Round or anatomical implants: how to choose the right shape for your breast augmentation

What are round implants?

Round implants have a symmetrical shape, with the same volume along every axis. They are designed to give projection both in the upper pole (the top of the breast) and in the lower, producing an effect of fullness in the cleavage.

Advantages of the round implant:

• More volume in the upper pole: ideal for patients wanting a marked, visible cleavage.
• Complete symmetry: should it rotate, the visual result is unaffected, since its shape is constant.
• Wide availability: there are many sizes and projections within this category.
• Easier to place: they adapt to various surgical techniques, in both the submuscular and the subglandular plane.

Points to bear in mind:

• In very slim patients, or those with little breast tissue, they can show more if the plane of placement and the firmness of the silicone gel are not well chosen.
• The effect can look less natural where a soft transition between chest and breast is wanted, particularly if implants with high or ultra-high projections are chosen.

What are anatomical implants?

Also known as teardrop implants, anatomical implants mimic the natural shape of the female breast. They have a wider base and more marked projection in the lower part, which allows a more gradual slope and a more realistic profile.

Advantages of the anatomical implant:

• A more natural result: above all in profile, since it respects the natural proportions of the breast.
• Indicated in tuberous breasts and in reconstruction: they allow the lower pole to be shaped precisely.
• Less volume in the upper pole: ideal for anyone wanting a more discreet or less marked shape.

Points to bear in mind:

• Should it rotate, it can change the shape of the breast, which sometimes calls for further surgery.
• They usually have a rough surface to prevent movement, which means a more precise surgical technique.
• They require a more rigorous anatomical assessment to ensure they fit properly.

A visual comparison, and results

The most evident difference between the two types is the visual result at the cleavage. Round implants produce a fuller, higher cleavage, while anatomical ones offer a gentler slope from the chest to the nipple.

The choice depends on factors such as:

• The amount of existing breast tissue.
• The patient’s height and build.
• The volume wanted.
• The shape and proportions of the chest.
• Personal expectations (a natural effect or a marked cleavage).
• Lifestyle (whether high-impact sport is played frequently, for example).
• Tolerance of the risk of rotation if an anatomical implant is chosen.

Which type do patients choose most?

Most women having a breast augmentation for aesthetic reasons tend to choose round implants. They are after a visible improvement in volume and cleavage, with proportionate results. Anatomical implants, by contrast, are indicated more often in reconstructive surgery or where the patient wants a breast with a more natural upper pole, particularly in patients starting from breasts with little volume.

These days we frequently speak of ergonomic implants, meaning round implants with softer cohesive gels that allow more natural behaviour in the upper pole, closely resembling that of anatomical implants, while avoiding the risk of complications from the implant rotating and giving results that feel very natural to the touch.

There is no universally better option, only an individual choice. What is ideal for one woman may not be for another. That is why it is essential that the surgeon analyses each patient’s anatomy and aesthetic goals before proposing a shape of implant.

Does the shape affect how long the result lasts?

Both types of implant have similar durability when high-quality materials are used and they are placed properly. What differs is how they behave visually as time goes on. With round implants, the upper pole can keep a more constant projection, while anatomical ones keep their natural slope even as the tissues age.

It is important to understand that the result will also depend on lifestyle, on future pregnancies, on the elasticity of the skin and on the surgical technique used.

Can you tell the difference? What the best study available says

This is the question that really matters, and it has an answer with a name attached. In 2017 a randomised trial was published in which 75 patients had a round implant in one breast and an anatomical one in the other during the same operation. Both sides were photographed in theatre and the images shown, without saying which was which, to ten plastic surgeons and ten people outside the profession.

• The surgeons saw no difference at all in 43.6% of cases; the lay observers, in 29.2%.
• Where they did see a difference, neither group systematically preferred the anatomical side: the surgeons judged it superior in 51.1% of cases against 48.9% for the round, with no statistical significance.
• And the most uncomfortable figure: the surgeons correctly identified which shape each implant was only 26.5% of the time.

It is worth understanding what this means and what it does not. It does not mean the shape of the implant is irrelevant, but that in a breast with sufficient cover the result is governed by the pocket, the breast base and the volume, not by the profile of the implant: once it is in and the patient is standing, the anatomical behaves largely like the round.

What the anatomical implant obliges you to accept

An anatomical implant has a top and a bottom, so if it turns, it shows. To stop it turning it has to grip the tissues, and that is achieved with a textured surface: a smooth anatomical implant is not a real option.

That risk deserves a name, because it is the one most likely to show itself: rotation of the implant. If an anatomical implant turns on its axis, the volume intended for the lower pole ends up where it should not be and the breast changes shape: an asymmetry or an odd contour appears that was not there on leaving theatre. It is more likely in the first few weeks, before the capsule has finished forming, and where the pocket is a little larger than the implant. And it has a further drawback: it is not corrected by massage or by waiting — it means going back to theatre to reorient the implant, adjust the pocket or replace it with a round one. With a round implant this complication simply does not exist: however it turns, its shape is the same.

That detail matters, because the risk of implant-associated anaplastic large cell lymphoma is not the same for every surface: it follows a gradient of roughness. In the Australian and New Zealand registry, with 81 confirmed cases, the more aggressive textures showed a far higher risk than the microtextured ones — 16.5 times that of a Siltex in the case of Biocell and 23.4 times in the case of polyurethane.

That figure has to be read carefully, because it is more alarming than it should be: these are risks of some surfaces relative to others, not absolute figures, and the reference they are compared with — the microtextured implant — is at the low end. The implants withdrawn from the market in 2019 were Allergan’s Biocell range, those with the most aggressive texture. The micro- and nanotextured surfaces used today carry a far lower risk, and in certain indications — a breast lift with an implant, for example — they are worth using to optimise the result.

The practical conclusion is not that the anatomical implant is worse, but that choosing it is not free: it obliges a rougher surface and adds the risk of rotation. So in a standard augmentation with good cover, a round implant is a reasonable choice; and the anatomical shape is reserved for cases where the problem to be solved is the vertical distribution of volume: tuberous breasts, narrow bases with a short lower pole, or reconstruction.

The medical consultation: a shared decision

At the Instituto de Cirugía Plástica del Mediterráneo we carry out a detailed assessment of each case, analysing not only the physical aspect but also the patient’s motivations and preferences. During the consultation we show physical models, before-and-after images and volume trials, to help each woman visualise the effect of both options and make an informed decision.

We also explain the adjustments that follow from the type of implant chosen, such as the most suitable plane of placement, whether an associated breast lift is needed, and the follow-up afterwards.

Choosing between a round and an anatomical implant is an important decision in a breast augmentation. It is not only about appearance but about anatomical fit, safety and personal expectations. While round implants offer a fuller cleavage and a more marked shape, anatomical ones give a more natural and realistic profile.

In both cases, success depends on precise surgical planning and clear communication between patient and surgeon. If you are considering a breast augmentation and have doubts about which shape to choose, we invite you to a consultation at our clinic in Valencia, where we will help you make the best decision for you.

Frequently asked questions

What visual difference is there between a round and an anatomical implant?

The shape of the implant defines the silhouette of the cleavage, beyond the volume or the plane. The round one spreads the volume evenly and gives a fuller, higher cleavage; the anatomical one concentrates the volume in the lower pole and leaves a gentler slope from the chest to the nipple.

Is the difference really noticeable?

Less than people think, and there is an excellent study. In 2017 a randomised trial was published in which 75 patients had a round implant in one breast and an anatomical one in the other during the same operation, and the photographs were shown blind to ten plastic surgeons and ten lay people. The surgeons saw no difference at all in 43.6% of cases; the lay observers, in 29.2%.

And when they did notice, which did they prefer?

Neither group consistently preferred the anatomical side: the surgeons rated it superior in 51.1% against 48.9% for the round one, with no statistical significance. And the most uncomfortable finding: the surgeons correctly identified which shape each implant was only 26.5% of the time.

Does that mean the shape is irrelevant?

No. It means that in a breast with enough cover the result is governed by the pocket, the breast base and the volume, not by the profile of the implant: once inside and with the patient standing, the anatomical one largely behaves like the round one.

What happens if an anatomical implant rotates?

The volume intended for the lower pole ends up where it should not be and the breast changes shape: an asymmetry or an odd contour appears. It is more likely in the first weeks, before the capsule finishes forming. And it is not corrected with massage or by waiting: it means going back to theatre to reorient the implant, adjust the pocket or replace it with a round one. With a round implant this complication simply does not exist.

Can an anatomical implant be smooth?

No. An anatomical implant has a top and a bottom, so it needs to grip the tissues in order not to turn, and that requires a textured surface: the smooth anatomical implant does not exist as a real option.

Does that have safety implications?

The risk of implant-associated anaplastic large cell lymphoma follows a gradient of roughness. In the Australian and New Zealand registry, with 81 confirmed cases, the most aggressive textures showed risks far above those of a microtextured implant — 16.5 times for Biocell and 23.4 for polyurethane. These are risks of some surfaces relative to others, not absolute figures. Biocell implants were withdrawn in 2019; the micro- and nanotextured surfaces used today carry a much lower risk.

Is there a middle option?

Yes: the so-called ergonomic implants, which are round with a softer cohesive gel. They achieve a natural-looking upper pole, very close to that of anatomical implants, without the risk of rotation and with a very natural feel.

So when is an anatomical implant chosen?

When the problem to solve is the vertical distribution of the volume: tuberous breasts, narrow bases with a short lower pole, or reconstruction. In a standard augmentation with good cover, the round implant is a reasonable choice. It is not that the anatomical one is worse, it is that choosing it is not free.

Does the shape affect how long the result lasts?

Durability is similar in both with quality materials and correct placement. What changes is the visual behaviour over time, and lifestyle, future pregnancies, skin elasticity and surgical technique also come into it.

What is taken into account in deciding?

The amount of existing breast tissue, the patient’s height and build, the volume wanted, the shape and proportions of the chest, personal expectations, the type of life — for example whether impact sport is played — and the tolerance of the risk of rotation if an anatomical implant is chosen.

Sources

• Hidalgo DA, Weinstein AL. Intraoperative Comparison of Anatomical versus Round Implants in Breast Augmentation: A Randomized Controlled Trial. Plast Reconstr Surg. 2017;139(3):587-596. PMID 28234826 — 75 patients with one implant of each shape in each breast, assessed blind by 10 surgeons and 10 lay observers: no aesthetic superiority for the anatomical implant.
• Magnusson M, Beath K, Cooter R, Locke M, Prince HM, Elder E, Deva AK. The Epidemiology of Breast Implant-Associated Anaplastic Large Cell Lymphoma in Australia and New Zealand Confirms the Highest Risk for Grade 4 Surface Breast Implants. Plast Reconstr Surg. 2019;143(5):1285-1292. PMID 30789476 — 81 confirmed cases; the risk tracks the roughness of the surface: 16.5 times that of a Siltex for Biocell and 23.4 for polyurethane.