Epidemiology

Despite advances in surgical interventions and an emphasis on prevention programs, studies have shown a continued increase in the prevalence of people living with limb loss. There were nearly 2 million people living with limb loss in the United States in 2005. One study found that the incidence of dysvascular amputations increased by 27% between 1988 and 1996, although the incidence of civilian traumatic amputations decreased and congenital and cancer-related amputations remained stable. The prevalence of individuals living with limb loss is anticipated to continue to increase in the future as a result of a number of factors, including the aging of the overall population with increased life expectancy and an increase in the incidence of diabetes mellitus (DM). Studies predict a doubling of the elderly dysvascular amputation population by 2030, and that the overall amputation population prevalence will double by 2050.

Approximately 185,000 new amputations are performed in U.S. civilian hospitals each year, and in 2009, hospital costs associated with amputation totaled more than $8.3 billion. A large number of amputations are also performed each year in the U.S. Department of Veterans Affairs (VA) medical facilities, with an average of 7669 new amputation procedures performed annually between 2008 and 2013. The total population of veterans with amputations being treated in VA medical centers annually has increased from approximately 25,000 in 2000 to more than 80,000 in 2013. In addition, an increase in amputations of traumatic etiology has been seen in the U.S. Department of Defense (DOD) and VA health care systems as a result of military conflicts in Afghanistan and Iraq. Between 2001 and January 2014, these military conflicts resulted in 1638 U.S. service members who had sustained combat-related amputations, excluding those with amputations of the fingers and toes.

The majority of people with lower limb amputations have acquired their amputations as a result of disease processes, such as DM or peripheral vascular disease. Amputations secondary to vascular conditions and DM have been reported to account for 82% of limb loss related hospital discharges and 97% of vascular-related amputations involve the lower limb. Trauma-related amputations account for approximately 16% of amputations and those resulting from malignancy and congenital deformity are responsible for approximately 1% of amputations each. DM increases the risk of amputation to a greater degree than either smoking or hypertension. DM is reported to contribute to 67% of all amputations. The age-adjusted amputation rate for persons with DM has been found to be 18 to 28 times greater than that of people without DM. Among people with a lower extremity amputation, smoking cigarettes has been associated with a reamputation risk 25 times that of nonsmokers.

Amputations caused by disease processes generally occur in the aging individual and are associated with numerous comorbidities, such as cardiovascular disease, hypertension, end-stage renal disease, and arthritis. People with amputations caused by trauma, including military-related injuries, are predominantly younger in age and typically require a longer continuum of care following their amputations. These individuals may have more specialized prosthetic and rehabilitation needs secondary to the increased likelihood of returning to work or high-level sports and recreational activities. Individuals with military-related traumatic amputations also require management of commonly associated injuries, such as traumatic brain injury, hearing loss, visual impairment, and posttraumatic stress disorder (PTSD).

The most frequent level of amputation in the lower extremity varies according to the etiology. Toe amputations are the most common level overall when counting both major and minor amputations. With advances in limb salvage techniques, the number of partial foot amputation procedures has shown a significant increase over the past 10 to 15 years. The transtibial level is the most common major amputation level in the lower extremity, with transfemoral being the second most common.

Survival rates after amputation are quite variable depending on the cause of the amputation. The 30-day mortality following a vascular-related amputation ranges from 9% to 21%. More long-term survival has been reported to be 48% to 69% at 1 year, 42% at 3 years, and 35% to 45% at 5 years. DM and end-stage renal disease have been shown to negatively affect survival, with 5-year survival rates as low as 31% and 14%, respectively. Individuals with traumatic amputations have been noted to have significant cardiovascular and metabolic issues, which appear to be related to their traumatic amputation and not accounted for by obesity, sedentary lifestyle, or tobacco use. Despite these findings, individuals requiring an amputation secondary to a traumatic injury tend to have relatively normal long-term survival rates.

Amputation Terminology

The International Organization for Standardization (ISO) terminology for the description of both acquired amputations and congenital limb deficiencies has been widely accepted by clinicians, researchers, and professional organizations. Table 10-1 provides a comparison of the ISO terminology and the more traditional, common terminology, and a description of each level of acquired lower limb amputation. Although the common terminology is still used, use of the ISO terminology is recommended to improve the accuracy and consistency of amputation level description. The major and minor classification of amputation levels is also included in Table 10-1 . Major amputations have traditionally included amputations that occur at the ankle disarticulation level and more proximal. Although still frequently used, the major and minor amputation terminology can be misleading because amputation levels classified as minor (partial foot and digit amputations) can still have significant functional and quality of life implications for the individual with the amputation.

Rehabilitation Implications of Amputation Level and Surgical Technique

Both the level of amputation and the specific techniques used during surgery can have a profound impact on long-term functional outcomes following lower limb amputation. This impact can be expressed in terms of successful prosthetic mobility, prosthetic socket comfort, and a reduction of skin breakdown complications. Although the primary goal of amputation surgery is removal of the diseased, damaged, or dysfunctional portion of the limb, the surgery must also result in a residual limb that is optimized for motion, motion control, and proprioceptive feedback to achieve the most successful outcomes. Amputation surgery should not be considered to be a procedure of last resort or a failure of care. Instead, amputation surgery should be viewed as a reconstructive procedure that has the potential to improve a person’s functional independence, mobility, and quality of life. Although advances in surgical techniques have made limb salvage a more viable option in certain circumstances, delaying definitive amputation with attempts at limb salvage that have a low likelihood of success can create negative consequences.

Several principles should be considered in relation to the impact of amputation surgery level on rehabilitation outcomes. It is generally recommended to preserve as much limb length as possible at the time of amputation surgery. Although this principle holds true in many situations, there are instances in which preserving additional length has no functional benefit and may actually result in a less optimal outcome. For example, performing a transtibial amputation in the distal third of the tibia is typically not recommended because this may limit the use of high-profile prosthetic feet, the lack of soft tissue coverage in the distal third of the tibia can lead to decreased comfort and an increased risk of skin breakdown when wearing a prosthesis. Partial foot amputations provide the potential for short distance ambulation without a device, but these amputation levels are difficult to fit with an adequate prosthesis and also have a high rate of equinovarus deformity secondary to muscular imbalance.

Disarticulation level amputations may provide sparing of additional limb length and can provide the advantage of continued bone growth in those who are skeletally immature at the time of amputation. Knee disarticulation level amputations also provide the potential advantages of distal weight-bearing, self-suspension, and a longer lever arm for greater prosthetic limb control. Amputations at the ankle disarticulation level afford the potential to ambulate short distances without a prosthesis. Disarticulation level amputations may also be favored at times in individuals with spinal cord injury to maintain muscle balance and reduce the risk of contracture formation. However, despite these apparent advantages, disarticulation level amputations are often not recommended because they can result in poorer cosmetic outcomes and may limit the availability of prosthetic component options.

Although the ultimate level of amputation is often dictated by the amount of blood flow and tissue viability in cases of vascular disease or by the extent of soft tissue and bone damage in cases of trauma, it is ideal for rehabilitation providers to provide input regarding the amputation level before the time of surgery when circumstances allow. Prediction of healing requires careful evaluation of multiple variables, including nutritional status and tissue perfusion. As noted, in persons with vascular disease, it is desirable to preserve length; however, performing the amputation at a more proximal level, where the likelihood of timely and successful healing is greater, may be a better option to facilitate rehabilitation and avoid multiple surgical interventions. In cases where there is a need for amputation secondary to cancer, preserving length always has to take lower priority to preserving the person’s life. In cases of extremity trauma, advanced surgical techniques with bone growth stimulation and tissue expanders have resulted in greater opportunities for both limb salvage and limb length sparing. The long-term outcomes of limb salvage compared with amputation after extremity trauma remain mixed, although recent studies of U.S. military personnel have shown improved overall functional outcomes, with the Short Musculoskeletal Function Assessment (SMFA) questionnaire, in those with amputations compared with those with limb salvage.

The surgical technique used at the time of amputation can also have a lasting impact on successful prosthetic limb use. Amputation surgery techniques should provide an adequate amount of soft tissue padding for a comfortable interface with the prosthetic socket while avoiding excessive, redundant soft tissues that can make donning the prosthesis difficult and allow excessive motion between the residual limb and the prosthetic socket during ambulation. Preserving skeletal length without adequate soft tissue coverage can lead to recurrent skin breakdown, soft tissue infections, osteomyelitis, and the need for revision surgery. Surgical techniques should also strive to avoid the development of adherent scar tissue over distal bone, which can lead to both pain and recurrent skin breakdown. Surgical technique can also have implications on the development of painful neuromas and heterotopic ossification (HO) in the residual limb.

Surgical management of the remaining muscular structures is also important. Myofascial closure involves closure of the muscle fascial envelope without attachment to the bone. This may provide adequate cushioning over the distal bone, but it provides limited stabilization of the muscle structure and may result in limited muscle power generation. Myoplasty techniques involve suturing of the muscle fibers and fascia. This may enhance muscle stability but can also result in a mobile sling of muscle that creates excess movement and the potential formation of painful bursa. With myodesis techniques, the muscle and fascia are directly sutured to the periosteum of the bone. This provides greater stabilization of the muscles and can enhance the contractile effectiveness and efficiency of the muscle. Adductor myodesis procedures to achieve muscle balance are especially important after transfemoral amputation to avoid excessive femoral abduction both in standing and during ambulation.

Residual Limb and Skin Care

Skin care represents an area of paramount importance that requires a consistent effort on the part of caretakers and the amputee. The latter should form strong, early habits for at least daily inspection of skin of the residual limb and the resolution of skin problems as soon as they develop. No condition should be considered too trivial to treat because a skin disorder, if neglected, has the potential to progress and cause much greater problems, such as sepsis and further surgical revision amputations. Through the use of a prosthesis, the residual limb skin of the amputee is subjected to numerous physical stressors. Friction, excessive pressures, humidity, sweating, and stretching are some of the mechanical ones that can create problems. The suction socket can create both positive and negative pressures, as can some other suspension systems.

General residual limb care recommendations include cleaning the residual limb daily, preferably in the evening, with soap and water. The limb should be pat dry. When the patient is not wearing the prosthesis, a shrinker or an ACE wrap should be applied to minimize or decrease swelling. After prosthetic limb wear, the residual limb should be examined for irritation, breakdown, blistering, or red areas. If any of these exist and a reddened area does not resolve within 20 minutes, the prosthesis should not be worn and a clinical professional should be consulted within 2 days. As the prosthesis is worn throughout the day, socks should be added to assure an appropriate fit is maintained. The amputee should make sure that the anatomic points of the residual limb line up appropriately with relevant points on the prosthesis (e.g., fibular head with the recess for this in the socket and patellar tendon with the patellar tendon bar). Transtibial amputees should keep the knee in full extension when not wearing the prosthesis and transfemoral amputees should not put a pillow under the residual limb or between the legs when in bed to prevent the formation of joint contractures. The skin should be examined once or twice a day, including the use of a mirror, if there are areas, such as the distal end, that are not easily viewed.

This type of close monitoring and care should also be applied to the contralateral extremity and foot. Daily cleansing, drying, and close inspection should occur, particularly for areas difficult to assess, such as between the toes, plantar surfaces of the foot, and the heel. Frequent assessment should also include sensation, pulses, edema, temperature, and examination for any evidence of any trophic or motor changes. Contralateral amputations are common; thus, aggressive preventive measures are warranted. Podiatric care of corns, calluses, and nails is also helpful in the prevention of complications.

In one study of lower extremity prosthetic users, five skin conditions comprised 79.5% of the skin problems in 337 lower extremities with a total of 528 skin lesions. These conditions included irritations, ulcers, inclusion cysts, verrucous hyperplasia, and calluses. In addition to these conditions, other reports indicate the following frequently occurring conditions: allergic contact dermatitis, acroangiodermatitis, epidermal hyperplasia, follicular hyperkeratosis, bullous disease, infections, and malignancies. Allergic contact dermatitis, an erythematous, weeping, and pruritic rash, can represent up to one third of the dermatoses seen in prosthetic wearers, often caused by the prosthetic materials. Patch testing should occur with the first round of testing, including standard allergens, components of the prosthesis, topical medications being used, and locally applied cosmetics and moisturizers. If the first panel is negative, then further testing can extend to adhesives and additional cosmetics. Treatment consists of elimination of the specific allergen and the use of topical and/or oral steroids.

When there is inadequate socket pressure on the distal end of the residual limb, verrucous hyperplasia can develop. This condition has a characteristic appearance consistent with its name “verrucous” or warty. Vascular injury or chronic bacterial infection can also play a role in its development. Shrinker socks and modification of the socket to apply appropriate pressures to the distal end help to resolve this problem. Topical antibacterial agents can be used for bacterial overgrowth.

Other residual limb problems can result from either inadequate socket fit or prosthetic alignment. For the transtibial amputee, bursae can develop. Bursitis from two types of bursae, synovial and adventitious, can develop, with the latter being more common. Synovial bursae develop during intrauterine life, whereas adventitious ones develop after birth. Synovial bursae are fluid-filled sacks that facilitate the movement between muscle and bone, ligaments, and/or tendons, whereas adventitious bursae develop from excessive shearing forces of the skin, particularly over bony surfaces. These shearing forces cause a breakdown of fibrous connective tissue with mucoid and myxomatous degeneration. There is no true synovial, endothelial lining. Bursitis results from either acute or chronic inflammation. On examination, the bursa is a fluctuant, painful swelling, generally over areas such as the fibular head, tibial tubercle, patella, or end of the residual limb. If needed, diagnosis can be confirmed through ultrasound or magnetic resonance imaging. The first line of treatment is usually a modification of the prosthesis. If there is suspicion of an infection, the bursa should be aspirated and the aspirant sent for analysis and culture.

Epidermoid inclusion cysts occur when elements from the epidermis are implanted in the dermis. The cells within the cyst produce keratin and the cyst can drain intermittently. These can be asymptomatic. If they do become symptomatic, they can present as small painful masses, which may also become infected. Treatment consists of excision, incision and drainage, and the use of antibiotics. When asymptomatic and unproblematic, these can be left alone.

Another common problem is hyperhidrosis, or excessive sweating, of the residual limb with use of the prosthesis. This situation can hinder the use of the prosthesis. Approximately 30% to 50% of amputees are affected. This condition has the potential to adversely affect the course of phantom limb pain (PLP) and residual limb pain (RLP). In small, uncontrolled trials, a single set of injections of botulinum toxin type B (1750 units) has been shown to reduce RLP, PLP, and sweating, and improve duration of prosthetic use and overall quality of life for up to 3 months.

HO results from the transformation of pluripotent, mesenchymal cells into osteoblasts that then create abnormal bone formation outside of the normal bone structure. The reasons for this transformation are not currently known. HO can occur weeks to months following amputation. The prevalence in service members with combat-related amputations is estimated to range from 36% to 63%. HO can be asymptomatic or cause symptoms that range in severity from mild to severe. It can also pose significant prosthetic fitting problems resulting in skin breakdown and RLP. In rare circumstances, however, HO can be beneficial and even facilitate fitting. In addition, HO can cause joint range-of-motion limitations and vascular or neurologic compromise that can create problems with mobility and ambulation. The diagnosis of HO occurs through assessment of characteristic symptoms, physical examination, and imaging. Characteristic complaints and examination findings include a change in pain, decreasing joint range of motion (ROM), residual limb swelling or warmth, and a change in socket fit. Imaging options include plain radiographs, computed tomography, magnetic resonance imaging, radionucleotide studies (triple phase bone scan), and ultrasound. Serum alkaline phosphatase levels can be monitored from the active phase into quiescence, but have limited specificity. Measures used to prevent formation or progression of HO include nonsteroidal antiinflammatory medications, bisphosphonates, and radiation therapy. Once the HO has matured, treatment options range from observation to surgical excision. Often, modifications are required to the socket to accommodate this bone growth.

Pain Management

Postamputation pain can range widely in both severity and persistence. The two fundamental types of pain are RLP and PLP. RLP involves pain that is restricted to the anatomic region of the residual limb. PLP involves pain that is perceived in the portion of the limb that is no longer present. This latter type of pain has an estimated prevalence of up to 85%, even years after amputation. Pain from the residual limb can also appear to radiate into the part of the limb that is no longer present. If there is no pain associated with amputated part of the limb, but there still are feelings and sensations in the portion of the limb that is no longer present, then this is called phantom limb sensation (PLS). PLS is nearly universal in the early recovery period postamputation. RLP can further be classified into either neuropathic or somatic origins. Neuropathic origins include neuromas and complex regional pain syndrome (CRPS). On dissection, neuromas demonstrate growths of Schwann cells amidst proliferating axons all encased within scar tissue. The free ends of the axons exist without Schwann cells and the anoxic environment of the scar tissue can create conditions in which the free nerve endings may fire repetitively. Virtually all amputees have neuromas at the site of the amputation, yet only 10% to 15% have pain from these neuromas. Diagnosis is confirmed by the presence of appropriate signs and symptoms. The pain from a neuroma is generally aching, cramping, or shooting with an intermittent, episodic nature. Provocation with pressure at the site of the neuroma helps to confirm the source. Treatment options consist of physical modalities, such as acupuncture, socket modifications, ultrasound, massage, vibration, and percussion. Nonsteroidal antiinflammatory medications, tricyclic antidepressants, and anticonvulsant medications are used with variable effectiveness. Injection with lidocaine, steroid, or phenol can be helpful. Radiofrequency ablation has also been used to treat this condition. Surgical excision can also be performed but runs the risk of creating a new, painful neuroma.

In addition to the development of neuromas, entrapment of nerves within scar tissue at the surgical incision site can occur, with resulting pain. Shear, pressure, and traction forces from the prosthesis can either evoke or worsen this pain. The socket can be modified to decrease pressures in this area or redistribute it. If this is ineffective, then injections into the scar or the use of oral medications are used. Surgical excision of this area is generally not effective.

Somatic pain in the residual limb can originate from a variety of sources, including HO, infection, tumor, ischemia, or arthritic joint changes. Infection may be superficial or occur in deeper tissues with development of osteomyelitis. Poor surgical technique that leaves bone improperly trimmed or muscle and fascia inadequately sutured can result in mechanical residual limb pain that can be exacerbated by wearing the prosthesis. Treatment can include socket or prosthetic modifications or surgical revision of the residual limb. Bony overgrowth can occur in children and more rarely in adults. Growth in the distal end can result in an irregular area of bone that projects into soft tissues, with the potential for causing pain and skin breakdown with prosthetic use. Socket modifications are attempted as a first-line effort to manage this situation, and surgical revision can be done if these efforts fail.

PLP can be perceived in any part of the missing amputated limb. The quality of pain can be variable and described as dull, squeezing, cramping, electrical-like, shooting, or sharp. It commonly manifests in an episodic manner with a severity that ranges from mild to severe and incapacitating. PLP tends to occur within the first few months after amputation and can persist indefinitely. The reported prevalence ranges up to 85% in the first years after surgery. Supraspinal, spinal, and peripheral mechanisms are thought to play a role in the origin of phantom sensations and PLP. Some findings point to a reorganization of the somatosensory cortex around the area representing the amputated part. Treatments can be directed at modulating the activities at any of these levels. Many treatment options have been tried to control PLP ( Box 10-1 ), even though there are few controlled studies to provide guidance in this area. Categories of pharmaceutical interventions include: N -methyl- d -aspartate (NMDA) receptor antagonists, opioids, anticonvulsants, antide­pressants, local anesthetics, and calcitonin. The NMDA receptor antagonists, such as ketamine, memantine, and dextromethorphan, are thought to exert to their effects at the dorsal horn. Opioids operate at both the spinal and supraspinal levels. Calcitonin exerts its effects centrally. The effectiveness of both calcitonin and anticonvulsants has varied in studies.

Psychological treatments, such as guided imagery, biofeedback, and hypnosis, have aimed at altering negative emotions, increasing adaptation to pain, and adjusting body image. Mirror therapy has some of the strongest research-based support. In this treatment, a mirror is placed adjacent to the intact limb and then moved in exercises designed to promote reorganization of the cortex with this visual input. Virtual reality systems have been used as an alternative to using mirrors.

Multiple electrical stimulation techniques have also been studied. Transcutaneous electrical nerve stimulation has shown promise. There are several studies that indicate effectiveness with placement of the electrodes on the intact limb. More invasive modalities have involved peripheral nerve stimulation, spinal cord stimulation, and deep brain stimulation. Pulse radio frequency energy treatment was reported as successful in one case study.

Psychological Support

An amputation and the associated changes in body image and functional capabilities can have a strong emotional impact that requires a period of adjustment and supportive interventions. Naturally, this adjustment involves not just the amputee but also their relationships and roles with regard to family and friends. The amputation of a body part has been compared with the loss of a loved one and the some have described the psychological process in three phases. In phase one, combined feelings of shock, confusion, and numbness lead to a general feeling of emptiness. Daily tasks can be overwhelming. In the second phase, mourning predominates and consumes most of the amputee’s energy and focus. Finally, the amputee progresses to the adjustment phase and the amputee finds a sense of self-worth and competency in daily life. Several factors may hamper a progression through the phases to successful adjustment. Such factors include insufficient support from family members and caregivers, negative emotional states, such as a feeling of social isolation, low self-esteem, and a lack of a sense of wholeness, social anxiety, and body image discomfort.

In a study examining the relationship among tenacious goal pursuit (TGP), flexible goal adjustment (FGA), and affective well-being in individuals with lower limb amputation, TGP and FGA had different relationships with subjective well-being. TGP signifies changing one’s life situation or behavior to facilitate goals, whereas FGA signifies changing goals to accommodate situational limitations. TGP seemed to foster a positive effect, whereas FGA played a role in reducing negative affect. According to the authors, these two factors could potentially serve two useful functions: identifying amputees who might have negative affective outcomes and providing useful areas of intervention to ameliorate negative affect.

One study evaluated the roles of positive attitudes for amputations, among other diagnoses, and found that hopefulness correlated positively with functional outcomes and participation during the inpatient rehabilitation program. Another study of young traumatic amputees reported that more than half had been given a formal psychological diagnosis. The most frequent included PTSD, anxiety, depression, and substance abuse, with some individuals having two or more. These psychological disorders have the capacity to impair adjustment to physical issues. Almost two thirds of individuals with combat-related amputations have PTSD; anxiety and depression occur in approximately a quarter; and substance abuse is found in approximately 6%. Level of amputation is associated with severity of psychological disorders.

In a study relating spirituality to quality of life of predominantly male subjects with traumatic, transtibial amputations, the researchers concluded that “existential spirituality,” female gender, and age greater than 50 years had a positive association with increased quality of life. Existential spirituality also correlated positively with satisfaction with life, health, and social integration.

Studies examining return to work after lower limb amputation reveal that, overall, the rate of return to work is around 66%. Although the percentage of amputees keeping their preamputation job ranged from 22% to 67%, the employment achieved after amputation necessitated more education, had greater complexity, and required less physical functional requirements. General parameters that influenced return to work included age, gender, and educational level. Medical factors included level of amputation, number of amputations, comorbidities, the cause for amputation, and continued medical issues with the residual limb. Functional and prosthetic factors that related to return to work were time to fitting of the prosthesis, comfort with wearing the prosthesis, ability to walk distances, and other physical limitations with walking. Vocational factors influencing return to work include support from an employer, salary, who initiated the effort (individual, employer, family, and agency), and a social support network.

Preprosthetic Phase Rehabilitation Considerations

The preprosthetic phase of rehabilitation therapy begins before the surgery and continues until the first fitting and training with a new prosthesis. Most patients fall within a certain timeframe for fitting of the initial or temporary prosthesis and then the subsequent definitive prosthesis. Before the surgery, the rehabilitative team, composed of the physiatrist, physical therapist (potentially including occupational therapy as well), and prosthetist, should provide guidance and information about the rehabilitation process that will unfold after the amputation has been performed. Instruction in proper bed and chair positioning should be provided and an emphasis placed on appropriate exercises to maintain the joint ROM as well as the strength and endurance of important muscle groups. Not all amputees will become prosthetic candidates and this issue must also be approached carefully. Psychological support for the pending “loss” should also be provided.

Where possible, influencing surgical decision on the length of preserved residual limb is critical. Of importance are the lengths of the residual bone (femur or tibia) and the overall limb (proximal mark to the end of the soft tissue). Starting points on the transfemoral limb can be either the ischial tuberosity or greater trochanter, whereas for the transtibial limb the tibial plateau or tibial tubercle can be used. The end point is either the end of the bone or the distal soft tissue. For transtibial amputations, the optimal length of the residual tibia measured from the tibial plateau is 3 to 6 inches. Too short a residual limb (i.e., <3 inches) will compromise control of the prosthesis and too long (i.e., 6 inches) of a residual limb may limit the ability to use the posterior compartment musculature for soft tissue coverage over the distal residual limb. For the transfemoral amputation level, preservation of length must be balanced against displacement of the prosthetic knee center of rotation too far distal compared with the nonamputated limb.

After surgery, the primary emphasis is on wound care and healing, pain management, edema control, maintaining ROM in joints, initiating strength and mobility exercises, overall residual limb and prosthetic use education, and psychological counseling. Edema control of the residual limb can be achieved in multiple ways, including soft dressings, ACE wraps, semirigid dressings, rigid dressings, rigid removable dressings, plaster casts, and immediate postoperative fitting of a prosthesis, all of which not only control edema but also help reduce pain and protect the residual limb and surgical area from trauma. The choice for edema control depends on many factors, including the preference of the surgeon and the familiarity of the staff with the different options. Studies examining efficacy have revealed varying outcomes, but most authors have concluded that semirigid and semirigid removable dressings having greater effectiveness for edema control than elastic wraps/garments, but only in the first few weeks.

In addition to edema control, shaping of the residual limb is also important. Ideally, the transfemoral residual limb would evolve into a conical shape, whereas the transtibial one should be more of a cylindrical one. Periodic circumferential measurements of the residual limb should be taken to assess volume and to help determine readiness for fitting. The transtibial residual limb has achieved a more mature shape when the distal end is slightly less in circumference than the proximal area. There is a more marked difference for the transfemoral residual limb.

Educating the preoperative and postoperative patient on appropriate position in bed and wheelchair is critical. In addition to assuring appropriate positioning in the bed and wheelchair to avoid flexion contractures of the hip and knee, monitoring of ROM in these areas should be performed regularly. Careful joint ROM measurements with a goniometer are important, with knee extension measured with the goniometer, the arms are carefully aligned with the femur and tibia, and hip assessment is performed with the Thomas test. Contractures of the hip and knee on the amputated side can hinder the process of fitting a prosthesis or prevent it altogether. A knee flexion contracture can increase the energy, strength, and endurance needed for prosthetic ambulation. A hip flexion contracture greater than 15 degrees makes prosthetic fit difficult, and appropriate alignment modifications to the prosthesis are required.

Preprosthetic mobility after surgery often involves the use of a wheelchair. With the loss of a limb, the center of mass (COM) has changed and balance within a wheelchair can become more precarious if adjustments are not made. Because the COM moves posteriorly, the wheelchair can be made more stable by also moving the axles of the posterior wheels posteriorly. This issue becomes even more significant for individuals with bilateral amputations. For those with very good single limb balance, ambulation with crutches may be a possibility; otherwise, the use of a walker can be useful for negotiating short distances. Practice in the parallel bars may be necessary before sufficient competence has been developed. These skills in ambulation without a prosthesis are not a necessary prerequisite for prosthetic training and ambulation.

Prosthetic Training Phase Considerations

Aside from strengthening, ROM, and endurance exercises, early training for the amputee with a prosthesis involves activities such as maintaining the COM within the base of support, standing and balancing on the prosthetic limb, and simple stepping exercises. Part of the early training in using a prosthesis concerns sock ply management. The patient must consistently apply these principles for as long as the prosthesis is used. The first principle for the amputee to understand is that the residual limb will vary in volume, and this requires an adjustment of prosthetic fit through the addition or deletion of socks. Prosthetic socks commonly come in one, three, five, and six ply. With wear, the socks tend to lose some of their thickness. Factors that affect limb volume include fluid shifts associated with renal failure and dialysis, muscle atrophy, weight gain or loss, and associated medical conditions, such as congestive heart failure. Wearing the prosthesis will create a pumping action that will force fluid out of the residual limb and reduce its size. During the first 3 to 12 months after amputation, the residuum will typically swell if a shrinker is not worn consistently. Socket changes are generally required when the amputee needs 15 ply or more of socks, to accommodate shrinkage of the residual limb. If the residual limb volume is stable for 8 to 12 weeks, then the time is appropriate for fitting of the definitive prosthesis, which usually occurs around 6 to 18 months after surgery.

Close observation of the patient during donning and doffing of the prosthesis can provide valuable information in determining issues with the fit of the socket. For the prosthesis with a pin lock system of suspension, the number of clicks gives some clue as to the level of fit. If the patient is only able to obtain a few clicks into the locking mechanism, the patient may not be fitting down into the socket completely. If the speed of the clicks increases, this could indicate that the residual limb has shrunk and that additional socks should be added. Ease of donning is also a clue. If the prosthesis can be slid onto the residual limb easily and without resistance, then more socks are needed. Red marks on the residual limb also give some indication of the fit. If the distal end of the limb is getting red and sore from too much pressure, then more socks are needed. If after walking with the prosthesis there are reddened areas (reactive hyperemia) that do not resolve after a few minutes, then the socket is creating excessive pressure on the residual limb in these locations, and adjustments have to be made. After the patient understands the importance of sock ply management and how to appropriately adjust this aspect, instruction in donning and doffing the prosthesis can occur. If a liner is being used, the liner must be applied with careful attention to technique. The liner should be turned inside out and the distal end of the residuum should be placed directly against the liner, which should then be rolled upward without any air pockets. An air pocket between the distal end of the residuum and the liner will create suction and will affect the skin accordingly. Liner care should include washing it with soap and water at the end of the day. Drying should occur with the fabric side directed outward. This position will protect the tacky inner area from trapping dirt, dust, and hair that can adversely affect the skin. Spraying the inner part of the liner with diluted rubbing alcohol once or twice a week can reduce the buildup of bacteria on the liner surface and help prevent residual limb infections.

Socks must be donned in a manner that eliminates wrinkles because these will create pressure areas that can cause skin breakdown. Wrinkles can be smoothed away with the tips of fingers. For the wearer of a transtibial prosthesis, the socket must be correctly aligned so that the bony prominences fit into the reliefs that were designed to accommodate them in the socket. The use of too many or too few socks can also prevent the correct seating of the residuum in the socket. In general, the socket should be donned in a consistent manner irrespective of the type of socket.

Once the correct donning technique has been mastered, the amputee can embark on other more advanced pregait activities. These exercises focus on fostering good balance and strength, weight-shifting, and on isolated parts of the gait cycle. Early training involves static weight-bearing, dynamic weight-shifting exercises, reaching activities, repeated stepping actions in all directions, identification, and elimination of gait deviations, and sit-to-stand and stand-to-sit exercises. Tap ups represent one activity that generates skill and confidence in weight-shifting and bearing weight on the prosthesis. Within the parallel bars, the first steps in learning the various parts of the gait cycle can begin. One of the first exercises involves learning the heel/toe pattern with the prosthetic leg. For the transfemoral amputee, this exercise will also initiate the learning process for manipulating the prosthetic knee. Ultimately and according to the patient’s capabilities and certainly staying within any safety considerations, the patient may be able to advance to walking on level surfaces in different settings and on uneven terrain. Negotiating environmental obstacles, such as ramps and curbs, will also be important.

Functional Classification

The Centers for Medicare and Medicaid Services (CMS) have published a functional classification system for individuals with amputations to guide prosthetic limb prescription based on the actual or potential functional abilities of the person. The guideline divides functional mobility into five categories and provides recommendations for the prescription of prosthetic components based on the functional mobility category ( Table 10-2 ). These five categories have been referred to as the Medicare Functional Classification Levels (MFCLs), the K-Level Modifiers, or the Functional Index Levels. Although the amputee’s functional mobility category determination should, to the extent possible, be based on objective clinical findings, the classification also allows for clinical judgment by the prescribing physician or team in predicting the anticipated functional level of the new amputee once they have been fit with the prosthesis. The determination should also take into account the individual’s medical conditions and medical comorbidities that could affect the person’s ability to function with the use of a prosthetic limb. The patient’s goals and desires for prosthetic use must be considered as part of the prescription process, and if the goals of the patient are not realistic with respect to the benefits of a prosthetic limb, education in this regard will be required. It should be emphasized that the final determination of the prosthetic prescription is ideally a team decision involving the physician, prosthetist, therapist, and patient.

Prosthetic Restoration

Socket Designs

The prosthetic socket serves as the platform for connecting the amputated residual limb to the prosthetic limb. In some circumstances, there is direct contact between the residual limb skin and the prosthetic socket, whereas in other circumstances, a liner or other materials are used as the interface between the residual limb and the socket. The socket itself can also function to suspend the prosthesis to the residual limb, but in most instances, the suspension is accomplished through an additional suspension method. For an ideal functional outcome with use of a prosthetic limb to be achieved, the socket must be comfortable and secure, and it must facilitate motion transfer from the residual limb to the prosthetic limb. Having a secure and comfortable connection allows the amputee to effectively weight-bear through the prosthesis and efficiently advance the limb during the swing phase of gait. Prosthetic sockets are made from various materials and there are a variety of socket designs that have been developed for each level of lower limb amputation. The most commonly used prosthetic socket designs are highlighted in the following sections.

Transtibial Socket Design

There are several different transtibial socket designs that are currently being used in the prosthetics field. Some of these designs are considered hybrid designs because they combine the features of one or more traditional designs. Independent of the type of design, the goal is to provide a socket that is well fitting, comfortable, and secure.

Patellar Tendon Bearing.

The major weight-bearing area for the residual limb in this design is at the patellar tendon with a counter force in the popliteal region. Current socket technology also provides a total surface contact with specific weight-bearing areas in the soft tissue regions of the residual limb. These would include the anterior muscle compartment, medial tibial flare, shaft of the fibula, gastrocnemius muscle, and the distal end which receives slight pressure. Excessive contact over bony areas is avoided. For the patellar tendon bearing (PTB) socket, the anterior trim line is proximal to the patellar tendon insertion on the patella. The medial-lateral trim line is at the midlevel of the medial condyle. The posterior trim line is at or just below the midpatellar tendon with reliefs for the medial and lateral hamstring tendons (generally at the bend of the knee so that the patient can bring the prosthesis to a 90-degree angle).

Patellar Tendon Bearing and Supracondylar/Suprapatellar.

The only difference between the PTB and the PTB-supracondylar/suprapatellar (PTB-SC/SP) socket design is the proximal trim line. By raising the trim line in the medial-lateral dimension to above the medial condyle, additional stabilizing support for the residual limb is provided with added suspension. With the suprapatellar extension, greater anterior/posterior support is provided with a knee hyperextension stop, as well as some additional suspension.

Total Surface Bearing.

This socket design creates more equal weight-bearing distribution throughout the socket. Unlike the PTB design, the total surface bearing (TSB) socket is designed to globally apply forces throughout the residual limb. There is very little pressure difference between areas and limited relief for bony areas. Many TSB designs use gel-type interfaces, which also facilitate the more even distribution of forces over a larger surface area. Trim lines are similar to the PTB design. Clinically, the typical transtibial socket design is a combination of both the traditional PTB and the TSB design.

Transfemoral Socket Design

As with transtibial socket designs, there are many versions of the transfemoral socket. Newer socket designs have flexible inner liners with hard external frames that can be fenestrated to allow for bony relief and muscle contraction. The external frames that attach the socket to the distal prosthetic components are laminated with carbon graphite and can be imprinted with a design of the patient’s choice. This feature allows for greater incorporation of the prosthesis into the patient’s lifestyle and body image.

Quadrilateral Socket (Quad Socket).

This type of socket is used only rarely today. As the name implies, this socket is rectangular in shape with the medial-lateral dimension being greater than the anterior-posterior dimension ( Figure 10-1 ) The scarpa’s triangle provides a posterior-directed force keeping the ischial tuberosity on a ledge, which is the major weight-bearing area of this design. The distal two thirds of the socket design have the general shape of the residual limb of the patient and is total contact in design with little to no muscle contouring. There is some hydrostatic weight-bearing through this more distal aspect of the socket.

Transverse cross-section of the proximal aspect of thigh and quadrilateral socket.

(From Schuch CM: Transfemoral amputation: prosthetic management. In Bowker JH, Michael JW, editors : Atlas of limb prosthetics: surgical, prosthetic, and rehabilitation principles, ed 2, St. Louis, 1992, Mosby-Year Book.)

Ischial Containment Socket.

The ischial containment socket is the most commonly used transfemoral socket design. The original design for this socket was described by Ivan Long, CP, as a Normal Shape Normal Alignment (NSNA) design. This socket design takes a more anatomic approach to transfemoral socket fitting with the ischial tuberosity now contained inside the proximal trim lines. The principle of this design is to provide a bony lock of the ischium in the prosthetic socket. The inclusion of the ischium along with the lateral femur and pubic ramus prevents excessive abduction of the femur and increases medial-lateral stability during the stance phase of gait. This is especially helpful for individuals with shorter residual limbs and for those with mild hip abductor weakness. The distal two thirds of this design have more muscle contouring compared with the quadrilateral socket.

Subischial Socket Design.

The third socket design is the subischial socket. The proximal trim line of this socket falls distal to the ischial tuberosity and relies completely on the thigh musculature for weight-bearing. This socket design usually involves an elevated suction socket and requires a patient that is attentive to their prosthetic care. Figure 10-2 demonstrates the three different transfemoral socket designs.

Transfemoral socket designs. Left, Ischial containment. Center, Quadrilateral. Right, Subischial.

(Based on an illustration by Brian Kausek.)

Prosthetic Limb Suspension

Suspension is the technique by which the prosthesis is connected and held onto a person’s residual limb ( Figures 10-3 to 10-6 ). Suspension can be provided through a variety of mechanisms, including the anatomic shape of the limb, a liner, a sleeve, or with suction. Suspension is a critical issue for successful use of lower extremity prostheses. Without proper suspension, the amputee patient cannot ambulate efficiently and will lack control over their prosthesis. Improper suspension can also increase the risk of falls with ambulation. This lack of suspension will negate the beneficial effects of any newer prosthetic component technology.

Electric vacuum pump system with key fob.

(LimbLogic, The Ohio Willow Wood Company, Mt Sterling, Ohio.)

Mechanical vacuum pump incorporated into prosthetic foot.

(Unity, Össur, Reykjavik, Iceland.)

Mechanical vacuum pump with vertical shock pylon.

(Harmony P3, Ottobock, Minneapolis, Minn.)

Transfemoral liner with distal mechanism for pin lock.

(Iceross, Össur, Reykjavik, Iceland.)

Suction Suspension

By creating a proximal seal within an airtight socket environment, suction sockets create a slight negative pressure to hold the prosthesis on to the residual limb. However, because of this negative pressure, a prosthesis with a lack of distal contact can create skin problems, including verrucous hyperplasia if the lack of distal contact is chronic in nature. Historically, this approach has used a direct skin fit (no socks or liners between the residual limb and socket). The advent of gel liners has enhanced traditional suction suspension methods.

Elevated Vacuum Suspension

Elevated vacuum suspension can be seen as a derivative of suction suspension facilitated in part by the advent of interface liners. In contrast to traditional suction socket systems in which air is passively expelled from the socket through a one-way air valve, elevated vacuum systems actively draw additional air from within the socket environment. These designs provide a secure fit and stabilize the prosthesis firmly to the patient’s residual limb. There are currently several mechanisms that are used to create an elevated vacuum suspension environment, all of which require a TSB socket. Elevated vacuum systems maintain an enhanced negative pressure between the gel liner and socket wall. This negative pressure provides suspension and may assist with maintaining stability of the patient’s residual limb volume. Elevated vacuum requires a pump that draws air out of the prosthetic socket. These pumps can be either manual or powered devices, and this technique can be used for either transtibial or transfemoral levels.

Pin Lock Suspension

Pin lock suspension requires a liner with a distal umbrella of an embedded mesh matrix and a threaded attachment site. A locking pin can then be threaded into that liner, which will then engage into a locking mechanism attached to the prosthetic socket. The lock can be either a clutch mechanism or rotary style. Locks can be either push or pull to unlock. Pin lock suspension provides a secure mechanical link between the amputee and the prosthesis. The gel liner holds onto the patient and the pin locks into the prosthesis. This system can be used for either transtibial or transfemoral amputation levels. Pin lock suspension can be very easy for the patient to use and offers an audible click to reinforce engagement of the lock. The biggest disadvantage is the potential for distal distraction and shearing forces on the tissues of the residual limb.

The lanyard strap suspension is a version of pin lock suspension. Instead of a pin and locking mechanism, a Velcro strap is attached to the gel liner and fed through an opening in the distal portion of a prosthesis by the patient and fastened on the exterior portion of the socket. This system requires that the patient has some manual dexterity but may be simpler than the pin lock to manage.

Alternate Suspension Designs

There are many other methods of suspending a prosthesis. Boxes 10-3 and 10-4 list the most commonly used suspension methods for transtibial and transfemoral level amputations. Sleeves, straps, belts, and buckles have been used in the past and are still being used in some cases either because of patient preference or because of anatomic considerations with the residual limb. These techniques can involve straps to proximal anatomic anchors. With transfemoral amputations, the suspension might involve a hip belt over the contralateral hip (Silesian Belt) or a combination of a hip joint, pelvic band, and waist belt. In transtibial level amputations, this could include a cuff suspension strap that is just proximal to femoral condyles.

Box 10-3

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