Heel height affects lower extremity frontal plane joint moments during walking

Wearing high heels alters walking kinematics and kinetics and can create potentially adverse effects on the body. Our purpose was to determine how heel height affects frontal plane joint moments at the hip, knee, and ankle, with a specific focus on the knee moment due to its importance in joint loading and knee osteoarthritis. 15 women completed overground walking using three different heel heights (1, 5, and 9 cm) for fixed speed (1.3 ms(-1)) and preferred speed conditions while kinematic and force platform data were collected concurrently. For both fixed and preferred speeds, peak internal knee abduction moment increased systematically as heel height increased (fixed: 0.46, 0.48, 0.55 N m kg(-1); preferred: 0.47, 0.49, 0.53 N m kg(-1)). Heel height effects on net frontal plane moments of the hip and ankle were similar to those for the knee; peak joint moments increased as heel height increased. The higher peak internal knee abduction moment with increasing heel height suggests greater medial loading at the knee. Kinetic changes at the ankle with increasing heel height may also contribute to larger medial loads at the knee. Overall, wearing high heels, particularly those with higher heel heights, may put individuals at greater risk for joint degeneration and developing medial compartment knee osteoarthritis.     

The effect of prosthetic alignment on hip and knee joint kinetics in individuals with transfemoral amputation

BackgroundProsthetic alignment directly affects the biomechanical loading in individuals with lower-limb amputation, and improper alignment may be contribute to the high incidence of hip and knee osteoarthritis (OA). The biomechanical changes caused by different alignments should be considered in prosthetic fitting. However, the quantitative effect of alignment on the kinetic features of individuals with transfemoral amputation remains unclear.Research questionAs important kinetics indexes, how are the hip and knee joint moments affected by prosthetic alignment in individuals with transfemoral amputation?MethodsGait tests of ten individuals with transfemoral amputation and fifteen individuals without amputation (control group) were performed. Several prosthetic alignment conditions were used, including the so-called “initial” alignment and eight malalignments. The hip and knee joint moments of the individuals with amputation under various alignments were analysed and compared with those of the control group. Statistical analyses were performed by one-way ANOVA, repeated measure multivariate ANOVA, and paired t tests.ResultsThe peaks and impulses of the hip abductor and external rotator moments on the residual side were significantly smaller than those of the control group (P < 0.0056). The peaks of the hip extensor, adductor and external rotator moments on the intact side were significantly larger than those on the residual side (P < 0.05). Alignment significantly affected the intact hip and knee joint moments for each individual with amputation (P < 0.00625), but there was no consistent effect among individuals.SignificanceThe significantly larger hip joint moment on the intact side of individuals with transfemoral amputation may be associated with the higher incidence of hip OA on the intact side. Alignment significantly affects the hip and knee joint moments of each individual with transfemoral amputation, but the individual responses to alignment changes are different. This situation may imply that the method for optimizing alignment should be personalized.     

The effect of prosthetic foot push-off on mechanical loading associated with knee osteoarthritis in lower extremity amputees

Lower extremity amputation not only limits mobility, but also increases the risk of knee osteoarthritis of the intact limb. Dynamic walking models of non-amputees suggest that pushing-off from the trailing limb can reduce collision forces on the leading limb. These collision forces may determine the peak knee external adduction moment (EAM), which has been linked to the development of knee OA in the general population. We therefore hypothesized that greater prosthetic push-off would lead to reduced loading and knee EAM of the intact limb in unilateral transtibial amputees.Seven unilateral transtibial amputees were studied during gait under three prosthetic foot conditions that were intended to vary push-off. Prosthetic foot-ankle push-off work, intact limb knee EAM and ground reaction impulses for both limbs during step-to-step transition were measured.Overall, trailing limb prosthetic push-off work was negatively correlated with leading intact limb 1st peak knee EAM (slope = −.72 ± .22; p = .011). Prosthetic push-off work and 1st peak intact knee EAM varied significantly with foot type. The prosthetic foot condition with the least push-off demonstrated the largest knee EAM, which was reduced by 26% with the prosthetic foot producing the most push-off. Trailing prosthetic limb push-off impulse was negatively correlated with leading intact limb loading impulse (slope = −.34 ± .14; p = .001), which may help explain how prosthetic limb push-off can affect intact limb loading.Prosthetic feet that perform more prosthetic push-off appear to be associated with a reduction in 1st peak intact knee EAM, and their use could potentially reduce the risk and burden of knee osteoarthritis in this population.     

Sound side joint contact forces in below knee amputee gait with an ESAR prosthetic foot

The incidence of knee and hip joint osteoarthritis in subjects with below knee amputation (BK) appears significantly higher compared to unimpaired subjects, especially in the intact side. However, it is controversial if constant higher loads on the sound side are one of the major factors for an increased osteoarthritis (OA) incidence in subjects with BK, beside other risk factors, e.g. with respect to metabolism. The aim wasto investigate joint contact forces (JCF) calculated by a musculoskeletal model in the intact side and to compare it with those of unimpaired subjects and to further elucidate in how far increased knee JCF are associated with increased frontal plane knee moments. A group of seven subjects with BK amputation and a group of ten unimpaired subjects were recruited for this study. Gait data were measured by 3D motion capture and force plates. OpenSim software was applied to calculate JCF. Maximum joint angles, ground reaction forces, and moments as well as time distance parameters were determined and compared between groups showing no significant differences, with some JCF components of knee and hip even being slightly smaller in subjects with BK compared to the reference group. This positive finding may be due to the selected ESAR foot. However, other beneficial factors may also have influenced this positive result such as the general good health status of the subjects or the thorough and proper fitting and alignment of the prosthesis.     

Compensatory mechanism involving the knee joint of the intact limb during gait in unilateral below-knee amputees

This study evaluated the asymmetry of knee kinetics during uncomfortable gait induced by prosthesis misalignment to further demonstrate the compensatory function of the knee joint of the intact limb during gait. Three-dimensional gait analysis including knee kinematics and kinetics at the beginning of stance phase was conducted in 15 healthy subjects and 17 unilateral trans-tibial amputees (TTA) walking at self-selected speed in three conditions of prosthetic alignment: initial alignment (IA); initial alignment altered either by 6 degrees of internal rotation (IR) or by 6 degrees of external rotation (ER) applied on the pylon. Patients reported best comfort of gait in IA condition and discomfort mainly in IR condition. Maximum knee flexion and knee total work at power phases K0-K2 were significantly higher in intact limbs compared to prosthetic and control limbs. In intact limbs, these variables had significantly higher values (+10-35%, p<0.05) in IR condition than IA condition whereas these were not altered across conditions in prosthetic limbs. In trans-tibial amputees, inducing uncomfortable gait by internally rotating the prosthetic foot did not alter the knee kinetics of the prosthetic limb, which suggests a protective mechanism. Knee kinetics of the intact limb did alter, which suggests a compensatory mechanism.     

Joint power distribution does not change within the contralateral limb one year after unilateral limb loss

BackgroundTo assist with forward progression during gait, persons with unilateral lower-limb amputation typically perform more work within the unaffected versus affected limb. However, prior cross-sectional (>2years post-amputation) studies cannot necessarily elucidate the origin or evolution of these compensatory mechanics.Research questionDo lower limb joint kinetics change during the initial stages of independent ambulation among persons with lower-limb amputation?MethodsNine males with unilateral lower-limb amputation (6 transtibial; 3 transfemoral) completed instrumented gait analyses (speed = 1.2 m/s) at 2 and 12-months post-independent ambulation. Within the unaffected limb, sagittal and frontal plane total positive and negative work, peak power, average positive power, and percent contribution of each joint were compared between time points using paired t-tests.ResultsNo differences existed between time points in total positive or negative work, at any joint (p > 0.038) in either plane. Similarly, there were no differences in percent contribution by each joint to total average power by sagittal (p > 0.15) or frontal (p > 0.32) planes.SignificancePersons with unilateral lower-limb amputation do not alter power distribution among joints within the unaffected limb during initial independent ambulation. However, compared to previous cross-sectional reports, smaller peak powers in the unaffected hip and knee here suggest mechanical work increases with time since amputation. Future research should longitudinally monitor segment mechanics to determine when deleterious strategies develop, as these have implications for joint degeneration and pain.     

Frontal Plane Landing Mechanics in High-Arched Compared With Low-Arched Female Athletes

OBJECTIVE:: To examine ground reaction forces (GRFs); frontal plane hip, knee, and ankle joint angles; and moments in high-arched (HA) and low-arched (LA) athletes during landing. DESIGN:: Experimental study. SETTING:: Controlled research laboratory. PARTICIPANTS:: Twenty healthy female recreational athletes (10 HA and 10 LA). INTERVENTIONS:: Athletes performed 5 barefoot drop landings from a height of 30 cm. MAIN OUTCOME MEASURES:: Frontal plane ankle, knee, and hip joint angles (in degrees) at initial contact, peak vertical GRF, and peak knee flexion; peak ankle, knee, and hip joint moments in the frontal plane. RESULTS:: Vertical GRF profiles were similar between HA and LA athletes (P = 0.78). The HA athletes exhibited significantly smaller peak ankle inversion angles than the LA athletes (P = 0.01) at initial contact. At peak vertical GRF, HA athletes had significantly greater peak knee (P = 0.01) and hip abduction angles than LA athletes (P = 0.02). There were no significant differences between HA and LA athletes in peak joint moments (hip: P = 0.68; knee: P = 0.71; ankle: P = 0.15). CONCLUSIONS:: These findings demonstrate that foot type is associated with altered landing mechanics, which may underlie lower extremity injuries. The ankle-driven strategy previously reported in female athletes suggests that foot function may have a greater relationship with lower extremity injury than that in male athletes. Future research should address the interaction of foot type and gender during landing tasks.     

Effect of prosthetic alignment on gait and biomechanical loading in individuals with transfemoral amputation: A preliminary study

BackgroundInappropriate biomechanical loading usually leads to a high incidence of hip and knee osteoarthritis (OA) in individuals with lower-limb amputation, and prosthetic alignment may be an important influencing factor. The effect of alignment on the lower limb loading remains quantitatively unclear, and the relationship between malalignment and joint diseases is undefined.Research questionHow does alignment affect spatiotemporal gait parameters and ground reaction force (GRF) in individuals with transfemoral amputation?MethodsGait tests of 10 individuals with transfemoral amputation were performed with recommended alignment and eight malalignments, including 10 mm socket translation (anterior, posterior, medial, and lateral) and 6° socket angular changes (flexion, extension, abduction, and adduction). Fifteen individuals without amputation were recruited as a control group. The differences in spatiotemporal and GRF parameters under different alignments were analyzed and compared with those of the control group. Statistical analyses were performed by one-way ANOVA, repeated measure multivariate ANOVA, and paired t tests.ResultsThe medial GRF peaks and impulse on both sides and load rate on the intact side are significantly higher than those of the control group (P < 0.0056). The propulsive and braking peaks, vertical impulse, and medial and vertical load rates of GRF on the intact side are higher than those on the residual side (P < 0.05). The alignment of socket adduction significantly increases medial GRF peak and impulse on both sides (P < 0.0056).SignificanceAlignments exert remarkable and complicated effects on the biomechanical performance. The considerably higher GRF on the intact side of the individuals with transfemoral amputation may lead to internal stress changes of the intact joint, which may be an inducement for high incidence of joint diseases. Probably due to the increased lateral deviation of the center of gravity, the socket adduction alignment significantly increases medial GRF, which may lead to an increased risk of knee OA.     

Contralateral hip and knee gait biomechanics are unchanged by total hip replacement for unilateral hip osteoarthritis

Both the hip and knee contralateral to a total hip replacement (THR) have an increased risk of osteoarthritis (OA) progression, and ultimate joint replacement. It is also known that abnormal gait contributes to OA progression. For these reasons, we conducted a longitudinal analysis of contralateral hip and knee gait during the first year after unilateral THR to determine whether abnormal contralateral gait biomechanics emerge after THR. We analyzed the sagittal plane dynamic range of motion and 3D peak external moments from the asymptomatic hip and knee contralateral to a THR in a group of 26 subjects, evaluated preoperatively, and 3, 12, 24, and 52 weeks after THR, and a group of control subjects. We used t-tests and repeated measures ANOVA to test the hypotheses that contralateral hip and knee gait parameters are normal preoperatively, but change after THR. Preoperatively, the contralateral hip abduction moment and the contralateral knee adduction, flexion, and external rotation moments were significantly higher than normal in the THR group (p ≤ 0.048). Apart from the peak hip extension moment, which decreased three weeks after surgery but returned to its preoperative value thereafter, there were no longitudinal changes during the study period (p ≥ 0.141). Preoperative gait abnormalities persisted postoperatively. Notably, the contralateral knee adduction moment was 32% higher than normal in the THR group. These results indicate a biomechanical basis for the increased contralateral OA risk after unilateral THR, and suggest that some patients may benefit from strategies to reduce loading on the contralateral limb.     

Gender differences in frontal and sagittal plane biomechanics during drop landings

PURPOSE: To determine gender differences in lower-extremity joint kinematics and kinetics between age- and skill-matched recreational athletes. METHODS: Inverse dynamic solutions estimated the lower-extremity flexion-extension and varus-valgus kinematics and kinetics for 15 females and 15 males performing a 60-cm drop landing. A mixed model, repeated measures analysis of variance (gender (*) joint) was performed on select kinematic and kinetic variables. RESULTS: Peak hip and knee flexion and ankle dorsiflexion angles were greater in females in the sagittal plane (group effect, P < 0.02). Females exhibited greater frontal plane motion (group (*) joint, P = 0.02). Differences were attributed to greater peak knee valgus and peak ankle pronation angles (post hoc tests, P = 0.00). Females exhibited a greater range of motion (ROM) in the sagittal plane (group main effect, P = 0.02) and the frontal plane (group (*) joint, P = 0.01). Differences were attributed to the greater knee varus-valgus ROM, ankle dorsiflexion, and pronation ROM (post hoc tests). Ground reaction forces were different between groups (group (*) direction, P = 0.05). Females exhibited greater peak vertical and posterior (A/P) force than males (post hoc tests). Females exhibited different knee moment profiles (Group main effect, P = 0.01). These differences were attributed to a reduced varus moment in females (post hoc tests). CONCLUSION: The majority of the differences in kinematic and kinetic variables between male and female recreational athletes during landing were observed in the frontal plane not in the sagittal plane. Specifically, females generated a smaller internal knee varus moment at the time of peak valgus knee angulation.     

Comparison of frontal plane trunk kinematics and hip and knee moments during anticipated and unanticipated walking and side step cutting tasks

BACKGROUND: Frontal plane trunk and lower extremity adjustments during unanticipated tasks are hypothesized to influence hip and knee neuromuscular control, and therefore, contribute to anterior cruciate ligament (ACL) injury risk. The aims of this study were to examine frontal plane trunk/hip kinematics and hip and knee moments (measures of neuromuscular control) during unanticipated straight and side step cut tasks. METHODS: Kinematic and kinetic variables were collected while subjects performed two anticipated tasks, including walking straight (ST) and side step cutting (SS), and two unanticipated tasks (STU and SSU). Foot placement, thorax-pelvis-hip kinematic variables and hip and knee moments were calculated over the first 30% of stance. FINDINGS: Hip abduction angles and knee moments were significantly affected by task and anticipation. Hip abduction angles decreased, by 4.0-7.6 degrees , when comparing the SSU task to the ST, STU and SS tasks. The hip abduction angles were associated with foot placement and lateral trunk orientation. INTERPRETATION: Hip abduction angles and foot placement, not lateral trunk flexion influence trunk orientation. Anticipation influences hip and knee neuromuscular control and therefore may guide the development of ACL prevention strategies.     

Joint contact forces can be reduced by improving joint moment symmetry in below-knee amputee gait simulations

Despite having a fully functional knee and hip in both legs, asymmetries in joint moments of the knee and hip are often seen in gait of persons with a unilateral transtibial amputation (TTA), possibly resulting in excessive joint loading. We hypothesize that persons with a TTA can walk with more symmetric joint moments at the cost of increased effort or abnormal kinematics. The hypothesis was tested using predictive simulations of gait. Open loop controls of one gait cycle were found by solving an optimization problem that minimizes a combination of walking effort and tracking error in joint angles, ground reaction force and gait cycle duration. A second objective was added to penalize joint moment asymmetry, creating a multi-objective optimization problem. A Pareto front was constructed by changing the weights of the objectives and three solutions were analyzed to study the effect of increasing joint moment symmetry. When the optimization placed more weight on moment symmetry, walking effort increased and kinematics became less normal, confirming the hypothesis. TTA gait improved with a moderate increase in joint moment symmetry. At a small cost of effort and abnormal kinematics, the peak hip extension moment in the intact leg was decreased significantly, and so was the joint contact force in the knee and hip. Additional symmetry required a significant increase in walking effort and the joint contact forces in both hips became significantly higher than in able-bodied gait.     

The impact of transfemoral socket adduction on pelvic and trunk stabilization during level walking – A biomechanical study

BackgroundIt is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements.Research questionHow do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane?MethodsSeven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed.ResultsIn the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC.SignificanceThe results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.     

The influence of sex and maturation on landing biomechanics: implications for anterior cruciate ligament injury

During landing and cutting, females exhibit greater frontal plane moments at the knee (internal knee adductor moments or external knee abduction moments) and favor the use of the knee extensors over the hip extensors to attenuate impact forces when compared with males. However, it is not known when this biomechanical profile emerges. The purpose of this study was to compare landing biomechanics between sexes across maturation levels. One hundred and nineteen male and female soccer players (9-22 years) participated. Subjects were grouped based on maturational development. Lower extremity kinematics and kinetics were obtained during a drop-land task. Dependent variables included the average internal knee adductor moment and sagittal plane knee/hip moment and energy absorption ratios during the deceleration phase of landing. When averaged across maturation levels, females demonstrated greater internal knee adductor moments (0.06±0.03 vs 0.01±0.02 N m/kg m; P<0.005), knee/hip extensor moment ratios (2.0±0.1 vs 1.4±0.1 N m/kg m; P<0.001) and knee/hip energy absorption ratios (2.9±0.1 vs 1.96±0.1 N m/kg m; P<0.001) compared with males. Higher knee adductor moments combined with disproportionate use of knee extensors relative to hip extensors observed in females reflect a biomechanical pattern that increases anterior cruciate ligament loading. This biomechanical strategy already was established in pre-pubertal female athletes.     

Gender differences in trunk, pelvis and lower limb kinematics during a single leg squat

The relationship between trunk and lower limb kinematics in healthy females versus males is unclear since trunk kinematics in the frontal and transverse planes have not been systematically examined with lower limb kinematics. The aim of this study was to investigate the existence of different multi-joints movement strategies between genders during a single leg squat. We expected that compared to males, females would have greater trunk and pelvis displacement due to less trunk control and display hip and knee movement consistent with medial-collapse (i.e. greater hip adduction, hip medial rotation, knee abduction, and knee lateral rotation) on the weight-bearing limb. Nine females and 10 males participated in the study. Kinematic data were collected using an 8-camera, 3D-motion-capture-system. Trunk relative to pelvis, pelvis relative to the laboratory, hip and knee angles in three planes (sagittal, frontal and transverse) were examined at two time events relevant to knee joint mechanics: 45° of knee flexion and peak knee flexion. Females flexed their trunk less than males and rotated their trunk and pelvis toward the weight-bearing limb more than males. Females also displayed greater hip adduction and knee abduction than males. Taken together these results suggest that females and males used different movement strategies during a single leg squat. Females displayed a trunk and pelvic movement pattern that may put them at risk of knee injury and pain.     

Long-distance walking effects on trans-tibial amputees compensatory gait patterns and implications on prosthetic designs and training

Trans-tibial amputees are advised to walk as much as able people to achieve healthy and independent life. However, they usually have difficulties in doing so. Previous researches only included data from a few steps when studying the gait of amputees. Walking over a long distance was rarely examined. The objective of this study was to investigate the changes in spatial-temporal, kinetic and kinematic gait parameters of trans-tibial amputees after long-distance walking. Six male unilateral trans-tibial amputees performed two sessions of 30-min walking on a level treadmill at their self-selected comfortable speed. Gait analysis was undertaken over-ground: (1) before walking, (2) after the 1st walking session and (3) after the 2nd walking session. After the long-distance walking, changes in spatial-temporal gait parameters were small and insignificant. However, the sound side ankle rocker progression and push-off were significantly reduced. This was due to the fatigue of the sound side plantar flexors and was compensated by the greater effort in the prosthetic side. The prosthetic side knee joint showed significantly increased flexion and moment during loading response to facilitate the anterior rotation of the prosthetic shank. The prosthetic side hip extensors also provided more power at terminal stance to facilitate propulsion. Endurance training of the sound side plantar flexors, and improvements in the prosthetic design to assist anterior rotation of the prosthetic shank should improve long-distance walking in trans-tibial amputees.     

Effect of contralateral cane use on hip moment impulse in the frontal plane during the stance phase

BackgroundRecent reports have shown that the daily cumulative moment in the frontal plane (i.e., product of hip moment impulse in the frontal plane during the stance phase and mean steps per day) is a risk factor for hip osteoarthritis. This study aimed to clarify the effect of contralateral cane use on hip moment impulse in the frontal plane of the stance limb.MethodsThis study included 15 healthy subjects who walked under four experimental conditions: (1) without a cane and (2–4) contralateral cane use with 10%, 15%, and 20% body weight support (BWS), respectively. To maintain the same walking speed in all conditions, the cadence was set to 80 steps/min, and the step length was fixed. The hip moment impulses in the frontal plane (i.e., area under the hip ab-adduction moment waveform) and peak hip adduction moments in all conditions were calculated.ResultsContralateral cane use significantly decreased the hip moment impulse in the frontal plane and peak hip adduction moment compared to non-cane use. Moreover, the hip moment impulse in the frontal plane and peak hip adduction moment decreased significantly with increased cane BWS. There were no significant differences in walking speed, cadence, and step length between the four conditions.ConclusionContralateral cane use decreases the hip moment impulse in the frontal plane and peak hip adduction moment in the stance limb. These findings may help clarify how to delay the progression of hip osteoarthritis.     

Trunk flexion during walking in people with knee osteoarthritis

BackgroundOver 50% of the body’s mass is concentrated within the head, arms and trunk. Thus, small deviations in the orientation of the trunk, during normal walking, could influence the position of the centre of mass relative to the lower limb joint centres and impact on lower limb biomechanics. However, there are minimal data available on sagittal kinematics of the trunk in people with knee osteoarthritis (OA) during walking.Research questionDo people with knee OA have altered kinematic patterns of the trunk, pelvis or hip compared with healthy control participants during walking?MethodsStatistical parametric mapping was used to compare sagittal and frontal plane kinematic patterns, during walking, between a healthy group and cohort of people with knee OA.ResultsIndividuals with knee OA walked with a mean increase in trunk flexion of 2.6°. Although this difference was more pronounced during early stance, it was maintained across the whole of stance phase. There were no differences, between the groups, in sagittal plane pelvic or hip kinematics. There were also no differences in trunk, pelvic or hip kinematics in the frontal plane.SignificanceMost previous gait research investigating trunk motion in people with knee OA has focused on the frontal plane. However, our data suggest that an increase in sagittal trunk flexion may be a clinical hallmark of people with this disease. Altered trunk flexion could affect joint moments and muscle patterns and therefore our results motivate further research in this area.     

Comparison of transtibial amputee and non-amputee biomechanics during a common turning task

The biomechanics of amputee turning gait has been minimally studied, in spite of its integral relationship with the more complex gait required for household or community ambulation. This study compares the biomechanics of unilateral transtibial amputees and non-amputees completing a common turning task. Full body gait analysis was completed for subjects walking at comparable self-selected speeds around a 1m radius circular path. Peak internal and external rotation moments of the hip, knee and ankle, mediolateral ground reaction impulse (ML GRI), peak effective limb length, and stride length were compared across conditions (non-amputee, amputee prosthetic limb, amputee sound limb). Amputees showed decreased internal rotation moments at the prosthetic limb hip and knee compared to non-amputees, perhaps as a protective mechanism to minimize stress on the residual limb. There was also an increase in amputee sound limb hip external rotation moment in early stance compared to non-amputees, which may be a compensation for the decrease in prosthetic limb internal rotation moment during late stance of the prior step. ML GRI was decreased for the amputee inside limb compared to non-amputee, possibly to minimize the body's acceleration in the direction of the turn. Amputees also exhibited a shorter inside limb stride length compared to non-amputees. Both decreased ML GRI and stride length indicate a COM that is more centered over the base of support, which may minimize the risk of falling. Finally, a longer effective limb length was found for the amputee inside limb turning, possibly due to excessive trunk shift.     

A characterisation of established unilateral transfemoral amputee gait using 3D kinematics,kinetics and oxygen consumption measures

BackgroundPersons with unilateral transfemoral (UTF) amputation are known to walk with less efficiency than able-bodied individuals, therefore understanding the gait deviations that drive this inefficiency was considered to be important.Research questionsWhat are the differences in gait outcomes between persons with UTF amputation and able-bodied persons? What is the prevalence of specific gait deviations within this group?MethodsUsing a cross-sectional study design, the level over ground gait of established prosthetics service users with UTF amputation using mechanical knee joints (n=60) were compared with able-bodied persons (n=10). Gait profile score, walking velocity, step length, step length symmetry ratio, step time symmetry ratio, vertical ground reaction force symmetry index, base of support, centre of mass deviation and metabolic energy expenditure were measured. All data were captured during walking on level ground at a self-selected speed. Prevalence of gait deviations for each UTF participant were assessed by inspection, using a predefined list of lower limb kinematic, upper body kinematic, ground reaction force and lower limb kinetic gait deviations.ResultsStatistically significant between-groups differences across all outcome measures were found, with all p-values <0.005, and effect sizes ranging from 'large' to 'huge'. The most prevalent gait deviations included: lack of prosthetic knee flexion in early stance (98%); lack of hip extension on the prosthetic side in late stance (82%): increased trunk side flexion range of motion across the gait cycle (92%); reduced anterior propulsion force on the prosthetic side in late stance (100%) and reduced prosthetic hip adduction moment in early stance (96%).SignificanceThe results of this study indicate that the magnitude of the differences between UTF amputees and able-bodied persons, across a comprehensive range of gait measures, are such that significant research into all aspects of prosthetic rehabilitation to reduce these differences is clearly justified.