Ponseti method casting is done in two parts. First, the lower half of the cast is applied with plaster and molded carefully. This half of the cast extends from the toes to just below the knee. After this, the knee is flexed, and the upper portion of the cast is applied, which extends to the upper thigh. The upper portion of the cast may be done with plaster or with a material called soft cast; both perform the function of holding the knee in the flexed position. By bracing the leg properly, the cast can be applied correctly.
Casts are applied by two members of the clubfoot casting team; the first person holds the leg and foot in place while the second person applies the Ponseti brace. The cast is then carefully molded while the plaster sets to hold the foot in position. Once the plaster hardens, we trim the material around the toes. The leg is then held and the knee flexed while the upper leg is wrapped with cotton and then cast material placed.
You may notice mild swelling of the toes the day the cast is applied. The toes should always have good circulation; this can be checked by pinching the toes and watching them change from white while pinching, back to the usual skin color when the pinch is released. If the toes are dark and cold and do not whiten with a pinch, this may mean that the cast is too tight. In this case, contact your Gillette care team right away to remove the cast.
Casts can be removed at home the morning of your clinic appointment or can be removed by providers in the clinic. We do not recommend taking the cast off the night before the appointment. Taking the cast off too early gives the foot a greater amount of time to tighten up before re-casting and may limit the possible correction of the next cast.
If your child has a combination cast (plaster and soft cast) you will initially unwrap the soft cast portion. There is a small overlapping tab that you can pull on, and the rest of that part of the cast will slowly unwrap, leaving the plaster part of the cast from the knee down. This part of the cast can be soaked off. If your child has an all plaster cast, the entire cast can be soaked off.
If you elect to have the cast removed in clinic, we will clean the leg before placing a new cast. We will weigh your child in clinic each week while your child has their cast off. This will give you an accurate weight to share with your pediatrician.
Removing a Cast Early
There are a few reasons you might need to remove a cast before your next appointment. Casts may become soiled, as the upper portion extends close to the diaper area. We will give you cotton wrap that you can apply around the top of the cast. Change the cotton wrap frequently to avoid soiling the cast material. If the top of the cast does get soiled, you can gently clean the area. If the cast is saturated with stool or gets submerged in water, we recommend removing the cast to avoid skin breakdown. This removal can be done at home or in clinic.
Cast slippage can occur. It happens infrequently, but can occur more frequently with small feet or feet that are in a neutral (ballerina) position. The best indicator of slippage is that the toes are no longer visible at the bottom of the cast. If this happens, we recommend prompt removal as the foot can develop skin irritation or swelling if the cast is no longer sitting in the appropriate position. If you have concerns, you can take a photo of the foot in the cast and send to your care team. Our providers will look and let you know if you need to come in for a cast change.
If the toes do not respond as normal to a pinch test, the cast may be too tight. Pinch the toes and make sure they change from white while pinching back to the usual skin color when the pinch is released. If the toes are dark and cold and do not whiten with a pinch, this may mean that the cast is too tight and the toes aren’t getting adequate blood circulation. Contact your care team if you have concerns.
If your child has vaccinations due during casting it safe for these to be done at the upper thigh above the cast. If the clubfoot is only on one side, try to do most of the vaccines in the unaffected leg. Split the vaccines between both legs if both legs are affected. There can be some mild swelling and soreness associated with the vaccines; you may give Tylenol if your child is uncomfortable. It is unlikely that your child will develop so much swelling that casts would need to be removed but if you have concerns, you may send a photo to the clubfoot team or remove the upper portion of the cast.