Cast and Offloading

Cast and Offloading | Singapore Diabetic Foot Centre


Diabetic foot ulcers are difficult to heal due to a multitude of factors, including excessive plantar pressure on the wound itself. The feet naturally bear the entire body’s weight, which can slow down the healing of a wound, if it is located in a high-pressure area. Offloading a wound is one of the crucial elements in healing a diabetic foot ulcer. To offloading the area, casting is an oft-employed technique. Correctly applied, it can be used to protect the foot and accelerate the healing of diabetic foot ulcers by redistributing weight along the entire sole of the foot. By relieving the pressure causing the ulceration, ulcers have a better chance of healing.


Casting the foot also reduces shear between skin and footwear. The twisting forces which occur in a normal gait cycle will add friction to an already vulnerable area of the foot, causing further damage to the wound. Casting inhibits excessive rotation and twisting of the foot and ankle which promotes better healing of a wound.


A basic activity like walking adds repetitive stress to the feet with every step taken. With a cast around the foot, the weight and pressure will be redistributed from the foot into the leg, allowing one to bear weight while protecting the wound. Thus, faster healing and tissue regeneration will be achieved. Many practitioners consider casting only for severe and chronic ulcerations. However, studies have proven that even “mild” ulcers will benefit greatly from effective offloading, with the ability to resolve a wound in a timely fashion.


With diabetes, Charcot arthropathy can arise causing joint dislocations and irreversible deformities of the foot. For this particular condition, casting is used in two different ways. The acute stage of a Charcot deformity arises with the foot showing signs of swelling, increased temperature and redness. This signals the starting of the bone-and-joint breakdown where the patient should not apply any weight to the foot; immediate offloading should be carried out.


The second instance is when the foot has already been deformed. Typically, a rocker-bottom appearance will occur where the middle portion of the foot is most prominent. The opportunity for ulceration to arise at that the bony prominence increases greatly. This is when the total contact cast is also needed to heal an ulceration in that region.


In these cases, casting is a very effective treatment modality in conjunction with stringent monitoring by a podiatrist. A cast should be worn for a minimum period of four weeks and usually changed in intervals of once each week. While this is a very effective method for treating diabetic wounds of the feet, not all are suitable for this treatment option. A podiatrist will carry out the necessary steps to determine if a patient is suitable to undergo this treatment.