Primary endpoints are arginine and Nitric Oxide levels in the plasma during normal and dysfunctional fracture healing the bone in patients with and without non-union Secondary endpoints are levels of Nitric Oxide citrulline, ornithine and other amino acids in bone and in plasma Other parameters: baseline demography details will be obtained, including possible confounders, such as bodyweight, smoking, alcohol abuse, which may interfere with the outcome of this study.