This trial is conducted in Africa, Europe and Middle East. This trial investigates the efficacy and safety of three dose levels of Norditropin® (growth hormone) as compared to placebo in the treatment of tibia fractures. The trial will be conducted in two parts: in the first part, the patients will be evaluated with regard to efficacy (fracture healing) and safety at short time intervals until week 24 post-surgery. In the second part, long-term safety and fracture healing up to 12 months post-surgery will be evaluated.