Monday, November 06, 2006

Limb Loss in Older Adults: Improving Outcomes While Reducing Costs

Preoperatively, a prosthetist can provide the surgeon with insight that can help ease the patient's adjustment to a prosthetic limb.

Of the more than 50,000 Americans who are expected to experience a lower-extremity amputation within the next year, more than two-thirds will be older adults. Peripheral vascular disease, with or without diabetes, is the primary causal factor; traumatic injury to the limb is the secondary cause. It is widely agreed that amputation is a surgery of last resort: irreparable loss of the blood supply to a diseased or injured limb is the only absolute indication for amputation.

Amputation is a particularly difficult outcome for older adults and their families. The aging process has already forced physical and mental limitations on many older individuals, and the prospect of prolonged rehabilitation can seem overwhelming. However, advances in the science of prosthetics have led to better long-range outcomes for older adult amputees. Health care professionals are in key positions to encourage these patients and to help them understand that their lifestyle can be restored.

Early Prosthetic Management

Clinical studies1 have demonstrated that early prosthetic management significantly aids in recovery, while simultaneously reducing medical costs. Whenever possible, a prosthetist should be included in the preoperative consultation. While the surgeon will not have long-term patient contact, prosthetic rehabilitation will continue for the rest of the patient's life. Developing a specialized care team at the outset—including the patient, an orthopedic or vascular surgeon, a physiatrist, a prosthetist, a psychologist, a representative of the patient's family, a general care physician, a physical therapist, a podiatrist, a pain management specialist, and a representative of the patient's family—provides the most efficient strategy for case management. There are numerous additional specialists who may be included on this multidisciplinary care team, depending on the patient's specific needs.

Preoperatively, the prosthetist can provide important insight into how the residual limb will interface with the socket of the prosthetic limb. The shape and contour of the distal end of the residual limb are important factors in reducing the potential for painful bone spurs. The manner in which the nerves are severed can help prevent neuromas from forming later. It is much easier for a patient to adjust to a transtibial prosthesis than to a transfemoral prosthesis; therefore, it is important to save the knee when possible. Together, the surgeon and prosthetist can determine the optimal point of amputation as it relates to the fit and function of the prosthesis.

Immediately postop, the prosthetist should apply a limb protector over the surgical dressing. This rigid covering creates a safe environment for the residual limb, protecting it from additional trauma and promoting healing. The limb protector prepares the limb for an initial prosthesis by reducing edema, increasing venous return, and narrowing the risk for infection. These combined attributes often result in early patient discharge, enhancing the cost-containment aspect of the case. The limb protector should be worn during hospitalization and after the patient's return home until the surgical site is completely healed.

Early ambulation encourages healing of the limb and can be tremendously beneficial to the patient's mental outlook As early as the day after surgery, the patient can don a temporary prosthesis and be touch-down weight bearing. The first temporary prosthesis is a preparatory system that is low in cost, averaging around $1,200. The use of immediate postoperative prosthetics (IPOP) results in shorter initial hospital stays, reduced time in skilled nursing facilities, and decreased incidence of return hospitalization.1

The low cost of an IPOP system makes it an attractive option for skilled nursing facilities. Typically, these facilities are reluctant to allow for the cost of a prosthesis to be included in the first 90 days of Medicare Part A; instead, they prefer that the prosthesis fall under Medicare Part B. An inexpensive IPOP can, however, fall under Part A, with the sophisticated final prosthesis being filed under Part B. This approach results in improved across-the-board outcomes: the patient's rehabilitation progresses more quickly; the skilled nursing facility discharges faster; and hospitalization and Medicare costs, return hospital stays, and revision surgeries are reduced.

Prosthetic Advances
The science of prosthetics has advanced dramatically over the past decade. This is due primarily to the evolution of new materials such as urethanes, mineral-based liners, improved silicones, titanium, and carbon fiber. Younger, more athletic amputees have pressed for high-performance legs and feet that enable them to run and sprint. This consumer demand has resulted in intensive research efforts and the development of a new breed of lower-extremity prosthetic limbs.

The very same attributes that athletes are looking for—lightweight, comfortable, responsive—also offer tremendous benefits to older adult amputees. Energy demands and cardiac workload are substantially increased for prosthetic users. Older adults often face limitations with reduced energy and cardiac function even before amputation. This further validates their need for lightweight, dynamic-performance prosthetic limbs.

The first component of the prosthesis is the socket. A greater understanding of the underlying anatomy has led to better surface matching between the residual limb and the socket. Bone, muscle, and vascular contouring greatly enhance circulation in the older adult's residual limb. The new socket materials are much more flexible than the previously used hard plastics—bending, expanding, and contracting along with the residual limb. Today's sockets are total contact, with a form fit that provides a massage-like quality that increases venous return. For the dysvascular amputee, additional physical benefits of the total-contact socket include reduced swelling in the residual limb and decreased pain and discomfort, particularly throbbing sensations. These sockets also allow older adults greater control of the prosthesis without surface damage to the fragile skin of their residual limbs. When walking, as an individual steps on the prosthetic side, the muscles in the residual limb expand and the socket also expands. When the muscles relax in the swing phase of the gait, the socket instantly contracts and clamps back onto the residual limb. This responsive quality of the socket material is known as memory.

Other components of the lower-extremity prosthesis have also been upgraded by new technology. The pylon, which connects the socket to the prosthetic foot, is the means by which weight load is transferred. Today's dynamic pylons emulate the function of the muscles and tendons they are replacing. They allow for flexibility during ambulation and can provide vertical shock absorption and torque absorption. The ankle and foot unit of the prosthesis should be adjustable and provide dynamic response. This combination offers extra cushioning and makes walking easier, thus allowing for an increased activity level and quality of life for the older adult.

A recent study indicates that when wearing a dynamic foot, users of below-knee prosthetics achieve the important goal of symmetry. This means that 50% of their time is spent on the sound foot, and 50% on the prosthetic foot.2 This is of special significance for older adults with diabetes or vascular problems because symmetry balances the stress on both the residual limb and the sound foot. When wearing a nondynamic foot, the ratio shifts and approximately 61% of the time is spent on the sound foot, with the remaining time spent on the prosthetic side.

It is important to provide an older adult with a high-performance prosthetic. These patients require the utmost in comfort and performance in order to thrive. The shock-absorbing qualities that are built into today's prosthetic components result in less injury to the dysvascular amputee's residual limb. This, in turn, minimizes further medical treatment and contains costs associated with injury, infection, pain management, and wound care.

Postamputation Care

Following an amputation, the two most critical points on the older adult's body are the residual limb and the sound foot. Both require extreme care and monitoring by a physician and prosthetist to help prevent pain, infection, and even additional amputation. The residual limb must be kept clean and dry at all times. Unless a suction-type socket is used, older adults should always wear a cushioning sock or liner between the residual limb and the socket. This protects the surface from the direct friction that accompanies ambulation, helping prevent abrasions and breakdown of the skin. Suction sockets touch the skin directly and are recommended primarily for above-knee users and patients with healthy skin on their residual limb. The residual limb should be examined regularly for signs of stress or injury.

Older adults who have lost a limb due to diabetes or vascular problems face a 33% chance of losing their sound limb within 5 years. The best preventive tool is a diabetic foot-care program that includes frequent examination of the foot for any signs of injury. Most older adults will need both a physician and a family member to help them maintain their foot-care program, particularly if a patient has failing eyesight. A podiatrist should be enlisted to clip the patient's toenails. Older adults with peripheral neuropathy need to have their sound foot examined daily by another individual.

Amputation is a difficult outcome for older adults, their families, and the medical care delivery system. With early prosthetic management, however, older adult amputees can benefit from faster recoveries, earlier discharges, and increased rehabilitation potential and independence. Advances in prosthetic design have resulted in greater comfort for the dysvascular amputee and a reduced incidence of injury or infection in the residual limb. In the managed care environment, where the focus is on cost constraint, these techniques deliver the best long-range outcomes for older adult amputees as well as for the care providers, insurance companies, and Medicare plans that serve them.

Kevin Carroll, CP, FAAOP is the vice president of prosthetics for Hanger Prosthetics & Orthotics, Oklahoma City. A practicing prosthetist who specializes in the prosthetic care of older adults, Carroll was recently named a Fellow by the American Academy of Orthotics & Prosthetics.

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