Robert Gailey

Review of secondary physical conditions associated with lower-limb amputation and long-term prosthesis use

Musculoskeletal imbalances or pathologies often develop into secondary physical conditions or complications that may affect the mobility and quality of life of people with lower-limb amputation. Using one or more prostheses causes people with amputation to alter the biomechanics of their movement. For example, people with lower-limb amputation often favor and stress their intact lower limb more during everyday activities. This can lead to degenerative changes such as osteoarthritis of the knee and/or hip joints of the intact limb. Since people with amputation spend less time on their residual limb, osteopenia and subsequent osteoporosis often occur secondary to insufficient loading through the long bones of the lower limb. A proper prosthetic fit increases the probability of equal force distribution across the intact and prosthetic limbs during ambulation, thus decreasing the risk of osteoarthritis. People with limb loss commonly complain of back pain, which is linked to poor prosthetic fit and alignment, postural changes, leg-length discrepancy, amputation level, and general deconditioning. We review the literature on secondary complications among people with lower-limb loss who are long-term prosthesis wearers.

The Amputee Mobility Predictor: An instrument to assess determinants of the lower-limb amputee's ability to ambulate☆☆☆

OBJECTIVES To describe the development of the Amputee Mobility Predictor (AMP) instrument designed to measure ambulatory potential of lower-limb amputees with (AMPPRO) and without (AMPnoPRO) the use of a prosthesis, and to test its reliability and validity. DESIGN Measurement study using known groups method and concurrence with existing measures. SETTING Academic medical center. PARTICIPANTS A convenience sample of 191 lower-limb amputee subjects who had completed prosthetic training, 24 in the reliability study (mean age +/- standard deviation, 68.3+/-17.9y, range, 28-99y) and 167 in the validity study (mean age, 54.8+/-18.6y; range, 18-100y). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Intra- and interrater reliability; construct validity by known groups method; concurrent validity by comparisons with 6-minute walk test, Comorbidity Index, age, and time since amputation; predictive validity by comparison with 6-minute walk test after controlling for other factors. RESULTS Interrater reliability was.99 for subjects tested with and without their prosthesis; intrarater reliability was.96 and.97. Both the AMPnoPRO (P<.0001) and the AMPPRO scores (P<.0001) distinguished among the 4 Medicare functional classification levels. The AMP correlated strongly with 6-minute walk scores (AMPnoPRO r=.69, P<.0001; AMPPRO r=.82, P<.0001) and the amputee activity survey (AMPnoPRO r=.67, P<.0001; AMPPRO r=.77, P<.0001), and negatively correlated with age (AMPnoPRO r=-.69, P<.0001; AMPPRO r=.56, P<.0001) and comorbidity (AMPnoPRO r=-.43, P<.0001; AMPPRO r=.38, P<.0001). CONCLUSION The AMP with and without a prosthesis are reliable and valid measures for the assessment of functional ambulation in lower-limb amputee subjects.

Energy expenditure of trans-tibial amputees during ambulation at self-selected pace

The purpose of this investigation was two-fold: 1) to compare the metabolic cost (VO2), heart rate (HR), and self-selected speed of ambulation of trans-tibial amputees (TTAs) with those of non-amputee subjects; and 2) to determine whether a correlation exists between either stump length or prosthesis mass and the energy cost of ambulation at the self-selected ambulation pace of TTAs. Subjects were thirty-nine healthy male non-vascular TTAs between the ages of 22 and 75 years (mean ± sd = 47 ± 16). All had regularly used their prosthesis for longer than six months and were independent of assistive ambulation devices. Twenty-one healthy non-amputee males aged 27–47 years (31 ± 6) served as controls. Subjects ambulated at a self-selected pace over an indoor course, with steady-state VO2, HR, and ambulation speed averaged across minutes seven, eight and nine of walking. Results showed that HR and VO2 for TTAs were 16% greater, and the ambulation pace 11% slower than the non-amputee controls. Significant correlations were not observed between stump length or prosthesis mass and the energy cost of ambulation. However, when the TTA subject pool was stratified on the basis of long and short stump length, the former sustained significantly lower steady-state VO2 and HR than the latter while walking at comparable pace. These data indicate that stump length may influence the metabolic cost of ambulation in TTAs.

Advances in Lower-limb Prosthetic Technology

The boundaries once faced by individuals with amputations are quickly being overcome through biotechnology. Although there are currently no prosthetics capable of replicating anatomic function, there have been radical advancements in prosthetic technology, medical science, and rehabilitation in the past 30 years, vastly improving functional mobility and quality of life for individuals with lower-limb amputations. What once seemed impossible is rapidly becoming reality. The future seems limitless, and the replication of anatomic function now seems possible.

The effects of prosthesis mass on metabolic cost of ambulation in non-vascular trans-tibial amputees

The effect of prosthesis mass on the metabolic cost of steady-state walking was studied in ten male non-vascular trans-tibial amputees (TTAs) and ten non-amputee controls. The subjects underwent four trials of treadmill ambulation, with each trial performed for nine minutes at level grade and 76 m/min. Twenty minutes of seated rest followed each trial. During trials numbers one and two, TTAs ambulated without mass added to their prosthesis. During the third and fourth trials, either 454 or 907 grammes mass (1 or 2lbs mass respectively) were randomly assigned and added to eithier the prosthesis or the leg of the non-amputee control. Subjects were blinded to the amount of mass added to their limb. Within-group comparisons across the four trials showed significant differences in oxygen consumption (VO2) and heart rate (HR) between the two non “mass added” trials, but no effect for addition of mass. The VO2 of TTAs was only 0.6ml/kg/min (4.7 percent) greater during walking following the addition of 907 grammes to the prosthesis than without mass addition at all, while HR averaged only 1.4 beats/min. higher under the same testing condition. Pearson-product moment correlations echoed these findings, as moderate, but in all cases, negative correlations were observed for associations among the factors of subject age, stump length, and prosthesis-shoe weight, and both VO2 and HR. It was concluded that adding up to 907 grammes mass to a non-vascular TTAs prosthesis will not significantly increase the energy expenditure or HR at a normal walking speed, and that elevated energy cost of ambulation in repeated measures testing without mass added may reflect task familiarisation and not an added burden of prosthesis mass.

Predictive Outcome Measures Versus Functional Outcome Measures in the Lower Limb Amputee

INTRODUCTION John Ware 1 wrote, “Life has two dimensions: quantity and quality.” The distinction between the two entities is well illustrated in the common greeting “may you have a long and healthy life” (p. 473). Length of life is expressed in terms of average life expectancy, mortality rates, death due to specific causes, and numerous other indicators. When defining the second dimension, quality of life encompasses standard of living, the quality of housing and the neighborhood in which one lives, job satisfaction, and many other factors. With regard to the amputee, it has been well established that for a number of vascular amputees who have undergone an amputation due to the magnitude of vascular compromise, life expectancy is relatively short. For the amputee who has lost a limb to tumor, trauma, or congenital condition, amputation has little or no bearing on life expectancy. Medical interventions have improved care to the point where the impact of amputation on longevity has decreased tremendously. So, as quantity of life improves, what about quality of life? The World Health Organization (WHO) defined health as a “state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.” Health connotes “completeness” – nothing is missing from the person; it connotes “proper functions” – all is working efficiently. That would suggest that if a prosthesis has the ability to improve the quality of life for the amputee, then it should be provided. This is not to say that the “best” prosthesis belongs on all patients, primarily because what is considered the “best” for one person may be a hindrance to another. For example, a prosthetic foot that provides a mechanical high energy return at terminal stance, propelling the limb into the swing phase of gait will be a tremendous asset for a strong person with a fast cadence. Conversely, the same foot might only throw a frail, elderly person off balance, resulting in the fear of falling and a tentative gait pattern. Unfortunately, we are not sure what the best prosthesis is for the different amputee populations. The dilemma becomes apparent when trying to determine what are the best prosthetic components for each individual amputee. Common indictors such as materials, time of fabrication, complexity of design, and cost do not dictate the “best” components for each individual. Matching functional ability with the proper components is the solution for optimizing physical performance. This is not a novel concept. In fact, if questioned, most clinicians would agree that marriage of the correct prosthetic components for the appropriate level of function is one of the primary goals of the rehabilitation team. However, this goal is apparently not so easy to achieve. At the very root of the problem is the inability to define a “successful prosthetic ambulator.” There are many interpretations for this common goal, from simply using the prosthesis “about an hour per day” to “prosthetic use without external support on a daily basis.” There is no agreement anywhere with regard to the threshold of “successful prosthetic use.” The question is whether there is one threshold or many as severe authors have advocated by virtue of offering multilevel functional scales and indices. There is a wide variety of indices published within the literature. In the United States today, it appears that only one index is of significant consequence to Medicare and managed care providers, the Durable Medial Equipment Regional Carrier (DMERC) K codes or Medicare’s Functional Classification Level (MFCL) index. Its exceptional importance is solely because assignment to a particular level of function within this index determines the level of prosthetic care, and, consequently, the financial reimbursement a prosthetist will receive for the prosthetic services rendered. After an extensive review of all available indices, the descriptors and selection of number of levels chosen for the MFCL index appears to be well constructed. This assumption is predicated on the basis that the MFCL index has a range from a fully dependent bed-bound amputee to a recreational athlete capable of higher level activities. Definitions clearly describe observable differences between each of the five levels using seemingly commonly assessed functional skills. It must be kept in mind, however, that as attractive as the MFCL may appear to be after initial examination, it was created based on content validity of a Medicare subcommittee and was not based on any formal scientific research. The use of a functional index seems to be reasonable, but ROBERT S. GAILEY, PhD, PT, is affiliated with the University of Miami School of Medicine, Department of Physical Therapy, Miami Veterans Affairs Medical Center, Miami, Florida.

The CAT-CAM socket and quadrilateral socket: a comparison of energy cost during ambulation.

Twenty unilateral trans-femoral amputees fitted with either the Contoured Adducted Trochanteric-Controlled Alignment Method (CAT-CAM) socket (n=10) or the quadrilateral (QUAD) socket (n=10), and a “non-amputee” control group (n=10) participated in the study. Subjects meeting the following criteria were studied: healthy males between the ages of 18 and 55 years, amputation due to non-vascular pathology, an unaffected sound limb, at least six months use of the test prosthesis, and a minimal stump length of 15 cm. Subjects ambulated in two randomized trials separated by 20 minutes of rest at 2 assigned speeds: a pace reflecting normal walking speed (97 m/min=2.5 mph) or a slower speed (48.5 m/min=1.25 mph). Heart rate (HR) and Oxygen uptake (VO2) measured during steady state walking were analyzed via two-way ANOVA. Differences among means were further analyzed using Tukey post hoc and simple effects tests. Significant differences were observed between the control group and CAT-CAM subjects with respect to VO2 (p < 0.05) and HR (p < 0.01) at the slower speed. The control group and subjects using the QUAD socket also differed with respect to VO2 (p < 0.01) and HR (p < 0.01) at the slower pace. Faster pace required more energy expenditure (p < 0.01) and produced higher HR (p < 0.01) than slower speeds. At faster pace, a significantly higher energy expenditure in the QUAD than the CAT-CAM group was observed (p<0.01). It is concluded that ambulating at normal pace using the CAT-CAM socket design uses less energy than when using a QUAD socket design.

Unilateral lower-limb loss: Prosthetic device use and functional outcomes in servicemembers from Vietnam war and OIF/OEF conflicts

Rehabilitation goals following major combat-associated limb loss in World War II and the Vietnam war focused on treatment of the injury and a return to civilian life. The goal for Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) servicemembers is to restore function to the greatest possible degree and, if they desire, return them to Active Duty, by providing them with extensive rehabilitation services and a variety of prosthetic devices. Our study determines the usefulness of these diverse types of prosthetic devices for restoring functional capability and documents prosthesis use and satisfaction. We compare servicemembers and veterans with major combat-associated unilateral lower-limb loss: 178 from the Vietnam war and 172 from OIF/OEF conflicts. Of survey participants with unilateral lower-limb loss, 84% of the Vietnam group and 94% of the OIF/OEF group currently use at least one prosthetic device. Reasons for rejection varied by type of device, but common reasons were pain, prosthesis too heavy, and poor fit. Abandonment is infrequent (11% Vietnam group, 4% OIF/OEF group). Future efforts should aim to improve prosthetic-device design, decrease pain, and improve quality of life for these veterans and servicemembers.

Comparison of three agility tests with male servicemembers: Edgren Side Step Test, T-Test, and Illinois Agility Test.

Performance-based outcomes such as the T-Test, Edgren Side Step Test (ESST), and Illinois Agility Test (IAT) have been used to assess agility in athletes and nonathletes; however, the reliability and validity of these tests have not been established. The purpose of this study was to establish the reliability and convergent construct validity of the ESST, T-Test, and IAT in young, nondisabled, physically active male servicemembers (SMs). Ninety-seven male Active Duty U.S. Army SMs completed the study. Statistically significant differences were not found between the ESST (p = 0.10), T-Test (p = 0.09), and IAT (p = 0.23) when administered twice within a 24 to 48 h period. These tests were found to have excellent interrater reliability and moderate to good test-retest reliability. A good positive relationship exists between the IAT and T-Test (r = 0.76, p < 0.001) and a moderate negative relationship exists between the ESST and both the T-Test (r = -0.69, p < 0.001) and IAT (r = -0.65, p < 0.001). The results suggest that these tests are valid measures of agility that uniquely assess movement in different planes, thus providing a comprehensive assessment of high-level mobility.

Symmetry in External Work (SEW): A novel method of quantifying gait differences between prosthetic feet

Unilateral transtibial amputees (TTAs) show subtle gait variations while using different prosthetic feet. These variations have not been detected consistently with previous experimental measures. We introduce a novel measure called Symmetry in External Work (SEW) for quantifying kinetic gait differences between prosthetic feet. External work is the result of changes in kinetic and potential energy of body center of mass (CoM). SEW is computed by integrating vertical ground reaction forces obtained using F-scan in-sole sensors. Since various prosthetic feet have different designs, we hypothesized that SEW will vary with the type of foot used. This hypothesis was tested with a single unilateral TTA using four prosthetic feet (Proprio, Trias+, Seattle Lite and SACH). The Proprio (mean symmetry 94.5% ± 1.1%) and the Trias+ (92.1% ± 2.5%) feet exhibited higher symmetry between the intact and prosthetic limbs, as compared to the Seattle (67.8% ± 19.3%) and SACH (35.7% ± 11.1%) feet. There was also a good agreement in vertical CoM excursion between the intact foot and prosthetic feet with heel-toe foot plate designs. Results indicate that SEW measure may be a viable method to detect kinetic differences between prosthetic feet and could have clinical applications because of relatively low cost instrumentation and minimal subject intervention.