Animation deformity happens when a breast implant visibly shifts, jumps, or distorts every time you flex your chest muscle. It occurs because the implant sits underneath the pectoralis major muscle, and when that muscle contracts, it pushes or pulls the implant into unnatural positions. The breasts may pop upward, shift outward, or flatten during everyday movements like pushing a door, lifting groceries, or exercising. The single most effective way to avoid it is choosing an implant placement that keeps the muscle away from the implant entirely.
Why Animation Deformity Happens
In traditional breast augmentation and most breast reconstruction after mastectomy, surgeons place implants beneath the pectoralis major, the large fan-shaped muscle across your upper chest. This is called subpectoral placement, and it has been the standard approach for decades because the muscle provides an extra layer of cushioning over the implant, reducing visible edges and rippling.
The tradeoff is that after healing, the skin and tissue tend to adhere to the muscle above the implant. Every time the pectoralis contracts, it pulls on the implant through the surrounding scar tissue (capsule). The result is visible, sometimes dramatic movement of the breast that doesn’t look or feel natural. In a randomized controlled trial published in Archives of Plastic Surgery, 100% of patients who received subpectoral implants showed some degree of animation deformity. For some people it’s barely noticeable; for others, it’s a significant cosmetic and functional concern.
Prepectoral Placement: The Most Direct Solution
Placing the implant above the pectoralis muscle, known as prepectoral placement, eliminates the core problem. Because the muscle sits entirely behind the implant and never contacts it, flexing your chest has no effect on the implant’s position. In the same randomized trial, only 23.8% of prepectoral patients showed any animation deformity, and the severity was dramatically lower (an average score of 0.4 on a standardized scale, compared to 3.6 for subpectoral).
Prepectoral placement has re-emerged as a preferred option in recent years, with studies showing cosmetic outcomes comparable to subpectoral techniques. It also tends to cause less postoperative pain and preserves normal chest wall anatomy. Surgeons often rate cosmetic results for prepectoral placement as equal to or better than subpectoral results.
The main limitation is tissue coverage. Without the muscle draped over the implant, you need enough skin and soft tissue to hide the implant edges. People with very thin skin or minimal breast tissue may see visible rippling or wrinkling along the upper pole of the breast. This is why prepectoral placement isn’t ideal for everyone, and your surgeon will assess your tissue thickness before recommending it.
How Acellular Dermal Matrix Helps
When an implant goes above the muscle, something still needs to support it and provide a smooth layer between the implant and skin. That’s where acellular dermal matrix (ADM) comes in. ADM is a sheet of processed tissue that acts as a biological hammock, wrapping around the implant to hold it in place and add a layer of soft tissue coverage.
In prepectoral procedures, ADM serves two purposes: it keeps the implant from shifting and it reduces visible rippling, especially in patients with thinner tissue. For patients at high risk of rippling, surgeons can combine ADM with fat grafting (injecting your own fat around the implant) to build up additional cushioning. This combination has made prepectoral placement viable for a wider range of body types than it was a decade ago.
Dual Plane Technique: A Middle Ground
If prepectoral placement isn’t an option for you, the dual plane technique offers a compromise that significantly reduces animation compared to full subpectoral placement. In this approach, the surgeon detaches the lower portion of the pectoralis muscle from the chest wall along the breast crease. The muscle slides upward so it covers roughly the upper two-thirds of the implant, while the lower third sits directly beneath the breast tissue with no muscle over it.
Because the muscle is released from its lower attachment, it has less leverage to pull on the implant during contraction. The result is noticeably less implant movement than traditional full submuscular placement. Athletic women who regularly exercise tend to benefit from dual plane because they get the coverage advantages of muscle over the upper pole without the pronounced distortion during chest workouts. Recovery time is also generally shorter than with full submuscular placement.
Implant Choice Matters Too
The type of implant can influence animation severity. Research has found that smooth, round implants are associated with greater deformity compared to textured options. The smooth surface allows the implant to glide more freely under muscle pull, amplifying visible movement. If you’re getting subpectoral placement, discussing implant surface and shape with your surgeon is worth the conversation, as the right combination can reduce (though not eliminate) the degree of distortion.
Bilateral procedures, where both breasts receive implants, also correlate with more noticeable animation. This may be partly because deformity on one side is more obvious when both breasts move asymmetrically during muscle use.
What Doesn’t Seem to Matter
You might assume that body weight, fitness level, or age would predict who develops animation deformity. They don’t. Studies examining BMI, patient age, hand dominance, and athletic activity have found no consistent correlation with the development or severity of the condition. Animation deformity is driven almost entirely by the relationship between the muscle and the implant, not by patient characteristics. This means you can’t prevent it through exercise modifications or weight management alone. The surgical approach is what determines your risk.
Correcting Animation After Surgery
If you already have subpectoral implants and are dealing with animation deformity, the most common correction is converting to prepectoral placement. This involves a second surgery where the implant is moved from beneath the muscle to above it, typically with full ADM coverage to support the new pocket. The conversion is well established, and many surgeons perform it specifically for patients who find animation deformity bothersome.
Not everyone with subpectoral implants needs correction. The deformity ranges from subtle movement visible only during intense exercise to dramatic shifting during simple arm movements. If yours falls on the mild end and doesn’t bother you, there’s no medical reason to revise it. But for those who avoid physical activity or feel self-conscious during normal movement, conversion surgery reliably solves the problem by breaking that muscle-to-implant connection permanently.
Questions to Raise With Your Surgeon
The most important conversation happens before your first surgery. If avoiding animation deformity is a priority, ask specifically about prepectoral placement and whether your tissue thickness supports it. If your surgeon recommends subpectoral placement, ask why, and whether a dual plane approach could work instead. Key questions to cover:
- Tissue assessment: Do you have enough skin and soft tissue for prepectoral placement, or would rippling be a concern?
- ADM use: Will the surgeon use a dermal matrix to support the implant and reduce rippling?
- Implant type: What surface texture and shape will minimize movement if subpectoral placement is necessary?
- Activity level: How will your exercise routine interact with the chosen placement, and what should you expect during chest-intensive movements?
Animation deformity is not an unpredictable complication. It’s a direct, mechanical consequence of putting an implant under a muscle. Understanding that relationship gives you the information you need to choose a surgical plan that avoids it from the start.