Can a MEDPOR Chin Implant Be Removed?

Julie, Chin implants can be removed. If it is smooth, it is easier to remove. If it is porous, the tissue ingrowth makes it more difficult to remove. If there was some technical error on the surgeon's part, it would not be unreasonable to expect to only pay for the hospital fees for the removal.
However, if you suffered some event (trauma for example) after the surgery which caused the implant to shift, then this should not be the surgeon's responsibility.

Yes, Medpor implants can be removed and you are right that at times because of tissue ingrowth it is a bit more involved usually than removing a silicone implant.

At two years following surgery there most likely will be a charge for this surgery.

I have removed Medpor chin implants, but it is much more difficult as the porous surface allows ingrowth of tissue which must be dissected away.  If you are reasonably happy with your current implant, there is an argument to leave well enough alone.   After an examination, your surgeon can make a more accurate recommendation.

Removing/replacing a medpor implant is not easy and may require more time than you would think.  I prefer using silicone implants.

Although it is time consuming, it is possible to either remove or modify a Medpor implant.  Medpor implants are characterized by tissue in growth which solidly fixes the implant to the bone.  Because of this, removal requires the entire implant to be carefully dissected.  With solid silicone, in contrast, removal generally only requires the capsule to be opened and the implant will pop right out.  Generally after removal, the chin is quite swollen and firm for a while.  In addition, the sensation nerve is at risk of injury and you may end up with a numb chin.

It sounds as though your problem is a technical one with the original surgery.  Most plastic surgeons will not charge a surgical fee for correcting this type of issue but you need to have a frank discussion with your doctor.