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If you are 21 years old, then your bones have fused and you have attained your adult height. Limb lengthening orthopedic surgeries using Ilizarov's technique may be undertaken, but the procedure required a whole 1 yr of bed rest
and pain suppression, during which a maximum of 7-9 cm of lengthening can be achieved. You will have to search for centers in India that undertake the surgery, as it is not done in most hospitals.