Methodologic issues

Comparisons of published study results for safety in amputation rehabilitation from descriptive studies or controlled studies are limited by the number and type of studies available and lack of a standard definition for safety outcome points in time to measure success and failure of different interventions. Published studies included original research articles, case reports, and review articles. Published studies are limited by sample size and methodical design.

Safety and the prosthesis

Receiving the prosthesis is often a focal point early in the rehabilitation of the person with amputation. Before receiving the device, there can be safety issues. Commonly, postoperative compressive and limb-shaping strategies are used. In some cases, incision lines can be stressed if attempting to don a shrinker when the scar is not closed. Poorly fit shrinkers can lead to improperly shaped limbs that are prone to skin breakdown. With regard to use of compression wrapping, potential concerns include a constrictive tourniquet effect with transverse, circularly applied wraps. Further, compressive wrap fasteners are sharp and there is an obvious concern for use with people whose sensation and circulation are compromised. A safer method of stump wrapping is the is the figure eight technique with use of tape for closing ends of elastic compression wrap.

In some cases, immediate postoperative prostheses or rigid dressings can be furnished. The purpose of these devices is to manage limb volume and provide closely supervised and early preprosthetic weight-bearing capabilities. They also have a secondary function of providing protection to the limb from external trauma and preventing knee contractures. There are numerous benefits such as limb conditioning and acclimation to donning a definitive device. However, these preprosthetic devices can be a source of safety concern. If supervision is inadequate, fitting is poor, structural strength is insufficient, and so forth, these devices can lead to skin and limb trauma, material failure, falls, and other problems. The literature is mixed on the use of these devices, with a generally positive view. A large retrospective review of literature spanning 1960 to 2002 compared measures of safety, efficacy, and clinical outcomes of various strategies of postoperative dressing and management in transtibial amputation. Analysis of 10 controlled studies supported only 4 of the 14 claims cited in the uncontrolled, descriptive studies reviewed. Postamputation dressing and management strategies aim to improve wound healing, control pain, allow early prosthetic fitting, and enable a quick return to function.

Once the time has come and prosthetic component selection proceeds, prescription is necessary. Risks are associated with underprescription and overprescription of components. In terms of underprescription, the active user who receives components below their functional capabilities is at risk of either experiencing poor performance from their prosthesis or potentially catastrophic component failure. The opposite phenomenon (overprescription of components) is equally problematic because higher-level components may require a more aggressive pattern of use to optimize function. This situation could introduce nonoptimal forces to the amputated residual limb. In addition, higher functioning components may introduce the possibility of participating in higher-level activities. For instance, some microprocessor knees may offer reciprocal stair descent (or ascent). Some users may feel obligated to attempt these activities to their detriment and without adequate training, strength, conditioning, and so forth.

With regard to the prosthesis itself, there are inherent safety issues with most elements of the prosthesis. For example, the socket has the complex task of supporting the residual anatomy and structurally interfacing with the components transferring forces between the body and environment. Socket fit can be poor because of anatomic challenges such as birth anatomy, and acquired and developed variations such as heterotopic ossification. Socket issues are one of the most common prosthetic problems.

The skin of the residual limb in lower limb amputees is prone to problems. The skin of the residual limb was not designed for load bearing, but that is what is required when using a lower extremity prosthesis. The skin of the residual limb is exposed to shear and stress forces, increased moisture, and prolonged exposure to the prosthesis. Consequently, various skin problems may develop. Frequently, treatment of skin-related prosthetic issues involves a period of time of not using the prosthesis. This situation increases the falls risk. It has been suggested that once the issue has been resolved, continued prosthetic use does not affect healing.

There is limited research on incidence of skin problems associated with amputation. One literature review in 2006 found only a single article describing the incidence and prevalence of skin problems in lower limb amputees. Observational studies have begun to describe potential determinants of skin problems of the residual limb in these individuals. Prevalence of skin problems ranges from 36% to 63%. Some features identified in the literature as associated with increased incidence of skin problems are increased prosthetic use, poor residuum or prosthetic hygiene, use of antibacterial soap, smoking, and individuals with transtibial residual limbs. Conversely, some published factors associated with reduced incidence of skin problems were higher age, amputation caused by peripheral arterial disease or diabetes, and use of a single-point cane or no walking aid compared with another type of walking aid. Reasons for these associations are clinically unclear; however, these seemingly contradictory findings may be caused by decreased use of the prosthesis or differences in reporting. Thus far, no relationship between the incidence of skin problems and socket design or prosthetic components has been identified. Further research is clearly needed to better understand the incidence of skin issues in the amputee population.

Suspension is an important component to evaluate. Beyond the obvious risk of suspension failure, pistoning or vertical prosthesis movement on the residual limb causes the prosthetic side to be effectively longer during swing. In addition to contributing to gait deviations, this situation can lead to the prosthesis catching on the floor or other objects and to trips and falls. Poor suspension also frequently leads to skin irritation this is due to friction or pistoning of the residual limb within the socket.

In addition to their contribution to gait deviations, poor fit, suspension, or alignment can make the prosthesis less stable, potentially reducing a user’s balance. The factors may also affect the user’s confidence in the prosthesis. If the user does not have confidence in the prosthesis, they may act tentatively, which can alter gait mechanics and hamper operation of safety features. For example, weight-activated safety features require a certain amount of body weight applied through the prosthesis. If the user fails to apply sufficient load through the prosthesis, the safety feature does not activate.

In regard to safety relative to prosthetic feet, some amputees adopt an ankle strategy to assist with postural control and balance. In order to effectively use an ankle strategy, ankle stiffness must be appropriately selected. Both ankle stiffness and the number of degrees of freedom available at the prosthetic ankle are factors during gait on prevailing terrain. In addition, during gait, the keel lever can affect knee stability. For instance, a keel lever that is too soft can result in a premature loss of anterior stability and knee buckling in terminal stance.

There are some situations in which a specialized prosthesis is required. For example, most prostheses are not designed for use in a wet environment. Showers, pools, and water sports may require a customized water prosthesis.

As stated earlier, the prosthesis is often a focal point in the rehabilitation of the amputee. Therefore, it is important that the entire health care team is involved with determining patient goals and expectations. It is equally important that the prosthesis includes correctly prescribed components such that safety issues are appropriately balanced with ambulatory and mobility demands. Furthermore, to optimize prosthetic function, appropriate training and rehabilitation on the functional implementation are crucial. Because of the prevalent rate of dependency for transfer and mobility early in the course of rehabilitation, there is increased risk of injury to members of the health care team and the patient’s caregivers. This subject is discussed next.

Safety and the prosthesis

Receiving the prosthesis is often a focal point early in the rehabilitation of the person with amputation. Before receiving the device, there can be safety issues. Commonly, postoperative compressive and limb-shaping strategies are used. In some cases, incision lines can be stressed if attempting to don a shrinker when the scar is not closed. Poorly fit shrinkers can lead to improperly shaped limbs that are prone to skin breakdown. With regard to use of compression wrapping, potential concerns include a constrictive tourniquet effect with transverse, circularly applied wraps. Further, compressive wrap fasteners are sharp and there is an obvious concern for use with people whose sensation and circulation are compromised. A safer method of stump wrapping is the is the figure eight technique with use of tape for closing ends of elastic compression wrap.

In some cases, immediate postoperative prostheses or rigid dressings can be furnished. The purpose of these devices is to manage limb volume and provide closely supervised and early preprosthetic weight-bearing capabilities. They also have a secondary function of providing protection to the limb from external trauma and preventing knee contractures. There are numerous benefits such as limb conditioning and acclimation to donning a definitive device. However, these preprosthetic devices can be a source of safety concern. If supervision is inadequate, fitting is poor, structural strength is insufficient, and so forth, these devices can lead to skin and limb trauma, material failure, falls, and other problems. The literature is mixed on the use of these devices, with a generally positive view. A large retrospective review of literature spanning 1960 to 2002 compared measures of safety, efficacy, and clinical outcomes of various strategies of postoperative dressing and management in transtibial amputation. Analysis of 10 controlled studies supported only 4 of the 14 claims cited in the uncontrolled, descriptive studies reviewed. Postamputation dressing and management strategies aim to improve wound healing, control pain, allow early prosthetic fitting, and enable a quick return to function.

Once the time has come and prosthetic component selection proceeds, prescription is necessary. Risks are associated with underprescription and overprescription of components. In terms of underprescription, the active user who receives components below their functional capabilities is at risk of either experiencing poor performance from their prosthesis or potentially catastrophic component failure. The opposite phenomenon (overprescription of components) is equally problematic because higher-level components may require a more aggressive pattern of use to optimize function. This situation could introduce nonoptimal forces to the amputated residual limb. In addition, higher functioning components may introduce the possibility of participating in higher-level activities. For instance, some microprocessor knees may offer reciprocal stair descent (or ascent). Some users may feel obligated to attempt these activities to their detriment and without adequate training, strength, conditioning, and so forth.

With regard to the prosthesis itself, there are inherent safety issues with most elements of the prosthesis. For example, the socket has the complex task of supporting the residual anatomy and structurally interfacing with the components transferring forces between the body and environment. Socket fit can be poor because of anatomic challenges such as birth anatomy, and acquired and developed variations such as heterotopic ossification. Socket issues are one of the most common prosthetic problems.

The skin of the residual limb in lower limb amputees is prone to problems. The skin of the residual limb was not designed for load bearing, but that is what is required when using a lower extremity prosthesis. The skin of the residual limb is exposed to shear and stress forces, increased moisture, and prolonged exposure to the prosthesis. Consequently, various skin problems may develop. Frequently, treatment of skin-related prosthetic issues involves a period of time of not using the prosthesis. This situation increases the falls risk. It has been suggested that once the issue has been resolved, continued prosthetic use does not affect healing.

There is limited research on incidence of skin problems associated with amputation. One literature review in 2006 found only a single article describing the incidence and prevalence of skin problems in lower limb amputees. Observational studies have begun to describe potential determinants of skin problems of the residual limb in these individuals. Prevalence of skin problems ranges from 36% to 63%. Some features identified in the literature as associated with increased incidence of skin problems are increased prosthetic use, poor residuum or prosthetic hygiene, use of antibacterial soap, smoking, and individuals with transtibial residual limbs. Conversely, some published factors associated with reduced incidence of skin problems were higher age, amputation caused by peripheral arterial disease or diabetes, and use of a single-point cane or no walking aid compared with another type of walking aid. Reasons for these associations are clinically unclear; however, these seemingly contradictory findings may be caused by decreased use of the prosthesis or differences in reporting. Thus far, no relationship between the incidence of skin problems and socket design or prosthetic components has been identified. Further research is clearly needed to better understand the incidence of skin issues in the amputee population.

Suspension is an important component to evaluate. Beyond the obvious risk of suspension failure, pistoning or vertical prosthesis movement on the residual limb causes the prosthetic side to be effectively longer during swing. In addition to contributing to gait deviations, this situation can lead to the prosthesis catching on the floor or other objects and to trips and falls. Poor suspension also frequently leads to skin irritation this is due to friction or pistoning of the residual limb within the socket.

In addition to their contribution to gait deviations, poor fit, suspension, or alignment can make the prosthesis less stable, potentially reducing a user’s balance. The factors may also affect the user’s confidence in the prosthesis. If the user does not have confidence in the prosthesis, they may act tentatively, which can alter gait mechanics and hamper operation of safety features. For example, weight-activated safety features require a certain amount of body weight applied through the prosthesis. If the user fails to apply sufficient load through the prosthesis, the safety feature does not activate.

In regard to safety relative to prosthetic feet, some amputees adopt an ankle strategy to assist with postural control and balance. In order to effectively use an ankle strategy, ankle stiffness must be appropriately selected. Both ankle stiffness and the number of degrees of freedom available at the prosthetic ankle are factors during gait on prevailing terrain. In addition, during gait, the keel lever can affect knee stability. For instance, a keel lever that is too soft can result in a premature loss of anterior stability and knee buckling in terminal stance.

There are some situations in which a specialized prosthesis is required. For example, most prostheses are not designed for use in a wet environment. Showers, pools, and water sports may require a customized water prosthesis.

As stated earlier, the prosthesis is often a focal point in the rehabilitation of the amputee. Therefore, it is important that the entire health care team is involved with determining patient goals and expectations. It is equally important that the prosthesis includes correctly prescribed components such that safety issues are appropriately balanced with ambulatory and mobility demands. Furthermore, to optimize prosthetic function, appropriate training and rehabilitation on the functional implementation are crucial. Because of the prevalent rate of dependency for transfer and mobility early in the course of rehabilitation, there is increased risk of injury to members of the health care team and the patient’s caregivers. This subject is discussed next.

Safety of the health care team and caregivers

Rehabilitation after amputation is a process. Involved in this process are several people, including health care team members and relatives and friends of the amputee. Commonly, patients need greater assistance early in the rehabilitation process as they are learning mobility and transfer skills without an anatomic connection to the floor. This situation requires new strategies for transferring into/out of chairs, cars, bed, bathtubs, and other environments, depending on previous function and goals. At times, in the early phase, family and friends may be tempted to provide high levels of assistance, introducing risk of injury to all involved. Considerable rates of injury are known to exist among rehabilitation professionals in association with patient-handling activities. It is plausible that the risk of injury in family caregivers of dependent loved ones such as amputees is greater, given that most of these individuals are untrained and the environment is likely ill equipped for safe handling and transfers.

Gait training the amputee has inherent safety considerations as well. Because amputees are known to have a pervasive rate of falls and balance compromise at high levels of function, those learning to ambulate may be at increased risk of falls. Thorough gait training should include a progression of not only skills (eg, weight shifting, stepping) but also a variety of environments. According to 1 study, most amputees (87%) experience at least 1 barrier in the environment. Gait training environments should include necessary therapeutic situations (eg, harness systems, treadmills) but also flat ground, prevailing terrain, ramps/hills, and stairs. Each new environment should ideally be practiced with progressively less support, introducing greater mobility; however, the potential for safety risk thereby increases. Stairs and ramps present unique challenges for amputees because of the altered forces on the prosthesis. It is important for the rehabilitation team to understand the functional capabilities of the particular prosthetic components as well as the individual to select the proper method of stair climbing or descending for that individual. Alternative methods such as seated stair handling may be considered for balance-impaired individuals or early in rehabilitation. In addition, if these environments, and others the amputee faces in the community, are not addressed, then ambulatory safety is not optimized for that patient.

Falls and lower extremity amputation

Lower extremity amputation is known to compromise gait, balance, and overall capacity to react to slips and trips. Thus, falls are pervasive and often seen as normal events in these individuals. In addition, when a limb is lost to vascular disease, several additional comorbidities and risk factors are in place that further increase the likelihood of falls. These factors include probable advanced age, presence of neuropathy, partial foot ulcerations or amputation on the sound side, and likely visual impairment.

The literature reports variation in fall incidence in individuals with lower extremity amputation based on clinical setting. Approximately 20% of lower extremity amputees fall while receiving inpatient rehabilitation acutely after limb amputation. Eighteen percent of those patients experience a fall-related injury. Wheelchair use, specifically self-transfers and reaching activities, have been identified as playing a major role in these falls. Risk factors associated with increased fall risk while undergoing inpatient rehabilitation have been identified and include age of 71 years or greater, prolonged length of stay (between 22 and 35 days), presence of 4 or more comorbidities, cognitive impairment, and use of benzodiazepines or opiates.

The incidence and risk factors associated with falls in individuals with lower extremity amputation in other care settings are less defined in the literature. Miller and colleagues reported that 52% of unilateral amputees living in the community fell within a 1-year period. Given that an estimated 1.8 million persons in the United States are living with limb loss, with that number expected to double by the year 2050, there is a great need for further work in this area. Specifically, efforts need to be made to acquire a greater understanding of fall-specific mechanisms, refine fall risk assessment, and develop an evidenced-based repertoire of fall-specific interventions customized to this patient population.

Despite the need for further research, some evidence does exist to guide health care providers in the management and treatment of fall risk in individuals with lower extremity amputation. Interventions showing promise include specialized componentry (ie, microprocessor knees), wheelchair design and user training, physical therapy intervention for gait/balance training, and the use of injury-reducing devices.

In a recent review of the literature by Highsmith and colleagues, safety, energy efficiency, and cost efficacy of C-Leg use for transfemoral amputees was summarized and reported. These investigators identified 7 articles pertinent to the topic of safety that met their established assessment criteria for methodologic quality and bias risk. These studies provided a grade B recommendation that after an accommodation period with a C-Leg, previous nonmicroprocessor knee users experience a decrease in the number and frequency of recalled stumble and fall events in addition to improved balance.

High fall incidence after limb amputation in the acute inpatient rehabilitation setting, which has been in large part related to wheelchair use, renders wheelchair skills training attractive as a fall prevention intervention. Dyer and colleagues reported preliminary data pertaining to a multidisciplinary fall prevention program implemented in this setting. This program included a multifaceted approach that spanned several risk domains to include overall risk assessment, environmental assessment, medication management, customized alteration of care plans in response to fall events, and continuous patient wheelchair skills training. Although the incidence of falls was reduced only marginally with this intervention in place, there was a marked reduction in the severity of falls and the incidence of repeat falls. This finding was encouraging given the scope of this problem in the inpatient rehabilitation setting after lower limb amputation.

Exercise intervention, specifically balance training, has been identified by many as a key element of any fall prevention program. A 20-minute balance training program performed on 5 consecutive days using a novel balance-specific mechanical apparatus on individuals with transtibial amputations was reported by Matjacic. Findings indicated improved performance on all functional outcome measures after intervention. Although falls was not an end point, the positive effect measured on balance and gait outcome is encouraging and investigation as to whether translation of these benefits to fall reduction warrants further study.

Many amputees require some type of assistive device when ambulating. Choices include single-point canes, quad-tip canes, forearm crutches, 2-wheeled walkers, and 4-footed walkers. In general, it is recommended to go from gait training in parallel bars to an appropriate assistive device to full weight bearing as quickly as possible. If walkers are to be used, a study by Tsai and colleagues of 20 persons found that 2-wheeled walkers allow individuals with lower limb amputations to walk more quickly and with less interruption. In addition, their walking was deemed no less safe than walking with a 4-footed walker.

Given the prevalence of falls and additional comorbidities that further increase fall risk in individuals with lower limb amputation, emphasis on injury prevention is imperative. Devices such as rigid dressings, stump protectors, and hip protectors should be considered for all individuals with lower limb amputations especially in those individuals at high risk for falls whose risk factors are not modifiable.

There are many needs and safety issues that are unique to persons with upper extremity amputations. Some of these issues include body image concerns, social isolation, overuse syndrome, significant impact on functionality of tasks/difficulties with activities of daily living (ADL), and skin integrity issues frequently caused by traumatic loss of the limb.

After any amputation, a person must deal with many psychosocial and adjustment issues. For a person with an upper limb amputation, these issues are magnified because of the inability to completely conceal an upper extremity prosthesis or missing limb. Upper extremities are visible in social situations and day-to-day activities (ie, shaking hands, eating, talking with hand gestures). Even if wearing an upper extremity prosthesis, a person may feel uncomfortable in social situations, because the prosthesis looks and functions noticeably different from a sound arm. Further complicating body image and other psychological issues, a person with an upper limb amputation may also be dealing with posttraumatic stress disorder, because upper limb amputations are frequently the result of traumatic loss. These issues may lead to low participation and social reintegration for some persons with upper extremity amputations.

Social isolation is yet another concern that persons with upper limb amputation may face. Because the number of persons with upper extremity amputation is significantly lower than those with lower extremity amputations, the person may not encounter others with an upper extremity limb loss, or not someone with the same level of amputation. Educational materials and support groups may be unintentionally focused on persons with lower extremity amputations because the numbers are so much greater. There is a wide range of potential levels of upper extremity amputation, so it may be difficult to find a peer visitor with the same level of limb loss.

Another concern is overuse syndrome. Many people with unilateral upper extremity amputations are at risk of developing a repetitive stress injury or problems associated with overuse of the contralateral limb. This situation can be caused by not wearing a prosthesis and performing all tasks, including tasks meant to be bilateral, using only the sound limb. Even those regularly using a prosthesis can encounter overuse issues, because the prosthesis is usually used as a tool, and the sound limb continues to function as the prime mover for all tasks. Some injuries associated with repetitive use/overuse are rotator cuff injuries, tendonitis, lateral/medial epicondylitis, and carpal tunnel syndrome. The frequency of overuse injuries has been reported as high as 50%. Another factor that affects overuse is the high rate of abandonment for persons with upper extremity amputations. The rejection or nonwear rate has been reported between 20% and 44%.

Although most persons with an amputation experience some change to or difficulty in task/ADL performance, there seems to frequently be a great impact on persons with upper extremity amputation. When a person with an upper extremity amputation loses the dominant arm, they have to relearn how to perform their basic ADL tasks. Many functional and ADL/instrumental ADL tasks are bilateral tasks, or tasks that require great hand and finger dexterity. Many of the tasks need to be performed by a different method or by using adaptive equipment and techniques. Upper extremity amputation makes it more difficult to use an assistive device for mobility, so for those with multiple injuries, the upper extremity amputation can exacerbate lower extremity mobility issues.

Because upper limb loss is frequently traumatic, it is not uncommon for a person with upper extremity amputation to have significant skin integrity issues, including burns, nonhealing wounds, repeated surgical/residual limb revisions, and extensive scarring. This situation can create multiple concerns for the person, including pain management, body image, psychological problems, ability to cope with and accept the amputation, infection, and difficulties being fitted for and wearing a prosthesis.

These are all potential concerns for any person with any amputation, but those with an upper extremity amputation may be at increased risk. These issues should be addressed early in the rehabilitation phase and should continue to be addressed throughout the rehabilitation process by all team members.