Aesthetically speaking it might be better for you...allow an improved aesthetic result if you waited a year after the orthognathic surgery before having the Cheeks Augmented with Cheek Implants. The orhtognathic surgery can sometimes have bone cuts along the lower edge of the cheek bones that might interfere with the implant placement. In addition, aesthetically as the jaw and the maxilla are moved...the degree of Cheek Augmentation desired will change...hence the 1 year wait. In fact, I just did a case a few days ago where the orthognathic procedure was done many years ago and we placed the implants were easilly for the desired aesthetic result. Hope this helps.
Web reference: http://www.drfpalmer.com