A review of user needs to drive the development of lower limb prostheses

Abstract

Background: The development of bionic legs has seen substantial improvements in the past years but people with lower-limb amputation still suffer from impairments in mobility (e.g., altered balance and gait control) due to significant limitations of the contemporary prostheses. Approaching the problem from a human-centered perspective by focusing on user-specific needs can allow identifying critical improvements that can increase the quality of life. While there are several reviews of user needs regarding upper limb prostheses, a comprehensive summary of such needs for those affected by lower limb loss does not exist.

Methods: We have conducted a systematic review of the literature to extract important needs of the users of lower-limb prostheses. The review included 56 articles in which a need (desire, wish) was reported explicitly by the recruited people with lower limb amputation (N = 8149).

Results: An exhaustive list of user needs was collected and subdivided into functional, psychological, cognitive, ergonomics, and other domain. Where appropriate, we have also briefly discussed the developments in prosthetic devices that are related to or could have an impact on those needs. In summary, the users would like to lead an independent life and reintegrate into society by coming back to work and participating in social and leisure activities. Efficient, versatile, and stable gait, but also support to other activities (e.g., sit to stand), contribute to safety and confidence, while appearance and comfort are important for the body image. However, the relation between specific needs, objective measures of performance, and overall satisfaction and quality of life is still an open question.

Conclusions: Identifying user needs is a critical step for the development of new generation lower limb prostheses that aim to improve the quality of life of their users. However, this is not a simple task, as the needs interact with each other and depend on multiple factors (e.g., mobility level, age, gender), while evolving in time with the use of the device. Hence, novel assessment methods are required that can evaluate the impact of the system from a holistic perspective, capturing objective outcomes but also overall user experience and satisfaction in the relevant environment (daily life).

Keywords: Lower limb prosthetics; Prosthesis requirements; User needs; User-centered design.

Fig. 1

Flowchart of inclusion and exclusion of articles during the systematic search process

Fig. 2

Demographics of the participant sample included in this review. Left: Distribution of unilateral, bilateral, or other amputations. Middle: Distribution of male and female participants. Right: Distribution of above-knee, below-knee, and other amputations

Fig. 3

Left: Distribution of the causes of amputation. Right: Age distribution (mean ± standard deviation) in 35 papers from which it was possible to retrieve the age, and the weighted average for the whole sample, weighted by the number of participants in each study

Fig. 4

Word cloud of identified user needs. The larger the words, the more often the specific need was mentioned in the literature. The words with an outline represent the most commonly expressed user needs

Fig. 5

Map of intrinsically related needs of lower-limb prosthesis users. Individual functional (top, green), psycho-cognitive (right, yellow), ergonomic (left, pink), and other needs (bottom, blue) are connected using solid black lines to denote the intrinsic relationship between the user needs, as expressed in the literature. The number on each line refers to the reference that established the relationship. For example, the needs e1 (good comfort) and e7 (good thermo-regulation/less sweating) have been connected through the reference [89] as the authors indicated that more than 53% of the prosthetic users are expressing discomfort due to excessive socket heat or sweating