Crooked nose after Rhinoplasty; why does that happen?

The nose is a complex structure consisting of  a small pair of bones, a pair of triangular cartilages in the middle, and a pair of horse shoe shaped cartilages in the tip, all supported by a thin piece of cartilage and bone called the septum.These structures can be weakened from previous trauma. After a rhinoplasty, the nose swells during the first 48 hours. It takes up to a year for all the swelling to disappear. During this time the nose can shift and settle, and look crooked. Most of the time, the nose will straighten as the final swelling leaves. Occasionally due to the strength of the cartilages, heaviness of the skin, possibly recurrence of a deviation of the septum as the healing proceeds, the nose may heal with asymmetries. If the surgeon used some grafts and they did not survive, this could account for asymmetries. Patient behaviors such as getting it bumped, or sleeping on one's side can cause asymmetries as well. Recovery from nose surgery requires patience- waiting a full year to see the final result. 

You have to understand that nose is a 3-Dimensional structure. The structure that determines the straightness is the nasal septum which is made of bone and cartilage. The cartilage has memory and spring back tendency. If one has a preexisting septal deviation and  if that condition is not addressed during rhinoplasty the nose will eventual veer to the side of the deviation. It is not "environmental" due to global warming etc. Incomplete evaluation and treatment is the cause.

 In our rhinoplasty practice, we have seen the very same thing happen in a few patients where the nose looked straight at 2-4 months after the procedure, and  then it started to become crooked. A touch up rhinoplasty was required to straighten the nose back to its  straight position. This is related to the healing processes and forces of contraction of the skin tissue envelope over the cartilaginous framework of the nose. Pre-existing warped cartilage can also cause this to occur. Rhinoplasty is a difficult endeavor, so choose your surgeon based on extensive experience. Even the most experienced surgeons will have  to perform touchups on a percentage of their  rhinoplasty patients.