Predictability in breast surgery: are breast implants more "predictable" than fat grafting?
December 20, 2022
July 31, 2023
By Dr. Andrew Campbell-Lloyd

Predictability in breast surgery: are breast implants more "predictable" than fat grafting?

Something I hear often (and I watched yet another plastic surgeon repeating this on their social media this morning) is that breast implants are more "predictable" than fat transfer.

That seems such a silly comparison to me, and it got me thinking about what it means for an operation to be "predictable".

Now, generally I try to avoid looking at social media, and I especially try to avoid looking at other plastic surgeons on social media. I don't follow plastic surgeons as a rule (with the exception of a few friends). I don't find any use in 'comparing' myself to my colleagues, and I find myself incredibly frustrated by a lot of what comes up. But every now and then I do go down that rabbit hole, and when I come out again I either have a solid dose of "ick" or I am frustrated by my own profession, both of which are not very useful things.

Ok, so let's start off with what predictable means in the context of breast surgery, and then we'll get onto the question of implants vs. fat graft.

So, when a surgeon talks about predictability in surgery, we are generally talking about our (and therefore our patients') ability to predict an outcome from surgery. So we're talking about expectation management in some respects. The breast will be a certain size, or a certain shape, or have a certain feel, or whatever. But there is more to it obviously. We're talking about a question of control: to what extent can we anticipate certain changes will take place as a direct consequence of the surgical manoeuvres we make. We're also talking about reproducibility: can we ensure that our outcomes will be same when we do the same thing in two (or more) different patients.

Now all of those issues are absolutely vital considerations when a surgeon proposes any operation to a patient, especially when it is an elective cosmetic procedure.

If we take those concepts of predictability and then apply them to breast implants and fat transfer, there are some interesting points to consider.

Breast implants are often said to be "predictable", but that only applies a very narrow definition of the word. Let's break it down to make a few things clear.

Breast implants vs. Fat transfer

First things first: the comparison is a false one. Any surgeon who tries to compare these two things is comparing apples and oranges. There are things that implants can do (like adding 500cc of volume in a single operation) to a breast that fat transfer cannot. The two things create totally different outcomes, for totally different patients, and surgeons should be setting patients' expectations in that way. But let's continue with this "comparison" for the sake of argument.

Volume: Implants = predictable; Fat transfer = relatively predictable.

  • The volume of a breast implant is predictable and stable over time. It is one of the main arguments for the use of an implant in certain situations. A 300cc silicone breast implants is never anything other than a 300cc silicone breast implant.
  • Fat transfer is subject to variability in volume retention. With careful technique a surgeon can typically expect approximately 2/3-3/4 of any injected fat graft to survive. It is commonly reported that fat transfer can reliably offer a 1 cup size increase in breast size. There is some uncertainty, but it is relatively predictable provided the surgeon knows what they are doing and is honest with their patients.

Shape: Implants = predictable; Fat transfer = predictable, but relies on the shape of the breast.

  • A breast implant has a certain shape and many surgeons will argue that the shape of the implant can "force" the breast to change in ways we might consider useful. There is an element of truth to this, but it is also a fact that breast implants can be distorted and become misshapen under the influence of capsular contracture, and muscle contraction, and certain anatomical features (the inframammary crease in particular) will not be amenable to being reshaped in all patients. However, breast implants do allow a certain degree of "reshaping" in properly selected patients.
  • Fat transfer relies on the shape of the breast into which it is being injected. Fundamentally, fat transfer does not have any "structural" properties. It is not "form-stable" like a silicone implant. A useful although somewhat glib analogy is that a breast implant is akin to making sand-castles with wet sand. Fat transfer on the other hand is like trying to make a sand-castle with dry sand. Unless the fat graft position is controlled by the breast (we can consider the pre-existing breast shape to be our metaphorical bucket for our sand), then there is no way of controlling the shape of the graft itself. This is why as a stand alone technique, fat transfer requires the patient to be content with their breast shape. If they are not, then a mastopexy combined with a fat transfer is necessary.

Position: Implants = UNPREDICTABLE; Fat transfer = predictable.

  • Breast implants ARE NOT STABLE IN POSITION OVER TIME. Ever. Despite all the arguments over the years about using textured implants to "stick" the implant in place like using velcro, or that the dual-plane pocket allows the implant to be "gripped" between the Pec major and Pec minor muscles, there is no way of ensuring that an inorganic silicone foreign body will stay where you want it to stay. Sorry. Having said that, breast implants will tend to create fullness where nature never intended it to be. That is, in the upper pole. That is a unique property of breast implants and it is why, for a woman who wishes to add upper pole fullness as a priority, fat transfer will not be a suitable stand-alone option. Will that fullness stay there over time? To some extent yes. I think it is also fair to say that for ladies with sub-pectoral/dual-plane breast implants, the upper pole fullness can then be exacerbated by capsular contracture which tends to pull the implant up, and often does so asymmetrically, so that one breast sits higher than the other.
  • Fat transfer will tend to preferentially add volume to the lower half of the breast. Despite attempts to position the graft higher in the breast, it doesn't tend to allow a surgeon the ability to add upper pole volume or roundness. The most obvious effects of fat transfer are in the expansion of the lower pole and increased projection behind the nipple. Once the fat transfer has settled, because it is natural tissue, it offers the benefit of acting predictably just as a natural breast would, over time. The fat transfer is not subjected to the same time-based risk of complications as breast implants.

Progression: Implants = UNPREDICTABLE; Fat transfer = predictable.

  • Breast implants ALWAYS CHANGE OVER TIME. It is unpredictable how they will change, and it is unpredictable when they will change. I have seen ladies with 20 year old implants that remain soft, comfortable and aesthetically pleasing to them. I have seen ladies with 2 year old implants that are contracted and hard, and I have seen ladies with 3 month old implants that have dropped, shifted or changed shape. So much for predictability.
  • Fat transfer (as I said above) is natural. It simply adds natural volume to a pre-existing breast shape. There is no progression over time beyond the change that the breast would otherwise have demonstrated. That is predictable.

Movement: Implants = predictably unnatural. Fat transfer = predictably natural.

  • Breast implants do not move like natural breasts because they aren't. Simple. The most obvious concern with the movement of the implants relates to "animation" deformities seen with subpectoral placement.
  • Fat transfer moves with the breast because it is fundamentally part of the breast. Also predictable.

Interaction with the breast: Implants = UNPREDICTABLE. Fat transfer = predictable.

  • A breast implant is, by definition, a foreign body. Breast implants behave very differently to natural breast tissue. That is why over time there is a tendency for the breast (which becomes looser with time) and the implant (which tends to become firmer with time) to experience a "dissociation". This is exacerbated by sub-pectoral placement which predisposes women to a "waterfall" deformity as the breast changes with age, pregnancy and breastfeeding, and weight fluctuation.
  • Fat transfer, once it has developed a new blood supply, is biologically incorporated into the natural breast tissue. There is no separation, no distinction between the two.  

Future Surgery: Implants = ABSOLUTE GUARANTEE of requiring future surgery; Fat transfer = not associated with a requirement for future surgery.

  • The ONLY predictable, 100% guaranteed aspect of having breast implants is that a woman will need another procedure at some point in the future. There are NO other absolute guarantees that can be offered in with respect to breast implants. Surgeons can make whatever claims they want (and they do), but if you take away all the bullshit, this is what it comes down to.

I recently read on a plastic surgeon's social media, the following claim:

Here is one of Australia's most "prominent" (if by prominent we mean 'followed') plastic surgeons making a pretty wild claim, as though through their sheer brilliance they can control a biological process like the response of the body to a silicone breast implant.

Is one better than the other?


This is the thing that bothers me - breast implants and fat transfer are fundamentally different operations that have different goals. Fat transfer can be used as an adjunct to breast implants in some patients and this can be very effective. But I do get frustrated at surgeons who try to draw a direct comparison between the two.

The reality is that breast implants remain an essential tool for plastic surgeons in overcoming certain issues and for many women they are an excellent option, offering long term positive outcomes and high satisfaction.

This isn't a question of one operation over the other.

I choose not to do primary cosmetic breast augmentation for my own reasons, and I am not here to tell anyone that breast implants (or the surgeons who use them) are necessarily bad.

But some of the stuff that people say online IS bad. It's wrong, it's disingenuous and it is often frankly silly.

Breast implants can be good, they can be bad. Fat graft can be good, it can be bad. It isn't the tool that should be questioned, it is the tradesman.

If a surgeon can't get a given outcome with fat graft, then either they don't know what they're doing, they picked the wrong patient for the technique, or they picked the wrong technique for the job. Same goes for breast implants.

It is fair to say that surgeons can modify the body's response to an implant, and in many ways we can mitigate the risk of complications including capsular contracture, but ultimately we can never control the effect of a breast implant over time.

So when a surgeon claims that breast implants are more predictable, keep some of this stuff in mind. Predictable means many things.

Predictably, I would argue, breast implants are unpredictable. They can, however, still be very useful.

Good luck out there.