At our center these fractures are managed by Plastic's rather than Orthopedics. When I was rotating through last month I asked one of the surgeons this question and the answer took about an hour. Ultimately, the more proximal along the shaft the more deformity that results. 45 degrees might be acceptable at the distal end of the shaft, but would result in substantially more difficulty the more proximal it occurs. This, along with consideration of metacarpal placement (is it angulated into the palm so that it will inhibit the patient's grip?), the patient's functional need and the patient's preference would guide my management strategy. Regardless, they would be referred for follow-up by Plastic's (ideally within 1 week, necessarily within 3 weeks).