Does having a computerized prosthetic knee influence cognitive performance during amputee walking?

OBJECTIVE: To compare objective cognitive performance and perception of cognitive burden during walking tasks using 2 different prosthetic knees: a computerized hydraulic knee (Otto Bock C-leg) and a noncomputerized hydraulic knee (Ossur Mauch SNS). DESIGN: Two-group crossover trial, with participants randomly assigned to order of prosthesis. Participants completed assessments under 2 conditions, a self-selected speed walk and a controlled speed walk, on 2 separate occasions (precrossover, postcrossover). SETTING: Veterans Health Administration hospital. PARTICIPANTS: Eight transfemoral amputees. INTERVENTION: Computerized versus noncomputerized prosthetic knee. MAIN OUTCOME MEASURES: Objective cognitive performance measures included verbal fluency (Controlled Oral Word Association Test, Category Test), attention and working memory (serial subtraction), and walking speed during cognitive tasks. Measures of perceived cognitive burden included subjective attentional requirements of walking and cognitive tasks and subjective general cognitive burden of prosthesis. RESULTS: There were no significant differences in objective cognitive performance on any task between prostheses, nor did walking speed vary by prosthesis during the free-speed walk. Participants reported that walking required less attention while wearing the C-leg and that the C-leg was less of a cognitive burden than the noncomputerized prosthesis. CONCLUSIONS: In nondemanding walking conditions with experienced amputees, participants reported that the more costly C-leg required less cognitive attention than the noncomputerized knee. However, this subjective experience did not translate to improved performance on neuropsychologic screening instruments or on walking speed. Noncomputerized prostheses may be adequate for a majority of amputees, and further research is needed to identify particular groups of amputees (ie, new amputees, amputees with complex physical or cognitive demands) who may benefit from computerized prostheses.     

Gait efficiency using the C-Leg

Microprocessor-controlled prosthetic knees are claimed to improve gait efficiency in transfemoral (TF) amputees. This hypothesis was tested in a prospective randomized crossover trial that compared the Mauch SNS knee and the C-Leg microprocessor-controlled knee in eight TF amputees. The subjects were given a 3-month acclimation period in each knee. Then, their net oxygen cost (mL/kg/m) was measured while they walked overground at four speeds in random order: 0.8 m/s, 1.0 m/s, 1.3 m/s, and self-selected walking speed (SSWS). The C-Leg caused small reductions in net oxygen cost that were not statistically significant compared with the Mauch SNS at any of the walking speeds (p > 0.190). Subjects chose higher SSWSs with the C-Leg compared with the Mauch SNS (mean +/- standard deviation = 1.31 +/- 0.12 m/s vs 1.21 +/- 0.10 m/s, respectively, p = 0.046) but did not incur higher oxygen costs (p = 0.270), which suggests greater efficiency only at their SSWS.     

Transfemoral amputee intact limb loading and compensatory gait mechanics during down slope ambulation and the effect of prosthetic knee mechanisms

BackgroundIntact limb knee osteoarthritis is a prevalent secondary disability in transfemoral amputees. Walking down a ramp may increase this risk due to excessive limb loading. We sought to determine whether intact limb loading differed between transfemoral amputees and controls during down slope ambulation, and the compensatory strategies transfemoral amputees used to modify intact limb loading. Secondarily, we sought to determine the effect of prosthetic knee type.MethodsFive unilateral transfemoral amputees and five non-amputee controls walked down a ramp and the following outcome measures were compared between amputees and controls and across prosthetic knee type (C-leg versus Power Knee): step length, walking speed, leading limb ground reaction forces, and trailing and leading limb ankle and knee energy absorption. Linear mixed effects regression was used to test for association between gait variables and limb.FindingsThere were no significant differences in intact limb loading between amputees and controls or between prosthetic knee types. Transfemoral amputees walked slower (C-leg - control = −0.29 m/s; P = 0.008, Power Knee – control = −0.38 m/s; P < 0.001) with a shorter intact limb step length (C-leg - control = −0.12 m/s; P < 0.001, Power Knee – control = −0.16 m/s; P < 0.001). The prosthetic trailing limb ankle absorbed less energy throughout stance than the trailing limb in controls (C-leg-control = −0.22 J/kg; P < 0.001, Power Knee – control = −0.22 J/kg; P < 0.001).InterpretationIntact limb loading in transfemoral amputees is equivalent to controls during down ramp ambulation, in spite of reduced prosthetic trailing limb energy absorption. The primary compensatory strategies include a reduced ambulation speed and intact limb step length, which reduces center of mass velocity at heel contact.     

Prosthetic gait of unilateral lower-limb amputees with current and novel prostheses: A pilot study

BackgroundNovel lower-limb prostheses aim to improve the quality of locomotion of individuals with an amputation. This study evaluates the biomechanics of a novel bionic foot during walking.MethodsAble-bodied individuals (n = 7) and individuals with a transfemoral (n = 6) or transtibial amputation (n = 6) were included. Able-bodied individuals conducted one experimental trial, whereas individuals with transtibial and transfemoral amputations conducted a familiarization (with current prosthesis) and two experimental trials using a passive and bionic prosthesis. Each trial consisted of 3 bouts of 2 min of treadmill walking at different speeds. Biomechanical data were gathered using a force platform and motion capture system and analysed using Statistical Parametric Mapping and (non)-parametric tests.FindingsConventional prosthetic feet alter gait patterns and induce locomotion difficulties. While walking at a normal speed with the passive prosthesis, transtibial amputees display reduced maximum heel forces, increased ankle and trunk angular velocities at midstance, and increased knee angle during stance and swing phases on their effected side (P ≤ 0.026). Improved lower-limb kinematics was demonstrated during slow and normal speed walking with the bionic prosthesis; however, dynamic trunk stability was negatively impacted during this condition. The bionic prosthesis did not benefit transfemoral amputees at any walking speed.InterpretationTranstibial amputees can better approximate typical movement patterns at slow and normal walking speeds using the novel bionic prosthesis; however the same benefit was not observed in transfemoral amputees.     

Loading rates in unilateral transfemoral amputees with running-specific prostheses across a range of speeds

BackgroundUnderstanding the potential risks of running-related injuries in unilateral transfemoral amputees contributes to the development and implementation of the injury prevention programme in running gait rehabilitation. We investigated the vertical ground reaction force loading in unilateral transfemoral amputees who used running-specific prostheses across a range of running speeds.MethodsTen unilateral transfemoral amputees and ten non-amputees performed running trials on an instrumented treadmill at the incremental speeds of 30, 40, 50, and 60% of their maximum acquired speeds. Per-step and cumulative vertical instantaneous loading rates were calculated from the vertical ground reaction force in the affected, unaffected, and non-amputated control limbs.FindingsBoth the per-step and cumulative vertical instantaneous loading rates of the unaffected limbs in runners with unilateral transfemoral amputation were significantly greater than the affected and non-amputated control limbs at all speeds.InterpretationThe results of the present study suggest that runners with unilateral transfemoral amputation may be exposed to a greater risk of running-related injuries in their unaffected limbs compared to the affected and non-amputated control limbs.     

Comparative Biomechanical Analysis of Current Microprocessor-Controlled Prosthetic Knee Joints

Bellmann M, Schmalz T, Blumentritt S. Comparative biomechanical analysis of current microprocessor-controlled prosthetic knee joints.

Objective

To investigate and identify functional differences of 4 microprocessor-controlled prosthetic knee joints (C-Leg, Hybrid Knee [also called Energy Knee], Rheo Knee, Adaptive 2).

Design

Tested situations were walking on level ground, on stairs and ramps; additionally, the fall prevention potentials for each design were examined. The measuring technology used included an optoelectronic camera system combined with 2 forceplates as well as a mobile spiroergometric system.

Setting

The study was conducted in a gait laboratory.

Participants

Subjects with unilateral transfemoral amputations (N=9; mobility grade, 3-4; age, 22-49y) were tested.

Interventions

Participants were fitted and tested with 4 different microprocessor-controlled knee joints.

Main Outcome Measures

Static prosthetic alignment, time distance parameters, kinematic and kinetic data and metabolic energy consumption.

Results

Compared with the Hybrid Knee and the Adaptive 2, the C-Leg offers clear advantages in the provision of adequate swing phase flexion resistances and terminal extension damping during level walking at various speeds, especially at higher walking speeds. The Rheo Knee provides sufficient terminal extension; however, swing phase flexion resistances seem to be too low. The values for metabolic energy consumption show only slight differences during level walking. The joint resistances generated for descending stairs and ramps relieve the contralateral side to varying degrees.When walking on stairs, safety-relevant technical differences between the investigated joint types can be observed. Designs with adequate internal resistances offer stability advantages when the foot is positioned on the step. Stumble recovery tests reveal that the different knee joint designs vary in their effectiveness in preventing the patient from falling.

Conclusions

The patient benefits provided by the investigated electronic prosthetic knee joints differ considerably. The C-Leg appears to offer the amputee greater functional and safety-related advantages than the other tested knee joints. Reduced loading of the contralateral side has been demonstrated during ramp and stair descent. Metabolic energy consumption does not vary significantly between the tested knees. Hence, this parameter seems not to be a suitable criterion for assessing microprocessor-controlled knee components.     

Walking characteristics of runners with a transfemoral or knee-disarticulation prosthesis

BackgroundRunning with prostheses has become a common activity for amputees participating in sports and recreation. However, very few studies have characterized the kinematic and kinetic parameters of walking in individuals with amputation who are runners. Thus, this study attempts to elucidate the kinematics and kinetics of walking in runners with a unilateral transfemoral amputation or knee-disarticulation.MethodsThis study experimentally compares the prosthetic and intact limbs of runners with prostheses as well as compares the findings against the limbs of age-matched able-bodied individuals while walking. Fourteen runners with a unilateral transfemoral amputation or knee-disarticulation were recruited and 14 age-matched able-bodied individuals were prepared using gait database. Spatiotemporal, kinematic, and kinetic parameters of walking were analyzed using a 3-demensional motion capture system.ResultsThe results showed that the peak ankle positive power at pre-swing and peak hip positive power from loading response to mid stance in the intact limb were significantly larger than that in the prosthetic limb. Moreover, to compensate for missing anatomical functions on the prosthetic limb, it appeared that the intact limb of the runners generated larger peak joint power by producing more ankle plantarflexor and hip extensor moments while walking.InterpretationThis study demonstrated that the runners rely on their intact limb while walking. Training of hip extensor muscles of the intact limb may be beneficial for these individuals.     

Energy expenditure and gait characteristics of a bilateral amputee walking with C-leg prostheses compared with stubby and conventional articulating prostheses

OBJECTIVE: To compare energy cost and stride characteristics during walking with 3 different types of prostheses in a person with bilateral knee disarticulations. DESIGN: Single-case study. Setting Pathokinesiology laboratory. PARTICIPANT: A subject with bilateral knee disarticulations and bilateral transradial amputations secondary to meningococcemia with purpura fulminans. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Energy cost, stride characteristics, and motion analysis. RESULTS: When wearing the C-Leg prostheses, the subject walked the farthest and fastest, with an overall lower rate of oxygen consumption and oxygen cost compared with walking with either of the other prostheses. Gait analysis while the patient was wearing the C-Leg prostheses revealed premature hip extension, absence of knee flexion during loading response, and a rate of swing in the referent range. CONCLUSIONS: Walking in a C-leg was the most efficient method of ambulation for our subject.     

Safety and function of a prototype microprocessor-controlled knee prosthesis for low active transfemoral amputees switching from a mechanic knee prosthesis: a pilot study

Purpose: Aim of this pilot study was to assess safety and functioning of a microprocessor-controlled knee prosthesis (MPK) after a short familiarization time and no structured physical therapy.

Materials and methods: Five elderly, low-active transfemoral amputees who were fitted with a standard non-microprocessor controlled knee prosthesis (NMPK) performed a baseline measurement consisting of a 3?D gait analysis, functional tests and questionnaires. The first follow-up consisted of the same test procedure and was performed with the MPK after 4 to 6?weeks of familiarization. After being refitted to their standard NMPK again, the subjects undertook the second follow-up which consisted of solely questionnaires 4?weeks later.

Results: Questionnaires and functional tests showed an increase in the perception of safety. Moreover, gait analysis revealed more physiologic knee and hip extension/flexion patterns when using the MPK.

Conclusion: Our results showed that although the Genium with Cenior-Leg ruleset-MPK (GCL-MPK) might help to improve several safety-related outcomes as well as gait biomechanics the functional potential of the GCL-MPK may have been limited without specific training and a sufficient acclimation period.

• Implications for Rehabilitation

• Elderly transfemoral amputees are often limited in their activity by safety issues as well as insufficient functioning regarding the non microprocessor-controlled knee prostheses (NMPK), thing that could be eliminated with the use of suitable microprocessor-controlled prostheses (MPK).

• The safety and functioning of a prototype MPK (GCL-MPK) specifically designed for the needs of older and low-active transfemoral amputees was assessed in this pilot study.

• The GCL-MPK showed indicators of increased safety and more natural walking patterns in older and low-active transfemoral amputees in comparison to the standard NMPK already after a short acclimatisation time and no structured physical therapy.

• Regarding functional performance it seems as if providing older and low-active transfemoral amputees with the GCL-MPK alone without prescribing structured prosthesis training might be insufficient to achieve improvements over the standard NMPKs.

     

The use of the 6-min walk test as a proxy for the assessment of energy expenditure during gait in individuals with lower-limb amputation

The objective of this study was to determine, and compare, the utility of the 6-min walk test (6 MWT) and self-selected walking speed over 15 m as proxies for the assessment of energy expenditure during gait in individuals with lower-limb amputation. Patients with unilateral, transfemoral amputation (n=6) and patients with unilateral, transtibial amputation (n=10) from community-based support groups participated in this study. Age-matched and body mass index-matched able-bodied controls (n=28) from a sample of convenience also participated. The main outcome measures were as follows: (a) distance, heart rate, oxygen consumption and oxygen cost during the 6 MWT and (b) self-selected walking speed over 15 m. Oxygen cost did not correlate significantly with self-selected walking speed over 15 m (ρ=-0.329) or average walking speed during the 6 MWT (ρ=-0.350). Significant correlations were not present between oxygen cost and the walking speed during the 6 MWT (range, ∣ρ∣: 0.210-0.531), although walking speeds at particular times of the 6 MWT demonstrated stronger correlations than others. Walking speed in the third min of walking during the 6 MWT recorded the strongest correlation with peak oxygen cost (ρ=-0.531). The 6 MWT is a submaximal measure in persons with lower-limb amputation. Self-selected walking speed over 15 m was not an appropriate proxy for the assessment of the energy cost of gait. Individuals with a lower-limb amputation require approximately 3 min of continuous walking to re-establish homoeostasis in heart rate, oxygen consumption and oxygen cost. The nonsignificant correlation between walking speeds during the 6 MWT and oxygen cost suggest that the 6 MWT can provide an indication of oxygen cost, but caution should be exercised when using it as a sole proxy for the measurement of oxygen cost in individuals with lower-limb amputation.     

The mechanics of landing when stepping down in unilateral lower-limb amputees

BACKGROUND: The ability to successfully negotiate stairs and steps is an important factor for functional independence. While work has been undertaken to understand the biomechanics of gait in lower-limb amputees, little is known about how amputees negotiate stairs and steps. This study aimed to determine the mechanics of landing in unilateral lower-limb amputees when stepping down to a new level. A secondary aim was to assess the effects of using a shank-mounted shock-absorbing device (Tele-Torsion Pylon) on the mechanics of landing. METHODS: Ten unilateral amputees (five transfemoral and five transtibial) and eight able-bodied controls performed single steps down to a new level (73 and 219 mm). Trials were repeated in amputees with the Tele-Torsion Pylon active and inactive. The mechanics of landing were evaluated by analysing peak limb longitudinal force, maximal limb shortening, lower extremity stiffness, and knee joint angular displacement during the initial contact period, and limb and ankle angle at the instant of ground-contact. Data were collected using a Vicon 3D motion analysis system and two force platforms. FINDINGS: Amputees landed on a straightened and near vertical limb. This limb position was maintained in transfemoral amputees, whereas in transtibial amputees knee flexion occurred. As a result lower extremity stiffness was significantly greater in transfemoral amputees compared to transtibial amputees and able-bodied controls (P<0.001). The Tele-Torsion Pylon had little effect on the mechanics of landing in transtibial amputees, but brought about a reduction in lower extremity stiffness in transfemoral amputees (P<0.05). INTERPRETATION: Amputees used a stepping strategy that ensured the direction of the ground reaction force vector was kept anterior of the knee joint centre. Using a Tele-Torsion Pylon may improve the mechanics of landing during downward stepping in transfemoral amputees.     

Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg and Mauch SNS prosthetic knees

The C-Leg (Otto Bock, Duderstadt, Germany) is a microprocessor-controlled prosthetic knee that may enhance amputee gait. This intrasubject randomized study compared the gait biomechanics of transfemoral amputees wearing the C-Leg with those wearing a common noncomputerized prosthesis, the Mauch SNS (Ossur, Reykjavik, Iceland). After subjects had a 3-month acclimation period with each prosthetic knee, typical gait biomechanical data were collected in a gait laboratory. At a controlled walking speed (CWS), peak swing phase knee-flexion angle decreased for the C-Leg group compared with the Mauch SNS group (55.2 degrees +/- 6.5 degrees vs 64.41 degrees +/- 5.8 degrees , respectively; p = 0.005); the C-Leg group was similar to control subjects' peak swing knee-flexion angle (56.0 degrees +/- 3.4 degrees ). Stance knee-flexion moment increased for the C-Leg group compared with the Mauch SNS group (0.142 +/- 0.05 vs 0.067 +/- 0.07 N"m, respectively; p = 0.01), but remained significantly reduced compared with control subjects (0.477 +/- 0.1 N"m). Prosthetic limb step length at CWS was less for the C-Leg group compared with the Mauch SNS group (0.66 +/- 0.04 vs 0.70 +/- 0.06 m, respectively; p = 0.005), which resulted in increased symmetry between limbs for the C-Leg group. Subjects also walked faster with the C-Leg versus the Mauch SNS (1.30 +/- 0.1 vs 1.21 +/- 0.1 m/s, respectively; p = 0.004). The C-Leg prosthetic limb vertical ground reaction force decreased compared with the Mauch SNS (96.3 +/- 4.7 vs 100.3 +/- 7.5 % body weight, respectively; p = 0.0092).     

Improved ankle-foot system for above-knee amputees

Above-knee amputees were studied while wearing a prosthesis containing either a standard or a modified single axis foot. The modified foot allowed 12-15 degrees of dorsiflexion and reduced stiffness in the area of the metatarsal-phalangeal (MTP) joint. The amputees were allowed to vary the stiffness at the two joints to obtain what "felt best." The amputees agreed that in comparison to the standard single-axis foot, the modified foot: a) offered a more comfortable gait while walking on level ground; b) made walking up inclines easier; c) affected knee stability while walking on declines; and d) made foot placement on stairs and ladders more critical due to potential knee instability. As well as qualitative reactions, changes in the gait cycle were measured quantitatively for different speeds and inclinations of walking on a treadmill. Measurements from normal subjects matched by age and sex were used for control purposes. All participants wore soft-soled shoes. The amputees selected a stiffness that allowed a degree of dorsiflexion which precisely matched on average that of the normal subjects. In contrast, they selected a stiffness at the MTP joint which allowed very little flexion of the toes. Significant changes also occurred in the pattern of hip movements, so that they became much more symmetrical on the two sides, although substantial differences remained between the hip movements of the amputees and the normal subjects. If modifications in the ankle joint can be coupled with improvements in the knee joint to prevent potential instability, a much improved gait should be possible for above-knee amputees.     

A comparative evaluation of oxygen consumption and gait pattern in amputees using Intelligent Prostheses and conventionally damped knee swing-phase control

OBJECTIVE: To compare the gait of amputees wearing conventionally damped pneumatic swing-phase control knees and microchip-controlled Intelligent Prostheses. DESIGN: Crossover trial. SETTING: An amputee rehabilitation centre in a teaching hospital. PARTICIPANTS: Ten established unilateral transfemoral prosthetic users were asked to participate in the trial; all agreed. INTERVENTIONS: The amputees were assessed wearing pneumatic swing-phase control knees and then with the Intelligent Prosthesis. MAIN OUTCOME MEASURES: Oxygen consumption while walking at different speeds on a treadmill, video-recording of gait assessed by a panel and temporal-spatial parameters of gait whilst walking at slow, fast or normal speeds in a gait laboratory. RESULTS: Mean oxygen cost for all subjects at 0.69 m/s was 0.33 ml/kg.m with the conventional limb and 0.30 ml/kg.m with the Intelligent Prosthesis (p = 0.01). At 1.25 m/s the mean oxygen cost for the conventional limb was 0.24 ml/kg.m and for the Intelligent Prosthesis was 0.22 ml/kg.m (not significant). The ANOVA analysis showed that oxygen cost was similar at normal walking speeds but increased more at lower speeds for the pneumatic swing-phase control leg compared to the Intelligent Prosthesis (p < 0.02). There were no significant differences in subjective gait evaluation or temporal and spatial gait parameters. CONCLUSION: At lower speeds oxygen cost was lower with the Intelligent Prosthesis. Gait analysis detected no significant changes between the two legs.     

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.     

Effect of an Intelligent Prosthesis (IP) on the walking ability of young transfemoral amputees: comparison of IP users with able-bodied people

OBJECTIVE: To make a comparative study of energy expenditure and walking speeds between able-bodied people and young Intelligent Prosthesis (IP) users and to demonstrate the effect of IP on the walking ability of young amputees. DESIGN: The test subjects were eight young traumatic transfemoral amputees. Fourteen able-bodied persons served as controls. All amputees used an IP, and they had all undergone a prosthetic rehabilitation program for 8 wk. IP users, who had completed the rehabilitation program, were instructed to walk at speeds of 30, 50, 70, 90, and 110 m/min. Measurements of energy expenditure while walking were taken. The most metabolically efficient waking speed was also determined. RESULTS: On average, the IP users experienced an oxygen uptake that was 24.1% and 24.2% higher than those for the controls at speeds of 70 and 90 m/min, respectively. It was also determined that the most metabolically efficient walking speed for the IP users was the same as for the controls. CONCLUSIONS: This study showed that young IP users who undergo an adequate prosthetic rehabilitation program can achieve remarkably improved walking performance. Young IP users could walk at the normal speeds of able-bodied people, with only around a 24% increase in energy expenditure.     

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.     

Gait asymmetry of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees

Background

Amputees walk with an asymmetrical gait, which may lead to future musculoskeletal degenerative changes. The purpose of this study was to compare the gait asymmetry of active transfemoral amputees while using a passive mechanical knee joint or a microprocessor-controlled knee joint.

Methods

Objective 3D gait measurements were obtained in 15 subjects (12 men and 3 women; age 42, range 26–57). Research participants were longtime users of a mechanical prosthesis (mean 20 years, range 3–36 years). Joint symmetry was calculated using a novel method that includes the entire waveform throughout the gait cycle.

Findings

There was no significant difference in hip, knee and ankle kinematics symmetry when using the different knee prostheses. In contrast, the results demonstrated a significant improvement in lower extremity joint kinetics symmetry when using the microprocessor-controlled knee.

Interpretation

Use of the microprocessor-controlled knee joint resulted in improved gait symmetry. These improvements may lead to a reduction in the degenerative musculoskeletal changes often experienced by amputees.