***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The functional differences between persons with amputation who are classified as Medicare Functional Classification Level (MFCL)-2 and -3 include the abilities to walk at various cadences and to negotiate environmental barriers outside the home . This study compared the effect of active microprocessor control and passive mechanical control of the prosthetic knee on function and safety in 17 subjects with transfemoral amputation ( 8 MFCL-2 and 9 MFCL-3 ) . Assessed functional tasks included hill and stair descent , an attentional dem and task , and an obstacle course . Self-reported measures included concentration , multitasking ability , and numbers of stumbles and falls .  Active knee control was associated with significant improvements ( p < 0.05 ) in hill and stair gait , speed ( hills , obstacle course , and attentional dem and task ) , and ability to multitask while walking for both cohorts . MFCL-2 subjects also reported a significant reduction ( p < 0.01 ) in uncontrolled falls . Over the study , 50 % of MFCL-2 subjects and 33 % of MFCL-3 subjects transitioned to a higher MFCL . Results suggest that active knee control improves function and reduces the frequency of adverse events in a population that is at risk for falls . Use of active knee control may allow persons with amputation to exp and their functional domain , transition to a higher MFCL , and access additional prosthetic options Microprocessor-controlled prosthetic knees are cl aim ed to improve gait efficiency in transfemoral ( TF ) amputees . This hypothesis was tested in a prospect i ve r and omized 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 r and om 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 + /- st and ard 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 OBJECTIVE To evaluate the gait of transfemoral amputee patients using a prosthesis with a 4-bar linkage knee joint with either a mechanical swing phase control ( Otto Bock 3R20 ) or a pneumatic swing phase control ( Tehlin knee ) . DESIGN R and omized cross-over trial . SETTING Rehabilitation Department of a university hospital in The Netherl and s. PATIENTS Twenty-eight subjects with unilateral transfemoral amputation for reasons other than chronic vascular disease ; ages between 16 and 65 years and familiar with the use of the Otto Bock 3R20 knee .  SELECTION PROCEDURE a consecutive sample . INTERVENTION The Otto Bock 3R20 was used by the subjects before they entered the study . The patients changed to the Tehlin knee at r and om either after 1 or 2 assessment s with the Otto Bock 3R20 . MAIN OUTCOME MEASURES Temporal and kinematic variables in gait analysis ( speed recordings were taken before and after the equipment for the measurements of the other parameters was placed on the patients ) . Subjective scores for comfortable and fast ambulation were obtained by means of 2 question naires . Question naire A consisted of multiple choice questions ( maximum score : 5 ) and questions using an 8-point rating scale ( maximum score : 7 ) . In question naire B , the patient was asked to compare the present prosthesis with the previous one . RESULTS Fast walking speed in gait analysis was higher with the Tehlin knee than with the 3R20 ( without equipment 95 % confidence interval ( CI ) .02-.09 m/sec , with equipment CI .04-.11 ) , while comfortable walking speed was not higher with the Tehlin knee ( without equipment CI -.20-.20 m/sec , with equipment CI .00-.05 ) . Symmetry of walking as regards swing phase duration was closer to 100 % with the Tehlin knee than with the 3R20 ( comf . walking CI 4 % to 19 % , fast walking CI 7 % to 17 % ) . Knee joint range of motion during swing phase was smaller with the Tehlin knee than with the 3R20 ( comf . walking CI 1.8 degrees-8.7 degrees , fast walking CI 2.0 degrees-9.5 degrees ) . Knee flexion duration during swing phase was shorter for the Tehlin knee than for the 3R20 at fast walking speed ( CI 6 - 46msec ) , while knee flexion duration from and to 10 degrees flexion was shorter for the Tehlin knee at comfortable speed ( CI 18 - 67msec ) and fast speed ( CI 20 - 64msec ) . In question naire A the amputees reported the Tehlin knee  to be better for fast walking ( part A1 CI .01-.52 , part A2 CI .13-.98 ) and in question naire B for both comfortable and fast walking The C-Leg ( Otto Bock , Duderstadt , Germany ) is a microprocessor-controlled prosthetic knee that may enhance amputee gait . This intrasubject r and omized study compared the gait biomechanics of transfemoral amputees wearing the C-Leg with those wearing a common noncomputerized prosthesis , the Mauch SNS ( Ossur , Reykjavik , Icel and ) . 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 result ed 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 ) Johansson JL , Sherrill DM , Riley PO , Bonato P , Herr H : A clinical comparison of variable-damping and mechanically passive prosthetic knee devices . Am J Phys Med Rehabil 2005;84:563–575 . Objective : Although variable-damping knee prostheses offer some improvements over mechanically passive prostheses to transfemoral amputees , there is insufficient evidence that such prostheses provide advantages at self-selected walking speeds . In this investigation , we address this question by comparing two variable-damping knees , the hydraulic-based Otto Bock C-leg and the magnetorheological-based Össur Rheo , with the mechanically passive , hydraulic-based Mauch SNS . Design : For each prosthesis , metabolic data were collected on eight unilateral amputees walking at self-selected speeds across an indoor track . Furthermore , kinetic , kinematic , and electromyographic data were collected while walking at self-selected speeds across a 10-m walkway in a laboratory . Results : When using the Rheo , metabolic rate decreases by 5 % compared with the Mauch and by 3 % compared with the C-leg . Furthermore , for the C-leg and Rheo knee devices , we observe biomechanical advantages over the mechanically passive Mauch . These advantages include an enhanced smoothness of gait , a decrease in hip work production , a lower peak hip flexion moment at terminal stance , and a reduction in peak hip power generation at toe-off . Conclusion : The results of this study indicate that variable-damping knee prostheses offer advantages over mechanically passive design s for unilateral transfemoral amputees walking at self-selected ambulatory speeds , and the results further suggest that a magnetorheological-based system may have advantages over hydraulic-based design OBJECTIVE To evaluate differences in function , performance , and preference between mechanical and microprocessor prosthetic knee control technologies . DESIGN A-B-A-B reversal design . SETTING Home , community , and laboratory environments . PARTICIPANTS Twenty-one unilateral , transfemoral amputees . INTERVENTION Mechanical control prosthetic knee versus microprocessor control prosthetic knee ( Otto Bock C-Leg ) . MAIN OUTCOME MEASURES Stair rating , hill rating and time , obstacle course time , divided attention task accuracy and time , Amputee Mobility Predictor score , step activity , Prosthesis Evaluation Question naire score , Medical Outcomes Study 36-Item Short-Form Health Survey score , self-reported frequency of stumbles and falls , and self-reported concentration required for ambulation . RESULTS Stair descent score , hill descent time , and hill sound-side step length showed significant ( P<.01 ) improvement with the C-Leg . Users reported a significant ( P<.05 ) decrease in frequency of stumbles and falls , frustration with falling , and difficulty in multitasking while using the microprocessor knee .  Subject satisfaction with the C-Leg was significantly ( P<.001 ) greater than the mechanical control prosthesis . CONCLUSIONS The study population showed improved performance when negotiating stairs and hills , reduced frequency of stumbling and falling , and a preference for the microprocessor control C-Leg as compared with the mechanical control prosthetic knee This study investigated energy expenditure and obstacle course negotiation between the C-leg ® and various non-microprocessor control ( NMC ) prosthetic knees and compared a quality of life survey ( SF-36v2 ™ ) of use of the C-leg ® to national norms . Thirteen subjects with unilateral limb loss ( 12 with trans-femoral and one with a knee disarticulation amputation ) participated in the study . The mean age was 46 years , range 30 – 75 . Energy expenditure using both the NMC and C-leg ® prostheses was measured at self-selected typical and fast walking paces on a motorized treadmill . Subjects were also asked to walk through a st and ardized walking obstacle course carrying a 4.5 kg ( 10 lb ) basket and with h and s free . Finally , the SF-36v2 ™ was completed for subjects while using the C-leg ® . Statistically significant differences were found in oxygen consumption between prostheses at both typical and fast paces with the C-leg ® showing decreased values . Use of the C-leg ® result ed in a statistically significant decrease in the number of steps and time to complete the obstacle course . Scores on a quality of life index for subjects using the C-leg ® were above the mean for norms for limitation in the use of an arm or leg , equal to the mean for the general United States population for the physical component score and were above this mean for the mental component score . Based on oxygen consumption and obstacle course findings , the C-leg ® when compared to the NMC prostheses may provide increased functional mobility and ease of performance in the home and community environment . Question naire results suggest a minimal quality of life impairment when using a C-leg ® for this cohort of individuals with amputation 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 
    Output:
    
Fluid knee benefits and indications : Knees with hydraulic or pneumatic swing resistance are indicated for active walkers , permitting increased walking comfort , speed , and symmetry .
Microprocessor knee benefits : Compared with nonmicroprocessor knees : a ) With respect to self-report indices and measures , microprocessor knees are indicated to reduce stumbles , falls , and associated frustrations as well as the cognitive dem and s of ambulation .
b ) With respect to self-report indices and measures , microprocessor knees are indicated to increase confidence while walking , self-reported mobility , satisfaction , well-being , and quality of life .
c ) With respect to physical performance indices and measures , microprocessor knees are indicated to increase self-selected walking speed , walking speed on uneven terrain , and metabolic efficiency during gait .
Microprocessor knees for limited community ambulators : Among limited community ambulators , microprocessor knees are indicated to enable increases in level ground walking speed and walking speed on uneven terrain while substantially reducing uncontrolled falls and increasing both measured and perceived balance .