Abstract
Clinical relevance
A greater understanding of users’ perceptions of their prostheses is needed to help prioritise upper limb prosthetic design features and to improve usage of, and user satisfaction with, upper limb appendages.
Introduction
Acquired limb loss and congenital limb deficiency are profound and life-altering experiences for individuals (due to the complexity of issues surrounding prosthesis use in children and adolescents, the focus of this review will be on adult upper limb prosthesis users). For upper limb loss in particular, the combined reduction in function and cosmetic appearance, alongside the inability to easily hide the amputated hand or arm out of sight can result in a traumatic experience. 1 The human hand provides us with the complex functions of gripping power, dexterity and sensory feedback. At the same time it provides us with the ability to express ourselves through gesticulation and physical contact with others. Over the past decade or so, calls have been made for upper limb prostheses which are both cosmetically appropriate and functional in design,2-4 and for greater user involvement in the design process. 5 With this in mind, this review paper aims to explore our current understanding of users’ perceptions of the constructs of both cosmesis and function of upper limb prostheses.
The call for upper limb prostheses that are both cosmetic and functional has already been stated in the literature on product design. 6 These authors note that ‘movement is an essential part of cosmesis’, and yet, until recently, upper limb appendages have been typically either cosmetic or functional. Recent technological developments within the field of externally controlled prosthetic hands are moving toward devices that are both functional and cosmetic, including the i-Limb hand (by TouchBionics) and bebionic hand (by RSLSteeper). While these developments are designed alongside user preferences, it is commonly presumed by some experts within the field of prosthetics that the more lifelike in shape and colour a limb is, the more cosmetically acceptable it will be to amputees. 7 Aside from knowing that both cosmesis and function are considered important, what users themselves understand by ‘cosmetic’ or ‘functional’ is less clear. Moreover, the role of functionality and movement of prostheses as part of cosmesis warrants further investigation. a
The importance of users’ perceptions is made apparent in the literature on prosthetic use and abandonment. Recent research by Biddiss and Chau,5,8 for example, estimates that approximately 20% of upper limb users do not use their prostheses. The reasons for abandonment include a range of factors, being particularly affected by the cause and level of limb absence and the gender of users. The level of comfort, functionality and appearance of the devices used were also factors involved in prosthesis abandonment. Biddis and Chau’s extensive review of the literature 5 achieved much in terms of mapping out the extent of upper limb prosthesis use and abandonment over the past 25 years, though the authors note that further work is needed on consumer satisfaction to bridge the gap between product design and daily use. Specifically, they note that ‘previous studies may not have captured changes in consumer views brought about by social and technological developments’. 5 Prosthesis abandonment, therefore, is an ongoing concern, and a greater understanding of how users’ needs are met by advances in prosthetic design is likely to be helpful in reducing device abandonment in the future.
In contrast to research on device abandonment, a body of literature is available which documents actual use of upper limb prostheses. This includes important work by Lindner and colleagues, 9 who have reviewed and analysed outcome measures in upper limb prosthesis users. This work highlights those measures which provide reliable data on the functionality of devices, though they note that some aspects of prosthetic use (such as social interaction and body image, particularly for paediatric users) are less widely covered. Other studies which examine the use of upper limb prostheses include work by Fraser, 10 who video-recorded users in their own homes performing three everyday tasks. The aim of this research was to assess the extent to which individuals used their prosthetic devices for these tasks. Other research on the use (or abandonment) of upper limb prostheses includes work in Sweden 11 and Slovenia. 12
The development of upper limb prostheses that are both cosmetically acceptable and functional is now underway and research reviewing the use and abandonment of upper limb prostheses is also well established. What is less clearly understood are users’ perceptions, meanings of, and experiences of their upper limb prostheses in terms of cosmesis and function. The role of psychology is highly relevant here, and the work of the Trinity Psychoprosthetics Group in Dublin has achieved much in terms of establishing the benefits of psychological input, though more work is still required. 1 For instance, while the Trinity Group is at the forefront of developing psychological tools for prosthetic research and practice, the range of methodologies currently being used to explore users’ perceptions is limited. The aim of this systematic review is to consolidate our current understanding of adult upper limb prosthesis users’ perceptions of cosmesis and function in prostheses.
Methods
Search strategy
A comprehensive literature search was undertaken in July 2010. Searches for scientific publications were performed in the following databases: CINAHL, Cochrane Library, Medline and PsychInfo. Combinations and variations of the following keywords were included (though not limited to): prosthesis, amputation, upper limb, lower limb, cosmetic, satisfaction, attitudes, body image, adjustment, adaptation, function, movement, strength, grip and outcome. The term ‘lower limb’ was also initially included in the search so that papers which commented on both upper and lower limb prosthetics could be included in the review. Search terms for both quantitative and qualitative methods were also included for completeness. All English language scientific publications from January 1990 to July 2010 were considered. It was decided that publications prior to 1990 would not be applicable due to the advances in prosthetic hardware and standard cosmetic coverings made in the last 20 years.
The inclusion criteria are: studies of adult (over 18 years of age), upper limb prosthetic users which must consider both cosmesis and function, and users’ perceptions of cosmesis and function. Following a discussion between all authors, these criteria were selected to provide a clear and applicable focus for the review.
Search outcome and quality appraisal
Overall, 602 papers were retrieved using the above search method. Due to the broad spectrum of associated search terms used, a large number of inappropriate research papers were found. All abstracts identified from the search strategy were reviewed in relation to the inclusion criteria. Where appropriate, the paper was read in full to determine suitability. Subsequently 587 papers were excluded. Papers were excluded on the basis of not meeting the above criteria or, for example, including a single sentence which referred to user satisfaction rates. Many of the original 602 papers met only one or two of the above criteria. The 15 remaining papers were read in full and searched for related themes and findings. With so few papers meeting the inclusion criteria, no papers were excluded in respect of quality. The papers were, however, noted to be widely cited by other research in this field, and thus their inclusion represents the state of the field in this area at present. This issue will be discussed in more detail later in the review.
The first author conducted the initial complete search of the literature using the aforementioned databases and search terms. From this, a number of papers were identified according to the inclusion criteria. The second author then reviewed the included and excluded papers, including a check of cited literature, and concurred with the first author’s selection. All authors contributed to the writing of the review.
Findings
Fifteen papers focused on adult user’s perceptions of upper limb prosthetic cosmesis and function over the past 20 years (see Table 1 for a summary).
Summary of reviewed papers.
The majority of the papers (12) used questionnaires to collect data from participants, either by post or using online tools. Only three of the papers used other methods: semi-structured interviews13,14 and case studies. 15 Five of the papers examined both adults and children,16-20 six focused only on adults.13–15,21,22 The remaining four studies did not specify the age range, though in most cases it is likely that they referred only to adults.24-27 Where possible, themes were extracted from these four studies which related to adult prosthetic users only.
Upper limb amputees in the UK tend to be young males amputated due to traumatic injury but who are otherwise in good health. 28 This pattern was also noted in the reviewed papers, although these studies are based on samples from a range of countries and in which recruitment of sample groups varied. Specifically, the reviewed studies noted traumatic accidents as accounting for between 81% 16 and 70% 18 of upper limb amputation in body-powered users or 61.9% in all users. 25 Amputation at transradial level was also the most common location of absence,16,17,19,20,22,23,27 though two papers reported a greater incidence of transhumeral amputation, at 45% above elbow 21 and 71% above elbow. 25
The use of different prosthetic devices varied across the papers, though most of the studies surveyed users of body-powered, myoelectric and/or cosmetic devices. Rates of use for each of these devices varied, though body-powered was the most common upper limb device overall. Although all papers focused on both perceptions of cosmesis and function, the predominant focus was on function and particularly on users’ satisfaction and needs with regard to particular characteristics of the prostheses, such as weight, fit and comfort.
Key themes
Two key areas were identified in the majority of the reviewed papers: (1) user satisfaction with current prostheses; and (2) priorities for future development of prostheses. In addition, a further theme was identified in the three qualitative studies: (3) social implications of wearing prostheses.
1. User satisfaction with current prostheses
A key question for most of the studies was ‘how satisfied are you with your prosthesis?’ and this was frequently answered by considering users’ satisfaction of a specific function or characteristic of the prosthetic device. A notable example was the study conducted in the USA by Atkins et al., 16 which is arguably one of the largest reviews of upper limb amputees published to date. Over 1,020 body-powered users, 438 externally-powered users and 117 bilateral users of upper limb prostheses were surveyed. No cosmetic limb users were included. Satisfaction ratings included assessment of economic cost: of those adults using electric devices, 22% felt that they were too expensive, whereas 15% of the body-powered adult users rated their devices as too expensive. The cost of repairs and the frequency of maintenance was also an issue with over a third of body-powered users rating these devices as needing the most frequent repairs, though differences in health provision across the USA was not discussed in the paper.
Users’ satisfaction ratings in other studies varied considerably. Both Datta et al. 24 (where around two thirds wore cosmetic devices) and Nielsen 23 report satisfaction ratings of 77%; though it is difficult to relate their findings as the percentage of participants using cosmetic prostheses included in the Nielsen study is not known. In comparison, Dudkiewicz et al. 25 (where cosmetic users accounted for around three quarters of the sample) observed ratings as low as 55%, Davidson 18 found satisfaction ratings of 24% (though again, the percentage of different prosthetic devices is not known in this study).
In terms of functional ability, upper limb users have been found to be most dissatisfied with their ability to use their prostheses for food preparation and consumption, dressing and DIY tasks, 18 problems with heat and sweating,18,19,25,27 problems with the weight of the prostheses,19,22,25 and lack of comfort.18,27 These ratings were from users with either cosmetic or functional prostheses.
The variation in satisfaction ratings appears to be due, in part, to the types of devices used, which is linked, in turn, to the level of amputation and to the working conditions of the individual. For instance, Biddiss et al.’s 17 online survey noted that adult users with above-elbow amputations were more likely to choose a body-powered hook over an electric hand. Kejlaa’s study 19 noted that workers involved in heavy industry employment most often used body-powered devices, office workers or those in education used electric devices, and those in light work or who were retired used cosmetic devices. 19 Similarly, other studies suggest an association between satisfaction rates and usage rates. For example, Davidson’s study 18 noted a moderate (0.66 correlation) association between those who had a lower rate of using their prostheses, and those who reported being dissatisfied overall with their prostheses. In other studies, those using cosmetic devices gave a higher satisfaction rate with their prostheses, either overall or in terms of appearance.24,25 Pylatiuk et al.’s study of myoelectric users found that 50% of women and 58% of men were ‘less’ or ‘not’ content with the cosmetic appearance of their prostheses. 20 Again, though, there is inconsistency in the findings, Kejlaa 19 found that those using cosmetic devices identified the most problems with their prostheses.
Cultural or social variations in the use and satisfaction of prosthetic devices have also been noted. For example, Biddiss et al. note that a higher proportion of body-powered hooks are used in the USA than in Canada or the Netherlands. 17 This is also noted in the Atkins et al. USA study, 16 which reported two thirds of respondents using a body-powered hook to one third using an electric hand. In Europe, there appears to be a higher incidence of the use of cosmetic or electric devices, though again there is no clear pattern. Such cultural variations may be due, in part, to differential health resources. For example, cost and availability of devices within each country or region is likely to differ, though this information is not discussed in detail in either of these studies. Gaine et al. found that users favoured cosmetic or electric devices for social outings, but there was a preference for electric devices as these were considered to combine both function and appearance. 26 Kejlaa also noted that electric devices were preferred when cosmesis was considered to be important. 19
2. Priorities for future development of prostheses
The second key feature identified in the reviewed papers was their focus on identifying users’ priorities for future design in upper limb prosthetics. The Biddiss et al. paper, 17 for example, notes that ‘electric hands spark the greatest interest for future use in both adult and pediatric populations’. They further noted that, ‘Users of body-powered hooks and electric hands value function and comfort most highly, while users of passive hands ranked appearance and comfort at the forefront’. This pattern is reported in other studies. For instance, in a study where most individuals used electric devices, Gaine et al. concluded that the main priority was to improve function rather than cosmesis. 26 Similarly, Schaffalitzky et al.’s case study approach, including two upper limb amputees, found that both used body-powered devices and both favoured function over cosmesis. 15
Other studies, however, report different conclusions. Kyberd et al.’s UK study 27 – where 60% of users had body-powered devices and only 24% cosmetic devices – found that users prioritised cosmesis or function, with little compromise between the two factors. Similarly, Kyberd et al.’s later study in Sweden 22 also noted that both electric and cosmetic users desired an improved appearance in their prostheses. Participants in Nielsen’s 1991 study rated comfort more highly (52%), followed by function (38%), cosmesis (7%) and cost (4%). The myoelectric users in Pylatiuk et al.’s study 20 prioritised sensory aspects: emphasising the benefits of being able to feel the force of the grip of the device, and being able to detect temperature.
The findings from the Atkins et al. study 16 warrant closer attention. Participants were asked to rank order 17 items to indicate their priorities, a ranking of 1 showing top priority. Externally-powered prosthetic users gave their top rankings to the ability to use fine movement of the fingers and thumb, holding of small and large objects were ranked 5 and 7 respectively while the prosthesis looking more like a human hand was ranked 16th out of 17 items. It is interesting to speculate the preference for fine finger movement of the hand over cosmetic similarity to a human hand. Although it is easy to assume this priority is to do with increased function, the ability to grip and manipulate a range of objects is only ranked 5 and 7. If function was the only priority, then achieving these goals by any means possible would likely have been given a higher rating. Instead, however, we see a request for more anatomically correct movement of the hand to achieve this, suggesting perhaps that the appearance of movement, as well as the functional ability of movement, is as important to amputees. On the surface, this possible explanation seems to be contradicted by the ranking of the importance of having a lifelike cosmesis of the hand. It may be the case, however, that the questionnaire implies that looking like a human hand is simply a static attribute and has not considered the dynamic cosmesis of natural holistic and prosthetic movement. Despite this, however, Atkins et al concluded that priority should be given to function, rather than appearance, with little consideration of how these two constructs might be intrinsically linked.
3. Social implications of wearing a prosthesis
Of the reviewed studies, only three used methods other than questionnaires, and these are three of the more recent studies in the review.13-15 All three studies used interviews to examine the experience (and perceptions) of wearing an upper limb prosthesis, in contrast to previous other qualitative work which seeks to understand the experience of being an amputee more generally.29-31 A key finding from these studies was the focus placed on looking ‘normal’ and of ‘fitting in’ with others in various social settings. Whether prostheses were perceived as functional or cosmetic was understood in terms of how it allowed the user to act out what Murray terms ‘corporeal rules’. 13 For example, being able to eat with a knife and fork, was understood not simply as a functional ability but as a social ability; to be able to eat as an adult without having to ask others to help cut up the food.
Participants in these three studies noted the importance of impression management, of how the prosthesis could be used to manage the user’s self-image and how they were perceived by others. From Saradjian et al.’s study, 14 for example, it was found that when considering participants’ awareness of their physical bodily difference, a change in self-image was closely entwined with the perceived reactions of others. Participants also reported that the use of prostheses helped them to conceal their differences, as they present a more ‘normal’ appearance than they would without the prosthesis, and therefore moderated other people’s reactions. A particularly interesting finding of the study was that participants were aware of the need to alter their body posture, and realised that they had to learn how to ‘carry’ the prosthetic limb. The discussion of successful adjustment to prosthetic use was therefore equated to that of facilitating a normal appearance. In turn, this highlights the possibility that cosmesis stretches beyond the static form of a prosthesis into the cosmesis of both prosthetic and integrated holistic body movement.
The complexity and combined dependence of function and cosmesis, to each other and in relation to psychosocial meaning of wearing an upper limb prosthesis, has been explored further by work by Schaffalitzky et al. 15 This study reported on the interviews of two upper limb amputees using the repertory grid technique 32 in order to explore individual values and preferences regarding their prosthesis. In both of these interviews, however, and in line with previous other research, the constructs of cosmesis and function are dealt with separately. What is particularly interesting are the conclusions drawn about one of the participants which show that while cosmesis was deemed to be ‘unimportant’ to the patient, the two most important constructs for the same patient where detailed as ‘functionality’ and ‘not standing out’. With no further explanation of the construct of ‘not standing out’, it could be questioned if this construct had elements of both static appearance as well as the prosthetic and holistic movement involved.
Discussion
The main conclusions drawn from the reviewed studies are a little ambiguous due to the disparity of upper limb prosthetic users reviewed, though we can note some tentative patterns. Upper limb prosthetic users with cosmetic devices appear to be mostly satisfied with the appearance of their devices, and those with electric or body-powered devices are most concerned about the heat and weight of their devices, and on improving functional ability. There appears to be an association between degree of prosthetic use and satisfaction, though at this stage it is not clear which factor influences the other. Priorities for improving the design of future prostheses are mostly concerned with function, but also with movement (such as being able to move digits independently, or with movement of the wrist). Cosmesis, it appears, is important, but not as important as functional ability.
There are, however, some issues concerning the way in which users’ perceptions of cosmesis and function are examined (i.e. the methods used), and our understanding of these terms more broadly (definitions). Limitations of the current review will also be considered. These issues will now be addressed in turn.
First, the limited range of methods used in research on users’ perceptions of upper limb prostheses is apparent from the literature review. As noted earlier, the majority of the papers reviewed used questionnaires, enabling researchers to reach a larger population of prosthesis users at any one time. The disadvantage of this method is that there is a defined limit to the level of detail that can be included in responses, and in terms of how participants’ responses are interpreted. Even demographic information can become problematic. For example, the majority of studies classified users in terms of the prosthetic device that they wore, though both studies by Kyberd and colleagues22,27 found that some users (28% of the sample in 2007) were using more than one device. Hence, making interpretations as to user’s perceptions, use or circumstances on the basis of (one of) their prosthetic devices may already be limiting our understanding of how these perceptions, and choices, are associated with different devices at different times and uses.
Items within these questionnaires frequently asked users to rate their perception of cosmesis and function of their prosthesis separately, with few offering the opportunity for participants to add their own additional comments (where these were included, such responses have not yet been analysed 16 ). Although the parameter of function was often broken down into the individual rating of specific tasks or isolated movements (such as ‘using a knife or fork’, or ‘movement of digits’), the parameters by which to assess cosmesis were more often left undefined. For example, a questionnaire item might be phrased, ‘are you satisfied with the appearance of your prosthetic device’, with little or no room for users to specify particular aspects of the appearance (such as the colour, shape, prosthetic/holistic movement and so on) that they were satisfied with or not. It is only in the qualitative studies that these concepts are more fully explored in terms of combining cosmesis/function, and users’ perceptions of dynamic cosmesis.
The constrained nature of closed questionnaire responses highlights the second issue: how cosmesis and function are defined. Not only was there little room for participants to specify the characteristics of their prostheses that might be considered cosmetically appropriate, but the definition of cosmesis itself across studies was not clearly defined. It became evident that the majority of the studies implied that cosmesis was a static attribute, and in some cases merely associated with the application of a cosmetic glove placed over the prosthetic hand. Many of these studies did not refer to the general static shape or prosthetic movement of the components. Moreover, there was no reference to the patient’s ability to naturally integrate with the prosthetic device, i.e. how the prosthesis moves and how this affects the holistic movement of the user. This issue was raised by participants in the Murray 13 and Saradjian studies, 14 but the matter was not taken further by the researchers themselves.
Only the study by Biddis, Beaton and Chau 17 went a step further in tackling the ambiguity surrounding the term ‘cosmesis’. This work indicated a high priority for cosmetic improvements for body-powered adult hands. A valuable aspect of this study was the inclusion of subcategories of ‘cosmesis’: such as glove durability, colour, size, appearance under clothing, and how lifelike the prosthesis was. Questions regarding the functions of grasp, dexterity and wrist movement, however, were categorised separately under ‘function’. So, in line with the other reviewed studies, cosmesis and function were treated as separate components of prosthetic use.
The potential problem of treating cosmesis and function separately has already been noted by the findings of Desmond and MacLachlan during their development of the TAPES upper measurement. 21 Among other findings, their work concluded that prosthetic satisfaction was a uni-dimensional construct where cosmesis and functional satisfaction where integral to one another. In turn, these results seem to indicate that questionnaires which attempt to assess or rank function and cosmesis of an upper limb prosthesis separately are fundamentally flawed, providing a rather limited amount of relevant information surrounding the importance of these combined properties.
Finally, limitations of the current review are considered. While every effort was made to include all papers in the current review period, only English language papers were used and therefore scientific research published in other languages has not been reviewed. It was argued that the initial search terms were deliberately broad so as to include papers that used different terms for the criteria items (this was particularly important for inclusion of work relating to cosmesis and function). This, however, resulted in a large initial sample, and a large number of subsequently excluded papers. The remaining 15 papers were not further refined for quality purposes. This is clearly a weakness in the current review, and thus a tentative approach should be made when making claims about the findings from individual papers. It was noted, however, that the 15 papers are for the most part, widely cited elsewhere in the literature, and thus to exclude any might have biased the current review.
Conclusion
Anecdotally, clinicians routinely report that the cosmetic appearance of upper limb prostheses is one of the most significant factors for amputees in their desire to appear as normal as possible. Despite this, there is limited research on the combined perceived cosmesis and function of upper limb prosthetics by users themselves. This may be due to two factors. First, the numbers of upper limb amputees are usually lower than those for lower limb amputees. In the UK, for example, approximately only 4% of new referrals to prosthetic clinics are upper limb amputees. In 2006–7, this equated to just 215 new upper limb amputees. 28 Second, definitions of the terms ‘cosmesis’ and ‘function’, in relation to prosthetic limb use, are not clear. For example, the work of Hill et al. 33 on the use of outcome measures in upper limb prosthetics, commented on the fact that the term ‘function’ could have very different applied meanings depending on the category of health professional or engineer using it. It was stated that for the occupational therapist, ‘function’ would be used to define the user’s ability to accomplish activities of daily living. It was thought, however, that prosthetists and engineers may see ‘function’ as meaning the technical performance of a device, such as hand speed or grip power. It was therefore acknowledged that without a common, well-defined terminology there was opportunity for misinterpretation of findings regarding prosthetic function. 33
In addition, even the most fundamental question of what is perceived as ‘cosmetic’ by prosthetic upper limb users is not well defined. Consequently, parameters by which to assess this attribute are unclear. For example, it is still not known if it is the static appearance of the limb, its movement, function or the combination of all of these factors that makes a prosthesis cosmetically acceptable. What is appreciated is that all these factors will be influenced by the type of prosthesis that is prescribed. Nevertheless, it is commonly accepted by practitioners that the appearance, movement and usefulness of a prosthesis will have a large bearing on patients’ satisfaction, use and acceptance or abandonment of the prosthesis, as well as impact on the psychosocial well-being and adjustment of the amputee. Further work into the relationship between functionality and cosmesis is needed to develop our understanding of these issues.
Footnotes
Acknowledgements
The authors would like to thank the two anonymous reviewers and the journal editor for their thoughtful comments and helpful suggestions on an earlier version of this paper.
Notes
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.