Can Implants That Have Been Placed over the Muscle Be Replaced Behing the Muscle?

Implants placed behind the muscle have better coverage so they typically show less rippling than sublandular implants.  Also, submuscular position of implants have a lower risk of capsular contracture.  Change of pocket from subglandular to submuscular can be performed but, it has its inherant risks that must be discussed with the patient. 

Breast implant revision surgery is often about "site change", i.e. the change in placement of the breast implant from in front of the pec to behind the pec muscle.

A plastic surgeon experienced in revision surgery will be able to give you options as to what may be best in your particular case.

Women who have particularly thin breast also benefit from increasing the breast tissue thickness over the implant with fat transfer.