This is a good question for a tough problem.  There are many “fixes” for implants that have problems such as malposition, sliding, symmastia, rippling, capsule contracture, bottoming out and asymmetry.
I have found that a good starting point is choosing the best implant available on the market.  Like many other problems in life, starting with the best available product goes a long way to either deal with or mask many concerns or problems.  For this reason, I use Sientra breast implants.  They have a 20 year warranty, the lowest capsule contracture rate of all implants in the industry and their naturally feeling gummy bear implants come in many shapes and sizes to help your surgeon match your goals.  Sientra’s textured implants can also be placed above the muscle to avoid muscle animation deformity.  The Velcro effect of the textured surface allows the use of much different sized implants than conventional breast implants without having to use internal slings or bras such as an acellular dermal matrix.
I have used these implants in many revision breast augmentation surgery cases with excellent success.