Relationship between Asymmetry of Gait and Muscle Torque in Patients after Unilateral Transfemoral Amputation

When the Going Gets Tough: A Review of Total Hip Arthroplasty in Patients with Ipsilateral Above- and Below-Knee Amputation

Life expectancy and overall function of amputated patients have improved significantly over the last few decades; for this reason, amputees are more exposed to primary or secondary degenerative disease of the hip, requiring total hip arthroplasty (THA) surgery. However, during training, not all the surgeons acquire adequate skills to manage these patients, and only a few studies and case reports describe technical pearls and outcomes of THA in patients with ipsilateral lower limb amputation, either above or below the knee. The objective of this narrative review is to present current evidence and surgical tips for performing THA in ipsilateral amputated patients, with a focus on the differences between patients with above- (AKA) and below-knee amputation (BKA). We reviewed manuscripts in major scientific databases, cross-referencing to retrieve adjunctive manuscripts, and summarized all relevant cases. We found 17 manuscripts, spanning 70 years of literature, collecting a total of 39 patients who underwent THA on an ipsilateral amputated limb: 13 AKA, 23 BKA, and 3 through-knee-amputation (TKA). The cohort primarily consists of patients with post-traumatic hip arthritis, often associated with sequelae such as fractures to other bones, soft tissue compromise and heterotopic calcifications. Managing with amputated patients requires careful planning, which includes the study of the residual bone, muscle anatomy, and the level of femoral amputation, as these factors present significant surgical challenges, especially in patients without a knee joint. In dealing with the post-traumatic and multi-comorbidity patients, rehabilitation goals should be considered prior to surgery and should drive the surgical strategy. We found that BKA patients typically have high functional demands, necessitating precise positioning of the components and an aggressive post-operative physiotherapy regimen to avoid unsatisfactory outcomes. AKA patients, on the other hand, often present with altered anatomy, and typically require more surgical instruments and expertise to achieve intraoperative dislocation of the hip joint.

Cumulative loading increases and loading asymmetries persist during walking for people with a transfemoral bone-anchored limb

BACKGROUND

A bone-anchored limb (BAL) is an alternative to a traditional socket-type prosthesis for people with transfemoral amputation. Early laboratory-based evidence suggests improvement in joint and limb loading mechanics during walking with a BAL compared to socket prosthesis use. However, changes in cumulative joint and limb loading measures, which may be predictive of degenerative joint disease progression, remain unknown.

RESEARCH QUESTION

Do cumulative total limb and hip joint loading during walking change using a BAL for people with unilateral transfemoral amputation, compared to prior socket prosthesis use?

METHODS

A case-series cohort of eight participants with prior unilateral transfemoral amputation who underwent BAL hardware implantation surgery were retrospectively analyzed (4 M/4 F; BMI: 27.7 ± 3.1 kg/m2; age: 50.4 ± 10.2 years). Daily step count and whole-body motion capture data were collected before (using socket prosthesis) and one-year after BAL hardware implantation. Cumulative total limb and hip joint loading and between-limb loading symmetry metrics were calculated during overground walking at both time points and compared using Cohen's d effect sizes.

RESULTS

One year after BAL hardware implantation, participants demonstrated bilateral increases in cumulative total limb loading (amputated: d = -0.65; intact: d = -0.72) and frontal-plane hip moment (amputated: d = -1.29; intact: d = -1.68). Total limb loading and hip joint loading in all planes remained asymmetric over time, with relative overloading of the intact limb in all variables of interest at the one-year point.

SIGNIFICANCE

Despite increases in cumulative total limb and hip joint loading, between-limb loading asymmetries persist. Habitual loading asymmetry has been implicated in contributing to negative long-term joint health and onset or progression of degenerative joint diseases. Improved understanding of methods to address habitual loading asymmetries is needed to optimize rehabilitation and long-term joint health as people with transfemoral amputation increase physical activity when using a BAL.

The relationship of hip strength to walking and balance performance in unilateral lower limb prosthesis users differs by amputation level

BACKGROUND

Safe and efficient locomotion is a frequently stated goal of lower limb prosthesis users, for which hip strength may play a central yet poorly understood role. Additional research to identify associations between hip strength, balance, and mobility among transtibial and transfemoral prosthesis users is required.

OBJECTIVE

To test whether residual and/or intact limb isometric hip strength was associated with lower limb prosthesis users' walking speed, endurance, and balance.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PARTICIPANTS

Convivence sample of 14 transtibial and 14 transfemoral prosthesis users.

METHODS

Multiple linear regression was used to evaluate the relationship between isometric measures of residual and intact limb hip strength and walking and balance performance.

MAIN OUTCOME MEASUREMENTS

Measures of isometric hip muscle strength, including peak torque, average torque, torque impulse, and torque steadiness (i.e. consistency with which an isometric torque can be sustained) were derived from maximum voluntary hip flexion, extension, abduction and adduction torque signals collected with a motor-driven dynamometer. Walking speed, endurance, and balance were assessed by administering the 10-meter walk test, 2-minute walk test, Four Square Step Test, and Narrowing Beam Walking Test, respectively.

RESULTS

Residual limb hip extensor max torque and abductor torque steadiness explained between 51% and 69% of the variance in transtibial prosthesis users' walking speed, endurance, and balance. In contrast, intact limb hip abductor torque impulse explained between 33% and 48% of the variance in transfemoral prosthesis users' walking speed, endurance, and balance.

CONCLUSIONS

Our results suggest that unilateral transtibial and transfemoral prosthesis users' walking and balance performance may depend on different hip muscles, and different facets of hip strength. Amputation level-specific hip strength interventions may therefore be required to improve walking and balance performance in unilateral transtibial and transfemoral prosthesis users. The "intact leg strategy" adopted by transfemoral prosthesis users may be due to a variety of prosthesis and biomechanical factors that limit the efficiency with which transfemoral prosthesis users can exploit the strength of their residual limb hip muscles while walking.

A Comprehensive, Multidisciplinary Assessment for Knee Osteoarthritis Following Traumatic Unilateral Lower Limb Loss in Service Members

INTRODUCTION

Knee osteoarthritis (KOA) is a primary source of long-term disability and decreased quality of life (QoL) in service members (SM) with lower limb loss (LL); however, it remains difficult to preemptively identify and mitigate the progression of KOA and KOA-related symptoms. The objective of this study was to explore a comprehensive cross-sectional evaluation, at the baseline of a prospective study, for characterizing KOA in SM with traumatic LL.

MATERIALS AND METHODS

Thirty-eight male SM with traumatic unilateral LL (23 transtibial and 15 transfemoral), 9.5 ± 5.9 years post-injury, were cross-sectionally evaluated at initial enrollment into a prospective, longitudinal study utilizing a comprehensive evaluation to characterize knee joint health, functionality, and QoL in SM with LL. Presences of medial, lateral, and/or patellofemoral articular degeneration within the contralateral knee were identified via magnetic resonance imaging(for medically eligible SM; Kellgren-Lawrence Grade [n = 32]; and Outerbridge classification [OC; n = 22]). Tri-planar trunk and pelvic motions, knee kinetics, along with temporospatial parameters, were quantified via full-body gait evaluation and inverse dynamics. Concentrations of 26 protein biomarkers of osteochondral tissue degradation and inflammatory activity were identified via serum immunoassays. Physical function, knee symptoms, and QoL were collected via several patient reported outcome measures.

RESULTS

KOA was identified in 12 of 32 (37.5%; KL ≥ 1) SM with LL; however, 16 of 22 SM presented with patellofemoral degeneration (72.7%; OC ≥ 1). Service members with versus without KOA had a 26% reduction in the narrowest medial tibiofemoral joint space. Biomechanically, SM with versus without KOA walked with a 24% wider stride width and with a negative correlation between peak knee adduction moments and minimal medial tibiofemoral joint space. Physiologically, SM with versus without KOA exhibited elevated concentrations of pro-inflammatory biomarker interleukin-7 (+180%), collagen breakdown markers collagen II cleavage (+44%), and lower concentrations of hyaluronic acid (-73%) and bone resorption biomarker N-telopeptide of Type 1 Collagen (-49%). Lastly, there was a negative correlation between patient-reported contralateral knee pain severity and patient-reported functionality and QoL.

CONCLUSIONS

While 37.5% of SM with LL had KOA at the tibiofemoral joint (KL ≥ 1), 72.7% of SM had the presence of patellofemoral degeneration (OC ≥ 1). These findings demonstrate that the patellofemoral joint may be more susceptible to degeneration than the medial tibiofemoral compartment following traumatic LL.

Above knee socket prosthesis use changes proximal femur morphology

Patients with transfemoral amputation (TFA) are up to six times more likely to develop hip osteoarthritis (OA) in either or both the intact and residual limb, which is primarily attributed to habitually altered joint loading due to compensatory movement patterns. However, joint loading patterns differ between limbs, which confounds the understanding of loading-induced OA etiology across limbs. It remains unknown if altered loading due to amputation results in bony shape changes at the hip, which is a known etiological factor in the development of hip OA. Retrospective computed tomography images were collected of the residual limb for 31 patients with unilateral TFA (13F/18M; age: 51.7 ± 9.9 y/o; time since amputation: 13.7 ± 12.4 years) and proximal femur for a control group of 29 patients (13F/16M; age: 42.0 ± 12.27 years) and used to create 3D geometries of the proximal femur. Femoral 3D geometric variation was quantified using statistical shape modeling (SSM), a computational tool which placed 2048 corresponding particles on each geometry. Independent modes of variation were created using principal component analysis. 2D radiographic measures of the proximal femur, including common measures such as α-angle, head neck offset, and neck shaft angle, were quantified on digitally reconstructed radiographs (DRRs). SSM results were then compared to 2D measures using Pearson correlation coefficients (r). Two-sample t-tests were used to determine if there were significant differences between the TFA and control group means of 2D radiographic measurements (p < 0.05). Patients with TFA had greater femoral head asphericity within the SSM, which was moderately correlated to head-neck offset (r = -0.54) and α-angle (r = 0.63), as well as greater trochanteric torsion, which was strongly correlated to the novel radiographic measure of trochanteric torsion (r = -0.78), compared to controls. For 2D measures, the neck-shaft angle was smaller in the TFA group compared to the control group (p = 0.01) while greater trochanter height was larger in the TFA group compared to the control group (p = 0.04). These results indicate altered loading from transfemoral prosthesis use changes proximal femur bony morphology, including femoral head asphericity and greater trochanter changes. Greater trochanter morphologic changes, though not a known factor to OA, affect moment arm and line of action of the primary hip abductors, the major muscles which contribute to joint loading and hip stability. Thus, chronic altered loading of the amputated limb hip, whether under- or overloading, results in bony changes to the proximal femur which may contribute to the etiological progression and development of OA.

Ground reaction forces during double limb stances while walking in individuals with unilateral transfemoral amputation

The asymmetrical gait of individuals with unilateral transfemoral amputation has been well documented. However, there is not a wealth of investigation into asymmetries during the double limb stance depending on whether the intact or prosthetic limb is leading. The first aim of this study was to compare ground reaction forces during the double limb stance of individuals with unilateral transfemoral amputation depending on whether their intact (initial double limb stance) or prosthetic (terminal double limb stance) limb was leading. The second aim of this study was to compare the asymmetry ratio of ground reaction forces during the double limb stance between individuals with and without unilateral transfemoral amputation. Thirty individuals, fifteen with unilateral transfemoral amputation and fifteen who were able-bodied, were recruited for this study. Each individual walked on an instrumented treadmill for 30 s at eight different speeds, ranging from 2.0 km/h to 5.5 km/h with .5 km/h increments. Ground reaction force parameters, temporal parameters, and asymmetry ratios of all parameters were computed from the data collected. The appropriate statistical analyses of all data based on normality were conducted to investigate the aims of this study. Significant main effects of speed, double limb stance, and their interactions were found for most parameters (p < .01 or p < .05). Individuals with unilateral transfemoral amputation spent a longer duration in terminal double limb stance than initial double limb stance at all tested speeds. They also experienced significantly higher peak vertical ground reaction force during initial double limb stance compared to terminal double limb stance with increasing walking speed. However, during terminal double limb stance, higher anteroposterior ground reaction force at initial contact was found when compared to initial double limb stance. Significant differences between individuals with unilateral transfemoral amputation and able-bodied individuals were found in asymmetry ratios for peak vertical ground reaction force, anteroposterior ground reaction force, anteroposterior shear, and mediolateral shear at all tested speeds. Asymmetrical loading persists in individuals with unilateral transfemoral amputation during double limb stance. Increasing walking speed increased ground reaction force loading asymmetries, which may make individuals with unilateral transfemoral amputation more susceptible to knee osteoarthritis or other musculoskeletal disorders. Further study is necessary to develop ideal gait strategies for the minimization of gait asymmetry in individuals with unilateral transfemoral amputation.

Correlation of Femoral Muscle Volume Using Three-Dimensional Modeling and Locomotor Function After Unilateral Trans-femoral Amputation

OBJECTIVE

To evaluate the relationship between femoral muscle volume (FMV) and physiological outcomes after trans-femoral amputations (TFAs) affecting overall locomotor function in patients.

METHODS

Seven individuals who underwent TFA and had been using a prosthesis participated in this cross-sectional study. Gait and balance were assessed using clinical tests, such as 10-m walk test, 6-minute walk test, Berg Balance Scale, and automatic balance system. Respiratory gas analysis was performed to check oxygen consumption rate. Five participants were evaluated for bilateral FMV by MR imaging and FMV was reconstructed using three-dimentional remodeling.

RESULTS

In five participants, significant differences were found between the non-involved and involved sides in femur length, total FMV, and functional muscle volume (all p<0.01) in all groups except for the hip adductor volume. The %mean difference between the non-involved and involved sides was 30% for femur length, 52.55% for hip flexor volume, 26.55% for hip adductor volume, 51.86% for hip extensor volume, and 60.21% for knee extensor volume. The hip flexor volume to hip extensor volume ratio in the involved limb and oxygen consumption rate during comfortable gait were negatively correlated (r=-0.96, p=0.04).

CONCLUSION

In individuals who underwent unilateral TFA, hip girdle muscle imbalance in the involved limbs may be associated with oxygen consumption rate while using a prosthesis.

Estimation of Gait Parameters for Transfemoral Amputees Using Lower Limb Kinematics and Deterministic Algorithms

Accurate estimation of gait parameters depends on the prediction of key gait events of heel strike (HS) and toe-off (TO). Kinematics-based gait event estimation has shown potential in this regard, particularly using leg and foot velocity signals and gyroscopic sensors. However, existing algorithms demonstrate a varying degree of accuracy for different populations. Moreover, the literature lacks evidence for their validity for the amputee population. The purpose of this study is to evaluate this paradigm to predict TO and HS instants and to propose a new algorithm for gait parameter estimation for the amputee population. An open data set containing marker data of 12 subjects with unilateral transfemoral amputation during treadmill walking was used, containing around 3400 gait cycles. Five deterministic algorithms detecting the landmarks (maxima, minima, and zero-crossings [ZC]) in the foot, shank, and thigh angular velocity data indicating HS and TO events were implemented and their results compared against the reference data. Two algorithms based on foot and shank velocity minima performed exceptionally well for the HS prediction, with median accuracy in the range of 6–13 ms. However, both these algorithms produced inferior accuracy for the TO event with consistent early prediction. The peak in the thigh velocity produced the best result for the TO prediction with <25 ms median error. By combining the HS prediction using shank velocity and TO prediction from the thigh velocity, the algorithm produced the best results for temporal gait parameters (step, stride times, stance, and double support timings) with a median error of less than 25 ms. In conclusion, combined shank and thigh velocity-based prediction leads to improved gait parameter estimation than traditional algorithms for the amputee population.

Symmetry Function: The Differences between Active and Non-Active Above-the-Knee Amputees

The number of patients with unilateral above-knee amputation (AKA) due to non-vascular causes has remained stable over the years, at 0.92 per 1000 people per year. Post-AKA individuals are at risk of experiencing a higher incidence of chronic pain. Post rehabilitation, it is estimated that between 16−62% of patients with musculoskeletal disabilities fail to meet the minimum criteria for physical activity in comparison to a healthy population. The current study included 14 participants (11 men and 3 women) with a mean age of 46.1 ± 14.2 years, body height of 1.76 ± 0.09 m, and weight of 79.6 ± 18.3 kg, who were all post-unilateral above-the-knee amputees. Patients in the study were divided into two groups: active (AC) and non-active (NAC). This study was conducted in a certified Laboratory of Biomechanical Analysis using the BTS Smart-E system (BTS Bioengineering). In order to investigate the symmetry function (SF) of gait, the only measurements included were the time series assessment of gait variables defining pelvic and lower limb joint motion and ground reaction forces (GRF). Both groups had an asymmetrical gait pattern with a different magnitude and relative position in the gait cycle, which was revealed by SF. The differences in terms of median, minimum, and maximum were statistically significant (p < 0.05), with SF ranging from −25 to 24% for the AC group and from 43 to 77% (59% on average) for the NAC group. The AC’s pattern was more symmetrical compared to the NAC’s pattern, especially in the case of pelvic and hip joint motion.

Kinetic Gait Parameters in Unilateral Lower Limb Amputations and Normal Gait in Able-Bodied: Reference Values for Clinical Application

Unilateral lower limb amputations usually present with asymmetric interlimb gait patterns, in the long term leading to secondary physical conditions and carrying the risk of low physical activity and impairment of general health. To assess prosthetic fittings and rehabilitation measures, reference values for asymmetries as well as the most significant gait parameters are required. Kinetic gait data of 865 patients with unilateral lower limb amputations (hip and knee disarticulations, transfemoral, transtibial and foot amputations) and 216 able-bodied participants were quantitatively assessed by instrumented gait analyses. Characteristic spatiotemporal (stance time, walking speed, step length and width) and ground reaction force parameters (weight-acceptance and push-off peak) were contrasted to normal gait. All spatiotemporal and ground reaction force parameters differed significantly from normal gait with the largest differences in transfemoral amputations. These also differed between amputation levels and showed age-dependencies. The stance time and push-off peak difference were identified as the most discriminative parameters with the highest diagnostic specificity and sensitivity. The present results mark the first step to establishing universal reference values for gait parameters by means of which the quality and suitability of a prosthetic fitting and the rehabilitation progress can be assessed, and are generalizable for all adults with unilateral lower limb amputations in terms of level walking.

Walking abilities improvements are associated with pelvis and trunk kinematic adaptations in transfemoral amputees after rehabilitation

BACKGROUND

Rehabilitation can be proposed to transfemoral amputees to improve functional abilities and limit the risk of early degeneration of the musculoskeletal system partly due to altered kinematic behavior. The main aim of this study was to assess the impact of functional rehabilitation on clinical walking tests, gait symmetry and pelvis and trunk kinematics in transfemoral amputees during overground walking.

METHODS

Eleven transfemoral amputees followed a functional rehabilitation program with objectives aimed at improving walking abilities and gait symmetry. Clinical functional tests, symmetry between prosthetic and intact sides and trunk and pelvis motions were recorded before and after rehabilitation.

FINDINGS

Clinical walking tests were improved after rehabilitation (p < 0.05), and step width was reduced (p = 0.04). Regarding symmetry between the single stances on the prosthesis and intact sides, only a significant decrease in trunk frontal inclination asymmetry was noted after rehabilitation (p = 0.01). Pelvic frontal obliquity was significantly increased during prosthetic (p = 0.02) and intact single stances (p = 0.005).

INTERPRETATION

Our study showed a positive effect of rehabilitation on transfemoral amputees functional abilities. These improvements were associated with higher pelvic mobility in frontal plane and a more symmetrical redistribution of the frontal trunk sway around the vertical axis during gait. These results suggest the importance of a postural reeducation program for transfemoral amputees aimed at improving pelvic dynamic control while repositioning the trunk by postural corrections during gait.

Effects of step frequency during running on the magnitude and symmetry of ground reaction forces in individuals with a transfemoral amputation

BACKGROUND

Individuals with unilateral transfemoral amputation are prone to developing health conditions such as knee osteoarthritis, caused by additional loading on the intact limb. Such individuals who can run again may be at higher risk due to higher ground reaction forces (GRFs) as well as asymmetric gait patterns. The two aims of this study were to investigate manipulating step frequency as a method to reduce GRFs and its effect on asymmetric gait patterns in individuals with unilateral transfemoral amputation while running.

METHODS

This is a cross-sectional study. Nine experienced track and field athletes with unilateral transfemoral amputation were recruited for this study. After calculation of each participant's preferred step frequency, each individual ran on an instrumented treadmill for 20 s at nine different metronome frequencies ranging from - 20% to + 20% of the preferred frequency in increments of 5% with the help of a metronome. From the data collected, spatiotemporal parameters, three components of peak GRFs, and the components of GRF impulses were computed. The asymmetry ratio of all parameters was also calculated. Statistical analyses of all data were conducted with appropriate tools based on normality analysis to investigate the main effects of step frequency. For parameters with significant main effects, linear regression analyses were further conducted for each limb.

RESULTS

Significant main effects of step frequency were found in multiple parameters (P < 0.01). Both peak GRF and GRF impulse parameters that demonstrated significant main effects tended towards decreasing magnitude with increasing step frequency. Peak vertical GRF in particular demonstrated the most symmetric values between the limbs from - 5% to 0% metronome frequency. All parameters that demonstrated significant effects in asymmetry ratio became more asymmetric with increasing step frequency.

CONCLUSIONS

For runners with a unilateral transfemoral amputation, increasing step frequency is a viable method to decrease the magnitude of GRFs. However, with the increase of step frequency, further asymmetry in gait is observed. The relationships between step frequency, GRFs, and the asymmetry ratio in gait may provide insight into the training of runners with unilateral transfemoral amputation for the prevention of injury.

[Functional rehabilitation after transfemoral amputation : Shaft prosthesis or endo-exo prosthesis?]

BACKGROUND

After transfemoral amputation a prosthesis is required to restore autonomous standing and bipedal locomotion. Attachment of the prosthesis can be achieved either classically via socket suspension with a shaft in the stump or directly via implantation of an intramedullary transcutaneous femoral prosthesis (osseointegrated prosthesis).

AIM

A fully instrumented gait analysis should enable objectification of the anticipated advantages of the EEP with respect to the gait pattern and individual mobility.

MATERIAL AND METHODS

In two patients with a unilateral transfemoral amputation a comprehensive gait analysis was carried out prior to and 6 months (patient 1) or 11 and 20 months (patient 2) after switching from a socket prosthesis to an EEP. This was carried out in the Gait Realtime Analysis Interactive Lab (GRAIL), a fully instrumented gait laboratory with virtual reality and enables assessment close to the conditions of daily life.

RESULTS

In both cases the gait analysis confirmed the advantages associated with an EEP for the transmission of force to the prosthesis and the accompanying improvement in gait symmetry.

A review of musculoskeletal adaptations in individuals following major lower-limb amputation

Structural musculoskeletal adaptations following amputation, such as bone mineral density (BMD) or muscle architecture, are often overlooked despite their established contributions to gait rehabilitation and the development of adverse secondary physical conditions. The purpose of this review is to provide a summary of the existing literature investigating musculoskeletal adaptations in individuals with major lower-limb amputations to inform clinical practice and provide directions for future research. Google Scholar, PubMed, and Scopus were searched for original peer-reviewed studies that included individuals with transtibial or transfemoral amputations. Summary data of twenty-seven articles indicated reduced BMD and increased muscle atrophy in amputees compared to controls, and in the amputated limb compared to intact and control limbs. Specifically, BMD was reduced in T-scores and Z-scores, femoral neck, and proximal tibia. Muscle atrophy was evidenced by decreased thigh cross-sectional area, decreased quadriceps thickness, and increased amounts of thigh fat. Overall, amputees have impaired musculoskeletal health. Future studies should include dysvascular etiologies to address their effects on musculoskeletal health and functional mobility. Moreover, clinicians can use these findings to screen increased risks of adverse sequelae such as fractures, osteopenia/porosis, and muscular atrophy, as well as target specific rehabilitation exercises to reduce these risks.

Overall Greater Demands on the Musculoskeletal System at Multiple Walking Speeds in Service Members With Lower Limb Loss

Individuals with lower limb loss often walk with altered/asymmetric movement mechanics, postulated as a catalyst for development of low back and knee pain. Here, the authors simultaneously investigated trunk-pelvic movement patterns and lower limb joint kinematics and kinetics among 38 males with traumatic, unilateral lower limb loss (23 transtibial and 15 transfemoral), and 15 males without limb loss, at a self-selected and 2 standardized (1.0 and 1.6 m/s) speeds. Individuals with versus without lower limb loss walked with greater trunk range of motion in the frontal and transverse planes at all speeds (despite ∼10% slower self-selected speeds). At all speeds, individuals with versus without limb loss exhibited +29% larger medial ground reaction forces, and at 1.6 m/s also exhibited +50% to 110% larger vertical hip power generation, +27% to 80% larger vertical hip power absorption, and +21% to 90% larger medial-lateral hip power absorption. Moreover, pervasive biomechanical differences between transtibial versus transfemoral limb loss identify amputation-level movement strategies. Overall, greater demands on the musculoskeletal system across walking speeds, particularly at the hip, knee, and low back, highlight potential risk factors for the development/recurrence of prevalent secondary musculoskeletal conditions (eg, joint degeneration and pain) following limb loss.

Trunk Muscle Characteristics: Differences Between Sedentary Adults With and Without Unilateral Lower Limb Amputation

OBJECTIVE

The primary purpose of this study was to compare trunk muscle characteristics between adults with and without unilateral lower limb amputation (LLA) to determine the presence of modifiable trunk muscle deficits (ie, impaired activity, reduced volume, increased intramuscular fat) evaluated by ultrasonography (US) and magnetic resonance imaging (MRI). We hypothesized that compared with adults without LLA (controls), individuals with transfemoral or transtibial LLA would demonstrate reduced multifidi activity, worse multifidi and erector spinae morphology, and greater side-to-side trunk muscle asymmetries.

DESIGN

Cross-sectional imaging study.

SETTING

Research laboratory and imaging center.

PARTICIPANTS

Sedentary adults (n=38 total) with LLA (n=9 transfemoral level; n=14 transtibial level) and controls without LLA (n=15).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We examined bilateral multifidi activity using US at levels L3/L4-L5/S1. MRI was performed using 3-dimensional quantitative fat-water imaging; bilateral L1-L5 multifidi and erector spinae were manually traced, and muscle volume (normalized to body weight) and percentage intramuscular fat were determined. Between-group and side-to-side differences were evaluated.

RESULTS

Compared with adults without LLA, participants with LLA demonstrated reduced sound-side multifidi activity; those with transfemoral LLA had larger amputated-side multifidi volume, whereas those with transtibial LLA had greater sound- and amputated-side erector spinae intramuscular fat (P<.050). With transfemoral LLA, side-to-side differences in erector spinae volume, as well as multifidi and erector spinae intramuscular fat, were found (P<.050).

CONCLUSIONS

Impaired trunk muscle activity and increased intramuscular fat may be modifiable targets for intervention after LLA.

Symmetry function in gait pattern analysis in patients after unilateral transfemoral amputation using a mechanical or microprocessor prosthetic knee

BACKGROUND

Above-knee amputations (AKAs) contribute to gait asymmetry. The level of asymmetry is affected by the type of knee prosthetic module. There is limited evidence suggesting that more technically advanced solutions (microprocessor modules; MicPK) are superior to less advanced ones (mechanical modules; MechPK). The study aimed to evaluate the variable range of hip and pelvic joint movements during gait and look for differentiating areas with an increased level of asymmetry of the gait cycle in individuals who underwent an AKA and are equipped with MicPK or MechPK.

METHODS

Twenty-eight individuals participated in the study; 14 were assigned to a study group of individuals who underwent a unilateral AKA, and the other 14 were healthy participants as a control group. The movement task was recorded using the optoelectronic SMART-E system following the standard Davis protocol (the Newington model). A new method of quantifying gait symmetry using the symmetry function (SF) is proposed. SF is an integral measure of absolute differences in time-standardized signals between sides throughout the whole cycle of motion variability.

RESULTS

In the frontal plane, there were significant differences between groups in the asymmetry of the range of movement in the hip joint of the intact limb. In the middle of the support phase, the intact limb was more adducted in individuals with MicPK and less abducted in people with MechPK (differences in mean 180%, p < 0.000; max 63%, p < 0.000; min 65%, p < 0.000). In the sagittal plane, the range of asymmetry of the flexion and thigh extension of the intact limb was similar to and only slightly different from the physiological gait. In the transverse plane, higher asymmetry values were noted for individuals with MicPK. In the final stage of the swing phase, the thigh was more rotated both externally and internally. The size of the asymmetry, when compared to gait of healthy individuals, reached 50% (differences in mean 115%, p < 0.232; max 62% p < 0.26; min 50, p < 0.154).

CONCLUSIONS

In the study group, the assessed ranges of pelvic and thigh movement in the hip joint differed only in the frontal plane. Individuals who underwent a unilateral above-knee amputation may gain less from using MicPK than anticipated.

Movement asymmetry during low and high demand mobility tasks after dysvascular transtibial amputation

BACKGROUND

Movement asymmetries between lower limbs are commonly exhibited by adults after transtibial amputation. However, the degree of movement asymmetry between low- and high-demand functional tasks remains unknown.

METHODS

Kinematic and kinetic data were collected during overground walking (low-demand) and step ascent (high-demand) tasks for two groups: 1) persons with transtibial amputation and 2) healthy matched peers. Analysis of covariance was used to compare sagittal-plane peak knee moment and joint angle (primary) and hip and ankle moments and joint angles, vertical ground reaction force and impulse (secondary).

FINDINGS

Within transtibial amputation group comparisons showed significantly greater between-limb asymmetry in peak knee moment (p < .01), vertical impulse (p < .01), peak vertical ground reaction force (p = .05), peak ankle angle (p < .01) and peak ankle moment (p < .01) with the step ascent task compared to overground walking. The transtibial amputation group had greater between-limb asymmetry during step ascent in peak knee moment (p < .01), vertical impulse (p < .01), peak vertical ground reaction force (p = .04) and peak ankle angle (p < .01) than healthy matched peers. During overground walking, the transtibial amputation group had greater between-limb asymmetry in peak vertical impulse (p = .05) and peak ankle moment (p < .01) than healthy matched peers.

INTERPRETATION

Movement asymmetry is increased during step ascent compared to overground walking for adults with transtibial amputation. While the restoration of overground walking is the focus of post-amputation rehabilitation and prosthetic design, higher demand tasks should also be considered to maximize mobility for adults with transtibial amputation.

Transfemoral Socket Fabrication Method Using Direct Casting: Outcomes Regarding Patient Satisfaction with Device and Services

BACKGROUND

Direct Socket for transfemoral (DS-TF) prosthetic user is a novel method of fabricating a laminated interface on to the residual limb but requires different training, production method and service model than what most prosthetists are familiar with. This method and model may improve patient satisfaction by enabling interface fabrication and delivery in one visit.

OBJECTIVES

Document patient satisfaction regarding DS-TF interface versus the prosthetic users' previous socket in terms of interface function and the clinic service model.

METHODOLOGY

In this longitudinal study (from July 2018 to April 2020), the DS-TF was implemented in six prosthetic clinics across the United States. Certified prosthetists (CP) and assistants were trained using a standard protocol. 47 prosthetic users participated, both those in need of a new socket and those without need. Two modules from the Orthotics and Prosthetics Users' Survey (OPUS), involving questions related to satisfaction with the Device and Services, was used to evaluate each DS-TF user outcome vs. baseline. The only part of the prosthesis that was replaced was the interface, except in 2 cases.

FINDINGS

Each DS-TF interface was fabricated, fit and delivered in a single clinic visit. At 6-months follow-up, 38 users reported an average of 29.8% increase in satisfaction with their new interface compared with original, and a 14.8% increase in satisfaction with the services they received from the clinic in providing of the new prosthesis vs. their original prosthesis. The main outcome increases were between baseline (initial fitting) and 6-week follow-up and remained consistent after 6 months. This improvement was consistent irrespective if the user needed a new socket for clinical reasons or not.

CONCLUSIONS

This study shows that after a standardized training and implementation, the DS-TF fabrication process including a new interface, improves the user's satisfaction with their prosthetic device and services.

Successful prosthetic rehabilitation and gait analysis of individual with bilateral transtibial amputation: A case study with comparison to able-bodied gait

Background:

Intensive rehabilitation of individuals with bilateral lower limb loss poses a great challenge to both rehabilitation team and amputees themselves due to unavailability of a sound leg to provide stability in standing and gait. Although gait characteristics of individuals with unilateral transtibial amputations are well documented in the literature, very less is known about those with bilateral limb loss.

Aim:

To examine the gait characteristics of an individual with bilateral transtibial amputation (BTA) and its comparison with an able-bodied (AB). This study also provides a real-life presentation of successful prosthetic rehabilitation.

Case content and methodology:

Temporal–spatial, kinematic and kinetic gait parameters were analysed for a 45-year-old male individual with traumatic BTA using prosthesis in a motion analysis laboratory setting with force platform (BTS P-6000) and cameras with reflective markers (BTS SMART-DX6000).

Findings and conclusion:

Variances in many temporal–spatial, kinematic and kinetic parameters were observed. The findings of temporal–spatial parameters revealed that the individual with BTA walked with slower speed, lower cadence, shorter step lengths and wider step width compared to that of AB. Ankle dorsiflexion, stance knee flexion and swing hip hiking were reduced in an individual with BTA compared to AB. In kinetics, he demonstrated low peak ankle muscle power, increased muscle power amplitudes and phase duration at the hip and knee joints compared to AB individual. The combination of an intensive prosthetic rehabilitation led to completely independent and remarkable degree of functional ambulation.

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

BACKGROUND

Persons 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 QUESTIONS

What 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?

METHODS

Using 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.

RESULTS

Statistically 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%).

SIGNIFICANCE

The 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.

A New Method of Evaluating the Symmetry of Movement Used to Assess the Gait of Patients after Unilateral Total Hip Replacement

Purpose

We propose a new concept of symmetry, the symmetry function, as a continuous function of the percentage of differences between sides of body movement and normalised throughout the whole range of motion. The method is used to assess the dynamical symmetry of gait of patients after unilateral total hip replacement (asymmetric group) and healthy people (symmetric group) and also to reveal discrepancies between normal and abnormal movement patterns.

Methods

The gait of twelve male patients (49.7 ± 2.8 y), six weeks after unilateral total hip replacement (uTHR), was analysed against the gait of thirteen healthy men (36.1 ± 3.1 y). The speed of healthy men was matched to the speed of the patients. Comparison of the affected limb in uTHR patients with the healthy limb of able-bodied men was carried out on the basis of the highest symmetry values in the sagittal plane.

Results

In uTHR patients, the symmetry function provides information on the symmetry of movements in the whole range of motion in contrast to symmetry indices which are calculated for selected parameters or peak values. Research revealed average asymmetric discrepancies for pelvic tilt up to 250% for the entire gait cycle with a peak of approx. 400% at the end of the loading response and terminal swing phases. Asymmetry of gait observed in other joints was below 200% of the mean range of motion.

Conclusions

Regions of the greatest asymmetry in pathological movements are usually different from the region of the greatest range of motion. Therefore, it is insufficient to measure symmetry only for selected regions during motion. The symmetry function is a simple method which can complement other robust methods in time series data evaluation and interpretation.