The occurrence of diabetes, already the leading cause of limb loss in the United States, is growing. Prosthetists, orthotists and pedorthists see more patients with diabetes than any other presenting condition. If any patient type can be described as the foundation of O&P practice in this country, it would be the older diabetic individual with peripheral sensory neuropathy.
Despite decades of progress in managing the disease, the course of diabetes still frequently culminates in varying degrees of lower-limb morbidity and ultimately amputation. An estimated 90,000 lower-limb amputations were performed on diabetic patients last year with vascular insufficiency secondary to diabetes as the predominant cause.
With other types of practitioners usually involved in diabetic limb care, we frequently do not see a diabetic patient until an infection, lesion or deformity has progressed to the point that amputation has become the best option, and we are engaged to provide prosthetic management. However, be assured our team is well prepared to help at risk patients preserve their intact limbs, be it one limb following amputation of the other… or both.
Another disturbing diabetes statistic reveals that up to 50 percent of surviving diabetic amputees will lose their contralateral limb within five years of an initial amputation. Our goal is not to add to that number. In the case of unilateral diabetic amputees, it is not uncommon to have rigorous orthotic-pedorthic management under way for the non-amputated leg while active prosthetic care is in progress.
Such is particularly the case during the period of extensive gait training that accompanies the recent amputee’s transition to prosthetic ambulation when considerable additional loading is applied to the remaining foot’s plantar surface.
Protecting The Neuropathic Foot
O&P concern for diabetic patients, whether or not they have already undergone an amputation, stresses sound foot management through regular careful observation, patient education and orthotic-pedorthic support. The goal is to prevent elevated plantar pressures and trauma, which unresolved can quickly lead to plantar ulcerations, often the first insult in a series of events leading to amputation.
The primary weapon against plantar ulcers for the diabetic patient is properly prescribed and fabricated therapeutic footwear – including specially constructed shoes, modifications, and custom-molded inserts.
Other orthotic measures include supportive and protective componentry for specific conditions, such as a custom-molded ankle-foot orthosis (AFO) or Charcot Restraint Orthotic Walker (CROW). Charcot deformities of the foot and ankle often beset diabetic patients. Appropriate treatment consists of joint immobilization using total contact casting, a solid ankle AFO or CROW boot. The CROW is sometimes a nice alternative to casting because it provides the needed total contact, immobilization and pressure relief but can be removed periodically for bathing and dressing changes.
While amputation of a part of a lower limb may be a sound therapeutic decision, it does not resolve the host of conditions that likely prompted the amputation in the first place for the aging diabetic patient: ischemia and/or neuropathy in the lower limb, generalized muscle weakness, lack of coordination and balance, and visual and cognitive impairments. Thus, continuing aggressive management of these conditions with the O&P practitioner as an involved participant remains an important management strategy.
Prosthetic Implications Of Diabetes
Complications of diabetes frequently also complicate prosthetic rehabilitation of the new diabetic amputee. Common issues include ischemia and/or neuropathy in both the amputated and contralateral limb; poor muscle strength, coordination and endurance; visual impairment; balance problems; cognitive difficulty; and desire to resume an active lifestyle. The first determination is whether the patient can indeed benefit from a prosthetic limb. The recuperating amputee must possess certain prerequisite capabilities to advance to prosthetic use, notably the ability to rise from bed or chair and pivot on the contralateral limb and sufficient hand and arm strength to maneuver prosthetic components. These prerequisites also require an adequate level of balance and cognition.
Slow wound healing is a hallmark of advanced diabetes, especially in the lower limb. A commonly accepted guideline is to begin the transition to a prosthesis about six weeks post-op, barring lingering complications.
One approach is to provide a preparatory, or training, limb when the wound has sufficiently healed and all edema and infection issues have been resolved. A preparatory limb is a relatively simple and inexpensive device that enables the rehabilitative team to assess the patient’s ambulation potential. When the amputee’s strength returns and the diabetes is under reasonable control, transition to a definitive prosthesis can begin.
Another method is to provide definitive limb components from the outset, then provide a new socket when the residual limb matures, 4-8 months later. This course enables the use of more advanced components up front and eliminates the need to retrain the patient in the use of a different prosthesis after the preparatory period.
Prosthetic Component Selection
Lightweight, durability and ease of use are particularly important attributes in prosthetic legs for diabetic patients. Because sores and infection occur so frequently in insensate limbs, optimal socket design and appropriate liners are vital to prosthetic success.
Flexible, dynamic sockets help prevent undue pressure over sensitive skin or nerve areas and bony prominences. Gel liners help reduce friction and skin irritation and increase tolerance for forces within the socket.
For above-knee diabetic amputees, a lightweight knee component providing a high degree of stability is usually prescribed. Polycentric designs are a frequent choice with some incorporating a locking device to prevent knee buckling while standing.
Lightweight foot components appropriate to the amputee’s activity level will help maximize the benefit the older diabetic patient receives from a prosthetic limb.
Good options for seniors with diabetes include the new Flex-Foot Assure, Endolite Senior, and the still-reliable SACH (solid ankle, cushion heel) foot, among others.
Our practitioners are dedicated to providing the best possible outcome for our diabetic patients. We are available to help with patient education, resolve componentry issues as they occur, and assist patients in achieving the compliance necessary for success. For additional information, give us a call.
Statistics About Diabetes And Amputation
Recent American Diabetes Association and Centers for Disease Control statistics relating to the incidence and outcomes of diabetes in America and around the globe indicate a still-growing health issue:
• The CDC estimates that 23.6 million Americans – 8% of the population – have diabetes, 5.7 million are undiagnosed.
• Nearly 30% of diabetics age 40 and older have impaired sensation in their feet. An estimated 15% of people with diabetes will develop foot ulcers.
• Diabetes was the underlying cause in an estimated 90,000, primarily lower-extremity, amputations in the U.S. last year. Worldwide, diabetes is linked to one million foot and leg amputations annually.
• More than 60% of non-traumatic lower limb amputations occur in people with diabetes. The amputation rate for people with diabetes is 10 times higher than for people without diabetes.
• 1 of every 10 health care dollars in the U.S. is spent on direct and indirect costs of diabetes.