NEW YORK (Reuters) -- New research indicates that a non-removable cast helps diabetic foot sores heal faster than special shoes that are typically used.

People with diabetes are prone to developing sores or ulcers on their feet. Untreated, these ulcers can become quite serious and may even result in toe or foot amputation.

A standard treatment is to reduce pressure on the ulcer through the use of shoes or crutches. However, for these devices to work, patients must use them consistently for several weeks at a time. Unfortunately, many patients don't comply with these instructions.

Because compliance is so critical, Dr. Georges Ha Van, from the Pitie-Salpetriere Teaching Hospital in Paris, and colleagues decided to create and test a cast that might enhance compliance and, thereby, improve ulcer healing.

The cast the researchers designed is made out of fiberglass with rubber heels placed around an opening that allowed access to the ulcer site. Like a standard cast, the boot-shaped cast is nearly impossible for the patients to remove themselves.

In the new study, reported in the medical journal Diabetes Care, the authors tested the cast on 42 diabetics with deep or long-standing ulcers.

Fifty-one diabetics with less severe ulcers who were treated with special shoes served as a comparison group.

Despite having more severe ulcers, 81 percent of cast-treated patients experienced ulcer healing compared with 70 percent of shoe-treated patients.

Moreover, the average healing time in the cast group was 69 days, nearly half the time seen in the shoe group.

With the exception of one patient who somehow managed to remove the cast, all of the patients in the cast group were completely compliant with treatment. In contrast, in the shoe group, only five patients were totally compliant.

Another benefit of the cast was a decreased risk of bone infection at the ulcer site, the authors note. Thirteen patients in the shoe group experienced this complication compared with only three in the cast group. Shoes "afford less pressure relief than a cast boot and their acceptability is poor," the researchers state. "For us, the non-removable fiberglass cast boot remains the reference standard for the treatment of diabetic (foot) ulcers because it offers satisfactory (pressure relief) and high compliance and decreases the risk of (bone) infection."