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Energy cost of ambulation in trans-tibial amputees using a dynamic-response foot with hydraulic versus rigid 'ankle': insights from body centre of mass dynamics.

ABSTRACT: BACKGROUND:Previous research has shown that use of a dynamic-response prosthetic foot (DRF) that incorporates a small passive hydraulic ankle device (hyA-F), provides certain biomechanical benefits over using a DRF that has no ankle mechanism (rigA-F). This study investigated whether use of a hyA-F in unilateral trans-tibial amputees (UTA) additionally provides metabolic energy expenditure savings and increases the symmetry in walking kinematics, compared to rigA-F. METHODS:Nine active UTA completed treadmill walking trials at zero gradient (at 0.8, 1.0, 1.2, 1.4, and 1.6 of customary walking speed) and for customary walking speed only, at two angles of decline (5° and 10°). The metabolic cost of locomotion was determined using respirometry. To gain insights into the source of any metabolic savings, 3D motion capture was used to determine segment kinematics, allowing body centre of mass dynamics (BCoM), differences in inter-limb symmetry and potential for energy recovery through pendulum-like motion to be quantified for each foot type. RESULTS:During both level and decline walking, use of a hyA-F compared to rigA-F significantly reduced the total mechanical work and increased the interchange between the mechanical energies of the BCoM (recovery index), leading to a significant reduction in the metabolic energy cost of locomotion, and hence an associated increase in locomotor efficiency (p?

SUBMITTER: Askew GN

PROVIDER: S-EPMC6417010 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Energy cost of ambulation in trans-tibial amputees using a dynamic-response foot with hydraulic versus rigid 'ankle': insights from body centre of mass dynamics.

Askew Graham N GN McFarlane Laura A LA Minetti Alberto E AE Buckley John G JG

Journal of neuroengineering and rehabilitation 20190314 1

<h4>Background</h4>Previous research has shown that use of a dynamic-response prosthetic foot (DRF) that incorporates a small passive hydraulic ankle device (hyA-F), provides certain biomechanical benefits over using a DRF that has no ankle mechanism (rigA-F). This study investigated whether use of a hyA-F in unilateral trans-tibial amputees (UTA) additionally provides metabolic energy expenditure savings and increases the symmetry in walking kinematics, compared to rigA-F.<h4>Methods</h4>Nine a ...[more]

PMID: 30871573

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Project description:BackgroundTotal ankle arthroplasty (TAA) is becoming a more prevalent treatment for end-stage ankle arthritis. However, the effects of malalignment on TAA remain poorly understood.Questions/purposesThe purpose of this study was to quantify the mechanical effects of coronal plane malalignment of the tibial insert in TAA using cadaveric gait simulation. Specifically, we asked, is there a change in (1) ankle joint congruency, (2) kinematic joint position, (3) kinematic ROM, (4) peak plantar pressure, and (5) center of pressure with varus and valgus malalignment?MethodsA modified TAA was implanted into seven cadaveric foot specimens. Wedges were used to simulate coronal plane malalignment of the tibial insert. The degree of malalignment (tibial insert angle [TIA] and talar component angle [TCA]) was quantified radiographically for neutral and 5°, 10°, and 15° varus and valgus wedges. Dynamic walking at 1/6 of physiological speed was simulated using a robotic gait simulator. A motion capture system was used to measure foot kinematics, and a pressure mat was used to measure plantar pressure. Joint congruency was quantified as the difference between TIA and TCA. Continuous joint position, joint ROM, peak plantar pressure, and center of pressure for varus and valgus malalignment compared with neutral alignment were estimated using linear mixed effects regression. Pairwise comparisons between malalignment conditions and neutral were considered significant if both the omnibus test for the overall association between outcome and malalignment and the individual pairwise comparison (adjusted for multiple comparisons within a given outcome) had p ≤ 0.05.ResultsDescriptively, the TIA and TCA were both less pronounced than the wedge angle and component incongruence was seen (R = 0.65; p < 0.001). Varus malalignment of the tibial insert shifted the tibiotalar joint into varus and internally rotated the joint. The tibiotalar joint's ROM slightly increased as the TIA shifted into varus (1.3 ± 0.7° [mean ± SD] [95% confidence interval -0.7 to 3.4]; p = 0.03), and the first metatarsophalangeal joint's ROM decreased as the TIA shifted into varus (-1.9 ± 0.9° [95% CI -5.6 to 1.7]; p = 0.007). In the sagittal plane, the naviculocuneiform joint's ROM slightly decreased as the TIA shifted into varus (-0.9 ± 0.4° [95% CI -2.1 to 0.3]; p = 0.017). Hallux pressure increased as the TIA became more valgus (59 ± 50 kPa [95% CI -88 to 207]; p = 0.006). The peak plantar pressure slightly decreased in the third and fourth metatarsals as the TIA shifted into valgus (-15 ± 17° [95% CI -65 to 37]; p = 0.03 and -8 ± 4° [95% CI -17 to 1]; p = 0.048, respectively). The fifth metatarsal's pressure slightly decreased as the TIA shifted into valgus (-18 ± 12 kPa [95% CI -51 to 15]) or varus (-7 ± 18 kPa [95% CI -58 to 45]; p = 0.002). All comparisons were made to the neutral condition.ConclusionsIn this cadaver study, coronal plane malalignment in TAA altered foot kinematics and plantar pressure. In general, varus TAA malalignment led to varus shift and internal rotation of the tibiotalar joint, a slight increase in the tibiotalar ROM, and a slight decrease in the first metatarsophalangeal ROM, while a valgus TAA malalignment was manifested primarily through increased hallux pressure with a slight off-loading of the third and fourth metatarsals.Clinical relevanceThis study may increase our understanding of the biomechanical processes that underlie the unfavorable clinical outcomes (such as, poor patient-reported outcomes or implant loosening) that have been associated with coronal plane malalignment of the tibial component in TAA.

Project description:OBJECTIVE:To determine whether tibial neurolysis performed as a surgical intervention for patients with diabetic neuropathy and superimposed tibial nerve compression in the prevention of the diabetic foot is cost-effective when compared with the current prevention programme. DESIGN:A baseline analysis was built on a 5-year model to determine the cumulative incidence of foot ulcers and amputations with each strategy. Subsequently, a cost-effectiveness analysis and cohort-level Markov simulations were conducted with a model composed of 20 6-month cycles. A sensitivity analysis was also performed. SETTING:A Markov model was used to simulate the effects of standard prevention compared with tibial neurolysis on the long-term costs associated with foot ulcers and amputations. This model included eight health states. PARTICIPANTS:Each cohort includes simulated patients with diabetic neuropathy at different levels of risk of developing foot ulcers and amputations. PRIMARY AND SECONDARY OUTCOME MEASURES:The primary outcome was the long-term trends concerning the development of ulcers and amputations with each strategy. The secondary outcome measures were quality adjusted life years (QALYs), incremental cost-effectiveness and net monetary benefits of the optimal strategy. RESULTS:When compared with standard prevention, for a patient population of 10 000, surgery prevented a simulated total of 1447 ulcers and 409 amputations over a period of 5 years. In a subsequent analysis that consisted of 20 6-month cycles (10 years), the incremental cost of tibial neurolysis compared with current prevention was $12 772.28; the incremental effectiveness was 0.41 QALYs and the incremental cost-effectiveness ratio was $31?330.78. Survival was 73% for those receiving medical prevention compared with 95% for those undergoing surgery. CONCLUSION:These results suggest that among patients with diabetic neuropathy and superimposed nerve compression, surgery is more effective at preventing serious comorbidities and is associated with a higher survival over time. It also generated greater long-term economic benefits.

Dataset Information

Energy cost of ambulation in trans-tibial amputees using a dynamic-response foot with hydraulic versus rigid 'ankle': insights from body centre of mass dynamics.

Publications

Energy cost of ambulation in trans-tibial amputees using a dynamic-response foot with hydraulic versus rigid 'ankle': insights from body centre of mass dynamics.

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