Total contact casting (TCC) is considered to be the ‘gold standard’ in the treatment of diabetic foot ulcers. Although TCC is often very successful in healing diabetic foot ulcers, this treatment modality is not used as often as it could be.
What is TCC?
Total contact casting is a special casting technique designed to heal diabetic foot ulcers by relieving pressure on the prominent areas of the foot that are prone to skin breakdown and ulceration. The cast is applied so that the patient can remain ambulatory for the duration of the casting and is composed of fiberglass or plaster. Its purpose is to protect the ulcer, allowing for wound healing.
How does TCC promote healing of diabetic foot ulcers?
By distributing weight more evenly over the entire surface of the foot, rather than on a few select areas, TCC can effectively reduce pressure on the most vulnerable areas of the foot where ulceration is most likely to occur: “The principle involved here is that the cast is molded to the contours of the foot from the back of the heel through the arch region, in the region of the metatarsals, around them and even to the toes. Pressure is expressed in terms of force or pounds over area per square inch. Therefore, if the weight-bearing area is enlarged the pressure per unit of weight-bearing area diminishes. In this way the pressure which has been concentrated on the bony prominence is distributed over the entire plantar aspect of the foot, allowing reversal of the mechanism that caused the ulcer to occur” (American Orthopaedic Foot and Ankle Society, ND).
Indications and Precautions
Total contact casting is used to treat diabetic foot ulcers and Charcot foot. It is important that the patient have adequate blood supply to the foot. It is also crucial that the patient be monitored carefully, as diabetic patients often have diminished sensation in their feet, which could lead to the formation of additional ulcers or areas of irritation.
Patients should use a cane or crutches to prevent falls and prevent the application of pressure on the affected foot (unless weight bearing is to be permitted, in which case the sole of the cast should be modified appropriately). TCCs may cause musculoskeletal strain due to the weight of the cast, and patients should be asked to report any discomfort. Patients should be reminded to keep the cast dry.
How is the TCC applied?
The following depicts the usual steps when applying a total contact cast:
- Have the patient lie on his/her stomach with the affected leg pointing straight up (alternatively, the patient can sit on the treatment table with the affected leg hanging down, but this position is more awkward for the practitioner)
- Ensure that the ankle is bent in a neutral position
- Apply a thin dressing over the ulcer
- Apply a thin layer of stockinette
- Apply protective cast padding between the toes (to prevent the toes from rubbing together)
- Apply cast padding in a thin layer up the limb
- Apply secondary foam padding over vulnerable areas (inner and outer ankles, over the toes, front of the shin, sides of the cast)
- Apply the plaster undercoat smoothly to the foot and leg, covering the toes and going up the leg;
- The sole of the cast is applied so that it very closely molds the contours of the sole of the foot; any valleys in the sole are filled in with plaster of Paris (or other material) so that the sole is flat
- The cast may be reinforced with fiberglass and a rocker bottom sole or specially curved sole is applied for patients that are to be permitted to weight bear
How long must the TCC stay on?
TCCs are typically changed every week, or alternating weeks, depending on several factors, such as the amount of edema, the rate of healing, practitioner preference and patient tolerance. Use of TCC is continued until healing has occurred and the foot is ready for footwear or an orthotic.
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Foot Ulcers and the Total Contact Cast. American Orthopaedic Foot and Ankle Society. https://www.aofas.org/footcaremd/conditions/diabetic-foot/Pages/Foot-Ulcers-and-the-Total-Contact-Cast.aspx
Total Contact Casting. Wound Care Centers.org. http://www.woundcarecenters.org/article/wound-therapies/total-contact-casting
Myers, B. (2008). Appendix D: Total contact casting procedure and patient instructions. Wound Management: Principles and Practice (2nd edition). Pearson Prentice Hall. Upper Saddle River, New Jersey. pg. 464-465.