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Chapter 23 - Atlas of Limb Prosthetics: Surgical, Prosthetic, and Rehabilitation Principles Physical Therapy Management of Adult Lower-Limb Amputees
Robert S. Gailey, Jr., M.S.Ed., P.T.
Curtis R. Clark, P.T.
The prosthetist and the physical therapist, as members of the rehabilitation team, often develop a very close relationship when working together with lower-limb amputees. The prosthetist is responsible for fabricating and modifying the specific socket design and providing prosthetic components that will best suit the life-style of a particular individual. The physical therapist's role is threefold. First, the amputee must be physically prepared for prosthetic gait training and educated about residual-limb care prior to being fitted with the prosthesis. Second, the amputee must learn how to use and care for the prosthesis. Prosthetic gait training can be the most frustrating, yet rewarding phase of rehabilitation for all involved. The amputee must be patiently educated in the biomechanics of prosthetic gait. Once success is achieved, the amputee may look forward to resuming a productive life. Third, the therapist should introduce the amputee to higher levels of activities beyond just learning to walk. Although the amputee may not be ready to participate in recreational activities immediately, providing the names of support groups and disabled recreational organizations can furnish the necessary information for the individual to seek involvement when ready.
PRESURGICAL MANAGEMENT
Initial Patient Contact
This time provides an opportunity for the therapist to introduce himself to the patient and, in conjunction with other qualified members of the rehabilitation team, to prepare the patient for the events to come. Specifically, the therapist will attempt to develop a professional rapport with the patient and earn his trust and confidence. This period also offers the therapist an excellent opportunity to explain the time frame of the rehabilitation process. Fear of the unknown can be extremely frightening to many patients; therefore, having the comfort of knowing what the future holds as well as what will be expected of them can ease the process. A visit from another amputee who has been successfully rehabilitated can assist in this process. The visiting amputee should be carefully screened by appropriate personnel and should have a suitable personality for this task. Additional considerations should be given to similarities between level of amputation, age, gender, and outside interests. If available, any information on various prostheses or videos showing recreational activities may benefit the patient. The therapist must also keep in mind how much information the patient is psychologically prepared to hear. Many hospitals have affiliations with local support groups, where amputees visit other amputees to help them throughout the healing process.
The pragmatic aspect of the therapist's responsibilities presurgically will include discussing the possibilities of phantom limb sensation and discomfort, joint contracture prevention, as well as overall functional assessment. If the patient so desires, a prosthesis may be introduced at this point to satisfy curiosity.
POSTSURGICAL MANAGEMENT
Evaluation
Past Medical History
A complete medical history should be taken from the patient or obtained from the medical records to provide the therapist with information that may be pertinent to the rehabilitation program.
Mental Status
An accurate assessment of the patient's mental status can lend insight into the likely comprehension level for future prosthetic care. The therapist should be concerned with assessing the patient's potential to cognitively perform activities such as donning and doffing the prosthesis, residual-limb sock regulation, bed positioning, skin care, safe ambulation, and other functional activities of the amputee. If the patient does not possess the necessary level of cognition, family members and/or friends should become involved in the rehabilitation process to help ensure a successful outcome.
Range of Motion
A functional assessment of gross upper-limb and sound lower-limb motions should be made. A measurement of the residual limb's range of motion (ROM) should be recorded for future reference. Joint contractures are complications that can greatly hinder the amputee's ability to ambulate efficiently with a prosthesis; thus extra care should be taken to avoid them. The most common contracture for the transfemoral amputee is hip flexion, external rotation, and abduction, while knee flexion is the most frequently seen contracture for the transtibial amputee. During the ROM assessment the therapist should determine whether the patient has a fixed contracture or just soft-tissue tightness from immobility that can be corrected within a short period of time. This may affect the manner in which the prosthesis is fabricated.
Strength
Functional strength of the major muscle groups should be assessed by manual muscle testing of all limbs including the residual limb and the trunk. This will help determine the patient's potential skill level to perform activities such as transfers, wheelchair management, and ambulation with and without the prosthesis.
Sensation
Evaluation of the amputee's sensation is useful to both the patient and therapist alike. The therapist can gain insight into the possible insensitivity of the residual limb and/or sound limb. This may affect proprioceptive feedback for balance and single-limb stance, which in turn can lead to gait difficulties. The patient must be made aware that decreased pain, temperature, and light touch sensation can increase the potential for injury and tissue breakdown.
Bed Mobility
The importance of good bed mobility extends beyond simple positional adjustments for comfort or to get in and out of bed. The patient must acquire bed mobility skills to maintain correct bed positioning in order to prevent contractures or excessive friction of the sheets against the suture line or frail skin. If the patient is unable to perform the skills necessary to maintain proper positioning, assistance must be provided. As with most patients, adequate bed mobility is a basic requirement for higher-level skills such as bed-to-wheelchair transfers.
Balance/Coordination
Sitting and standing balance are of major concern when assessing the amputee's ability to maintain the center of gravity over the base of support. Coordination assists with ease of movement and the refinement of motor skills. Both balance and coordination are required for weight shifting from one limb to another, thus improving the potential for an optimal gait. After evaluating mental status, ROM, strength, sensation, balance, and coordination, the therapist will have a good indication of what would be the most appropriate choice of assistive device to use initially with the individual amputee.
Transfers
Transfer skills are essential for early mobility. Additional functional transfers such as toilet, shower, and car transfers must also be assessed before discharge to more completely determine the patient's level of independence. For transtibial amputees who are not ambulatory candidates, a very basic prosthesis may be indicated for transfers only.
Wheelchair Propulsion
The primary means of mobility for a large majority of amputees, either temporarily or permanently, will be the wheelchair. The energy conservation of the wheelchair over prosthetic ambulation is considerable with some levels of amputation. Therefore, wheelchair skills should be taught to all amputees during their rehabilitation program.
Ambulation With Assistive Devices Without a Prosthesis
A traditional evaluation of the amputee's potential for ambulation is performed, including strength of the sound lower limb and both upper limbs, single-limb balance, coordination, and mental status. The selection of an assistive device should meet with the amputee's level of skill, while keeping in mind that with time the assistive device may change. For example, initially an individual may require a walker, but with proper training, forearm crutches may prove more beneficial as a long-term assistive device.
Some patients who have difficulty in ambulating on one limb secondary to obesity, blindness, or generalized weakness can still be successful prosthetic ambulators when the additional support of a prosthesis is provided (Fig 23-1a. and Fig 23-1b.).
Cardiac Precautions for Amputees
During the initial chart review, the therapist should make note of any history of coronary artery disease, congestive heart failure, peripheral vascular disease, arteriosclerosis, hypertension, angina, arrhythmias, dyspnea, angioplasty, myocardial infarction, arterial bypass surgery, as well as prescribed cardiovascular medications that may affect the blood pressure and heart rate.
The heart rate and blood pressure of every patient should be closely monitored during initial training and thereafter as the intensity of training increases. If the amputee experiences persistent symptoms such as shortness of breath, pallor, diaphoresis, chest pain, headache, or peripheral edema, further medical evaluation is strongly recommended.
Patient Education: Limb Management
Limb Care
It is important that the patient understand the care of the residual limb and sound limb. For example, the dysvascular patient's prosthetic gait training could be delayed 3 to 4 weeks if an abrasion should occur. The patient must be taught the difference between weight-bearing areas and pressure-sensitive areas and also be oriented to the design of the socket and the functions of the prosthetic componentry.
Problem Detection/Skin Care
Every patient should be instructed to visually inspect the residual limb on a daily basis or after any strenuous activity. More frequent inspection of the residual limb should be routine in the initial months of prosthetic training. A hand mirror may be used to view the posterior aspect of the residual limb. Reddened areas should be monitored very closely as potential sites for abrasions. If a skin abrasion occurs, the patient must understand that in most cases the prosthesis should not be worn until healing occurs.
Prosthetic Management
The socket should be cleaned daily to promote good hygiene and prevent deterioration of prosthetic materials. As a rule, solid plastic materials are cleaned with a damp cloth and foam materials with rubbing alcohol. The patient should also be reminded that routine maintenance of the prosthesis should be performed by the prosthetist to ensure maximum life and safety of the prosthesis.
Sock Regulation
Sock regulation is of extreme importance to prevent pistoning from occurring. The patient should carry extra socks at all times in case of pistoning or extreme perspiration. A thin nylon sock (sheath) should cover the residual limb to assist in reducing friction at the residual-limb/socket interface. Stump socks are available in assorted plies or thickness that permit the patient to obtain the desired fit within the socket. Socks should be applied wrinkle free, with the seams horizontal and on the outside to prevent additional pressure on the skin.
Donning and Doffing of the Prosthesis
Today, there is a wide variety of suspension systems for all levels of amputation. To list just a few possibilities, the transtibial amputee has the option of a hard socket with or without a soft insert, which could include auxiliary suspension, a medial wedge, and suction or suction silicone sockets, while the transfemoral amputee has the choice of a nonsuction external suspension or a suction suspension socket that can be donned with an elastic bandage, pull sock, wet fit, or a silicone sleeve. The methods of donning each of these combinations are too numerous for the scope of this chapter; however, what is important is that the amputee become proficient in the method of donning and doffing his particular prosthesis.
Residual-Limb Wrapping
Early wrapping of the residual limb can have a number of positive effects: (1) decrease edema and prevent venous stasis by ensuring a proper distal-to-proximal pressure gradient, (2) assist in shaping, (3) help counteract contractures in the transfemoral amputee, (4) provide skin protection, (5) reduce redundant-tissue problems, (6) reduce phantom limb discomfort/sensation, and (7) desensitize the residual limb with local pain. Controversy does exist concerning the use of traditional elastic bandaging vs. the use of residual-limb shrinkers. Currently, many institutions prefer commercial shrinkers for their ease and reproducibility of donning. Advocates of elastic bandaging state that more control over pressure gradients and tissue shaping is provided. Regardless of individual preference, application must be performed correctly to prevent (1) circulation constriction, (2) poor residual-limb shaping, and (3) edema (Fig 23-2. and Fig 23-3.).
Preprosthetic Exercise
Strengthening
Eisert and Tester first described dynamic residual-limb exercises in 1954. Since then, their antigravity exercises have been the most favored method of strengthening the residual limb. These dynamic exercises require little in the way of equipment. A towel roll and step stool are all that is required. They also offer benefits aside from strengthening, such as desensiti-zation, bed mobility, and joint ROM. The exercises are relatively easy to learn and can be performed independently, thus permitting the therapist to spend patient contact time on other more advanced skills.
Incorporating isometric contractions at the peak of the isotonic movement will help to maximize strength increases. A period of a 10-second contraction followed by 10 seconds of relaxation for 10 repetitions gives the patient an easy mnemonic to remember, the "rule of ten." The rationale behind a 10-second contraction is that a maximal isometric contraction can be maintained for 6 seconds; however, there is a 2-second rise time and a 2-second fall time for a total of 10 seconds.
All amputees should consider performing abdominal and back extensor strengthening exercises to maintain trunk strength, decrease the possible risk of back pain, and assist in the reduction of gait deviations associated with the trunk.
The following illustrations demonstrate the basic dynamic strength training program for transfemoral and transtibial amputees (Fig 23-4.).
Amputees who have access to isotonic and isokinetic strengthening equipment can take advantage of the benefits derived from these forms of strengthening with few modifications in their positioning on the machines.
Range of Motion
Prevention of decreased ROM and contractures is a major concern to all involved. Limited ROM can often result in difficulties with prosthetic fit, gait deviations, or the inability to ambulate with a prosthesis altogether. The best way to prevent loss of ROM is to remain active and ensure full ROM of affected joints. Unfortunately, not all amputees have this option, and therefore, proper limb positioning becomes important. The transfemoral amputee should place a pillow laterally along the residual limb to maintain neutral rotation with no abduction when in a supine position. If the prone position is tolerable during the day or evening, a pillow is placed anteriorly under the residual limb for 20 to 30 minutes, two to three times daily, to maintain hip extension. Transtibial amputees should avoid knee flexion for prolonged periods of time. A stump board will help maintain knee extension when using a wheelchair. All amputees must be made aware that continual sitting in a wheelchair without any effort to promote hip extension may lead to limited motion during prosthetic ambulation (Fig 23-5.).
Amputees who have already developed a loss of ROM may benefit from many of the traditional therapy procedures such as passive ROM, contract-relax stretching, soft-tissue mobilization, myofascial techniques, joint mobilization, and other methods that promote increased ROM.
Functional Activities
Encouraging activity as soon as possible after amputation surgery helps speed recovery in several ways. First, it will offset the negative affects of immobility by promoting movement through the joints, muscle activity, and increased circulation. Second, the patient will begin to re-establish personal independence, which may be perceived as threatened due to limb loss. Finally, the psychological advantage derived from activity and independence will continue to motivate the patient throughout the rehabilitation process.
General Conditioning
A decrease in general conditioning and endurance are contributory factors leading to difficulties in learning functional activities and prosthetic gait training. Regardless of age or present physical condition, a progressive general exercise program should be prescribed for every patient beginning immediately after surgery, continued throughout the preprosthetic period, and finally incorporated as part of the daily routine.
The list of possible general strengthening/endurance exercise activities is long: cuff weights in bed, wheelchair propulsion for a predetermined distance, dynamic residual-limb exercises, ambulation with an assistive device prior to prosthetic fitting, loweror upper-limb ergometer work, wheelchair aerobics, swimming, aquatic therapy, lowerand upper-body strengthening at the local fitness center, and any sport or recreational activity of interest. The amputee should select one or more of these, begin participation to tolerance, and progress to 1 hour or more a day.
The advantages of participation extend well beyond improving the chances of ambulating well with a prosthesis. The individual has the opportunity to experience and enjoy activities thought impossible for an amputee. If difficulties are experienced, the amputee is still within an environment where assistance may be readily obtained either from the therapist or from a fellow amputee who has mastered a particular activity.
Bed Mobility
The severely involved patient may be taught to utilize a trapeze, side rail, or human assistance when learning bed mobility. This practice, however, should not be employed for the general amputee population because, while easier initially, continued use of these methods will only hamper the future rehabilitation process. Regardless of age, each patient should be taught a safe and efficient manner in which to roll, come to sitting, or adjust their position. Log rolling, followed by side lying to sitting or supine lying on elbows to long sitting, are two acceptable methods that incorporate all the necessary skills for efficient bed mobility.
Transfers
Once bed mobility is mastered, the patient must learn to transfer from the bed to a chair or wheelchair and then progress to more advanced transfer skills such as to the toilet, tub, and car. Unilateral amputees initially are taught single-limb transfers where the wheelchair is positioned on the sound-limb side and the patient pivots over the limb while maintaining contact with either the bed or chair. In most cases, it is advised that transfers to both the sound and involved side be taught since the patient will frequently be in situations where transferring to the sound side will not be possible. As the patient's single-limb standing balance improves, more advanced transfers may be taught to improve the patient's independence. In cases where an immediate postoperative or preparatory prosthesis is utilized, weight bearing through the prosthesis can assist the patient in the transfer and provide additional safety.
Bilateral amputees who are not fitted with an initial prosthesis transfer in a "head-on" manner. The wheelchair approaches the mat or chair, with the front of the chair abutting the transferring surface. The patient then slides forward onto the desired surface by lifting the body and pushing forward with both hands. Until adequate strength of the latissimus dorsi and triceps is attained for this transfer, a lateral sliding-board transfer will be necessary to minimize friction and to cross the gap between the chair and desired surface (Fig 23-6.).
Wheelchair Propulsion
Wheelchair mobility is the first skill that will give the amputee independence in the world outside of the hospital room. The degree of skill and mastery of the wheelchair varies depending on age, strength, and agility. Basic skills such as forward propulsion, turns, and preparation for transfers, i.e., parking and braking, should be taught immediately. Later, advanced wheelchair skills should be taught: ascending and descending inclines, wheelies, floor-to-wheelchair transfers, and curb jumping. The time dedicated to wheelchair skills is dependent on the degree to which the amputee may potentially require the wheelchair. Bilateral and older amputees may require greater use of the wheelchair, while unilateral and younger amputees will be more likely to utilize other assistive devices when not ambulating with their prosthesis. Because of the loss of body weight anteriorly the amputee will be prone to tipping backward while in the standard wheelchair. Amputee adapters set the wheels back approximately 5 cm, thus moving the amputee's center of gravity forward to prevent tipping, especially when ascending ramps or curbs.
Unsupported Standing Balance
In preparation for ambulation without a prosthesis, all amputees must learn to compensate for the loss of weight of the amputated limb by balancing the center of gravity over the sound limb. Although this habit must be broken when learning prosthetic ambulation, single-limb balance must be learned initially to provide confidence during stand pivot transfers, ambulation with assistive devices, and eventually hopping, depending on the amputee's level of skill. A patient should be able to balance for at least 0.5 seconds to allow for smooth and safe progression of an assistive device during ambulation.
One method of progressive ambulation starts with the amputee standing in the parallel bars while using both hands for support. Once confidence in standing with double arm support is attained, the hand on the same side as the amputated limb should be removed from the bars; subsequently both hands are removed as independent balance is achieved. In order to improve balance and righting skills, the patient should be challenged by gently tapping the shoulders in multiple directions or tossing a ball back and forth (Fig 23-7.). Allow enough time between taps or throws for the patient to regain a comfortable standing posture. Once confidence is gained within the parallel bars, the patient should practice these skills outside the parallel bars, eventually progressing to hopping activities.
Ambulation With Assistive Devices
All amputees will need an assistive device for times when they choose not to wear their prosthesis or for occasions when they are unable to wear their prosthesis secondary to edema, skin irritation, or poor prosthetic fit. Other amputees will require an assistive device while ambulating with the prosthesis. There are a variety of assistive devices to choose from. While safety is a primary factor in selecting an appropriate assistive device, mobility is a secondary consideration that cannot be overlooked. The criteria for selection should include (1) unsupported standing balance, (2) upper-limb strength, (3) coordination and skill with the assistive device, and (4) cognition. A walker is chosen when a amputee has fair to poor balance, strength, and coordination. If balance and strength are good to normal, forearm crutches may be used for ambulation with or without a prosthesis. A quad or straight cane may be selected to ensure safety when balance is questionable while ambulating with a prosthesis.
Pregait Training
Balance and Coordination
After the loss of a limb, the decrease in body weight will alter the body's center of gravity. In order to maintain the single-limb balance necessary during stance without a prosthesis, ambulating with an assistive device, or single-limb hopping, the amputee must shift the center of gravity over the base of support, which in this case is the foot of the sound limb. As amputees become more secure in their single-limb support, there is greater difficulty in reorienting them to maintaining the center of gravity over both the sound and prosthetic limbs. Ultimately, amputees must learn to maintain the center of gravity and their entire body weight over the prosthesis. Once comfortable with weight bearing equally on both limbs, the amputee can begin to develop confidence with independent standing and eventually with ambulation.
Orientation to the Center of Gravity and Base of Support
Orientation of the center of gravity over the base of support in order to maintain balance requires that the amputee become familiar with these terms and aware of their relationship. The body's center of gravity is located just anterior to the second sacral vertebra. Average persons stand with their feet 5 to 10 cm (2 to 4 in.) apart, varying according to body height. Various methods of proprioceptive and visual feedback may be employed to promote the amputee's ability to maximize the displacement of the center of gravity over the base of support. The amputee must learn to displace the center of gravity forward and backward, as well as from side to side (Fig 23-8. and Fig 23-9.). These exercises vary little from traditional weight-shifting exercises, with the one exception that concentration is placed on the movement of the center of gravity over the base of support rather than weight bearing into the prosthesis. Increased weight bearing will be a direct result of improved center of gravity displacement and will establish a firm foundation for actual weight shifting during ambulation.
Single-Limb Standing
Weight acceptance in the prosthesis is one of the most difficult challenges facing both therapist and amputee. Without the ability to maintain full single-limb weight bearing and balance for an adequate amount of time (0.5 seconds minimum) the amputee will exhibit a number of gait deviations, including (1) decreased stance time on the prosthetic side, (2) a shortened stride length on the sound side, or (3) lateral trunk bending over the prosthetic limb. Strength, balance, and coordination are the primary physical factors influencing single-limb stance on a prosthesis. Additionally, fear, pain, and lack of confidence in the prosthesis must be considered when an amputee is demonstrating extreme difficulty in overcoming weight bearing on the prosthesis. It is important to recognize the need to promote adequate weight bearing and balance on the prosthesis prior to and during ambulation.
Single-limb balance over the prosthetic limb while advancing the sound limb should be practiced in a controlled manner so that when required to do so in a dynamic situation such as walking, this skill can be employed with relatively little difficulty. The stool-stepping exercise is an excellent method by which this skill may be learned. Have the amputee stand in the parallel bars with the sound limb in front of a 10- to 20-cm (4- to 8-in.) stool (or block), its height depending on the patients level of ability. Then ask the amputee to step slowly onto the stool with the sound limb while using bilateral upper-limb support on the parallel bars. To further increase this weight-bearing skill ask the patient to remove the sound-side hand from the parallel bars and eventually the other hand. Initially, the speed of the sound leg will increase when upper-limb support is removed, but with practice the speed will become slower and more controlled, thus promoting increased weight bearing on the prosthesis (Fig 23-10.).
The amputee's ability to control sound-limb advancement is directly related to the ability to control prosthetic limb stance. The following are three contributing factors that may help the amputee achieve adequate balance over the prosthetic limb. First, control of the musculature of the residual limb is necessary to maintain balance over the prosthesis. Second, the patient must learn to utilize the available proprioceptive sensation at the residual-limb/socket interface to control the prosthesis. Third, the amputee must visualize the prosthetic foot and its relationship to the ground. New amputees will find it difficult to understand this concept at first but will gain a greater appreciation as time goes on.
Gait-Training Skills
Sound Limb and Prosthetic Limb Training
Another component in adjusting to the amputation of a limb is restoration of the gait biomechanics that were unique to a particular person prior to the amputation. That is to say, not everyone has the same gait pattern. Prosthetic developments in the last decade have provided limbs that more closely replicate the mechanics of the human leg. Therefore, the goal of gait training should be the restoration of function to the remaining joints of the amputated limb. Prosthetic gait training should not alter the amputee's gait mechanics for the prosthesis, but instead, the mechanics of the prosthesis should be designed around the amputee's individual gait.
Pelvic Motions
The pelvis, with the body's center of gravity, moves as a unit in four directions: it displaces vertically, shifts laterally, tilts horizontally, and rotates transversely. Each of these motions can directly affect the amputee's gait and result in gait deviations or increased energy consumption during ambulation. If restoration of function to the remaining joints of the amputated limb is a goal of gait training, then the pelvic motions play a decisive role in determining the final outcome of an individual's gait pattern.
- Vertical displacement is simply the rhythmic upward and downward motion of the body's center of gravity. The knee must flex 10 to 15 degrees during foot flat, and full extension must be obtained during midstance. The transtibial amputee has the ability to flex and extend the knee during the stance phase of gait. The transfemoral amputee is at a disadvantage because the knee must remain in extension throughout the entire stance phase to avoid buckling of the knee (Fig 23-11.).
- Lateral shift occurs when the pelvis shifts from side to side approximately 5 cm (2 in.). The amount of lateral shift is determined by the width of the base of support, which is 5 to 10 cm (2 to 4 in.), depending on the height of the individual. Amputees have to spend an inordinate amount of time in single-limb standing on the sound limb when they are on crutches and hopping without the prosthesis or during relaxed standing. Because of this, they become adept at maintaining their center of gravity over the sound limb and therefore have a habit of crossing midline with the sound foot, which leaves inadequate space for the prosthetic limb to follow a natural line of progression. The result is an abducted or circumducted gait with greater-than-normal lateral displacement of the pelvis toward the prosthetic side. While more frequently observed in transfemoral amputees, this altered base of support may also be seen with transtibial amputees (Fig 23-12.).
- Horizontal dip of the pelvis is normal up to 5 degrees; anything greater is considered a gluteus me-dius gait. Usually, this is directly related to weak hip abductor musculature, more specifically, the gluteus medius. Maintenance of the residual femur in adduction via the socket theoretically places the gluteus medius at the optimal length-tension ratio. However, if the limb is abducted, the muscle is placed in a compromised position and is unable to function properly. The result is a gluteus medius gait where the trunk leans laterally over the side of the weak limb in an attempt to maintain the pelvis in a horizontal position (Fig 23-12.).
- Transverse rotation of the pelvis occurs around the longitudinal axis approximately 5 to 10 degrees to either side. This transverse rotation assists in shifting the body's center of gravity from one side to the other. In addition, it also helps to initiate the 30 degrees of knee flexion during toe-off that is necessary to achieve 60 degrees of knee flexion during the acceleration phase of swing. Knee flexion during toe-off is created by other influences as well, including plantar flexion of the foot, horizontal dip of the pelvis, and gravity. No prosthetic foot permits active plantar flexion, and horizontal dip greater than 5 degrees is abnormal; therefore restoration of transverse rotation of the pelvis becomes of great importance in order to obtain sufficient knee flexion (Fig 23-13.).
Normalization of trunk, pelvic, and limb biomechanics can be taught to the amputee in a systematic way. First, independent movements of the various joint and muscle groups are developed. Second, the independent movements are incorporated into functional movement patterns of the gait cycle. Finally, all component movement patterns are integrated to produce a smooth normalized gait.
One suggested method of training is as follows:
- Strengthening of all available musculature by dynamic residual-limb exercises (see "Preprosthetic Exercise").
- Proprioceptive neuromuscular facilitation (PNF), Feldenkrais, or any other movement awareness techniques may be performed for trunk, pelvic, and limb re-education patterns. These exercises encourage rotational motions and promote independent movements of the trunk, pelvic girdle, and limbs.
- Pregait training exercises (see "Pregait Training").
- Sound-limb stepping within the parallel bars is performed with the amputee stepping forward and backward, heel rise to heel strike, with both hands on the bars. The purpose of this activity is for the amputee and therapist to become familiar with the gait mechanics of the sound limb without having to be concerned about weight bearing and balance on the prosthetic limb. This also affords the therapist an opportunity to palpate the anterior superior iliac spines (ASIS) in order to gain a feeling for the patient's pelvic motion, which in most cases is close to normal for that individual (Fig 23-14.).
- Prosthetic-limb stepping in the parallel bars is similar to the activity described above except that the amputee uses the prosthetic limb. As the therapist palpates the ASIS, in many cases a posterior rotation of the pelvis will be observed. This is often the result of the amputee's attempt to kick the prosthesis forward with the residual limb. The pelvis rotates posteriorly, just as it would if someone were kicking a football.It is important that the amputee feel the difference between the pelvic motion on the prosthetic side and the sound side.
- To restore the correct pelvic motion, the amputee places the prosthetic limb behind the sound limb while holding on to the parallel bars with both hands. The therapist blocks the prosthetic foot to prevent forward movement of the prosthesis. Rhythmic initiation is employed to give the amputee the feeling of rotating the pelvis forward as passive flexion of the prosthetic knee occurs. As the amputee becomes comfortable with the motion, he can begin to move the pelvis actively, eventually progressing to resistive movements when the therapist deems them appropriate (Fig 23-15.).
- Once the amputee and therapist are satisfied with the pelvic motions, the swing phase of gait can be taught. The amputee is now ready to step forward and backward with the prosthetic limb. Attention must be given to the pelvic motions, that the line of progression of the prosthesis remains constant without circumducting, and that heel contact occurs within boundaries of the base of support (Fig 23-16.). As the amputee improves, release the sound-side hand from the parallel bars and eventually both hands. There should be little if any loss of efficiency with the motion, but if there is, revert to the previous splinter skill.
- Return to sound-limb stepping with both hands on the parallel bars. Observe that the mechanics are correct and that the sound foot is not crossing midline as heel strike occurs. When ready, have the amputee remove the sound-side hand from the bars. At this time, there may be an increase in the speed of the step, a decrease in step length, and/or lateral leaning of the trunk. This is a direct result of the inability to bear weight or balance over the prosthesis. Cue the amputee in remembering the skills learned while performing the stool-stepping exercise (see "Pregait Training"). After adequate skill is perfected, sound-limb stepping without any hand support may be practiced until sufficient mastery of single-limb balance over the prosthetic leg is acquired (Fig 23-17.).
- When each of the skills described above is developed to an acceptable level, the amputee is ready to combine the individual skills and actually begin walking with the prosthesis. Initially, begin in the parallel bars with the therapist and amputee facing each other, the therapist's hands on the amputee's ASISs, and the amputee holding onto the bars. As the amputee ambulates within the bars, the therapist applies slight resistance through the hips to provide proprioceptive feedback for the pelvis and musculature of the involved lower limb.
- When both the therapist and the amputee are comfortable with the gait demonstrated in the parallel bars, the same procedure as described above is practiced out of the bars, with the amputee initially using the therapist's shoulders as support and progressing to both hands free when appropriate. The therapist may or may not continue to provide proprioceptive input to the pelvis (Fig 23-18.). As the amputee begins to ambulate independently, verbal cueing may be necessary as a reminder to keep the sound foot away from midline in order that the proper base of support can be maintained.
Maintenance of equal stride length may not be immediately forthcoming because many amputees have a tendency to take a longer step with the prosthetic limb than the sound limb. When adequate weight bearing through the prosthetic limb has been achieved, have the amputee begin to take longer steps with the sound limb and slightly shorter steps with the prosthetic limb. This principle also applies when increasing the cadence. When an amputee increases his speed of ambulation, the prosthetic limb often compensates by taking a longer step, thus increasing the asymmetry. By simply having the amputee take a longer step with the sound limb and a moderate step with the prosthetic limb, increased speed of gait is accomplished without increased asymmetry.
- Trunk rotation and arm swing are the final missing components in restoring the biomechanics of gait. During human locomotion, the trunk and upper limbs rotate opposite the pelvic girdle and lower limbs. Trunk rotation is necessary for balance, momentum, and symmetry of gait. Many amputees have a decreased trunk rotation and arm swing, especially on the prosthetic side. This may be the result of fear of displacing their center of gravity too far forward or backward over the prosthesis (Fig 23-19.).
Normal cadence is considered to be 90 to 120 steps per minute, or 2.5 mph. Arm swing provides balance, momentum, and symmetry of gait and is directly influenced by the speed of ambulation. With acceleration of gait, arm swing excursion becomes greater, thus permitting a more efficient gait due to increased forward momentum. Similarly, amputees who walk at slower speeds will demonstrate a diminished swing excursion and hence less gait efficiency.
Restoring trunk rotation and arm swing is easily accomplished by utilizing rhythmic initiation or passively cueing the trunk as the amputee walks. The therapist stands behind the amputee with one hand on either shoulder. As the amputee walks, the therapist gently rotates the trunk. When the left leg steps forward, the right shoulder is rotated forward and vice versa. Once the amputee feels comfortable with the motion, he can actively take over the motion.
Amputees who will be independent ambulators as well as those who will require an assistive device can benefit to varying degrees from the above systematic rehabilitation program. Most patients can be progressed to the point of ambulating out of the parallel bars. At that time, the amputee must practice ambulating with the chosen assistive device and maintaining pelvic rotation, an adequate base of support, equal stance time, and equal stride length, all of which can have a direct influence on the energy cost of walking. Trunk rotation will be absent in amputees utilizing a walker, but those ambulating with crutches or a cane should be able to incorporate trunk rotation into their gait.
Variations
Naturally, the time and degree of prosthetic training required is individual to each amputee, depending on many factors such as age and motivation, as well as the cause and level of amputation.
Syme ankle disarticulates have a major advantage over transtibial amputees due to the ability to bear weight distally. This allows them to have better kinesthetic feedback for placement of the prosthetic foot. Because of this kinesthetic capability and the increased length of the lever arm, minimal prosthetic gait training is required. Although Syme ankle disarticulates are able to progress rapidly with weight shifting and other basic gait skills, they may require practice to attain equal stride length and stance time.
Knee disarticulates have several advantages over transfemoral amputees, including a longer lever arm, enhanced muscular control, improved kinesthetic feedback, and greater distal-end weight bearing. Although these advantages do provide an opportunity for decreased rehabilitation time, the knee disarticulate must learn all the same skills as a transfemoral amputee.
Hip disarticulates and transpelvic (hemipelvectomy) amputees have the additional responsibility of learning to master the skills of a mechanical hip joint as well as the knee joint and foot/ankle assembly. The gait-training procedures are essentially the same as for transfemoral amputees. In some cases the mechanical hip joint may dictate that a slight vaulting action is necessary in order to clear the ground.
Amputees of all levels should be educated in residual-limb sock regulation, knowledge of pressure and relief areas, care of the prosthesis, and residual-limb donning and doffing techniques.
Advanced Gait-Training Activities
Stairs
Ascending and descending stairs is most safely and comfortably performed one step at a time (step by step). A few exceptional transfemoral amputees can descend stairs step over step, with or without a railing, or by the "jackknifing" method. Even fewer, very strong transfemoral amputees can ascend stairs step over step. Most transtibial amputees have the option of either method, while hip disarticulates and transpelvic amputees are limited to the step-by-step method.
Step By Step
This method is essentially the same for all levels of amputees. When ascending stairs, the body weight is shifted to the prosthetic limb as the sound limb firmly places the foot on the stair. The trunk is slightly flexed over the sound limb as the knee extends and raises the prosthetic limb to the same step. The same process is repeated for each step. When descending stairs, the body weight is shifted to the sound limb, which lowers the prosthetic limb to the step below primarily by eccentric contraction of the quadriceps muscle. Once the prosthetic limb is securely in place, body weight is transferred to the prosthetic limb, and the sound limb is lowered to the same step.
Transfemoral Amputees: Step Over Step
Timing and coordination become critical factors in executing stair climbing step over step. As the transfemoral amputee approaches the stairs, the prosthetic limb is the first to ascend the stairs by rapid acceleration of hip flexion with slight abduction in order to achieve sufficient knee flexion to clear the step. Some transfemoral amputees will actually hit the approaching step with the toe of the prosthetic foot to achieve adequate knee flexion. With the prosthetic foot firmly on the step, usually with the toe against the step riser, the residual limb must exert a great enough force to fully extend the hip so that the sound foot may advance to the step above. As the sound-side hip extends, the prosthetic-side hip must flex at an accelerated speed to achieve sufficient knee flexion to place the prosthetic foot on the next step above.
Descending stairs is achieved by placing only the heel of the prosthetic foot on the stair below and then shifting the body weight over the prosthetic limb, thus passively flexing the knee. The sound limb must quickly reach the step below in time to catch the body's weight. The process is repeated at a rapid rate until a rhythm is achieved. Most transfemoral amputees who have mastered this skill descend stairs at an extremely fast pace, much faster than would be considered safe for the average amputee. In fact, both ascending and descending stairs step over step for transfemoral amputees is so difficult and energy demanding that the majority who master these skills still prefer the step-by-step method.
Transtibial Amputees: Step Over Step
When ascending stairs, the transtibial amputee who does not have the ability to dorsiflex his foot/ankle assembly must generate a stronger concentric contraction of the knee and hip extensors in order to successfully transfer body weight over the prosthetic limb.
Descending stairs is very similar to normal descent with one exception: only the prosthetic heel is placed on the stair. This compensates for the lack of dorsiflex-ion within the foot/ankle assembly.
Crutches
When using crutches with stairs, hold both crutches in the hand opposite the handrail, or use both crutches in the traditional manner.
Curbs
The methods described for stairs are identical for curbs. Depending on the level of skill, the amputee can step up or down curbs with either leg.
Uneven Surfaces
A good practice with gait training is to have the amputee ambulate over a variety of surfaces, including concrete, grass, gravel, uneven terrain, and varied carpet heights. Initially, the new amputee will have difficulty in recognizing the different surfaces secondary to the loss of proprioception. To promote an increased awareness, spending time on different surfaces and becoming visually aware of the changes help to initiate this learning process. Additionally, the amputee must realize that it is important to observe the terrain ahead to avoid any slippery surfaces or potholes that might result in a fall.
Ramps and Hills
Ascending inclines presents a problem for all amputees because of the lack of dorsiflexion present within most prosthetic foot/ankle assemblies. For most amputees, descending inclines is even more difficult than ascending, primarily because of the lack of plantar flexion in the foot/ankle assembly. Prosthesis wearers with knee joints have the added dilemma of the weight line falling posterior to the knee joint, resulting in a flexion moment.
When ascending an incline, the body weight should be slightly more forward than normal to obtain maximal dosiflexion with articulating foot/ankle assemblies or to keep the knee in extension. Depending on the grade of the incline, pelvic rotation with additional acceleration may be required in order to achieve maximal knee flexion during swing.
Descent of an incline usually occurs at a more rapid pace than normal because of the lack of plantar flexion resulting in decreased stance time on the prosthetic limb. Amputees with prosthetic knees must exert a greater-than-normal force on the posterior wall of the socket to maintain knee extension.
Most amputees find it easier to ascend and descend inclines with short but equal strides. They prefer this method since it simulates a more normal appearance as opposed to the sidestepping or zigzag method.
When ascending and descending hills, the amputee will find sidestepping to be the most efficient means. The sound limb should lead and provide the power to lift the body to the next level, while the prosthetic limb remains slightly posterior to keep the weight line anterior to the knee and act as a firm base.
During descent the prosthetic limb leads but remains slightly posterior to the sound limb. The prosthetic knee remains in extension, again acting as a form of support so that the sound limb may lower the body.
For hip disarticulates or transpelvic amputees, sidestepping is the most common alternative regardless of the grade of the incline.
Sidestepping
Sidestepping, or walking sideways, can be introduced to the amputee at various times throughout the rehabilitation program. He can begin with simple weight shifting in the parallel bars and later perform higher-level activities such as unassisted sidestepping around tables or a small obstacle course that requires many small turns. During early rehabilitation this skill provides the amputee with a functional exercise for strengthening the hip abductors and, later in the rehabilitation process, with an opportunity to progress into multidirectional movements.
Backward Walking
Walking backward is not difficult for transtibial amputees but poses a problem for amputees requiring a prosthetic knee since there is no means of actively flexing the knee for adequate ground clearance. In addition, the weight line falls posterior to the knee, and this causes a flexion moment with possible buckling of the knee.
The most comfortable method of backward walking is by the amputee vaulting upward (plantar-flexing) on the sound foot to obtain sufficient height so that the prosthetic limb that is moving posteriorly can clear the ground. The prosthetic foot is placed well behind the sound limb, with the majority of the body's weight being born on the prosthetic toe, thus keeping the weight line anterior to the knee. The sound limb is then brought back, usually at a slightly faster speed and a somewhat shorter distance. The trunk is also maintained in some flexion in order to maintain the weight forward on the prosthetic toe. With a little practice most amputees become quite proficient in backward walking.
Multidirectional Turns
Changing direction during walking or maneuvering within confined areas often magnifies an amputee's difficulty in controlling the prosthesis. Situations such as crowded restaurants, elevators, or just simply turning around are often overcome by "hip-hiking" the prosthesis and pivoting around the sound limb. This method is effective but hardly the most aesthetic means of maneuvering.
When turning to the sound side, two key factors for a smooth transition should be remembered: first, maintain pelvic rotation in the transverse plane, and second, perform the turn in two steps. Simply move the prosthetic limb over the sound limb 45 degrees, rotate the sound limb 180 degrees, and complete the turn by stepping in the desired direction with the prosthetic limb and leading with the pelvis to ensure adequate knee flexion (Fig 23-20.).
Turning to the prosthetic side is performed almost exactly the same way as turning to the sound side with one exception: slightly more weight is maintained on the prosthetic toe in order to keep the weight line anterior to the knee, thus preventing knee flexion. For example, by crossing the sound limb 45 degrees over the prosthetic limb, the weight line is automatically thrown forward. The prosthetic limb is rotated as close to 180 degrees as possible without losing balance (135 degrees is usually comfortable), and the turn is completed by stepping in the desired direction with the sound limb. If necessary, remind the amputee to maintain knee extension by applying a force with the residual limb against the posterior wall of the socket (Fig 23-21.).
One exercise that will reinforce turning skills is follow the leader, where the amputee follows the therapist who is making a series of turns in all directions and with various speeds and degrees of difficulty.
The level of skill in turning will vary among amputees. All functional ambulators should be taught to turn in both directions regardless of the prosthetic side. Those with poor balance may be limited to unidirectional turns and require a series of small steps to complete the turn.
Tandem Walking
Walking with a normal base of support is of prime importance. However, tandem walking can assist with balance and coordination and improve prosthetic awareness for the amputee. Place a 5- to 10-cm (2- to 4-in.)-wide strip on the floor. The amputee is asked to walk in three different ways: first, with one foot to either side of the line; second, heel to toe with one foot in front of the other; and third, with one foot crossing over in front of the other so that neither foot touches the line and yet the left foot is always on the right side and vice versa.
Braiding
Braiding (cariocas) may be taught either in the parallel bars or in an open area depending upon the person's ability. Simple braiding is one leg crossing in front of the other. As the amputee's skill improves, the prosthetic limb can alternate, first in front of and then behind the sound limb, and vice versa. As ability improves, the speed of movement should increase. With increased speed the arms will be required to assist with balance, and likewise, trunk rotation will increase, further emphasizing the need for independent movement between the trunk and pelvis (Fig 23-22.).
Single-Limb Squatting
Single-limb balance is taught during the early stages of rehabilitation for crutch walking, hopping, and other skills. Single-limb squatting is considerably more difficult but can help improve balance and strength. When first attempting this skill, half squats with a chair underneath the individual are recommended in case balance is lost.
Falling
Falling or lowering oneself to the floor is an important skill to learn not only for safety reasons but also as a means to perform floor-level activities.
During falling, amputees must first discard any assistive device to avoid injury. They should land on their hands with the elbows slightly flexed to dampen the force and decrease the possibility of injury. As the elbows flex, they should roll to one side, further decreasing the impact of the fall.
Lowering the body to the floor in a controlled manner is initiated by squatting with the sound limb followed by gently leaning forward onto the slightly flexed upper limbs. From this position the amputee has the choice of remaining quadruped or assuming a sitting posture.
Floor to Standing
Many techniques exist for teaching the amputee how to rise from the floor to a standing position. The fundamental principle is to have the amputee use the assistive device for balance and the sound limb for power as the body begins to rise. Depending on the type of amputation and the level of skill, the amputee and therapist must work closely together to determine the most efficient and safe manner to successfully master this task.
Running Skills
For most amputees, the inability to run is the single most common factor limiting participation in recreational activities, and yet it is the most desired skill. Many amputees who do not have a strong desire to run for sport or leisure do have an interest in learning how to run for the simple peace of mind of knowing that they could move quickly to avoid a threatening situation. Rarely, if ever, is running taught in the rehabilitation setting. Running, as with all gait-training and advanced skills, takes time and practice to master. If the amputee is exposed to the basic skills of running during rehabilitation, then the individual may make the decision to pursue running at a later date.
Syme ankle disarticulates and transtibial amputees do have the ability to achieve the same running biomechanics as able-bodied runners if emphasis is placed on the following principles. At ground contact, the hip on the amputated side should be flexed and moving toward extension with the knee flexed and the prosthetic foot passively dorsiflexing. The knee flexion not only permits greater shock absorption but in addition creates a backward force between the ground and the foot to provide additional forward momentum. As the center of gravity passes over the prosthesis during the stance phase, the ipsilateral arm should be fully forward (shoulder flexed to 60 to 90 degrees), while the contralateral arm is simultaneously extended. Extreme arm movement can initially be difficult for the amputee concerned with maintaining balance. During late mid-stance to toe-off, the hip should be forcefully driven downward and backward through the prosthesis as the knee extends. If the prosthetic foot is of the dynamic-response type, the force produced by hip extension should deflect the keel so that additional push-off will be provided by the prosthetic foot. Forward swing and the float phase are periods when the hip should be rapidly flexing and elevating the thigh. The arms should again be opposing the advancing lower limb, with the ipsilateral arm backward and the contralateral arm forward. During foot descent, the hip should be flexed and then begin to extend as the knee is rapidly extending and reaching forward for a full stride (Fig 23-23.).
Transfemoral amputees and knee disarticulates traditionally run with a period of double support on the sound limb during the running cycle, commonly referred to as the "hop-skip" running gait pattern. The typical running gait cycle begins with a long stride by the prosthetic leg, followed by a shorter stride with the sound leg. In order to give the prosthetic leg sufficient time to advance, the sound leg takes a small hop as the prosthetic limb clears the ground and moves forward to complete the stride. The speed that a transfemoral amputee runner may achieve will be hampered because every time either foot makes contact with the ground, the foot's forces are traveling forward and the reaction force of the ground must therefore be in a backward or opposite direction (Newton's third law). The result is that each time the foot contacts the ground, forward momentum is decelerated. In other words, with every stride the amputee is slowing down when running with the "hop-skip" gait.
The ability to run "leg over leg" has been achieved by a number of transfemoral amputees who have developed this technique through training and working with knowledgeable coaches. The transfemoral amputee takes a full stride with the prosthetic leg, followed by a typically shorter stride with the sound leg. With training, equal stride length and stance time may be achieved. This running pattern is a more natural gait where the double-support phase of the sound limb is eliminated and forward momentum maintained by both legs. Initially, problems that may occur include excessive vaulting off the sound limb to ensure ground clearance of the prosthetic limb, decreased pelvic and trunk rotation, decreased and asymmetrical arm swing, and excessive trunk extension. Again with training, many of these deviations will decrease and possibly be eliminated (Fig 23-24.).
The transfemoral amputee has an additional consideration when learning to run. To date, no knee system permits flexion during the prosthetic support phase, and this results in the residual limb having to absorb the ground reaction force during initial ground contact. Another problem with present knee units that transfemoral amputees must contend with is maintaining the appropriate cadence during swing. Hydraulic knee units offer the ability to adjust the hydraulic resistance during knee flexion and extension. During running, less resistance in extension permits faster knee extension, while increased resistance in flexion decreases the amount of heel rise with beginning runners. Seasoned runners often reduce knee flexion resistance to permit the prosthetic shank to bounce off the socket and thus return to the extended position at an accelerated rate. Collectively, these adjustments decrease the amount of time required for the prosthetic swing phase.
The "leg-over-leg" running style does permit the transfemoral amputee to run faster for short distances but at a greater metabolic cost. While the "leg-overleg" style is preferred, the hop-skip method is often more easily taught and less demanding physically on the amputee. If the sole purpose of instructing running is to permit the individual to move quickly in a safe and sure manner, the hop-skip method is most frequently suggested.
Recreational Activities
By definition, recreation is any play or amusement used for the refreshment of the body or mind. That is to say, the term recreational activities need not exclusively mean athletics such as running or team sports. In fact, many people enjoy recreational activities such as gardening, shuffleboard, or playing cards as a means of socializing or relaxing. A comprehensive rehabilitation program should include educating the amputee on how to return to those activities that are found pleasurable. For example, the therapist can teach physical splinter skills such as weight shifting, necessary to help the amputee participate in shuffleboard, or various methods of kneeling for gardening. In addition, there are many national and local recreational organizations and support groups that provide clinics, coaching, or another amputee who can teach from experience how to perform various higher-level recreational skills. Providing the amputee with information on how to contact these groups is the first step to mainstreaming the patient back into a life-style complete with recreational skills as well as activities of daily living.
CONCLUSION
In summary, the physical therapist must work closely with the rehabilitation team to provide comprehensive care for the amputee. An individualized program must be constructed according to the level of ability and skill of each patient. The primary skills of preprosthetic training help build the foundation necessary for successful prosthetic ambulation. The degree of success the amputee experiences with ambulation may directly influence how much the prosthesis will be used and how active a life-style is chosen. Therefore, the primary goal of the rehabilitation team should be to make this transitional period as smooth and successful as possible.
Acknowledgment
We would like to thank Mr. Frank Angulo for his time and talents in creating the illustrations in this chapter.
References:
- Davis GJ: A Compendium of Isokinetics in Clinical Usages and Rehabilitation Techniques, ed 2. S & S Publishing, La Crosse, Wise, 1985.
- Eisert O, Tester OW: Dynamic exercises for lower extremity amputees. Arch Phys Med Rehabil 1954; 35:695-704.
- Murray MP: Gait as a total pattern of movement. Am J Phy Med Rehabil 1967; 16:290-333.
- Murray MP, Drought AB, Kory RC: Walking patterns of normal men. J Bone Joint Surg [Am] 1964; 46: 335-360.
- Peizer E, Wright DW, Mason C: Human locomotion. Bull Prosthet Res 1969; 10:48-105.
Chapter 23 - Atlas of Limb Prosthetics: Surgical, Prosthetic, and Rehabilitation Principles
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