If the implants have been placed properly, squats should not affect the placement. The implant itself may break or crack with heavy lifting, but they will stay in place.
Dear Happy, Since you are 10 years after the butt implants surgery, the capsule (scar) around them is solid and strong, so you can not cause any harm by performing squats. I limit my patients in regard to intense physical activity after butt implants surgery to 6-8 weeks. After that time period, there are no limitation on any physical activity. You mentioned that your butt implants are "pretty low". If you are happy with that position, no problem, however if you would like to improve on the implants position, a new pocket can be created holding the implants higher, in a more attractive position. Obviously, you will have to go through a period of 8 weeks with no squats... I hope this helps, Dr Widder