You can gain up to 3 inches with a single bilateral limb lengthening surgery, ... Or be exact: Femurs (Thighs): 6 - 8 cms Tibias (Calfs) : 5 - 7 cms However, you may even opt to have two limb-lengthening surgeries, with a gap of 3/6 months between the two surgeries, and gain up to 6 inches or 12 - 15 cm. The doctors practice limb lengthening surgery with 4 methods, each varying in costs, post-surgery recovery time, and patient comfort. Please note that the height gains are similar with all methods, internal, external, and combination methods. The reason is that the height gain is dependant on the flexibility of the patient's leg muscles and nerves. Anything more than 8 cm on femurs and 7 cm on the Tibias, increases the risk of muscular or nerve damage.