A surgical procedure sometimes offered to people with diabetes to reduce their risk of foot ulcers may have drawbacks.

Because of nerve damage resulting from diabetes, people can lose sensation in their feet and this can lead to recurrent ulcers on the soles. Lengthening the Achilles tendon can improve the situation by increasing ankle mobility, thus allowing pressure on the foot to be spread more evenly, and by reducing point-pressures while walking.

However, while Achilles tendon lengthening (ATL) can reduce ulcer recurrence in people with diabetes, it fails to improve their physical functioning or perceived disability, according to a report in the medical journal Diabetes Care.

“Recurrent ulcers are a multifactorial problem, and an ATL is not a panacea for treatment,” Dr. Michael J. Mueller from Washington University School of Medicine, St. Louis, Missouri, told Reuters Health.

“Patients still must pay close attention to good diabetes care - especially watching their glucose levels, wearing appropriate footwear, and monitoring their skin daily for unnoticed injury,” he advised.

The standard treatment for foot ulcers involves encasing the foot in a cast to alleviate pressure points, so-called total contact casting.

Mueller and his colleagues investigated whether ATL combined with total contact casting improved functional limitations and the patient’s perceived disability, compared with total contact casting alone, in 28 diabetic patients with recurrent foot ulcers.

The team found that physical performance test scores, a measure of functional ability, did not differ significantly between the two treatments. However, the average measure of perceived disability improved slightly after total contact casting but worsened slightly after ATL.

“The results of this study suggest that treatment with ATL or total contact casting had no major effect on functional limitations over an 8-month time period as measured with the physical performance test, but perceived disability was greater in the ATL group,” the researchers conclude.

“Achilles tendon lengthening is useful for decreasing ulcer recurrence rates,” Mueller said, “but patients should be warned about weakness in the plantar flexor muscles (calf) that may cause some instability and perceived disability during walking.”

People who experience such problems with walking after the procedure should seek physical therapy, he suggested.

“We have just received funding to see if injections of botulinum toxin (Botox) into the plantar flexor muscles will work just as well at ATL in reducing ulcer recurrence rates without the negative changes in perceived disability,” Mueller added. “We hope the Botox decreases push-off force during walking and thereby reduces forefoot pressures.”

His group is also working on “a sensory shoe that would give feedback if a certain pressure threshold is exceeded.”

SOURCE: Diabetes Care, July 2004.