Will Filling out the Lateral Buttock with Fat Grafting Make my Hips Look Rounder? Im 23, 5'11 166lbs (photo)

Thanks for your question.  It looks like you would be a great candidate for fat grafting to the butt and hips based on your photos.  The fat grafting procedures also involve liposculpture of your mid section to give you the hourglass figure you are seeking.  Fat grafted to the hips has the same chance of survival as fat grafted to the buttocks.  Certainly, not all fat will survive the transfer, but fat on the hips is no more likely to resorb than fat on the butt.

Here is the "skinny" on fat transfer to the hips or buttocks: 

Liposuction aspiration collects a mixture of healthy fat cells, injured and disrupted ones which looks like oil, and the tumescent fluid consisting of local anesthetic, epinephrine and sterile saline. Only live healthy cells will survive and so they must be isolated first from the general liposuction harvested fat material.The Fat Transfer Procedure involves harvesting by  liposuction with a small cannula, rinsing with sterile saline solution and reinectiing it (lipoinjection or fat transfer) through a very small cannula (fine metal tube - like a needle with a blunt end and side hole) through a needle stick opening. There are many variations such as use of a centrifuge, and using enriched growth cell factors or enriched stem cells but at present I have not found this to be of benefit.
Of MOST IMPORTANCE is the selection of a skilled plastic surgeon who is board certified by the American Board of Plastic Surgery that has experience in this technique. For example injecting the fat with a large cannula or not distributing the fat in a manner so it is interspersed between healthy native fat cells will result in decreased survival, and injecting it too close to the skin can result in nodules that can be visible

Allow me to share with you what you may not hear from others.  Currently the only two safe and effective methods for Buttock (and Hip) Augmentation are Autologous Fat Transfer (transfer of your own fat to the buttocks, aka "Brazilian Butt Lift") and Buttock or Hip Implants (semi-solid soft silicone rubber implants).  Both are very good options so what it comes down to, like any surgery, is proper patient selection.  Indeed because at least 50+ % (and more for the hip area) of the fat transferred will melt away within a year, most patients are not good candidates because they lack an adequate amount of fat to harvest.  Thus buttock/hip implants become a very good, safe, predictable, and long-term reliable option for most patients seeking buttock augmentation (at least in my practice). For the Buttocks, I personally recommend either the round or the oval shaped implants dependent upon the natural anatomic shape of the patient's buttock cheeks.  The implant is typically inserted through a 2 ½ inch long incision over the tailbone (concealed within the crevice between the top of the buttock cheeks).  The implant should always be placed under or within the gluteus maximus muscle.  In this position, the implant is less palpable, less visible, and does not sag or shift/migrate over time unlike implants placed on top of the muscle.  For Hip Implants, there is no good muscle in this location to place the implant under so the implant must be precisely positioned under a connective tissue layer called "fascia" just on top of the muscle.  A small one inch incision is usually placed just below the belt-line directly above the hip region.

Because of all this, it is extremely important to seek consultation with a board certified plastic surgeon who specializes in this technique.  Additionally, in this type of surgeons hands the often quoted "high risks" of complications especially infection are actually much lower around 5%. Glad to help...RAS