Amputation: energy cost of ambulation.

A mobile instrument system was used to measure energy consumption by indirect calorimetry at rest and during ambulation in 25 unimpaired subjects, 6 unilateral below-knee (BK) amputee patients, 6 unilateral above-knee (AK) amputee patients and 4 bilateral AK amputee patients. To prevent the introduction of gait difficulties among the impaired subjects, each subject was permitted to walk at his own comfortable speed. Since speed thus varied among subjects, ambulation data were expressed in units of energy per foot traveled. Statistical analyses of the mean oxygen costs indicated several significant differences among the groups. In comparison to unimpaired subjects, the mean oxygen consumption was 9% higher in unilateral BK amputee patients, 49% higher in unilateral AK amputee patients and 280% higher in bilateral AK amputee patients.     

Dynamic analysis of above-knee amputee gait

BACKGROUND: It is important to understand the characteristics of amputee gait to develop more functional prostheses. The aim of this study is to quantitatively evaluate amputee gait by dynamic analysis of the musculoskeletal system during level walking and stair climbing. METHODS: Dynamic analysis using gait analysis, electromyography and musculoskeletal modeling for above-knee amputees (n=8) and healthy adults (n=10) was performed to evaluate the muscle balance, muscle force, and moment of each major muscle in each ambulatory task. Time-distance parameters and the kinematic parameter of gait analysis were calculated, and a root mean square electromyogram of major muscles and hamstring and tibialis anterior coactivity was measured using electromyography. Lastly, dynamic analyses of above-knee amputee gaits were performed using musculoskeletal models with scaled bones and redefined muscles for each subject. FINDINGS: Most kinematic parameters showed statistically no difference among the tasks, excluding pelvic tilt, pelvic obliquity, and hip abduction. Major muscle activities and coactivities of the hamstring and tibialis anterior showed that the stair ascent task needed more muscle activity than the stair descent task and level walking. The muscle activity and coactivity of amputees were greater than those of healthy subjects, excluding the hamstring coactivity during stair ascent (P<0.05). Lastly, dynamic analysis showed that weakened abductor and excessive adductor and then inadequate torque during all tasks were quantitatively observed. INTERPRETATION: Dynamic analysis of amputee gait enabled us to quantify the contribution of major muscles at the hip and knee joint mainly in daily ambulatory tasks of above-knee amputees and may be helpful in designing functional prostheses.     

Long-term clinical outcomes of Iranian veterans with unilateral transfemoral amputation

Aim. To study long-term outcome of unilateral above-knee amputation.

Objective. Long-term clinical symptoms and functional status of above-knee amputees are not well documented. The purpose of this study was to document the long-term outcome of war related above-knee amputations.

Context. The study consisted of a comprehensive assessment and examination and review of history and wartime medical records of 31 Iranian above-knee amputees from the Iraq–Iran war by using a detailed questionnaire. The average follow-up was 17.5 years (range from15 to 22 years). All patients were males and had been combatants.

Results. The most common agent of war injury was a shell with an incidence of 45.1%, while land mines and direct bullet shots were the following causes of war injury resulting in amputation in 41.9% and 12.9%, respectively. Clinical symptoms included phantom sensation in 27 patients (87%), phantom pain in 14 patients (45.1%), phantom movement in 5 patients (16.1%) patients and stump pain in 20 patients (64.5%). Additionally, 19 patients (61.2%) suffered from back pain, 17 patients (54.8%) complained of contra lateral ( non-amputated) knee pain and 4 patients (14.8%) complained of ipsilateral hip pain. Seventeen patients (54%) reported psychological problems. Eighteen cases (58%) were employed or had been employed for multiple years after amputation. All patients (100%) were married and 30 (96.7%) had offspring.

Conclusions. The study showed that our patients had significant rates of amputation symptoms after an average of two decades of amputation, but on the other hand good family and social function of the patients were recorded. Amputation is not a static disability but a progressive deteriorating condition that affects the health condition of the amputee over time.     

Insights into amputee running. A muscle work analysis.

Five young, active, unilateral below knee amputees wearing the SACH prosthetic foot, and six normal subjects participated in the study. Subjects ran at a controlled velocity of 2.8 m/s +/- 10% over a ground reaction force plate while being filmed with a video camera. Joint moments, power outputs and mechanical work characteristics were then calculated. During stance phase the amputee prosthetic limb exhibited a marked reduction in total work. There was a reduction in the mechanical work at the knee and the prosthetic foot/ankle with a compensatory increase in mechanical work by the hip musculature. The intact stance phase limb mechanical work characteristics were not significantly different from normal. The hip flexors were the only muscle group in the swing phase prosthetic limb with a significant increase in muscle work compared with normal subjects. The intact swing phase limb in contrast exhibited a marked increase in concentric muscle work by the hip flexors and eccentric muscle work by the knee flexors in early swing phase, and an increase in concentric hip extensor and eccentric knee flexor muscle work in late swing phase. The major compensatory patterns, therefore, that allow below knee amputees to run appear to be an increase in stance phase hip muscle work on the prosthetic limb and increased hip and knee muscle work on the intact limb during swing phase.     

Sprint kinematics of athletes with lower-limb amputations.

OBJECTIVE: To determine and compare the kinematics of the sound and prosthetic limb in five of the world's best unilateral amputee sprinters. SUBJECTS: Five men, all unilateral lower-limb amputee (one transfemoral, four transtibial) athletes. The individual with transfemoral amputation used a Endolite Hi-activity prosthesis incorporating a CaTech hydraulic swing and stance control unit, a Flex-Foot Modular III, and an ischial containment total contact socket. Those with transtibial amputations used prostheses incorporating a Flex-Foot Modular III and patellar tendon-bearing socket, with silicone sheath liner (Iceross) and lanyard suspension. DESIGN: Case series. Subjects were videotaped sprinting through a performance area. Sagittal plane lower-limb kinematics derived from manual digitization (at 50 Hz) of the video were determined for three sprint trials of the prosthetic and sound limb. Hip, knee, and ankle kinematics of each subject's sound and prosthetic limb were compared to highlight kinematic alterations resulting from the use of individual prostheses. Comparisons were also made with mean data from five able-bodied men who had similar sprinting ability. RESULTS: Sound limb hip and knee kinematics in all subjects with amputation were comparable to those in able-bodied subjects. The prosthetic knee of the transfemoral amputee athlete fully extended early in swing and remained so through stance. In the transtibial amputee athletes, as in able-bodied subjects, a pattern of stance flexion-extension was evident for both limbs. During stance, prosthetic ankle angles of the transtibial amputee subjects were similar to those of the sound side and those of able-bodied subjects. CONCLUSION: Prosthetic limb kinematics in transtibial amputee subjects were similar to those for the sound limb, and individuals achieved an "up-on-the-toes" gait typical of able-bodied sprinting. Kinematics for the prosthetic limb of the transfemoral amputee subject were more typical of those seen for walking. This resulted in a sprinting gait with large kinematic asymmetries between contralateral limbs.     

Bilateral lower extremity dressing frame.

Completely independent application of lower extremity prostheses and clothing is essential but often difficult to accomplish in optimal rehabilitation of the bilateral above-knee amputee. This paper suggests an occupational therapy treatment plan for above-knee amputations, discusses reasons for dependency and decreased use of lower extremity prostheses and clothing, and describes a bilateral lower extremity dressing frame designed for independent application of prostheses and lower extremity clothing. The cost of rehabilitation can be justified once independence in application of prostheses and clothing is accomplished and functional ambulation is achieved.     

Patient preference and gait efficiency in a geriatric population with transfemoral amputation using a free-swinging versus a locked prosthetic knee joint

OBJECTIVE: To investigate patient preference, walking speed, and prosthetic use in a geriatric population with transfemoral amputation using a free-swinging prosthetic knee or a locked knee joint. DESIGN: Before-after trial. SETTING: Ambulatory patients at an amputee rehabilitation facility. PARTICIPANTS: A convenience sample of 14 geriatric individuals with a unilateral dysvascular transfemoral amputation (age range, 61-80y), who were using a prosthesis with a free-swinging knee in the community, 3 months after discharge from an amputee rehabilitation program. INTERVENTION: Change from a free-swinging knee to a locked knee. MAIN OUTCOME MEASURES: Patient preference, distance walked in 2 minutes, and prosthetic use as measured by the Houghton Scale. RESULTS: Eleven of 14 participants preferred the locked knee. Irrespective of preference, the mean 2-minute walk distance was 44.9 +/- 28.9m with the free-swinging knee and 54.4 +/- 35m with the locked knee (P = .001). Prosthetic use was greater with the locked knee (7.8 +/- 2.2) than with the free-swinging knee (6.6 +/- 2.5) (P = .01). CONCLUSIONS: Most geriatric participants with transfemoral amputation preferred locked knees and walked faster and used their prostheses more when using a locked knee prosthesis.     

Rehabilitation of patients with end-stage renal failure after lower extremity amputation

Four patients with end-stage renal failure on maintenance hemodialysis and one patient with near end-stage renal failure received inpatient rehabilitation following lower extremity amputation. All were prosthetically restored. Three of the patients had bilateral below-knee amputations and were ambulatory at the time of discharge, including the patient with near end-stage renal failure who was on maintenance hemodialysis at follow-up. One unilateral below-knee amputee was also ambulatory at discharge. The other unilateral below-knee amputee had an ulcer on the other foot and used a pylon for transfers only. To assess the prevalence of patients on maintenance hemodialysis with lower extremity amputations, a survey of 310 patients at four dialysis units was performed. Of the 310 patients 2.9 percent had at least one amputated lower extremity and 1.0 percent had bilateral lower extremity amputations. Preliminary data and the potential for functional results following prosthetic restoration suggest the need for further research concerning prosthetic restoration in the lower extremity amputee with end-stage renal failure.     

Causes and correction of abnormal gait patterns due to prosthesis in above-knee amputees

Abnormal gait patterns cause an increase in the energy cost of walking in above-knee amputees. Disturbances of the walking pattern are often caused both by the amputated patient himself and by incorrect prosthetic fitting. The early detection and correction of causative factors is of great importance for successful rehabilitation of these amputees. During the follow-up examinations the prosthesis must be inspected for a correct fitting and individually appropriate knee stabilizing components. Prior to any corrective measures it must be excluded that the artificial limb has been put on incorrectly by the amputee himself.     

Biomechanical analysis of the influence of prosthetic feet on below-knee amputee walking

Although energy storing prosthetic feet have achieved widespread clinical acceptance, the effect of these components on the biomechanics of below-knee amputee gait is poorly understood. The purpose of this study was to determine the biomechanical adaptations used by the below-knee amputee while wearing a conventional prosthetic foot and to assess the influence of energy storing prosthetic feet on these adaptations. Mechanical power outputs of the lower extremity in five normal and five below-knee amputee subjects using the SACH, Seattle and Flex feet were studied. Ground reaction forces and kinematic data were collected at a walking speed of 1.5 m/s and were used to determine the muscular power outputs of the lower extremity during stance. Consistent patterns of muscular power output at the hip and knee of the residual limb occur. While wearing the SACH foot, negligible energy generation occurs at the prosthetic foot during pushoff. A decrease in energy absorption at the knee during the first half of stance and an increase in energy generation by the hip extensors were the major adaptations noted in the proximal muscle groups. Compared to the SACH foot, the energy storing feet demonstrated increased energy generation during pushoff. Despite the improvements in the performance of the energy storing prosthetic feet, no significant differences were found in the pattern or magnitude of knee and hip power outputs compared to the SACH foot.     

Biomechanical adaptations of transtibial amputee sprinting in athletes using dedicated prostheses

OBJECTIVE: To determine the biomechanical adaptations of the prosthetic and sound limbs in two of the world's best transtibial amputee athletes whilst sprinting. DESIGN: Case study design, repeated measures. BACKGROUND: Using dedicated sprint prostheses transtibial amputees have run the 100 m in a little over 11 s. Lower-limb biomechanics when using such prostheses have not previously been investigated. METHODS: Moments, muscle powers and the mechanical work done at the joints of the prosthetic and sound limbs were calculated as subjects performed repeated maximal sprint trials using a Sprint Flex or Cheetah prosthesis. RESULTS: An increased hip extension moment on the prosthetic limb, with an accompanying increase in the amount of concentric work done, was the most notable adaptation in Subject 1 using either prosthesis. In Subject 2, an increased extension moment at the residual knee, and an accompanying increase in the amount of total work done, was the most notable adaptation using either prosthesis. This later adaptation was also evident in Subject 1 when using his Sprint Flex prosthesis. CONCLUSIONS: Increased hip work on the prosthetic limb has previously been shown to be the major compensatory mechanism that allow transtibial amputees to run. The increased work found at the residual knee, suggests that the two amputee sprinters used an additional compensatory mechanism. RELEVANCE: These findings provide an insight into the biomechanical adaptations that allow a transtibial amputee to attain the speeds achieved when sprinting.     

Prosthetic rehabilitation of geriatric amputee patients: a follow-up study

During a four-year period, 116 lower extremity amputee patients older than 65 years were evaluated and treated by our department. Fifty-nine patients with below-knee (BK) amputations, 22 with above-knee (AK) amputations, and 15 with bilateral amputations were fitted with prostheses and trained in their use. A follow-up study on all patients was done at an average of 22 months after they had completed their training program but not earlier than after 6 months. Of all BK amputees who had been fitted with a prosthesis, 73% were using it fulltime and as their main mode of locomotion; 25% were using it part of the time. The results were less favorable for AK and for bilateral amputee patients: 50% of AK amputees and 33% of the bilateral amputees had become fulltime users of their prostheses. Age alone was not a major determining factor in success or failure of prosthetic rehabilitation. Failures usually were due to concurrent medical disease or mental deterioration. The study indicates that the effort and expense of fitting and training geriatric patients with prostheses may be well worthwhile.     

Preliminary evaluation of an automatically stance-phase controlled pediatric prosthetic knee joint using quantitative gait analysis

OBJECTIVES: To evaluate the effects on gait of a new pediatric prosthetic knee joint using an automatic stance-phase lock (ASPL), shown previously to help prevent falls, and to propose future design considerations and prosthetic alignments. DESIGN: Case series and crossover trial. SETTING: Human movement laboratory. PARTICIPANTS: Three children with unilateral above-knee amputations and 3 children with bilateral above-knee or below-knee amputations. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Spatiotemporal, kinematic, and kinetic gait parameters. RESULTS: Spatiotemporal parameters indicated higher gait velocities with the ASPL knee joint for the children with unilateral amputations. The increased speed, as expected, was associated with increased temporal interlimb asymmetry, joint moments and powers, and excessive prosthetic knee range of motion in swing. A trend toward increased pelvic motions was observed with ASPL knee when compared with conventional knees. CONCLUSIONS: The biomechanic performance of the single-axis ASPL knee joint was shown to be comparable with more complex polycentric pediatric prosthetic knee joint technologies worn by the children in this study.     

Surgical correction of leg alignment in unilateral knee osteoarthrosis reduces the load on the hip and knee joint bilaterally

Seventeen patients with strictly unilateral medial knee osteoarthrosis that justified surgical treatment constituted the study group. No patient had any symptoms from the hip or ankle joints or from the other knee. Eight patients were operated with high tibial osteotomy and nine were operated with unicompartmental prosthetic replacement (Brigham model). The forces and the external moment about the hip, knee, and ankle joints of the involved and uninvolved leg were calculated before and 1 year after corrective surgery and compared to the external moment in 10 normal controls. Clinical examinations was performed and the hip-knee-ankle angle in the involved leg was determined from whole-leg weightbearing radiographs before and 1 year after surgery. The external moments about the hip, knee, and ankle joints and the knee moment arms at mid-stance in the frontal plane during gait were determined with a Kistler force plate and a videorecording system. All patients improved clinically after surgery. The mean hip-knee-ankle angle changed from 11 degrees of varus to 0 degrees. In the uninvolved leg the mid-stance adduction moments about the hip and knee joints were significantly increased compared to normal subjects in the control group before surgery, but reduced to a normal level 1 year after surgery. This reduction was mainly due to a significant reduction of the medially directed force. The moments about the ankle joints were not found to be changed by the knee deformity or by the corrective surgery. RELEVANCE: This study demonstrates that a varus malalignment in the osteoarthrotic knee is accompanied by increased load about the uninvolved hip and knee joint. One might expect a more rapid progression of degenerative changes in joint cartilage as a consequence of such increased load. The reduced load after surgical correction of leg alignment might be beneficial to patients with osteoarthrosis of their hip and knee joints.     

Alignment of lower-limb prostheses

Alignment of a prosthesis is defined as the position of the socket relative to the other prosthetic components of the limb. During dynamic alignment the prosthetist, using subjective judgment and feedback from the patient, aims to achieve the most suitable limb geometry for best function and comfort. Until recently it was generally believed that a patient could only be satisfied with a unique "optimum alignment." The purpose of this systematic study of lower-limb alignment parameters was to gain an understanding of the factors that make a limb configuration or optimum alignment, acceptable to the patient, and to obtain a measure of the variation of this alignment that would be acceptable to the amputee. In this paper, the acceptable range of alignments for 10 below- and 10 above-knee amputees are established. Three prosthetists were involved in the majority of the 183 below-knee and 100 above-knee fittings, although several other prosthetists were also involved. The effects of each different prosthetist on the established range of alignment for each patient are reported to be significant. It is now established that an amputee can tolerate several alignments ranging in some parameters by as much as 148 mm in shifts and 17 degrees in tilts. This paper describes the method of defining and measuring the alignment of lower-limb prostheses. It presents quantitatively established values for bench alignment position and the range of adjustment required for incorporation into the design of new alignment units.     

Visual input: its importance in the control of postural sway.

A new and measurable parameter in the study of static equilibrium is described. Using a minicomputer, the locus of postural sway was measured during 1 minute periods in 144 volunteer subjects, including 105 control subjects and 39 persons with above-knee amputations. It was hypothesized that the above-knee amputee group had lost a relatively predictable degree of proprioception and kinesthetic sense. Vestibular mechanisms were normal and, therefore, constant in both groups. Using a simple arithmetic formula, the effect of such loss of proprioception was estimated by comparing the amputee group with the nonamputee group, while the contribution of visual input was estimated by comparing both groups with their eyes open and closed. Using this parameter, no clear age dependency was demonstrated. The mean locus of sway for the amputee group was the same as the nonamputee group with the eyes open. However, a comparison of the eyes open/eyes closed ratio in both groups demonstrated a significantly greater increase for the amputee group than for control subjects (p less than 0.001). In the future, mean locus of sway might provide a useful clinical method of measurement and the eyes open/eyes closed ratio might provide a simple and useful method to communicate the dependency upon vision in individual patients.     

Interface pressures in above-knee sockets

The interface pressures in above-knee sockets of amputee patients were measured during the stance phase of the gait cycle. The pressures were monitored with a pneumatic sensor array that covered the inside of the socket. A pressure map of the socket surface was developed. This map has been related to the fit of the prosthetic socket. The pressures generated by the quadrilateral socket and the Normal Shape Normal Alignment (NSNA) socket were compared. Significant variations were noted in pressure distribution between the two sockets, but the magnitudes of the pressures in well-fitting sockets of both types were similar. Thus, magnitude of pressure in an above-knee socket may provide a more useful guide than distribution for predicting the fit of an appliance.     

单侧小腿截肢患者穿假肢后的步态运动学参数研究

目的 采用计算机辅助康复环境(CAREN)步态评估系统分析单侧小腿截肢患者穿假肢后的步态运动学参数,并分析其产生差异的原因。 方法 选取单侧小腿中段截肢但均装配假肢的受试者9例设为假肢组,同期选择健全受试者11例设为标准组,通过CAREN步态评估系统对2组受试者的步态运动学参数进行收集、处理、分析,并根据分析报告阐明产生差异原因。 结果 假肢组步态时相性指数为(0.88±0.04),其假肢侧的步长、支撑期百分比、髋关节支撑期最大伸展角度、膝关节支撑期最大屈曲角度、踝关节足跟着地背屈角度、踝关节支撑期最大背屈角度、踝关节支撑期最大跖屈角度与健侧比较,差异均有统计学意义(P<0.05）。假肢组假肢侧的步行速度、步态周期、跨步长、支撑期百分比、髋关节足跟落地屈髋角度、髋关节支撑期最大伸展角度、髋关节支撑期最大屈曲角度、膝关节足跟着地屈膝角度、踝关节足跟着地背屈角度、踝关节支撑期最大跖屈角度、踝关节支撑期最大背屈角度与标准组双侧均值比较,差异均有统计学意义(P<0.05）。 结论 单侧小腿截肢者穿戴假肢后步态时相对称性为（0.88±0.04）,假肢侧踝关节运动学参数显著弱于自身健侧,其时空与运动学参数也显著弱于健全人。