Walking ability of individuals fitted with transfemoral bone-anchored prostheses: A comparative study of gait parameters

OBJECTIVE

This study presents the walking abilities of participants fitted with transfemoral bone-anchored prostheses using a total of 14 gait parameters.

DESIGN

Two-centre retrospective cross-sectional comparative study.

SETTING

Research facilities equipped with tridimensional motion capture systems.

PARTICIPANTS

Two control arms included eight able-bodied participants arm (54 ± 9 years, 1.75 ± 0.07 m, 76 ± 7 kg) and nine participants fitted with transfemoral socket-suspended prostheses arm (59 ± 9 years, 1.73 ± 0.07 m, 80 ± 16 kg). The intervention arm included nine participants fitted with transfemoral bone-anchored prostheses arm (51 ± 13 years, 1.78 ± 0.09 m, 87.3 ± 16.1 kg).

INTERVENTION

Fitting of transfemoral bone-anchored prostheses.

MAIN MEASURES

Comparisons were performed for two spatio-temporal, three spatial and nine temporal gait parameters.

RESULTS

The cadence and speed of walking were 107 ± 6 steps/min and 1.23 ± 0.19 m/s for the able-bodied participants arm, 88 ± 7 steps/min and 0.87 ± 0.17 m/s for the socket-suspended prosthesis arm, and 96 ± 6 steps/min and 1.03 ± 0.17 m/s for bone-anchored prosthesis arm, respectively. Able-bodied participants and bone-anchored prosthesis arms were comparable in age, height, and body mass index as well as cadence and speed of walking, but the able-bodied participant arm showed a swing phase 31% shorter. Bone-anchored and socket-suspended prostheses arms were comparable for age, height, mass, and body mass index as well as cadence and speed of walking, but the bone-anchored prosthesis arm showed a step width and duration of double support in seconds 65% and 41% shorter, respectively.

CONCLUSIONS

Bone-anchored and socket-suspended prostheses restored equally well the gait parameters at a self-selected speed. This benchmark data provides new insights into the walking ability of individuals using transfemoral bionics bone-anchored prostheses.

Trends and Opportunities in Health Economic Evaluations of Prosthetic Care Innovations

Overcoming obstacles to prosthetic fittings requires frequent tryouts of sockets and components. Repetitions of interventions are upsetting for users and place substantial economic burden on healthcare systems. Encouraging prosthetic care innovations capable of alleviating clinical and financial shortcomings of socket-based solutions is essential. Nonetheless, evidence of socio-economic benefits of an innovation are required to facilitate access to markets. Unfortunately, complex decisions must be made when allocating resources toward the most relevant health economic evaluation (HEE) at a given stage of development of an innovation. This paper first, aimed to show the importance and challenges of HEEs of intervention facilitating prosthetic fittings. Next, the main trends in HEEs at various phases of product development and clinical acceptance of prosthetic care innovations were outlined. Then, opportunities for a basic framework of a preliminary cost-utility analysis (CUA) during the mid-stage of development of prosthetic care innovations were highlighted. To do this, fundamental and applied health economic literature and prosthetic-specific publications were reviewed to extract and analyse the trends in HEEs of new medical and prosthetic technologies, respectively. The findings show there is consensus around the weaknesses of full CUAs (e.g., lack of timeliness, resource-intensive) and strengths of preliminary CUAs (e.g., identify evidence gaps, educate design of full CUA, fast-track approval). However, several obstacles must be overcome before preliminary CUA of prosthetic care innovations will be routinely carried out. Disparities of methods and constructs of usual preliminary CUA are barriers that could be alleviated by a more standardized framework. The paper concludes by identifying that there are opportunities for the development of a basic framework of preliminary CUA of prosthetic care innovations. Ultimately, the collaborative design of a framework could simplify selection of the methods, standardise outcomes, ease comparisons between innovations and streamline pathways for adoption. This might facilitate access to economical solutions that could improve the life of individuals suffering from limb loss.

A Preliminary Cost-Utility Analysis of the Prosthetic Care Innovations: Basic Framework

A preliminary cost-utility analysis (CUA) of prosthetic care innovations can provide timely information during the early stage of product development and clinical usage. Concepts of preliminary CUAs are emerging. However, several obstacles must be overcome before these analyses are performed routinely. Disparities of methods and high uncertainty make the outcomes of usual preliminary CUAs challenging to interpret, appraise and share. These shortcomings create opportunities for a basic framework of preliminary CUAs. First, I introduced a basic framework of a preliminary CUA built around a series of constructs and hands-on recommendations. Then, I appraised this framework considering the strengths and weaknesses, barriers and facilitators, and return on investment. The design of the basic framework was determined through the review of health economic and prosthetic-specific literature. A preliminary CUA comparing the costs and utilities between usual intervention and an innovation could be achieved through a 15-step iterative process focusing on feasibility, constructs, analysis, and interpretation of outcomes. This CUA provides sufficient evidence to identify knowledge gaps and improvement areas, educate about the design of subsequent full CUAs, and obtain fast-track approval from governing bodies. Like previous CUAs, the main limitations were inherent to the constructs (e.g., narrow perspective, plausible scenarios, mid-term time horizon, substantial assumptions, data mismatch, high uncertainty). Key facilitators potentially transferable across preliminary CUAs of prosthetic care innovations included choosing abided constructs, capitalizing on prior schedules of expenses, and benchmarking baseline or incremental utilities. This new approach with preliminary CUA can simplify the selection of methods, standardize outcomes, ease comparisons between innovations, and streamline pathways for adoption. Further collegial efforts toward validating standard preliminary CUAs will facilitate access to economic prosthetic care innovations, improving the lives of individuals suffering from limb loss worldwide.

Health Service Delivery and Economic Evaluation of Limb Lower Bone-Anchored Prostheses: A Summary of the Queensland Artificial Limb Service's Experience

The emergence of skeletal prosthetic attachments leaves governmental organizations facing the challenge of implementing equitable policies that support the provision of bone-anchored prostheses (BAPs). In 2013, the Queensland Artificial Limb Service (QALS) started a five-year research project focusing on health service delivery and economic evaluation of BAPs. This paper reflects on the QALS experience, particularly the lessons learned. QALS' jurisdiction and drivers are presented first, followed by the impact of outcomes, barriers, and facilitators, as well as future developments of this work. The 21 publications produced during this project (e.g., reimbursement policy, role of prosthetists, continuous improvement procedure, quality of life, preliminary cost-utilities) were summarized. Literature on past, current, and upcoming developments of BAP was reviewed to discuss the practical implications of this work. A primary outcome of this project was a policy developed by QALS supporting up to 22 h of labor for the provision of BAP care. The indicative incremental cost-utility ratio for transfemoral and transtibial BAPs was approximately AUD$17,000 and AUD$12,000, respectively, per quality-adjusted life-year compared to socket prostheses. This project was challenged by 17 barriers (e.g., limited resources, inconsistency of care pathways, design of preliminary cost-utility analyses) but eased by 18 facilitators (e.g., action research plan, customized database, use of free repositories). In conclusion, we concluded that lower limb BAP might be an acceptable alternative to socket prostheses from an Australian government prosthetic care perspective. Hopefully, this work will inform promoters of prosthetic innovations committed to making bionic solutions widely accessible to a growing population of individuals suffering from limb loss worldwide.

A Preliminary Cost-Utility Analysis of the Prosthetic Care Innovations: Case of the Keep Walking Implant

Several obstacles must be overcome before preliminary cost-utility analyses (CUA) of prosthetic care innovations can be routinely performed. The basic framework of preliminary CUAs and hands- on recommendations suggested previously might contribute to wider adoption. However, a practical application for an emerging intervention is needed to showcase the capacity of this proposed preliminary CUA framework. This study presented the outcomes of preliminary CUA of the distal weight bearing Keep Walking Implant (KWI), an emerging prosthetic care innovation that may reduce socket fittings for individuals with transfemoral amputation. The preliminary CUAs compared the provision of prosthetic care without (usual intervention) and with the KWI (new intervention) using a 15-step iterative process focused on feasibility, constructs, analysis, and interpretations of outcomes from an Australia government prosthetic care perspective over a six-year time horizon. Baseline and incremental costs were extracted from schedules of allowable expenses. Baseline utilities were extracted from a study and converted into quality-adjusted life-year (QALY). Incremental utilities were calculated based on sensible gains of QALY from baselines. The provision of the prosthetic care with the KWI could generate an indicative incremental cost-utility ratio (ICUR) of -$36,890 per QALY, which was $76,890 per QALY below willingness-to-pay threshold, provided that the KWI reduces costs by $17,910 while increasing utility by 0.485 QALY compared to usual interventions. This preliminary CUA provided administrators of healthcare organizations in Australia and elsewhere with prerequisite evidence justifying further access to market and clinical introduction of the KWI. Altogether, this work suggests that the basic framework of the preliminary CUA of a prosthetic care innovation proposed previously is feasible and informative when a series of assumptions are carefully considered. This study further confirms that preliminary CUAs prosthetic care interventions might be a relevant alternative to full CUA for other medical treatments.

Investigation of Localized Skin Temperature Distribution Across the Transtibial Residual Limb

BACKGROUND

Interventions to resolve thermal discomfort as a common complaint in amputees are usually chosen based on the residual limb skin temperature while wearing prosthesis; whereas, less attention has been paid to residual limb skin temperature while outside of the prosthesis. The objective of this study was to explore the localized and regional skin temperature over the transtibial residual limb (TRL) while outside of the prosthesis.

METHODOLOGY

Eight unilateral transtibial adults with traumatic amputation were enrolled in this cross-sectional study. Participants sat to remove their prostheses and rested for 30 minutes. Twelve sites were marked circumferentially in four columns (anterolateral, anteromedial, posteromedial, and posterolateral) and longitudinally in three rows (proximal, middle, and distal) over the residual limb and used for attachment of analog thermistors. Skin temperature was recorded and compared for 11 minutes. Furthermore, the relationship of skin temperature with participants' demographic and clinical characteristics was explored.

FINDINGS

The whole temperature of the TRL was 27.73 (SD=0.83)°C. There was a significant difference in skin temperature between anterior and posterior columns. Likewise, the distal row was significantly different from the proximal and middle rows. The mean temperature at the middle and distal zones of the anteromedial column had the highest and lowest skin temperatures (29.8 and 26.3°C, p<0.05), respectively. The mean temperature of the whole TRL had no significant relationships (p>0.05) with participants' demographic and clinical characteristics.

CONCLUSIONS

An unequal distribution of temperature over the TRL was found with significantly higher and lower temperatures at its anterior column and distal row, respectively. This temperature pattern should be considered for thermoregulation strategies. Further investigation of the residual limb temperature with and without prosthesis, while considering muscles thickness and blood perfusion rate is warranted.

Design for Transtibial Modifiable Socket for Immediate Postoperative Prosthesis

Amputations are long-standing surgical procedures that have been performed for centuries; however, very little attention and urgency have been given to immediate restoration of movement and return to a normal lifestyle. In many cases, the time between amputation and prosthetic fitting can pause recovery and development of new routines. To increase recovery, immediate postoperative prostheses (IPOPs) have been developed yet these are under-utilized because of concerns for wound healing and complications with vascular diseases. Subsequently, we designed a transtibial IPOP that utilizes an ergonomic modifiable socket that allows for examination, wound care, and in situ edema control. Additionally, the IPOP facilitates early weight bearing and protects the amputated limb from external trauma postoperatively. Our purpose is to introduce this technology and describe how its unique design will serve to provide potential benefits and positive effects on patients who have undergone amputations.