Amputations and Prosthetics







The world breaks everyone and afterward many are strong at the broken places.


Ernest Hemingway




CRITICAL POINTS





  • Amputation of an upper limb affects physical and psychological well-being and requires renegotiation of every aspect of daily life.



  • An interdisciplinary team approach is essential to address the many needs of amputee patients.



  • Early initiation of rehabilitation creates an expectation of recovery and demonstrates the interdisciplinary team’s commitment to facilitate the patient’s return to independence.



  • Education of the patient begins immediately and continues throughout the rehabilitation process.



  • The therapist is instrumental in helping the patient develop a vision of independence that includes the integration of a prosthesis for a satisfying life after amputation.



  • Connection to other amputees is critical for acceptance and adjustment to limb loss.



  • Early prosthetic fitting is associated with successful use of the prosthesis and a return to gainful employment. *




* See Gaine WJ, Smart C, Bransby-Zachary M. Upper limb traumatic amputees, review of prosthetic use. J Hand Surg (British). 1997;22B:(1)73-76 and Kejlaa GH. Consumer concerns and the functional value of prostheses to upper limb amputees. Prosthetic and Orthotics International. 1993;17:157-163.

Working with upper limb amputee patients is both rewarding and challenging. There are many facets of the rehabilitation process such as residual limb care, knowledge of mechanical operations of prosthetic equipment, behavioral health adjustments to amputation, phantom pain and sensations, adaptive equipment options, muscle retraining, and optimal use of a prosthesis for task accomplishments. This chapter provides guidelines to improve efficiency and uniformity in the delivery of rehabilitation services for the upper limb amputee.




Etiology and Classification of Upper Limb Amputations


Causes of amputation include vascular disease, trauma, and malignancy of bone and joint. Ninety percent of acquired upper limb amputation occurs from trauma involving machinery, explosives, projectiles, motor vehicle accidents, burns, electrical, and cold exposure injuries. The majority of traumatic amputations occurs in young males, with one study reporting a male-to-female ratio of 8 : 1; therefore, when appropriate, the pronoun “he” is used in this chapter to refer to the singular tense of the amputee patient.


The incidence of amputation in the United States is estimated at 185,000 per year. The most recent prevalence data are derived from the National Health Interview Survey-Disability done in 1996, which did not separate upper from lower limb amputations. These data reported 1.2 to 1.9 million people in the United States living with an amputation. Multistate probabilistic models estimated prevalence of amputation in the United States to be upward of three million people by 2050.




Interdisciplinary Team Approach


Amputation of an upper limb affects physical and psychological well-being and requires renegotiation of every aspect of daily life. Addressing the many needs of amputee patients is best accomplished by an interdisciplinary team. The clinical team may include the following professionals: vocational counselor, occupational therapist, physical therapist, social worker, psychologist, prosthetist, physiatrist, dietitian, and rehabilitation nurse. Many medical centers and rehabilitation facilities host amputee clinics to promote this team approach. If this format is not available, it becomes critical (at a bare minimum) to develop open lines of communication among the patient, therapist, prosthetist, and physician.




Initial Evaluation


It is important to meet the patient as soon as possible after limb amputation. Early initiation of rehabilitation creates an expectation of recovery and demonstrates the interdisciplinary team’s commitment to facilitate the patient’s return to independence. The initial encounter is one of mutual information exchange through interview, formal evaluation, and education and instruction. During this initial interaction, the patient is helped to commit to a rehabilitation program to regain his functional independence.


The operative report is reviewed to learn how the surgeon stabilized muscles over the distal bone. Two procedures are done. Myoplasty involves muscle-to-muscle closure. Myodesis involves the attachment of muscle to periosteum or bone, which is the preferred surgical procedure for patients at all levels of amputation.


The postoperative pain management plan is reviewed. If an indwelling nerve block was placed to diminish the intensity of postoperative pain, the patient may have decreased sensory and motor function in the limb. The patient’s pain level is noted, and the type, duration, location, and intensity are documented.


Similar to standard rehabilitation evaluations, a thorough medical history is taken, with note made of the mechanism of injury and of co-morbidities, such as vision and hearing loss, bone and soft tissue injuries, brain injury, and burns. These are common in patients who have sustained amputations caused by trauma.


The interview portion of the evaluation provides valuable information needed to plan a holistic rehabilitation program. The therapist asks the patient about his goals; vocational responsibilities; avocational interests; support systems; roles and responsibilities at home, work, and in the community; and pain tolerance and past experiences dealing with and overcoming hardship and pain. The patient’s familiarity with anyone living with amputation is determined. This provides the therapist with insight as to the patient’s exposure to and level of understanding of amputees.


Systematic evaluation of the current level of functioning in activities of daily living (ADL), and an assessment of the overall cognitive status is conducted because it influences decisions about prosthetic prescription.


The therapist measures and makes a note of residual limb length, shape, distal soft tissue coverage, edema; skin grafts, lesions, sutures, characteristics of other scars; upper trunk and neck mobility; range of motion of remaining joints; sensation; and muscle strength. Evaluation of strength, dexterity, sensation, and range of motion in the contralateral upper limb is performed.


Education and Resources


Education of the patient begins immediately and continues throughout the rehabilitation process. The patient’s expectation of rehabilitation, goals, and the progression toward goals are discussed as well as the importance of his compliance and motivation in promoting an optimal outcome. The therapist is instrumental in helping the patient develop a vision of independence that includes the integration of a prosthesis for a satisfying life after amputation. An attitude of optimism and encouragement is critical; this initial meeting is overwhelming. Written materials, such as InMotion magazine by the Amputee Coalition of America (ACA), are helpful.


The therapist can make recommendations regarding adaptive equipment to address functional difficulties. If unable to directly issue equipment, a list of the recommended items and resources are offered ( Box 99-1 ). Connection to other amputees is critical for acceptance and adjustment to limb loss. A powerful resource is a peer-visitor (certified through the ACA) who serves as a role model of someone living and dealing with amputation ( Box 99-2 ).



Box 99-1

Recommended Adaptive Equipment





  • One-handed washcloth mitt



  • Mounted (one-handed) nail clippers



  • Sling backpack



  • Electric letter opener



  • Electric hands-free can opener



  • Electric toothbrush



  • One-handed cutting board



  • Dycem



  • Electric razor



  • Dr. Grip pen



  • Button hook



  • Elastic shoe laces or LockLaces



  • Knork



  • One-handed (“tuning fork”) dental flossers



  • Zipper (neck) ties



  • Universal cuff



  • Card Player Card Holder




Box 99-2

Recommended Resources for Therapists and Patients






The patient undoubtedly has questions about prosthetics. His expectations of a prosthesis are often lofty and false. The therapist should avoid offering too many details about prosthetics during the initial visit. The function of the prosthesis in the protection of the remaining upper limb from repetitive stress injuries and reduction in phantom limb pain are emphasized as two main reasons to wear a prosthesis. He may later choose to function without a prosthesis, but, initially, time and energy are invested in prosthetic training and rehabilitation.


Behavioral Health Implications


The amputee patient experiences a variety of emotions related to limb loss, such as helplessness, hopelessness, anger, social isolation, and fear of the future. Patients vary in psychological response based on emotional resources and coping abilities. Family and friends may offer support and alleviate psychological stress. If amputation was caused by trauma, additional concerns are warranted, and these patients are evaluated by a psychiatrist for post-traumatic stress conditions.


Results of survey research done with 44 amputees (10 upper limb) to determine factors influencing coping with life with a prosthesis revealed that the coping strategy and level of adjustment varied with age, and mechanism and site of amputation. Other studies have contradictory findings. Van Dorsten proposed a three-stage adjustment process of survival, recovery, and reintegration. He suggested that this process coincides with rehabilitation stages of preprosthetic, prosthetic, and vocational rehabilitation phases.


The many hours spent together during rehabilitation create a strong therapeutic bond. This bond is instrumental in helping the patient in the adjustment to amputation. The following are suggested actions to incorporate into rehabilitation treatment programs:




  • Provide adaptive equipment to expedite a return to independence.



  • Encourage establishment of habits, patterns, and routines to facilitate a sense of control and influence over situations.



  • Discuss body-image issues as they relate to physical ability, listen empathetically, and give positive feedback.



  • Engineer success at each rehabilitation session to bolster self-confidence.



  • Reinforce identity through occupation-based therapy activities to offset the (temporary or permanent) loss of familiar life roles.



  • Monitor changes in pain intensity and provide education regarding the relationship between pain and mood.





Caring for the Residual Limb


After the postoperative dressing is removed, the residual limb is wrapped with an elastic wrap in a figure-of-8 formation. The wrap is removed and reapplied every 3 hours. More compression is applied distally and less proximally to promote a tapered shape of the residuum needed for prosthetic fitting.


The patient progresses from an elastic wrap to an elastic stockinette. The stockinette is sewn closed in the middle and applied in a double-layer fashion. Alternatively, the stockinette can be applied half way, twisted at the bottom, and doubled back over the limb. When the residual limb is well healed (sutures removed with definitive wound closure), the patient progresses to a silicone gel–lined shrinker. Edema levels fluctuate over the course of recovery as the limb matures to final resting volume. The patient is advised to keep a compressive garment on the limb at all times, other than for cleaning, wound debridement, or preprosthetic training.


Caring for the residual limb includes desensitization. A fully desensitized limb is necessary to tolerate wearing of a prosthesis. Desensitization incorporates textures, contact particles, and vibration. Desensitization begins with gentle limb massage, light rubbing, percussion, and tapping the limb for ten minute sessions twice daily. The desensitization program is advanced by exposure of the following materials to the residual limb: cotton, silk, burlap, polyester, nylon, Velcro. Materials of graded textures can be attached to dowels to aid in application. Particle immersion involves the patient placing the limb into a container of various media such as cotton balls; uncooked pinto beans, rice, and macaroni; and small and large pebbles. During immersion activities, patients benefit from gentle weight-bearing onto the limb. Eventually patients tolerate electrical vibration to the limb. Desensitization is not considered a system of “toughening up” the residual limb for this erroneously implies aggressive exposure to materials and media.


Pain Management


Pain adversely affects quality of life. As the physician titrates the pain medication dose, therapists become active players in managing pain through nonpharmacologic modalities. Such modalities include transcutaneous electrical nerve stimulation, massage, biofeedback, mirror-box training, and desensitization. As patients become familiar with massage and desensitization procedures, active involvement should be encouraged.


Phantom limb pain, phantom limb sensation, and residual limb pain are three separate conditions but may be experienced together. Patients are taught to distinguish between all three. The exact etiology of phantom limb pain and sensation remains unknown.


Phantom limb sensation is characterized by nonpainful feelings in the amputated limb. Feelings can be interpreted in many ways: proprioception, temperature, itching, pressure, and tingling. Phantom limb pain is experienced in as many as 80% of amputees and is described as “stabbing” (24.3%) or “pins and needles” (20.5%). Residual limb pain is felt as pain in the remaining limb and is reported experienced by 60% of amputees. The most common cause is a painful neuroma.


Fear and anxiety in response to sensations in a limb that is no longer there may cause misinterpretation of phantom limb sensation as pain. Informing patients that phantom limb sensations are normal helps to alleviate anxiety.


Use of a Ramachandran mirror apparatus (mirror box) has been shown to lessen the magnitude of phantom limb pain. The mirror is positioned at midline, facing toward the patient’s intact limb; the patient is instructed to look into the mirror and watch the reflection of the intact limb, which now visually appears to be the missing limb. This illusionary image of the amputated limb provides feedback to the brain, closing the “broken” sensorimotor circuit of hand to brain. The patient spends 15 minutes making limb motions in front of the mirror while watching the reflection of movements produced by the intact limb. Patients who report feeling the phantom limb in a cramped and awkward position of discomfort mimic the motions to relieve the perceived cramp or reverse the contorted posture ( Fig. 99-1 ).




Figure 99-1


Ramachandran mirror box used for managing phantom limb pain.


Conditioning the Residual Limb


Conditioning the entire upper body aids in tolerance of the weight and stress of using a prosthesis. A light resistance exercise program is prescribed to address the strength of postural muscles. Strengthening can begin with isometric exercises with progression to TheraBand exercises (The Hygenic Corporation, Akron, Ohio). Resistance and repetitions are adjusted based on the patient’s overall fitness level and baseline strength.


Patients with amputations at or above the transhumeral level need scapular, shoulder, and chest motions to create excursion necessary to operate the prosthesis. All motions are included in a range of motion program. In addition, if a patient is to use a myoelectric prosthesis, muscles of the residuum must possess strength and endurance for efficient operation. After suture removal, training musculature in preparation for prosthetic use is begun.




Prosthetics


Amputee rehabilitation centers on the prosthetic prescription. This section provides an explanation of basic prosthetic principles necessary to design a rehabilitation program.


Ideally the patient is fit with a prosthesis as soon as the residual limb is healed and tissues can tolerate mechanical stress. Early fitting is associated with successful prosthesis use and a return to gainful employment. The desired end state of both prosthetic and rehabilitative care is to return the amputee to the most reasonable level of self-sufficiency. Not wearing a prosthesis is an option discussed with the patient; however, this choice is best made after a fair trial of prosthetic rehabilitation.


Prescription Decision


Ideally, the therapist, patient, and prosthetist work together to select the best choice of prosthesis. The following factors are considered in the decision: co-morbidities (impaired cognitive abilities, multiple-limb amputations, orthopedic injuries), motivation to learn and use a prosthesis, preference for cosmesis and function, residual limb attributes (length, range of motion, skin integrity, strength), hand dominance, life roles (work, home, community, leisure), and financial situation related to covering inherent costs. The general consensus among amputees and professionals involved in prosthetic rehabilitation is that the order of importance of the features of a prosthesis are comfort, function, and cosmesis ; however, each patient’s unique preferences and priorities must be considered.


The challenge of achieving optimal fitting and function increases progressively with higher amputation levels because the added weight of the necessary prosthetic componentry decreases likelihood of wear. To help with adjusting to the wear and operation of a prosthesis, an initial “test socket” or “check socket” is created before fabrication of the final model. The prosthetic componentry is connected to the test socket to create a preparatory prosthesis to permit early prosthetic training.


As the patient’s strength and skill improve, the prosthetist adjusts the control options and input characteristics of the prosthesis. It is important for the prosthetist and therapist to work closely together if an externally powered prosthesis is selected because of the ongoing microprocessing adjustments. The therapist must have a comprehensive understanding of the chosen prosthesis to adequately train the amputee patient in prosthetic use and to work with the prosthetist to choose the ideal input and control schemes.


Power Sources


Depending on the level of amputation, a prosthesis may have the following components: terminal device (TD), wrist unit, forearm or upper arm socket or component, elbow or shoulder unit or hinge. Before selecting each component, a power source is chosen. Prosthetists also plan for secondary, or “override” control options as part of the design.


A prosthesis can be controlled in one of four ways; each has advantages.



  • 1

    Body powered: activated by upper limb and body movements that transmit force through a cable system that operates distal components such as the TD


  • 2

    Externally powered: most common form is myoelectric; electromuscular activity is detected (and amplified) by surface electrodes within the socket; other externally powered control schemes are force-sensing resistors, servo and switch


  • 3

    Semiprehensile/passive: generally chosen for cosmetic purposes, although some function is possible to assist in low-demand bimanual tasks; fewer involved components make it lightweight


  • 4

    Hybrid: a unique option that combines body- and electrically powered components; generally the elbow is body powered (manual lock or passive friction) and the hand is electrically powered



Terminal Devices


Selecting the TD is the next most crucial decision. The TD is the distal-end component that essentially replaces the amputated hand ( Fig. 99-2 ). Available options depend on the chosen power source. Two primary options are hooks and hands, both of which provide fixed prehension. A split-hook TD provides precise grasping, allows good visibility of objects during grasp, and is lightweight, reliable, and affordable. A myoelectric hand TD is cosmetically appealing and offers a pinch force that is three to six times stronger than that of the split-hook TD.




Figure 99-2


Electric terminal device options: Greifer (Otto Bock) (left), electric terminal device (ETD) (Motion Control) (middle), hand with silicone sleeve covering (right).


A body-powered prosthesis with a split-hook TD can be designed to voluntarily open or close. The voluntary open option is more common. The patient places tension on the cable system by motions such as scapular protraction, shoulder forward flexion, and elbow extension, which open the TD. The amount of pinch force between the hooks comes from rubber bands. A voluntary closing system is the reverse of the voluntary open. The hook remains open at rest and closes when tension is placed on the cable. This requires constant tension on the cable to sustain the grasp of an object between the split-hook TD, or the patient locks the TD when needed, for example, to carry objects.


A body-powered prosthesis can have a mechanical hand as a TD. Adjustable springs, rather than rubber bands, create grasping force. In the mechanical hand TD, the ring and small fingers are fixed, and only the thumb and first two fingers move when tension is placed on the cable system. The hand TD on a body-powered prosthesis has less pinch strength and requires substantial effort. An electrically powered prosthesis can also accommodate a hook or hand TD. Many patients have a variety of TDs and select the best one for the chosen activity.


Otto Bock manufactures an alternate electric TD that is optimal for heavy work tasks. It is a durable, plastic, two-pronged device that provides symmetrical opposition with grip capabilities 50% to 75% greater than other TDs. The amputee can preposition the device in variable degrees of wrist flexion.


New technologies have led to advancements in TDs. For example, new components are more resistant to water and dust. Another notable advancement is operation speed. The Otto Bock SensorHand SPEED (Otto Bock, Minneapolis, Minnesota) provides almost instantaneous movement after residual limb muscle signal activation, thereby eliminating a response delay and improving the patient’s perception of prosthetic integration.


Shoulder, Elbow, and Wrist Units


Shoulder, elbow, and wrist joints may be controlled through passive friction, external power, or mechanical or active locking mechanisms. The mechanically locking elbow unit is the most common. In this configuration, the patient uses shoulder extension, abduction, and slight depression to activate the lock in one of many preset positions. Shoulder units are commonly configured to operate with passive friction or active locking. The shoulder is generally prepositioned in preparation for a task, and then the patient continues to operate the elbow and TD in sequence.


The wrist unit is the critical interface with the TD and allows rotation, which substitutes for movements of supination and pronation. Wrist rotation allows the patient to orient and preposition the TD and improve accomplishment of tasks. Various wrist units provide a quick disconnect option to allow changing to different TDs. When a wrist unit is controlled passively, through a constant friction design, the patient either uses the contralateral limb or a fixed object to apply pressure to manually rotate the TD. It is important to watch for and correct extreme proximal compensatory movements to substitute for forearm rotation.


Sockets


The socket is the portion of the prosthesis that encases the residual limb or contacts the chest and back in patients with interscapulothoracic or glenohumeral disarticulation amputations. Generally made of thermoplastic polymers, sockets are constructed according to characteristics of the residuum (length, girth, scar tissue, shape) and the amputee patient’s intended future use. Prosthetists consider such factors in light of the ability of the prosthesis to withstand rotary and axial forces. Sockets are designed to distribute force over a large enough area to improve comfort and not impede proximal joint motion. Sockets can be suspended through one or a combination of harnessing systems, suction (vacuum) systems, or anatomic contouring (supracondylar). It is also possible to create a shuttle–lock interface using a silicone suction sleeve that anchors to the distal socket. Socket comfort is related to long-term wear and use of a prosthesis and is therefore critical in constructing an acceptable prosthesis.


Harnessing Systems


A harnessing system connects the prosthesis to the body and “harnesses” body movements to operate prosthetic components. Harnesses are configured in numerous ways based on amputation level and characteristics of the residual limb. Popular harness formations are figure-of-9, figure-of-8, and chest-strap designs. Harness systems for patients with amputation at the transhumeral level fit tighter than systems for transradial amputation levels; this is necessary to capture more excursion (total of inches of cable travel). Prosthetists use rings and straps to configure a harness that permits suspension and captures excursion. The harnessing provides proprioceptive feedback when there is adequate resistance felt through the system. It is important to be familiar with the harnessing system to appropriately train the patient in donning and doffing procedures.


Wrist Disarticulation


Low-profile prosthetic componentry is necessary to provide a functional terminal device but not create a limb-length discrepancy with the intact limb. For example, if a standard myoelectric prosthesis is chosen, an electric wrist rotation unit is not an option because of the space needed to place it. However, Otto Bock manufactures a transcarpal hand that is a shorter electrical hand to eliminate length asymmetry. If a body-powered prosthesis is selected and the wrist styloids are adequate for suspension, the short triceps cuff harness with flexible elbow hinges is used to permit maximum forearm rotation.


Transradial Amputation


The patient with a transradial amputation can be fit with a body-powered or an electrically powered prosthesis. The optimal residual limb length is 10 cm proximal to the ulnar styloid. The residual limb is encased in a socket that is connected via a harness (for body powered) or self-suspending (for myoelectric). The Transradial Anatomically Contoured (TRAC) Interface is a type of self-suspension socket that combines design principles from two previous traditional sockets known as the Meunster type and the Northwestern University Supracondylar Suspension Technique. The TRAC interface contours intimately to the musculoskeletal characteristics of the residuum and allows greater elbow range of motion.


Elbow Disarticulation


The prosthesis of an amputee patient with an elbow disarticulation is constructed to match the length of the sound side. This is done by lowering the elbow joint center and shortening the prosthesis’ forearm shaft. The elbow joint is typically configured with externally locking hinges. A harness system is necessary for elbow and TD operation; however, suspension is achieved over the remaining humeral epicondyles.


Transhumeral Amputation


The patient with a transhumeral amputation must wear a harness system regardless of the primary power source of the prosthesis. The trim line of the socket may be cut out below the acromion if the residual limb is long enough. The optimal residual limb length is 14 cm proximal to the olecranon. Three common prosthetic platforms are prescribed: (1) DynamicArm (Otto Bock), (2) UtahArm3 (Motion Control, Salt Lake City, Utah), (3) Boston Digital Arm System (Liberating Technologies, Inc, Holliston, Massachusetts).


These myoelectric prostheses offer on-board microprocessors, allow simultaneous operation of components via many control options, and facilitate natural upper limb movements. The preference of one system over the other is generally not fixed, and prosthetists consider associated details when prescribing a system. It is important to know the details of the chosen prosthetic system. Each company provides valuable information online (see Box 99-2 ).


Glenohumeral Disarticulation


Creative prosthetic designs are needed at this amputation level to facilitate motion because little scapular abduction can be achieved. A chin-activated control can be mounted and used to control the elbow. A common configuration design is called the triple control in which the harness is anchored around the contralateral shoulder to control the TD; the strap through the axilla controls the elbow and a nudge-control switch or chest expansion strap operates the elbow movement. Research is under way to explore targeted muscle reinnervation in persons with transhumeral and higher level amputations. Results presented of six subjects (three with glenohumeral disarticulation and three with transhumeral level amputations) showed improved functional use of a prosthesis.


Interscapulothoracic Amputation


An acquired, unilateral amputation at this level generally dictates a prosthesis solely for cosmetic restoration. This is because of the substantial weight of the componentry of a body- or externally powered prosthesis, the difficulty in donning and operating the prosthesis, which requires multiple steps to control shoulder, elbow, wrist, and hand, and heat build-up during wear time. The MicroFrame interface is a popular design engineered to counter those common resistances to prosthetic use.

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Apr 21, 2019 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Amputations and Prosthetics
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