What are the limitations for having breasts up-lifted
(Mastopexy)?

Because it is not possible to recreate the natural attachment of the
breast to the tissues underneath, a mastopexy alone will not greatly
increase the fullness of the breasts above the nipples. Fullness above the nipples can be achieved, however, by increasing the size of the breasts with silicone implants.

The extra weight of the silicone implants may accelerate the return of the droopiness of the breasts and in any event there is a tendency for the breast to sink downwards as time goes by. You can lessen the rate at which this happens by supporting your breasts in a bra as much as possible.