Can breast implants that were placed under the muscle come out from under that muscle?

Hello,In my experience this is very rare but it would be possible especially for very large implants as less of the implant surface would be covered and secured by the muscle. Talk with your Plastic Surgeon in person if you think that you have an implant issue.All the best

In the case of submuscular implants, only the top of the implant is covered by muscle. The lower aspect of the implant is under gland, fat and skin. In the case of large implants, it is possible for the skin to stretch to the point that the implant comes out from under the muscle entirely. With smooth gel implants this is more likely. The result is rippling, sagging, and a general undesirable breast shape. This can be corrected but usually requires skin reduction and placement of a smaller textured implant. . 

Thank you for your question.  When breast implants are placed under the chest muscle they are not usually completely covered by the muscle.  In the most common operation the bottom of the muscle is left open and the implant drops partially below the muscle.  In most cases only 1/2-2/3 of the implant is totally covered by muscle. This is the preferred situation which allows the breast to form a normal shape with fullness beneath and below the nipple areola.