Dataset Information

Neuromuscular adaptations and sensorimotor integration following a unilateral transfemoral amputation.

ABSTRACT:

Background

Following an amputation, the human postural control system develops neuromuscular adaptations to regain an effective postural control. We investigated the compensatory mechanisms behind these adaptations and how sensorimotor integration is affected after a lower-limb transfemoral amputation.

Methods

Center of pressure (CoP) data of 12 unilateral transfemoral amputees and 12 age-matched able-bodied subjects were recorded during quiet standing with eyes open (EO) and closed (EC). CoP adjustments under each leg were recorded to study their contribution to posture control. The spatial structure of the CoP displacements was characterized by measuring the mean distance, the mean velocity of the CoP adjustments, and the sway area. The Entropic Half-Life (EnHL) quantifies the temporal structure of the CoP adjustments and was used to infer disrupted sensory feedback loops in amputees. We expanded the analysis with measures of weight-bearing imbalance and asymmetry, and with two standardized balance assessments, the Berg Balance Scale (BBS) and Timed Up-and-Go (TUG).

Results

There was no difference in the EnHL values of amputees and controls when combining the contributions of both limbs (p?=?0.754). However, amputees presented significant differences between the EnHL values of the intact and prosthetic limb (p?ConclusionThese results suggest that besides the asymmetry in load distribution, there exist neuromuscular adaptations after an amputation, possibly related to the loss of sensory feedback and an altered sensorimotor integration. The EnHL values suggest that the somatosensory system predominates in the control of the intact leg. Further, suppressing the visual system caused instability in amputees, but had a minimal impact on the CoP dynamics of controls. These findings points toward the importance of providing somatosensory feedback in lower-limb prosthesis to reestablish a normal postural control.

Trial registration

DRKS00015254 , registered on September 20th, 2018.

SUBMITTER: Claret CR

PROVIDER: S-EPMC6744715 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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Publications

Neuromuscular adaptations and sensorimotor integration following a unilateral transfemoral amputation.

Claret Claudia Ramos CR Herget Georg W GW Kouba Lukas L Wiest Daniel D Adler Jochen J von Tscharner Vinzenz V Stieglitz Thomas T Pasluosta Cristian C

Journal of neuroengineering and rehabilitation 20190914 1

<h4>Background</h4>Following an amputation, the human postural control system develops neuromuscular adaptations to regain an effective postural control. We investigated the compensatory mechanisms behind these adaptations and how sensorimotor integration is affected after a lower-limb transfemoral amputation.<h4>Methods</h4>Center of pressure (CoP) data of 12 unilateral transfemoral amputees and 12 age-matched able-bodied subjects were recorded during quiet standing with eyes open (EO) and clos ...[more]

PMID: 31521190

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Project description:IntroductionA unilateral transfemoral amputation (TFA) has a major impact on function. A leg-length discrepancy is the primary structural change, accompanied by the loss of lower-limb muscle volume and function. Prostheses can help individuals with a TFA to regain function, but such individuals still do not reach the functional level of unimpaired peers and exhibit gait deviations. This study gives insight into the causality between residual limb strength and gait deviations in individuals with a TFA.MethodsA convenient sample of 13 male individuals with a TFA (38.0 ± 12.6y; 179.7cm ± 6.5cm; 82.9kg ± 12.4kg) was recruited for this study. One participant with TFA was excluded, as he differed from the rest of the cohort, in residual limb length and the use of walking aids. A cohort of 18 unimpaired subjects served as a reference group (REF; nine females; 44y ± 13y; 174cm ± 9cm; 71kg ± 12kg). All participants underwent a conventional clinical gait analysis using a marker based 3D motion capture system and force platforms. Kinematics and kinetics were determined utilizing standard modelling methods. All subjects underwent a strength test, using a custom-made device to determine isometric moments of the hip joint in abduction, adduction, extension, and flexion. Peak values for maximum isometric moments for each movement direction and selected kinematic and kinetic values were derived from the results. Differences between subjects with TFA and unimpaired were compared using a Mann-Whitney U Test and associations between groups by Spearman's rank correlation.ResultsThe participants with a TFA showed a significantly lower maximum isometric moment for hip abduction (0.85 vs. 1.41 Nm/kg p < .001), adduction (0.87 vs. 1.37 Nm/kg p = .001) and flexion (0.93 vs. 1.63 Nm/kg p = .010) compared to the reference group. Typically reported gait deviations in people with a TFA were identified, i.e. significant lower cadence and increased step width. We further identified altered coronal plane hip and trunk kinematics, with significantly higher ranges of motion during involved side stance-phase. Gait kinetics of individuals with a TFA showed significantly lower peak values during stance for hip abduction, adduction and extension moments in comparison to the reference group. We identified a moderate negative correlation between maximum isometric moment for hip abduction and trunk obliquity range of motion (ρ = -0.45) for participants with a TFA, which was not significant (p = 0.14).ConclusionWe showed that there are strength deficits in individuals with TFA and, that there are moderate correlations between gait deviations, i.e. lateral trunk lean during involved side stance and isometric hip abductor moment. The relation between maximum moments during gait and the corresponding maximum isometric moment may therefore be helpful to detect strength related compensation mechanisms. However, the moderate, non-significant correlation between lateral trunk lean and isometric hip abductor moment was the only one which corresponded directly to a gait deviation. Thus results must be interpreted with care. This study suggests that gait deviations in individuals with TFA are multifactorial and cannot be exclusively explained by their strength deficits. Future studies should explore the relationship between strength with kinematics and kinetics during gait in this population.

Project description:OBJECTIVE:To identify timing, incidence, and risk factors for ipsilateral re-amputation within 12 months of first dysvascular amputation and to determine specific subgroups of patients at each amputation level that are at increased risk. METHODS:A retrospective cohort study evaluating 7187 patients with first unilateral transmetatarsal (TM), transtibial (TT), or transfemoral (TF) amputation secondary to diabetes and/or peripheral artery disease (PAD) were identified in the VA Surgical Quality Improvement Program database between 2004 and 2014. Re-amputation was defined as any subsequent ipsilateral soft tissue/bony revision or amputation to a higher level. Twenty-three potential pre-operative risk factors (and nine potential interactions) were identified. A backward stepwise Cox regression was used to identify risk factors. Incidence rates and hazard ratios (HR) with 95% confidence intervals (CI) were computed. RESULTS:The median time to highest level of re-amputation in the first year was 33 (interquartile range, 13-73) days. Risk of requiring at least one re-amputation was 41% (TM), 25% (TT), and 9% (TF). Risk factors associated with requiring re-amputation included chronic obstructive pulmonary disease, elevated white blood cell count, abnormal ankle brachial index (ABI), history of revascularisation, and alcohol misuse. TM patients who had diabetes only (HR 1.9; 95% CI 1.4-2.5), diabetes with an abnormal ankle brachial index (ABI) score (HR 2.4; 95% CI 1.8-3.2), and kidney failure (HR 1.7; 95% CI 1.3-2.1) were at the greatest risk of re-amputation. TT amputees who were smokers were also at an increased risk (HR 1.4; 95% CI 1.2-1.6). CONCLUSION:This research identified important risk factors for failure of primary healing and need for re-amputation at the TM and TT level. If considering a TM amputation, caution should be exercised in patients with diabetes, in particular those with an abnormal ABI and/or renal failure. At the TT level, caution should be exercised in those who smoke.

Project description:ObjectiveThe purpose of this study was to qualitatively assess the first-hand lived experiences of patients with amputation who had transitioned from a traditional socket (TS) to Osseointegration (OI) to impact their overall quality of life (QOL) and function.MethodsThis was a qualitative phenomenological study. Participants who had a unilateral transfemoral amputation and fit the study's inclusion criteria were interviewed in a semi-structured format regarding their quality of life and function before and after transitioning from a traditional socket (TS) to Osseointegration (OI). Responses were then analyzed through line-by-line coding to determine themes that were relevant to QOL outcomes for this study.ResultsEleven participants were interviewed in this study. The qualitative analysis demonstrated an emergence of 6 main themes consisting of "Improved Quality of Life," "Supportive Community," "Previous Ill-fitting Socket," "Greater Function," "Improved Osseo-perception," and "Promotion of Community Accessibility". Strengths included the use of an OI-specific quality of life assessment with adapted questions from validated outcome measures, international participants, and use of thematic analysis for data analysis. Weaknesses included sample size, niche participant population, and OI as a revision procedure only. More research is still necessary to explore/determine the benefits and detriments of Osseointegration as an alternative to traditional sockets for prosthetic devices.ConclusionIndividuals who have undergone Osseointegration procedure discuss being more satisfied with their prosthesis and quality of life when compared to their previous experience of a traditional socket.Impact statementThis is a first of its kind study reporting on the lived experiences of those who have undergone OI. The field of amputation rehabilitation is expanding rapidly and knowing how this procedure impacts quality of life is important for healthcare professionals to understand as new frontiers are explored in this field.

Dataset Information

Neuromuscular adaptations and sensorimotor integration following a unilateral transfemoral amputation.

Background

Methods

Results

Trial registration

Publications

Neuromuscular adaptations and sensorimotor integration following a unilateral transfemoral amputation.

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