Blisters (most common type of sore)

Sores on the heel are almost always friction blisters. A blister forms when the heel moves against the inside of the shoe and creates friction and heat. It is the same basic thing that causes blisters in new shoes or on hands during repeated work. When parents understand it in that real-world way, they can more easily understand why secure heel seating and a very tight shoe matter so much in preventing blisters.

Blisters are usually red on the outside and white in the center at first. That pattern strongly suggests friction and movement rather than pressure. They can be large, as shown in the first image, or very small and subtle, as seen to the right.

Even a very early blister can become more of an issue or take time to resolve even if the underlying movement is corrected.

Once the skin breaks, the blister becomes an open wound. Catching these blisters early and changing the way the foot is secured in the shoe is critical. If you know it is a blister, then you know the heel has been moving and the shoe has not been tightened secure enough. If caught early, it may heal simply by correcting the fit and eliminating the movement. It does not take much movement or much time in a loose shoe for a blister to form and then worsen.

Don’t Blame the Baby:

Slipping is caused by fit, heel position, and tightness. It is not caused by the baby being especially strong, stubborn, active, or “good at kicking them off.” No child “learns to kick their brace off”. Baby legs are strong, but that is exactly why the shoe has to be put on correctly. Once the bar is attached, it acts as a lever and can increase the force applied to the foot by many times.

Every application must end with a movement check—the push-and-pull-and-twist test by grasping the shoe at the heel of the shoe and the test must be performed with real effort. A gentle tug is not enough force to check for movement. If there is movement, the shoe needs to be redone.

Parents need to understand this clearly: if the heel moves inside the shoe, the shoe is not tight enough yet. As soon as they notice movement, remove and then re-don the shoe.

Tell parents very specifically:
Do not leave the foot inside a slipping shoe. If the heel moves, it must be redone.

This is not a race.

If the baby is upset or the parent is overwhelmed, it is recommended to stop, regroup, have some milk and cuddles, settle and relax, and then try again. It may take many attempts to get it right, and parents need to know that this is okay. It does get easier with time and practice.

If the heel can rise inside the shoe, then it can also move up and down. That movement is what causes friction blisters on the heel. Sometimes the heel also rises and presses against the inside of the shoe, which can cause a pressure sore instead of a blister. In rare cases, a foot that stays slipped up could even place the foot at risk in a way similar to a slipped cast, particularly in complex clubfoot.

Non-Clubfoot Pressure Sores (heels)

The three-strap infant shoes have a silicone liner with a deep heel pocket and heel counter. For the clubfoot, this is helpful because it keeps the heel seated and encourages the heel to drop.

In many unilateral cases, the unaffected foot does well in this design. In some children, however, the unaffected heel has a more prominent bony contour, and the heel counter creates a deep purple pressure sore.

This is not a friction blister caused by movement. It is a pressure injury.

That distinction matters, because the solution is not a tighter shoe or simply eliminating movement. As long as the heel counter continues to press into the heel, these sores are extremely difficult—and often impossible—to heal.

Even after a break from bracing, the sore often returns as soon as the shoe is put back on unless the pressure itself has been eliminated.

Doctors need to recognize these sores early and stop treating them like ordinary heel blisters. On the unaffected foot, a heel sore is rarely caused by movement unless the shoe is very loose.

The early appearance is distinctive: deep purple discoloration, sometimes with an indentation.

Early recognition is critical. Once this type of sore appears, it almost always worsens unless the pressure is relieved. Some appear overnight and are already severe when first noticed. Others evolve over several days, but they still become severe if the underlying pressure continues.

By the time the deep purple discoloration is obvious, deeper tissue has often already been injured. The skin may then slough, leaving an open wound.

Several solutions have been tried with limited success. These include pushing the foot forward with foam or corn pads, grinding down the heel counter inside the liner, or making a slit in the heel of the silicone liner.

In parent experience, the most consistently effective solution has been to cut a hole in the back of the shoe exactly where the heel counter or top of the deep heel pocket is pressing into the heel.

Parents can do this themselves with a sharp razor, such as an X-Acto knife or small box cutter. In many cases, this is more effective than repeated orthotics visits or hoping that grinding alone will be enough.

To find where to cut, place an adhesive dressing such as a Band-Aid or plaster over the sore and apply lipstick or petroleum jelly to the outside of the dressing to mark the center of the pressure point. Then press the foot into the shoe as usual and transfer that mark to the inside of the silicone liner.

That is where the cut should begin. Start with a small hole and enlarge it only as much as needed.

The shoe will generally continue to work well with this modification. Even if the heel portion of the silicone liner eventually weakens, the shoe still functions because it is the outer shoe material—not the liner alone—that secures the foot.

Most infants also outgrow each shoe size fairly quickly, so long-term liner durability is usually less important than preventing an ongoing pressure injury.

These images show several modifications that parents have tried. None appear to damage the function of the shoe. You may wish to explore which approach works best in your practice, but the cut-out hole has been reported by parents to work quickly and reliably, and in our experience it is often the most effective solution.

Pressure sores are deep/dark purple.
This must not be ignored, and the pressure must be eliminated immediately.

This is the same baby, the parents covered it with a “Band-Aid” type dressing. This only added more pressure.

Under Strap Pressure Sores

Conversely, a three-strap shoe may sometimes be tight enough to stop heel movement and prevent a heel blister, but still cause too much pressure under the middle strap. In that situation, the heel blister may be avoided, but a pressure sore can develop under the strap instead. It can feel like a catch-22. Pressure saddles are not usually very helpful and can sometimes make the heel problem worse by preventing the shoe from becoming tight enough and making it harder for the foot to dorsiflex and the heel to seat properly. Strap-related pressure sores are less common in single-strap or lace-up shoes, but they can still happen.

Pressure saddles have been around since the Mitchell shoe first came out available to parents in 2004 because it was clear early on that this kind of sore was a problem. They have never worked very well, if at all to solve an active sore. In an attempt to sort this issue after years of failing to really have a solution for parents, I began asking parents to make some changes to the position of the straps and stop leaving the top and lower straps looser. This was approximately 2 years ago, and after 1 year I knew it worked. The incidence of these sores is nearly nothing in the groups now, whereas we used to see 3-5 of these sores a week. Now it’s mostly redness that needs to be reduced, and this is a testament to the success of this technique.