Load characteristics following transfemoral amputation in individuals fitted with bone-anchored prostheses: a scoping review protocol

Reliable in vitro method for the evaluation of the primary stability and load transfer of transfemoral prostheses for osseointegrated implantation

Osseointegrated transfemoral prostheses experience aseptic complications with an incidence between 3% and 30%. The main aseptic risks are implant loosening, adverse bone remodeling, and post-operative periprosthetic fractures. Implant loosening can either be due to a lack of initial (primary) stability of the implant, which hinders bone ingrowth and therefore prevents secondary stability, or, in the long-term, to the progressive resorption of the periprosthetic bone. Post-operative periprosthetic fractures are most often caused by stress concentrations. A method to simultaneously evaluate the primary stability and the load transfer is currently missing. Furthermore, the measurement errors are seldom reported in the literature. In this study a method to reliably quantify the bone implant interaction of osseointegrated transfemoral prostheses in terms of primary stability and load transfer was developed, and its precision was quantified. Micromotions between the prosthesis and the host bone and the strains on the cortical bone were measured on five human cadaveric femurs with a typical commercial osseointegrated implant. To detect the primary stability of the implant and the load transfer, cyclic loads were applied, simulating the peak load during gait. Digital Image Correlation was used to measure displacements and bone strains simultaneously throughout the test. Permanent migrations and inducible micromotions were measured (three translations and three rotations), while, on the same specimen, the full-field strain distribution on the bone surface was measured. The repeatability tests showed that the devised method had an intra-specimen variability smaller than 6 μm for the translation, 0.02 degrees for the rotations, and smaller than 60 microstrain for the strain distribution. The inter-specimen variability was larger than the intra-specimen variability due to the natural differences between femurs. Altogether, the measurement uncertainties (intrinsic measurement errors, intra-specimen repeatability and inter-specimen variability) were smaller than critical levels of biomarkers for adverse remodelling and aseptic loosening, thus allowing to discriminate between stable and unstable implants, and to detect critical strain magnitudes in the host bone. In conclusion, this work showed that it is possible to measure the primary stability and the load transfer of an osseointegrated transfemoral prosthesis in a reliable way using a combination of mechanical testing and DIC.

Loading characteristics data applied on osseointegrated implant by transfemoral bone-anchored prostheses fitted with state-of-the-art components during daily activities

The data in this paper are related to the research article entitled "Load applied on osseointegrated implant by transfemoral bone-anchored prostheses fitted with state-of-the-art prosthetic components" (Frossard et al. Clinical Biomechanics, 89 (2021) 105457. DOI: 10.1016/j.clinbiomech.2021.105457). This article contains the overall and individual loading characteristics applied on transfemoral press-fit osseointegrated implant generated by bone-anchored prostheses fitted with state-of-the-art components during daily activities (i.e., microprocessor-controlled Rheo Knee XC knee, energy-storing-and-returning Pro-Flex XC or LP feet (ÖSSUR, Iceland)). Confounders of the loads are presented. The load profiles are characterized by the loading patterns, loading boundaries and loading local extrema of the forces and moments applied during straight-level walking, ascending and descending ramp and stairs at self-selected comfortable pace. The confounders of the loading information as well as new insights into inter-participants variability of loading patterns, loading boundaries and loading local extrema can inform the design of subsequent cross-sectional and longitudinal studies as well as literature reviews and meta-analyzes. The loading datasets are critical to clinicians and engineers designing finite element models of osseointegrated implants (e.g., medullar and percutaneous parts) and prosthetic components, algorithms capable to recognize the loading patterns applied on a residuum during daily activities, as well as clinical trials assessing the effects of particular prosthetic care interventions. Altogether, these datasets provide promoters of prosthetic care innovations with valuable insights informing the prescription of advanced prosthetic components to the growing population of individuals suffering from lower limb loss choosing bionics solutions. Online repository contains the files: https://data.mendeley.com/datasets/gmsyv97cpc/1.

Kinetics of Lower Limb Prosthesis: Automated Detection of Vertical Loading Rate

Vertical loading rate could be associated with residuum and whole body injuries affecting individuals fitted with transtibial prostheses. The objective of this study was to outline one out of five automated methods of extraction of vertical loading rate that stacked up the best against manual detection, which is considered the gold standard during pseudo-prosthetic gait. The load applied on the long axis of the leg of three males was recorded using a transducer fitted between a prosthetic foot and physiotherapy boot while walking on a treadmill for circa 30 min. The automated method of extraction of vertical loading rate, combining the lowest absolute average and range of 95% CI difference compared to the manual method, was deemed the most accurate and precise. The average slope of the loading rate detected manually over 150 strides was 5.56 ± 1.33 kN/s, while the other slopes ranged from 4.43 ± 0.98 kN/s to 6.52 ± 1.64 kN/s depending on the automated detection method. An original method proposed here, relying on progressive loading gradient-based automated extraction, produced the closest results (6%) to manual selection. This work contributes to continuous efforts made by providers of prosthetic and rehabilitation care to generate evidence informing reflective clinical decision-making.

Loading characteristics data applied on osseointegrated implant by transfemoral bone-anchored prostheses fitted with basic components during daily activities

The data in this paper are related to the research articles entitled “Kinetics of transfemoral amputees with osseointegrated fixation performing common activities of daily living” (Lee et al., Clinical Biomechanics, 2007.22(6). p. 665–673) and “Magnitude and variability of loading on the osseointegrated implant of transfemoral amputees during walking” (Lee et al., Med Eng Phys, 2008.30(7). p. 825–833). This article contains the overall and individual loading characteristics applied on screw-type osseointegrated implant generated by transfemoral bone-anchored prostheses fitted with basic components during daily activities at self-selected comfortable pace. Overall and individual data was presented for the (A) spatio-temporal characteristics, (B) loading patterns, (C) loading boundaries and (D) the loading local extremum during level walking, ascending and descending ramp and stairs. Inter-participant variability of these new datasets with basic components is critical to improve the efficacy and safety of prosthetic components as well as the design of future automated algorithms and clinical trials. Online repository contains the files: https://data.mendeley.com/datasets/hh8rjjh73w/1.

Automated characterization of anthropomorphicity of prosthetic feet fitted to bone-anchored transtibial prosthesis

OBJECTIVE

This study describes differentiating prosthetic feet designs fitted to bone-anchored transtibial prostheses based on an automated characterization of ankle stiffness profile relying on direct loading measurements. The objectives were (A) to present a process characterizing stiffness using innovative macro, meso and micro analyses, (B) to present stiffness profiles for feet with and without anthropomorphic designs, where anthropomorphicity is defined as a similarity of the moment-angle dependency in prosthetic and in the anatomical ankle, (C) to determine sensitivity of characterization.

METHODS

Three participants walked consecutively with two instrumented bone-anchored prostheses including their own prosthetic feet and Free-Flow foot meeting the anthropomorphicity criterion by design. Angle of dorsiflexion was extracted from video footage. Bending moment was recorded using multi-axis transducer attached to osseointegrated fixation. The automated characterization of stiffness involved a 12-step process relying on data-based criterion.

RESULTS

The meso analyses confirmed bilinear behavior of moment-angle curves with Index of Anthropomorphicity of -2.966±2.369 Nm/Deg and 2.681±1.089 Nm/Deg indicating a convex and concave shape of usual and Free-Flow feet without and with anthropomorphic designs, respectively.

CONCLUSIONS

The proposed straightforward meso analysis of the stiffness was capable to report clinical meaningful differences sensitive to feet's anthropomorphicity. Results confirmed the benefits for clinicians to rely on direct loading measurement providing individualized complementary insight into impact of components.

SIGNIFICANCE

This work could assist the developments of standards and guidelines for manufacturing and safe fitting of components to growing population requiring transtibial prostheses with socket or direct skeletal attachment worldwide.