and a tenotomy of the Achilles tendon was performed. At the time of the latest follow-up (average, five years; range, two to seven years), the average gain in length after the seventy procedures performed because of a limb-length discrepancy was 4.0+/-1.98 centimeters (range, 2.5 to 9.5 centimeters), or 14 percent (range, 7 to 45 percent). The average gain in length after the 160 procedures that were performed because of a short stature was 7.8+/-2.28 centimeters (range, 2.5 to fifteen centimeters), or 33 percent (range, 10 to 78 percent). Ten (14 percent) of the seventy procedures performed because of a limb-length discrepancy and forty-six (29 percent) of the 160 performed because of a short stature were associated with a complication. There was only one permanent sequela in the entire series. Although the three operative protocols resulted in similar healing indices, the rates of complications differed significantly among the groups (p<0.0001). Group C (the Garches device) had the lowest rate of complications (7 percent). It is important to be aware of potential complications as well as the need for additional procedures in order to avoid predictable problems. These procedures include percutaneous tenotomy of the Achilles tendon and fixation of the distal segment of the fibula to the tibia to maintain the integrity of the tibiotalar articulation and the alignment of the foot.