A blurred fracture line means that there is a sufficiently scabbed connection between the fractures, and the fracture site is well stabilized against rotational and lateral shear forces, and generally does not become displaced. Of course, re-fracture and displacement of the fracture can occur under certain circumstances, such as during strenuous physical activity, which can place a large load on the fracture site, and if the bone scab is not strong enough, the scab can break and re-fracture the fracture. In addition, if you fall again in the middle of an activity and the injury is at the same fracture site, it may cause re-fracture and fracture displacement.