Amputations

Joan E. Edelstein

Introduction

Amputation is the removal of a bodily segment. Geriatric patients are much more likely to have lower, than upper, limb amputations. Peripheral vascular disease, with or without diabetes, is the leading cause of amputation in the United States of America; dysvascular amputations are likely to increase (Fletcher et al., 2002). Trauma, congenital anomaly and cancer are other etiologies. Older people with amputations due to these causes usually have years of experience accommodating their lifestyles to cope with the interference with walking and other daily activities imposed by amputation. Nevertheless, insidious musculoskeletal, neuromuscular, integumentary and cardiopulmonary changes associated with aging are troublesome to older adults with amputations, regardless of cause, because of the added stress on remaining tissues that limb anomaly and a prosthesis impose.

Classification of amputations

Anatomic location is one way of classifying amputations. Partial foot amputations are very common among those with peripheral vascular disease. The levels include phalangeal, ray and transmetatarsal amputations. Removal of one or more phalanges compromises late stance. If an entire toe, including the proximal phalanx, is absent, then the longitudinal arch of the foot will flatten because the insertion of the plantar aponeurosis has been disrupted. A ray pertains to a metatarsal and its phalanges. Ray amputation interferes with late stance and the longitudinal arch; in addition, the foot will be narrowed. Transmetatarsal amputation has major negative effects on late stance, foot support and balance; the patient tends to lean backwards on the heel. In all instances of partial foot amputation, the patient should be fitted with a shoe that has a rocker sole to aid late stance and an arch support. The shoe insert for the individual with ray amputation must have a longitudinal segment to prevent the narrowed foot from sliding in the shoe.

Syme’s amputation involves surgical removal of the entire foot, except for the calcaneal fat pad. The fat pad is sutured to the distal tibia and fibula. The patient should have a Syme’s prosthesis, which replaces the shape and basic function of the foot. Syme’s and partial foot amputations provide good support and sensory feedback because the patient can stand on the distal end of the amputation limb (end-bearing).

Transtibial (below-knee) amputation is the most common site for major (that is, proximal to the ankle) lower-limb amputation (Fletcher et al., 2002). Retaining the anatomic knee enables the individual to sit and walk reasonably well. Geriatric patients with transfemoral (above-knee) amputation have poorer functional capacity, and generally rely on a wheelchair for community travel. Ankle, knee and hip disarticulations are uncommon, particularly among older adults.

The older person with bilateral amputations due to vascular disease generally sustained one amputation prior to the second one. The presence of diabetes accelerates loss of the contralateral limb, so anyone with an amputation due to diabetes must be taught proper care of the residual and contralateral limbs. (See the discussion of education and prevention in Chapter 46, Diabetes).

Related conditions

Those who sustain dysvascular amputation often have other vascular disease, including cardiovascular disease that compromises their ability to tolerate vigorous exercise. Severe cardiovascular disease, in which the patient has dyspnea at rest, contraindicates prosthetic fitting. Cerebrovascular disease is a frequent concomitant. Hemiparesis, usually ipsilateral, is not uncommon. Paresis does not preclude prosthetic use, particularly if the amputation antedated the stroke. When peripheral vascular disease in one limb is severe enough to lead to amputation, circulation in the opposite limb is also compromised. Individuals may complain of intermittent claudication after a short walk. Prosthetic fitting reduces stress on the remaining limb. The remaining foot is vulnerable to pressure sores, which can lead to amputation. Vigilant foot inspection and hygiene, as well as suitable footwear, are essential.

Peripheral vascular disease associated with diabetes is often accompanied by obesity, visual impairment, proprioceptive and tactile loss, and renal dysfunction, all of which complicate prosthesis use. Severe arthritis in the lower limbs or the hands hampers prosthetic donning and use.

Tests and related diagnoses

In addition to tests of the peripheral vascular system, including angiography and Doppler ultrasound, the patient with an amputation should be investigated for sensory diminution. Tactile sensation may be graded with a 10 g filament, while proprioception can be judged with balance testing. Heart rate and blood pressure should be monitored to keep the rehabilitation program at a challenging level without overstressing the patient.

The amputation limb requires daily inspection to identify any incipient ulceration. A patient who has had recent amputation should have the surgical scar examined to ascertain whether healing is proceeding satisfactorily. Amputation limbs at or above the transtibial level are measured longitudinally and circumferentially. The longer the amputation limb the more efficient the gait. The proximal circumferential measurement of the transtibial limb is taken at the fibular head. For the transfemoral limb it is taken at a fixed distance below the greater trochanter. Additional distal measurements are taken at 4-cm intervals. Consistent circumferential measurements indicate that edema has subsided and the patient is ready for a prosthesis.

Motor power and joint excursion in all limbs and the trunk should be assessed periodically. Weakness interferes with the ability to maintain sitting balance, transfer from bed to wheelchair, stand and manage a prosthesis. Hip and knee flexion contractures compromise prosthetic alignment and the patient’s ability to stand and walk with a prosthesis. The clinician should ask the patient about the presence and intensity of phantom (awareness of the missing body part) sensation and pain, which is highly prevalent (Ephraim et al., 2005). Many modalities reduce pain intensity.

The history should also include inquiry regarding the individual’s functional level prior to surgery. The person with bilateral amputation who could not use a unilateral prosthesis is unsuited for bilateral prostheses. Cognitive assessment is essential because dementia contraindicates prosthetic fitting. Other factors that influence rehabilitation include environmental features, such as the number of steps at the entrance and within the home, and the patient’s vocational and avocational interests. For example, someone who enjoyed golfing prior to surgery may benefit from a prosthetic foot that accommodates to the sloping terrain of a golf course.

Clinical relevance: mobility and rehabilitation

Preprosthetic rehabilitation involves measures designed to improve the health of the amputation limb and interventions that increase the individual’s independence. The goals of treating the amputation limb are to reduce postoperative pain, foster healing, stabilize limb volume, and prevent complications, particularly contractures and skin disorders. The patient should be guided toward increasing self-care, including dressing, grooming, personal hygiene, maneuvering in bed and various transfers, such as from bed to wheelchair, from wheelchair to toilet and standing. Some older individuals with unilateral amputation can negotiate short distances with a walker or a pair of crutches and the remaining leg. These activities should not be performed unless the patient is wearing a clean sock and a well-fitting shoe on the intact foot.

Most people with unilateral amputation or bilateral transtibial amputation receive prostheses (see Chapter 70, Prosthetics). Rehabilitation aims to enable the individual to don and use the prosthesis safely, either as the sole mode of locomotion or as an alternative to wheelchair mobility, particularly indoors. A preparatory prosthesis for balance during transfers or for cosmetic value may be considered. The clinic team, consisting of physician, physical therapist and prosthetist, should select the prosthetic components that will provide the patient with the best opportunity to accomplish meaningful activities and that are within the individual’s functional capacity. Medicare guidelines to prosthetic prescription (HCFA, 2001) are based on prediction of the function of individuals with unilateral amputation: