Could a seat belt during a car accident have caused my reconstructed breast implant to move out of pocket behind the chest wall?

The force of the crash could have moved the implant out of the pocket however I think it's more likely that the implant was slowly, over years, being pushed into a position that wasn't ideal.  The implant itself tolerates reasonable forces however is not to be thought of as lifetime device and will need exchange/revision at some point.  Conversion to a DIEP flap is certainly an option.  Best Wishes!!!

A capsule forms around each and every breast implant and only a very severe blow to the chest would disrupt this capsule. Nevertheless this is a possibility.

It is possible for a reconstruction implant to move laterally due to blunt trauma. If there is a question contact your plastic surgeon. 

I had a patient several years ago who was involved in a motor vehicle accident as an unrestrained driver. She had an intact implant that move laterally. Revision surgery went fine and everything is back to normal.

There is a possibility that the accident could have caused implant displacement. It is hard to tell without more details and a formal exam. 

When an implant is placed; the body forms a thin layer of scar tissue around it called the capsule. An implant can move within the capsule, which usually keeps the implant more or less in the same position. It is possible for a capsule to stretch slowly over time and therefore allow the implant to move more freely. This is seen when women lay down and the implant falls excessively to the side. This is due to the capsule or pocket being stretched, not the implant actually moving out of the pocket. In an accident situation, I guess it is possible for the capsule to be torn or ruptured and the implant to move out of the capsule, but I would consider this very unlikely especially if there was no pain involved. One other thing that can happen is that the capsule can thicken and shrink around the implant, and force the implant into an unnatural position. (Usually upwards), but this is usually associated with increasing firmness of the breast implant and breast and is known as capsular contracture.

What does your chosen Plastic Surgeon say? Over the internet can not tell if there is a causal relationship to the accident. Only IN PERSON examination MIGHT allow a response...