All articles are permanently available online to the public without restrictions or subscription fees. All articles are free to be used, cited, and distributed, on condition that appropriate acknowledgment is included. Authors are the copyright holders of their original contributions and grant the Canadian Online Publication Group (COPG) a license to publish the article and identify itself as the original publisher. CPOJ articles are licensed under the Creative Commons Attribution 4.0 International License. CPOJ Website: https://jps.library.utoronto.ca/index.php/cpoj/index Editorial Office: cpoj@online-publication.com ISSN: 2561-987X CPOJ is a member of, and subscribes to the principles of, the Committee on Publication Ethics (COPE). VOLUME 3, ISSUE 2 2020 RESEARCH ARTICLE Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 https://online-publication.com/wp/ http://creativecommons.org/licenses/by/4.0/ https://jps.library.utoronto.ca/index.php/cpoj/index mailto:cpoj@online-publication.com https://publicationethics.org/about/our-organisation https://publicationethics.org/about/our-organisation https://publicationethics.org/members/canadian-prosthetics-orthotics-journal https://doi.org/10.33137/cpoj.v3i2.34610 1 Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 RESEARCH ARTICLE USING PERFORATED LINERS TO COMBAT THE DETRIMENTAL EFFECTS OF EXCESSIVE SWEATING IN LOWER LIMB PROSTHESIS USERS Davies K.C1*, McGrath M1, Savage Z2, Stenson A2, Moser D1, Zahedi S1 1 Blatchford Group, Unit D Antura, Bond Close, Basingstoke, RG24 8PZ, UK. 2 Sheffield Mobility & Specialised Rehabilitation Centre, Northern General Hospital, Sheffield, UK. INTRODUCTION Excessive sweating at the residual limb affects the quality of life of up to 70% of people with amputation and is one of the most common complaints reported by prosthetic users.1–3 Indeed over 53% of lower limb amputees reported discomfort due to heat and/or perspiration4 while 66% felt that sweating impacted on their daily activities.5 Comparatively, only 2.9% of the general population have been medically diagnosed as suffering from excessive sweating, or “hyperhidrosis”.6 Sweating forms an effective way for reducing temperature and is an essential component of the body’s cooling process.7 When the skin is disrupted in some way, the body adapts in order to achieve the same cooling benefits and it is this adaptation that can prove problematic within prosthetics. People with lower limb amputation generally exert higher levels of energy during ambulation compared to able-bodied people. For unilateral transtibial amputees, this was around 16%,8 while with bilateral transtibial amputations, it is closer to 40%.9 Consequentially, body OPEN ACCESS Volume 3, Issue 2, Article No.1. 2020 Journal Homepage: https://jps.library.utoronto.ca/index.php/cpoj/index ABSTRACT BACKGROUND: Excessive sweating of the residual limb has a substantial effect on the daily activities of people with lower limb amputation. Prosthetic liners offer protection and comfort to sensitive areas but often exacerbate perspiration. They act as insulators, trapping sweat on the skin’s surface to the detriment of skin health. Recently, liners with perforations have been developed, allowing the moisture to escape. The goal of this study was to assess the impact of such liners. METHODS: A sample group of 13 patients with unilateral transtibial amputation, who wore a perforated liner (PL) as part of their current prescription, was compared to 20 control patients who wore non- perforated liners (NPL). During their routine appointments, they completed a survey of scientifically validated outcome measures relating to their limb health, pain and the impact on daily life over a 12- month period. RESULTS: Patients using the PL had healthier residual limbs, reporting higher scores on questions relating to limb health, experiencing fewer skin issues (p<0.001) and estimating a 61.8% lower rating in perceived sweat (p=0.004). Perhaps consequentially, there was a lower incidence of residual (p=0.012) and phantom (p=0.001) limb pain when compared to the control group. The prevalence of individual issues affecting the residual limbs of PL users was also lower. Of the issues that remained, only 23% were attributed to sweating in PL users, compared to 49% for the NPL group (p=0.066). PL users missed fewer days of work in the year (2.4 vs 11.6, p=0.267) and were also limited on fewer days (1.4 vs 75.4, p=0.009). CONCLUSION: The use of perforated liners shows much promise within prosthetic care, significantly improving the health of the residual limb. The observed effects on perceived sweat reduction, residual skin health, pain levels and patient limitation suggest that perforated liners are highly beneficial to patients. ARTICLE INFO Received: July 16, 2020 Accepted: August 29, 2020 Published: September 3, 2020 CITATION Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i 2.34610 KEYWORDS Prosthetics, Sweat, Prosthetic Liner, Perforated, Amputation, Residual limb health, Silicone liner, Amputee, Dysvascular, Temperature * CORRESPONDING AUTHOR: K.C Davies, Blatchford Group, Unit D Antura, Bond Close, Basingstoke, RG24 8PZ, UK. E-mail: katherine.davies@blatchford.co.uk ORCID: https://orcid.org/0000-0003-2933-4365 https://doi.org/10.33137/cpoj.v3i2.34610 https://jps.library.utoronto.ca/index.php/cpoj/index https://doi.org/10.33137/cpoj.v3i2.34610 https://doi.org/10.33137/cpoj.v3i2.34610 https://orcid.org/0000-0003-2933-4365 https://orcid.org/0000-0003-2933-4365 2 Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 ISSN: 2561-987X USING PERFORATED LINERS IN LOWER LIMB PROSTHESIS USERS Davies et al. 2020 CPOJ temperature rises and the body reacts accordingly. A transtibial amputation also reduces the skin’s surface area by around 10-15%,10 so in order to achieve the same cooling effect, the rate of sweat production from the remaining surface must increase proportionally. The combination of these factors means that people with amputation may produce more sweat. Prosthetic liners increase layers above the skin, offering protection and comfort to sensitive areas, but the materials are not breathable and act as insulators.11 This exacerbates the rise in temperature and traps the resultant sweat on the skin’s surface. Sustained exposure to moisture has a detrimental effect on the skin,12 leaving it more susceptible to injury. Skin disorders also become more problematic within the amputee population due to scar tissue and the high prevalence of vascular disease.13 This compromises blood flow, reducing healing capabilities and making the skin vulnerable.14,15 Renshaw found that skin previously wetted with water was more likely to blister than when it was dry.16 In addition, Hurkmans et al. found that sweat accumulation contributed towards skin irritation, perhaps even more so than infection.17 Perhaps unsurprisingly then, skin disorders are prevalent in this vulnerable population18 with wound infection rates ranging between 13-40%19 following amputation and residual limb pressure ulcers causing the majority of re-amputations.20–22 Various approaches have been trialled to improve excessive perspiration and heat,4 from the use of commercial or prescription anti-perspirants23 to more extreme options such as Botulinum Toxin injections.24,25 More prosthetic-specific solutions have also been tried and evaluated.26 Wernke et al. investigated the SmartTemp liner27 (Ohio WillowWood, Mt Sterling, OH, USA), which uses Phase Change Material in order to store and release heat energy. The liner effectively reduced the initial temperature of the residual limb and therefore the volume of sweat produced. However, these materials have a limit on the amount of cooling they provide28 and in another study29 thermally conductive silicone did not result in a significant improvement in climate control over plain silicone liners. More recently, a liner with perforations has been developed (Silcare Breathe, Blatchford, Hampshire, UK) allowing moisture to escape and keeping the residual limb dry.30 These liners reduced the prevalence of sweat remaining on the skin in all participants during trials30 and in published case studies.31 Evidence has suggested they are effective in the management of wounds and beneficial to residuum skin health, especially when used in combination with elevated vacuum.31 This study sought to determine the efficacy of perforated prosthetic liners for the purpose of sweat management, investigating what impact, if any, this made on patient outcomes. METHODOLOGY Evaluated technology This study examines the effects of a perforated liner (PL - Silcare Breathe, Blatchford Products Ltd., Hampshire, UK)I,II on patient outcome measures and residual limb health. It differs from previous silicone designs because it incorporates perforations along the length, and at the distal end, with the intention of improving skin interface microclimate control and hygiene of the residual limb (Figure 1). Figure 1: A cross-sectional image of the Silcare Breathe liner (Blatchford).I,II Moisture is transported away from the skin through perforations located along the sides and at the distal end of the liner. These perforations allow moisture produced by the body to be transported to the outside of the liner, so that it doesn’t remain on the surface of the skin. Moisture is then readily absorbed by the fabric on the outside of the liner, rather than by the silicone, so that it does not migrate back towards the skin and the liner can be more easily cleaned. Participants Suitable candidates (n=41) for the study were identified and approached by their prosthetists during routine appointments at Northern General Hospital in Sheffield. The cohort was then divided into PL users and a control group who wore conventional non-perforated liners (NPL). Participants had to have a transtibial amputation and were required to have been using their current prescription for a minimum of 12 months. All participants were established prosthesis users with a mobility level of K2 or above and were able to read and write in English, with sufficient cognitive ability. All patients provided informed, written consent. The study was approved by the Clinical Effectiveness Unit at Sheffield Teaching Hospitals. No interventional actions were taken and the ethics of the study conformed with the World Health Organisation Declaration of Helsinki.32 Data collection and measures All participants completed a survey of scientifically validated outcome measures during routine appointments. The Perforations transport moisture away from the skin Silicone liner (3.7mm mid-thickness) Material on outside of the liner absorbs moisture, preventing it from travelling back to the skin’s surface Residual limb Socket https://doi.org/10.33137/cpoj.v3i2.34610 3 Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 ISSN: 2561-987X USING PERFORATED LINERS IN LOWER LIMB PROSTHESIS USERS Davies et al. 2020 CPOJ surveys were comprised of selected sections of the Patient Evaluation Questionnaire33 (PEQ); a clinically validated patient-reported outcome measure that has been used successfully to analyse the use of prosthetic liners in previous studies.34–36 This questionnaire is organised into independent functional domain subsections,37 where the patient indicates a score out of 100 using a visual analogue scale (VAS) for each individual question. Every question relates to the previous four weeks and the overall average gives the score for the subset. For this study, the residual limb health subset was used, made up of questions about sweat inside the liner, smelliness, swelling, rashes, ingrown hairs and blisters. As well, individual PEQ questions relating to frequency, intensity and ‘bothersomeness’ of residual and phantom limb pain were included. Following PEQ scoring, lower scores indicated worse symptoms (e.g. 0 = extremely intense, 100 = extremely mild). For frequency of pain, a seven-point multiple choice format was used, rather than the visual analogue scale. These choices were “Never", "Only once or twice", "A few times (about once/week)", “Fairly often (2-3 times/week)", "Very often (4-6 times/week)", "Several times every day" and "All the time or almost all the time". In order to allow a quantifiable comparison between groups, these responses were assigned a score from 1 (least frequent) to 7 (most frequent), from which the mean and SD were calculated. In addition, questions specifically designed for this study were included in the surveys which related to the previous 12 months. These enquired about excessive sweating, number of socket adjustments required, what issues the patient experienced on their residual limb and the number of days work that had been missed or limited because of issues caused by sweating. Study group participants also filled out the survey retrospectively, with regards to their previous prescription. Due to the retrospective nature of these responses, it was thought that results might be unreliable and affected by bias. While the retrospective responses were comparable to those of the control group, the principal comparison reported in this work is between the study group’s current responses and responses from the control group. Data processing and analysis Residual limb issues were categorised into conditions and the frequency of each was recorded as a percentage of the population so that an objective comparison could be made. Participants were asked to estimate what percentage of their issues they attributed directly to sweat. This figure was then multiplied by the total number of issues each participant suffered from, to calculate the number of issues that each participant attributed to sweating. For all VAS and numerical responses, the mean and standard deviation for each outcome measure were found and used for comparisons. Data were tested for normality using the Shapiro-Wilk test. Homogeneity of variance was assessed using F tests for normal data and a Fligner-Killeen test in cases where the data were not normal. Dependent on the outcome, comparisons of means were made using t- tests, Wilcoxon tests or Kruskal-Wallis tests. For ordinal or nominal data (e.g. frequency of pain and prevalence of issues), comparisons were made using a chi-squared analysis. For all tests, p<0.05 indicated significance. RESULTS Demographics Of the overall cohort (n=41), 21 were identified as PL users. Out of these, eight patients did not use the liner consistently, or discontinued use, and were excluded. Of the remaining 13 participants, ten were male and three were female (age: 49 (SD=10) years; weight: 96 (SD=26) kg. Nine had used silicone liners in their previous prescription and four used conventional pelite liners in conjunction with a suspension sleeve; all now wore perforated silicone liners with either suction or pinlock suspension (Table 1). Table 1: Study group participant demographics. Gender Age (years) Weight (kg) Aetiology Previous prescription (suspension) Current prescription (suspension) PL01 M 57 92.5 Unknown Pelite liner and silo sheath (sleeve) Blatchford Silcare Breathe Cushion (suction) PL02 F 37 103 Infection Pelite liner and silipos sock (sleeve) Blatchford Silcare Breathe (pinlock) PL03 M 54 112 Trauma Össur liner (pinlock) Blatchford Silcare Breathe (pinlock) PL04 M 41 100.6 Trauma Blatchford liner (pinlock) Blatchford Silcare Breathe (pinlock) PL05 F 55 77 Congenital Össur liner (pinlock) Blatchford Silcare Breathe (pinlock) PL06 M 35 81.4 Infection Pelite liner (sleeve) Blatchford Silcare Breathe (pinlock) PL07 M 62 99.3 Unknown Össur liner (pinlock) Blatchford Silcare Breathe (pinlock) PL08 M 57 82.1 Vascular Össur liner (pinlock) Blatchford Silcare Breathe (pinlock) PL09 F 38 79.2 Trauma Blatchford cushioned liner (suction) Blatchford Silcare Breathe (pinlock) PL10 M 46 88.2 Trauma Alps liner (pinlock) Blatchford Silcare Breathe (pinlock) PL11 M 59 104.8 Trauma Alps liner (pinlock) Blatchford Silcare Breathe (pinlock) PL12 M 59 169.6 Vascular Pelite liner (sleeve) Blatchford Silcare Breathe Cushion (suction) PL13 M 41 62.9 Pain Management Blatchford cushioned liner (suction) Blatchford Silcare Breathe (pinlock) Mean - 49.3 96.4 - - - SD - 9.8 25.9 - - - https://doi.org/10.33137/cpoj.v3i2.34610 4 Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 ISSN: 2561-987X USING PERFORATED LINERS IN LOWER LIMB PROSTHESIS USERS Davies et al. 2020 CPOJ The control group was made up of the remaining 20 participants, 16 male and four female (age: 56 (SD=15) years; weight: 90 (SD=22) kg). All of them wore silicone prosthetic liners, using either suction or pinlock suspension, from various distributors (Table 2). Residual limb health and pain The mean residual limb health score for the PL group (75.0 (SD=22.9)) was significantly greater than that of the NPL group (58.4 (SD=22.7); p=0.046). For each of the six questions that constitute this subset, mean responses were higher for the PL group, indicating that problems were less prevalent, and that the limb was healthier. For two questions – the amount of sweat in their liner (p=0.004) and how smelly their limb was (p=0.012) – the difference in response reached statistical significance (Figure 2). Indeed, if the scale is inverted (so that a higher number indicates a higher quantity of sweat) PL users reported 61.8% less sweat remaining on the limb than the control group (p=0.004). When asked a binary yes/no question about whether they perceived the amount they sweat to be excessive (Table 3), 85% of the control group answered yes. In the study group, this was significantly less (p<0.001) with only 15% reporting excessive sweating. It is also worth noting that these participants added the caveat that this occurred only very rarely. PL users reported less intense residual limb pain (66.3 (SD=32.0)) and less intense phantom limb pain (48.6 (SD=35.4)) than the NPL control group (38.5 (SD=29.9)) and 37.2 (SD=37.0) respectively). While neither of these changes reached statistical significance (p=0.071 and p=0.360 respectively), how “bothersome” participants found pain in their residual limb did, with the PL group reporting that it was less bothersome (68.5 (SD=30.9)) than the NPL group (38.8 (SD=32.0), p=0.045). Significant differences were observed for the PL group, compared to the NPL group, in the frequency of residual limb pain (2.7 (SD=1.7) and 4.2 (SD=1.9), respectively; p=0.032) and the frequency of phantom limb pain (2.8 (SD=1.6) and 4.3 (SD=2.1), respectively; p=0.042). These results are shown in Figure 3 and Figure 4. A clear skew towards lower frequencies in the PL group here, indicates fewer occurrences of pain. Issues at the residuum The mean number of residual limb issues reported was significantly higher in the NPL control group (2.8 (SD=1.5)) than the PL group (1.2 (SD=1.0), p<0.001). Issues that were reported by both groups were chaffing, blisters, rashes, heat rash and pressure sores, with chaffing being the most prevalent issue in both groups (Figure 5). The frequency of all issues was lower in the PL group; the percentage of the population affected by chaffing differed significantly from 80% in the control group, to 46% in the PL group (p=0.002). Table 2: Control group participant demographics. Gender Age (y) Weight (kg) Aetiology Prescription (suspension) NPL01 F 49 80.0 Infection Össur liner (pinlock) NPL02 M 76 83.5 Trauma Össur liner (pinlock) NPL03 M 67 91.8 Trauma Össur liner (pinlock) NPL04 M 66 106.4 Infection Alps liner (pinlock) NPL05 M 30 69.3 Trauma Össur liner (pinlock) NPL06 M 70 79.6 Trauma Össur liner (pinlock) NPL07 M 31 83.6 Infection Alps liner (pinlock) NPL08 M 81 71.8 Vascular Blatchford liner (pinlock) NPL09 M 59 94.6 Trauma Alps liner (pinlock) NPL10 F 57 84.6 Trauma Össur liner (pinlock) NPL11 M 70 74.4 Vascular Össur liner (pinlock) NPL12 M 56 97.6 Trauma Blatchford liner (pinlock) NPL13 M 47 85.0 Trauma Alps liner (pinlock) NPL14 M 63 97.5 Unknown Ottobock cushioned liner (suction) NPL15 M 48 166.0 Unknown Alps liner (pinlock) NPL16 M 47 67.0 Vascular Alps liner (pinlock) NPL17 M 52 103.0 Unknown Össur cushioned liner (suction) NPL18 F 31 70.0 Trauma Blatchford liner (pinlock) NPL19 M 79 89.0 Trauma Ottobock custom silicone liner (pinlock) NPL20 F 47 116.0 Trauma Össur liner (pinlock) Mean - 56.3 90.5 - - SD - 15.4 22.1 - - Table 3: Results of additional questions included within survey. P values in bold text indicate significance (p<0.05). During the past 12 months… PL group (Mean (SD)) NPL group (Mean (SD)) p value Do you currently suffer from excessive sweating? Yes: 2 (15.4%) No: 11 (84.6%) Yes: 17 (85.0%) No: 3 (15.0%) <0.001 Approximately, how many socket adjustment appointments have you required? 1.8 (1.9) 2 (1.4) 0.610 What % of your residual limb issues (skin/tissue breakdown) would you attribute to sweating? 22.7 (33.2) 49.0 (39.5) 0.066 Have you taken any days off work, or were housebound, for skin issues? If so, how many days? N = 12 2.4 (6.0) N = 16 11.6 (21.9) 0.267 Have you limited the use of your prosthesis and activities due to discomfort caused by sweating? If so, how many days? N = 12 1.4 (2.9) N = 17 75.4 (130.6) 0.009 https://doi.org/10.33137/cpoj.v3i2.34610 5 Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 ISSN: 2561-987X USING PERFORATED LINERS IN LOWER LIMB PROSTHESIS USERS Davies et al. 2020 CPOJ The occurrence of blisters also changed significantly from 45% in the control group to 15% in the PL group (p=0.032); and differences in heat rashes (50% vs 23%) and fungal infection (20% vs 0%) approached significance (p=0.052 and 0.071 respectively). Although not significant, the occurrence of pressure sores changed from 35% in the control group to 15% of the PL group (p=0.138). Least prevalent issues within the control group (fungal infection, callusing, abscess) were not seen at all in the PL group. Figure 2: Residual limb health PEQ subset score for the NPL control group (grey) and the PL group (green). The error bars indicate ± one standard deviation from the mean. Asterisks (*) indicate a statistically significant change (p<0.05). 0 20 40 60 80 100 How much sweat? Smelliness Swelling Rashes Ingrown hairs Blisters Mean limb health P a rt ic ip a n t s c o re < - E x tr e m e i s s u e s N o i s s u e s - > Residual limb health PEQ score NPL group PL group 0 10 20 30 40 50 Never Only once or twice A few times (about once/week) Fairly often (2-3 times/week) Very often (4-6 times/week) Several times every day All the time P e rc e n ta g e o f p o p u la ti o n ( % ) Frequency of residual limb pain PL group NPL group Figure 3: PEQ pain subset results for the frequency of the residual limb pain experienced by both PL (striped) and NPL (grey) groups. A skew to the left indicates less pain. The difference between the group was significant (p<0.05) with PL users experiencing less pain. 0 10 20 30 40 50 Never Only once or twice A few times (about once/week) Fairly often (2- 3 times/week) Very often (4-6 times/week) Several times every day All the timeP e rc e n ta g e o f p o p u la ti o n ( % ) Frequency of phantom limb pain PL group NPL group Figure 4: PEQ pain subset results for the frequency of phantom limb pain experienced by both PL (striped) and NPL (grey) groups. A skew to the left indicates less pain. The difference between groups was significant (p<0.05) with PL users experiencing less pain. https://doi.org/10.33137/cpoj.v3i2.34610 6 Davies K.C, McGrath M, Savage Z, Stenson A, Moser D, Zahedi S. Using perforated liners to combat the detrimental effects of excessive sweating in lower limb prosthesis users. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.1. https://doi.org/10.33137/cpoj.v3i2.34610 ISSN: 2561-987X USING PERFORATED LINERS IN LOWER LIMB PROSTHESIS USERS Davies et al. 2020 CPOJ When patients were asked to rate how many of their issues they attributed directly to sweating, the percentage was lower for the PL group (Table 3). The control group estimated that on average, 49% of all issues were due to sweating, whereas the PL group attributed only 23% to sweat (Figure 6). Figure 6: The mean number of issues experienced by patients at their residual limb, and the percentage of those issues that were attributed to sweating (grey) or to other causes (green). Exact percentages are indicated within bars. This result did not reach statistical significance (p=0.066) due to the high variability between patients. When using the percentages to calculate the number of issues attributed to sweat however, the control group subjects averaged 1.7 (SD=1.7), while in the study group this was 0.3 (SD=0.5); a result that was significant (p=0.007). The number of workdays missed was lower in the PL group with a mean of 2.4 (SD=6.0) days taken off work due to issues compared to 11.6 (SD=21.9) in the control group (p=0.267, Table 3). The number of days limited by issues surrounding the prosthesis was significantly less, with the PL group limited a mean of 1.4 (SD=2.9) days and the control group 75.4 (SD=130.6) days (p=0.009). DISCUSSION This report investigated the clinical consequences of perforated prosthetic liners based on the feedback provided by study participants and a comparable control group. While patient-reported outcome measures can be subjective, large trends in the data can imply significant changes in patient outcome over a wider population. The results suggest perforated liner users have significantly more successful patient outcomes and experiences through better residual limb health and less frequent outbursts of pain. Overall, the study group showed better PEQ residual limb health scores (Figure 2). Within this subset, the score for every question was higher, indicating an increase in health and therefore a reduction of each adverse factor. Significant changes were seen in the amount of sweat present on the limb as well as in the limb’s odour. Given that malodour is a direct result of the bacterial secretions following a transformation of the compounds found in sweat,38 it seems logical that a decrease in odour would be attributable to a decrease in the amount of sweat inside the liner. The design of the perforated liner is such that once the moisture migrates to the outside of the liner, it is absorbed by the fabric lining. To this end, the odour is more likely to develop on the outside of the liner, and can be easily washed, instead of impregnating into the inner silicone where it lingers. 0 20 40 60 80 100 Chaffing Heat rash Blister Pressure sore Rash Fungal infection Callusing Abscess P e rc e n ta g e o f p o p u la ti o n ( % ) Occurrence of issues at the residual limb NPL group PL group Figure 5: Percentage of the group populations that were affected by individual issues at the residual limb. The NPL group are indicated in grey and the PL group in green. Asterisks (*) indicate statistically significant results (p<0.05) while obelisks (†) indicate results that approached significance (0.05