TABLE OF CONTENTS EXCECUTIVE SUMMARY..3 BACKGROUND.5 METHODOLOGY..5 OUTCOMES AND FINDINGS.9 EVALUATION..24 COMMUNICATION..25 EXTENSION OF RESULTS 26

Transcription

1 Final Report A RANDOMISED, SINGLE-BLINDED, CROSS-OVER TRIAL OF THE EFFECTIVENESS OF BELOW THE KNEE SUPPORT SOCKS (STOCKINGS) FOR WORKERS WHO STAND FOR PROLONGED PERIODS OF TIME Professor Neil Piller (Team leader) Ms. Amanda Moseley (Research Officer), Ms Jane Fauser (Research Assistant), Mr Bruce Forbes (Research Assistant) Department of Surgery & Lymphoedema Assessment Clinic, Flinders University & Medical Centre Bedford Park, South Australia 1

2 TABLE OF CONTENTS EXCECUTIVE SUMMARY..3 BACKGROUND.5 METHODOLOGY..5 OUTCOMES AND FINDINGS.9 EVALUATION..24 COMMUNICATION..25 EXTENSION OF RESULTS 26 RECOMMENDATION REFERENCES..27 2

3 EXECUTIVE SUMMARY The impact of three week s use of below the knee support stocks (Venosan 20-30mmHg graduated compression) on three sample groups, nursing staff, catering/cleaning staff and production workers was determined in a randomised single blinded, cross over trial. Each participant was randomised to either wearing the support stocks first for 3 weeks followed by a two week wash out then wearing ordinary work wear or to wearing ordinary work wear for 3 weeks followed by a two week wash out then wearing support stocks for 3 weeks. Measurements were taken before and after a shift twice a week except during the wash out period. Measurements included bio-impedance; which uses multi-frequency (5 500Hz) electricity to measure intracellular and extracellular fluid in the legs, perometry; which uses optoelectronics to measure the leg every 3mm to produce circumference and total volume, 10-point Likert Scale; which measured subjective leg symptoms including aching, heaviness, tightness, cramping and leg tiredness, and a body discomfort chart; where participants indicate on the body chart areas of discomfort and then rate the discomfort on a visual analogue scale. Below the knee support stocks had a statistically significant impact on whole group whole leg segmental fluid levels as determined by bio-impedance. The effect was greater in the left leg (48%) compared to the right leg (32%). Focus on below the knee changes using perometry showed a statistically significant whole group reduction of 66% for the right limb and 57% for the left limb. As a single group nurses showed the most significant reductions below the knee of 90% for the right leg and 77% for the left leg. In terms of subjective changes the whole group showed statistically significant improvements in aching (43%), heaviness (56%), tightness (66%) and tiredness (39%) when the support socks were used. Again the single group which showed the most significant improvement were the nurses. When the impact of the socks on body part discomfort was considered, in the whole group it was discomfort of the neck, shoulders (66%) and the lower back (85%) which were significantly improved. All other aspects of discomfort were also improved when the support socks were used although statistical significance was not attained due to large intra group response variation and sample size. Below the knee support socks seem to have a significant benefit for populations who spend a significant proportion of their working time standing. The impact on reducing fluid accumulations and improving the efficiency and effectiveness of the venous system and lymphatic system function may, in turn, improve cell and tissue health and may reduce the risk of development of future vascular problems. In addition, the reduced fatigue and body part discomfort may lead to reduced near miss and workplace related adverse 3

4 events, although this is yet to be strongly substantiated. Overall, below the knee support socks seem to be of significant benefit, most particularly to nursing staff. 4

5 BACKGROUND Workers who stand for prolonged periods of time are prone to fluid accumulation in the legs as the valves in both the vascular and lymphatic systems have to work against gravity to return the fluid back to the general circulation. This accumulation can result in swollen ('puffy') feet and leg discomfort, such as heaviness, tightness and aching. Over time with chronic distension the valves in the vascular system can fail, with the end-point being chronic venous insufficiency (CVI) 1. CVI results in inefficient removal of fluid from the limbs, with the legs becoming permanently swollen and uncomfortable. Workers who stand for prolonged periods of time are more susceptible to developing venous pathology, with studies showing a positive association between standing at work and venous disease 2, 3. Although several studies have shown the benefits of support socks for standing workers who already have venous disorders 4-6, none have examined the benefits of these socks in standing workers with no known venous pathology. Therefore the aim of this study was to investigate the benefits of below the knee support socks for workers with no known venous pathology who stood for prolonged periods at work. METHODOLOGY Study Design Three working populations were investigated; nurses, cleaning/catering staff and factory production workers (see description of each working site below). Those with known venous pathology (i.e.: varicose veins, previous deep vein thrombosis) or pre-existing limb swelling were excluded from the study. Venosan below the knee graduated compression (20-30mmHG) socks were investigated, with each participant being randomized using a randomized number table, into one of two groups: Group 1: wore below the knee support socks (BKSS) for 3 weeks, underwent 2 weeks of wash-out and then wore normal work wear (NWW) for 3 weeks. Group 2: wore NWW for 3 weeks, underwent 2 weeks of wash-out and then wore BKSS for 3 weeks. Each participant was given a verbal and written explanation of the study and signed a consent form before entering the study. Each participant was given a pair of the support stocks before commencement of the trial and given a verbal and written explanation as to when they had to wear them by Investigator 1 (Professor Neil Piller) who had performed the randomization. Measurements were taken before and after a shift twice a week by investigators 2, 3 & 4 (Amanda Moseley, Jan Fauser & Bruce Forbes) who were blinded to 5

6 the allocation. Each participant was instructed not to discuss what they were wearing with the investigators performing the measurements and to remove their socks before entering the measurement room so the investigators performing the measurements remained blinded. Measurements with validated equipment included; Perometry; the perometer (Pero-systems, Germany) is a previously validated 7-8 volume measuring system which is based upon a square measuring frame that contains rows of infra-red light emitting diodes on two sides and rows of corresponding sensors on the opposite two sides. The patient sits at one end with the foot resting centrally on an adjustable support. The frame is then moved along the length of the leg from the foot to the upper thigh. The limb casts shadows in two planes and using the cross-sectional information obtained, a computer software program builds up a whole leg volume and circumferential picture (at 4mm intervals) of the entire leg. Bio-impedance; body bio-impedance was measured in this clinical trial with an InBody 3.0 system manufactured in Korea by Biospace Ltd. The InBody 3.0 is a multifrequency body and segmental analyser (5 khz khz) where the patient stands erect on electrode footplates and holds electrodes in the hands, resulting in eight electrode contact sites. The fixed eight point contact overcomes the problems with variable electrode placement and surface area contact. The multi-frequency technique employed accurately quantifies both total body fluid and extra-cellular fluid in extremities, having the ability to distinguish the gain or loss of fluid from fat and muscle 9. Previous studies have proven the validity of bio-impedance in measuring body fluids in both healthy adults and patients with limb swelling General questionnaire; this recorded descriptive data such as age, gender, employment and exercise history. Subjective leg symptoms; including aching, heaviness, tightness, cramps and tiredness which were rated on a 10-point likert scale 13, where 1 = no problem and 10 = the worst imaginable problem. Body part discomfort scale; where participants indicated their degree of discomfort in different body parts using a body map 14, 15 and rated the discomfort on a visual analogue scale. Work Sites & Populations 1. Flinders Medical Centre: is a WorkCover exempt hospital which provides healthcare services to the Southern Region. Nurses from a variety of areas who spend the majority of the shift standing and walking around were involved in the trial. 6

7 2. Tempo Services: is a WorkCover insured company which provides support services such as catering and cleaning for Flinders Medical Centre. Cleaning/Catering workers are on their feet and walking around for the majority of the shift. 3. Bridgestone TG Australia, Edwardstown: is a WorkCover exempt company which provides rubber products to the automotive industry. Factory production workers either stand at work stations on rubber mats or move between work stations on concrete throughout the shift. Analysis All data was analysed using SPSS (v.12). All pre and post measurements were summated for each phase and ANOVA analysis was performed. Activities Undertaken to Meet the Project Tasks Ethics approval: the research protocol was submitted to and approved by the Flinders Research Ethics Committee. Establishment of work sites: the Occupational Health & Safety Department of Flinders Medical Centre, the manger of Tempo catering (Flinders Medical Centre) and the Occupational Health & Safety Officer and Managers at Bridgestone TG Australia (Edwardstown) were approached and asked whether their work groups would like to be involved in the trial. All agreed to participate and to give support to the study. Each was given information about the trial and the activities their workers would be involved in. Steering Committee: the above mentioned people were also asked to be a member of the study steering committee. The trial leader (Professor Neil Piller), the trial co-ordinator (Ms Amanda Moseley), a Vascular Surgeon (Dr Jack Walsh Flinders Medical Centre) and an Australian Nursing Federation representative (Mr Rob Hull) were also members of this committee. Recruitment: the following processes were undertaken to recruit people into the study: Posters advertising the trial were displayed on all Flinders Medical Centre notice boards on all levels of the hospital. Posters and leaflets were distributed to target areas where nurses stand for long periods of time, such as operating theatres, recovery and accident & emergency. Posters and leaflets were distributed to the Tempo kitchen/catering areas and attached to Tempo staff payslips. Posters and leaflets were distributed to the Occupational Health & Safety Officer of Bridgestone TG to display in areas where there were high worker volumes. 7

8 Articles about the trial (with an accompanying photo of staff wearing the support stocks) appeared in the Flinders Medical Centre newsletter (December 2003 issue) and the Sunday Mail (30/11/03). The study was also advertised on the Flinders Medical Centre intranet website. Investigator training: each investigator was given an orientation to the setting they would be working in, training on how to use the perometer and bio-impedance equipment and how to administer the subjective symptoms and body discomfort questionnaires. Trial entry: participants who expressed interest in the study were given a verbal and written explanation of the study and a consent form to sign. Each participant was randomised to either group, given support stocks and instructions on how to use them. Trial journey: participants were measured before and after a shift twice a week for each 3 week block, shifts included morning and afternoon. At the completion of the trial the participant was given the support stocks and a voucher for free tea/coffee and a scone at the institution s café as a gesture of appreciation. Data: all measurements were collected on standardised data sheets and kept in a locked filing cabinet. All data was entered into and analysed by SPSS (v.12). Problems encountered 79 participants were recruited to the study, however despite clear verbal and written information, 22 withdrew/were withdrawn because they were unable to meet the measurement/appointment criteria and 1 person withdrew because they did not like the sensation of the support socks. In particular it was hard to recruit people from the Tempo cleaning/catering group despite mass advertising (and the incentive of the free voucher at trial completion). The main obstacle was meeting the measurement criteria as it was felt that twice a week before and after a shift (especially since some staff started at 6am in the morning) was too difficult to adhere to. The investigation of the factory worker (Bridgestone T G Australia) group was delayed pending delivery of new measuring equipment (InBody Bio-impedance Analyser) from overseas and by the company (Bridgestone T G Australia) having an unforseen shut down/maintenance period which occurred in the middle of the year. This is not the normal practice for this particular company, with the shutdown/maintenance period normally occurring at the end of the year. Apart from the above two problems, all other study tasks were met. 8

9 OUTCOMES & FINDINGS Descriptive Statistics Overall 66 people participated in and completed the trial, 48 females and 18 males aged 20 65yrs (mean yrs). Three different working groups were involved in the trial; nurses, catering/cleaning staff and factory production workers, the descriptive statistics for each working group are presented in table 1. Table 1. Descriptive statistics of the three working populations Group n Females Males Age Nurses (92.6%) Catering/Cleaning 9 7 (77.8%) Factory Production (53.3%) 2 (7.4%) 2 (22.2%) 14 (46.7%) 24 55yrs ( ) 21 65yrs ( ) 20-63yrs ( ) 9

10 Background Information Table 2. Background information of the three working populations Group Current employment 4 6hrs standing 7-9hrs standing Smoker Exercise regime Exercise duration Overall yrs ( ) 11 (16.6%) 55 (83.4%) 15 (22.7%) None: 21.2% 1-2 x wk: 33.3% 3-4 x wk: 27.3% 5-6 x wk: 12.1% > 7 x wk: 6.1% Walking, bike riding & gym 0 mins: 19.7% 1 30mins: 28.8% 30-60mins: 25.8% 60-90mins: 18.2% mins: 3.0% > 120mins: 4.5% Nurses yrs ( ) 3 (11.1%) 24 (88.9%) 4 (14.8%) None: 3.7% 1-2 x wk: 44.4% 3-4 x wk: 37.0% 5-6 x wk: 11.1% > 7 x wk: 3.7% 0 mins: 3.7% 1 30mins: 29.6% 30-60mins: 40.7% 60-90mins: 18.5% mins: 7.4% Walking & gym Catering/ Cleaning yrs ( ) 2 (22.2%) 7 (77.8%) 3 (33.3%) None: 11.1% 1-2 x wk: 22.2% 3-4 x wk: 33.3% 5-6 x wk: 33.3% Walking & bike riding 0 mins: 11.1% 1 30mins: 33.3% 30-60mins: 11.1% 60-90mins: 33.3% mins:11.1% Factory Production yrs ( ) 6 (20.0%) 24 (80.0%) 8 (26.7%) None: 36.7% 1-2 x wk: 26.6% 3-4 x wk: 16.7% 5-6 x wk: 6.7% > 7 x wk: 13.3% Walking & gym 0 mins: 36.7% 1 30mins: 20.0% 30-60mins: 20.0% 60-90mins: 13.3% mins: 3.3% > 120mins: 3.3% 10

11 Figure 1a. Whole Group: Bio-impedance Right Leg Fluid Volume: Support vs. Normal Phase Normal Support Fluid Vol (mls) Pre Post Normal: 207mls Support: 140mls p =

12 Figure 1b. Whole Group: Bio-impedance Left Leg Fluid Volume: Support vs. Normal Phase Normal Support Fluid Vol (mls) Pre Post Normal: 211mls Support: 109mls p =

13 Table 3. Bio-impedance: Leg Fluid Volume for Each Working Group: Support v s Normal Phase R) LEG L) LEG Normal Support p Normal Support p Nurses 254mls 139mls mls 78mls Catering/Cleaning 167mls 129mls mls 106mls Production Workers 175mls 144mls mls 137mls

14 Figure 2a. Whole Group: Perometry: Right Below Knee Total Volume: Support v s Normal Phase Normal Support Total Vol (mls) Pre Post Normal: 48mls Support: 16mls p =

15 Figure 2b. Whole Group: Perometry: Left Below Knee Total Volume: Support v s Normal Phase Total Vol (mls) Pre Post Normal: 42mls Support: 18mls p =

16 Table 4. Perometry: Below the Knee Total Volume for Each Working Group: Support v s Normal Phase R) LEG L) LEG Normal Support p Normal Support p Nurses 67mls 7mls mls 9mls Catering/Cleaning 20mls 15mls mls 4 mls Production Workers 40mls 26mls mls 32mls

17 Table 5. Reported Subjective Leg Complaints for Whole Group & Individual Work Populations: Support v s Normal Phase Aching Heaviness Tightness Cramps Tiredness Whole Group S = 0.4 S = 0.4 S = 0.2 S = 0.0 S = 0.8 N = 0.7 N = 0.9 N = 0.6 N = 0.1 N = 1.3 p = p = p = p = p = Nurses S = 0.3 S = 0.3 S = 0.15 S = 0.08 S = 0.8 N = 1.0 N = 1.1 N = 0.7 N = 0.03 N = 1.7 p = p = p = p = p = Catering/Cleaning S = 0.1 S = 0.4 S = 0.3 S = 0.0 S = 0.6 N = 0.6 N = 0.8 N = 0.7 N = 0.1 N = 1.0 p = p = p = p = p = Production Workers S = 0.5 S = 0.4 S = 0.3 S = 0.1 S = 0.7 N = 0.7 N = 0.7 N = 0.6 N = 0.1 N = 0.8 p = p = p = p = p = Table 6. Body Discomfort Scale for Whole Group & Individual Work Populations: Support v s Normal phase Neck & Shoulders L) Arm R) Arm Lower Back Upper Back Whole Group S = 0.1 S = 0.10 S = 0.01 S = 0.06 S = 0.06 N = 0.3 N = 0.00 N = 0.05 N = 0.40 N = 0.07 p = p = p = p = p = Nurses S = 0.19 S = 0.04 S = 0.04 S = 0.16 S = 0.05 N = 0.59 N = 0.10 N = 0.02 N = 0.52 N = 0.03 p = p = p = p = p = Catering/Cleaning S = 0.02 S = 0.06 S = 0.17 S = 0.01 S = 0.12 N = 0.07 N = 0.13 N = 0.02 N = 0.30 N = 0.08 p = p = p = p = p = Production Workers S = 0.0 S = 0.02 S = 0.02 S = 0.01 S = 0.04 N = 0.3 N = 0.05 N = 0.10 N = 0.30 N = 0.10 p = p = p = p = p = S = support N = normal 17

18 Table 6. Body Discomfort Scale for Whole Group & Individual Work Populations: Support v s Normal phase L) Leg R) Leg Fatigue Whole Group S = 0.40 N = 0.30 p = Nurses S = 0.41 N = 0.73 p = Catering/Cleaning S = 0.22 N = 0.20 p = Production Workers S = 0.30 N = 0.20 p = S = 0.30 N = 0.50 p = S = 0.39 N = 0.79 p = S = 0.06 N = 0.32 p = 0.06 S = 0.20 N = 0.20 p = S = 1.4 N = 2.4 p = S = 1.7 N = 2.0 p = S = 1.5 N = 1.4 p = S = 2.0 N = 3.0 p = S = support N = normal Table 7. Whole Group: Subjective Comments about the Support Socks 44 of the participants chose to comment on the support socks, comments are summarised in the table below. Comment Number Percent Beneficial/felt good 24 55% Felt comfortable to wear 14 32% Difficult to get on/off 12 27% Legs less tired at end of the day 10 23% Ankles appeared less swollen 3 7% Socks were too long 8 18% Socks were too tight 4 9% Socks too hot 5 11% Socks itchy 3 7% Reduced lower back pain 3 7% Socks left ridges 1 2% Socks didn t make a perceived difference 4 9% 18

19 Discussion It is well documented that people who stand for long periods (particularly on hard surfaces) are prone to increased fluid accumulations in the lower legs as the valves in the venous and lymphatic systems fight to maintain their patency. Since both systems are very much capacitance vessels, they are reliant on the calf muscle pump to provide variations in tissue pressure to help maintain their function and to ensure that over-distension does not occur, thus leading to their failure to return any accumulated extracellular fluid either direct to the venous system or indirectly to it via the lymphatic system. In addition to the impact of the calf muscle pump another major factor known to control the amount of extra-cellular fluids and their contents is the extent of graduated external pressure on the tissues. This works by reducing the outflow of materials from the vascular system (thus reducing the load on the lymphatic system) and also acts to provide supporting pressure to ensure that the calf muscle pump works at optimal effectiveness, thus maintaining optimal tissue and cellular health. There was a deliberate intent in this study to recruit normal healthy workers, that is, those with no varicose or other lower limb disorders, although it is acknowledged that some may have had latent problems. As far as we are able to ascertain from the literature, no study to date has investigated the impact of support socks on other than groups with known venous pathologies. The background data on the various groups provided an interesting insight into their constituents however it was clear that the majority (83%) of the combined groups stood for more than 7 hours in the day. 22.7% of the overall sample smoked, with the highest levels being in the cleaning/catering group and the lowest in the nursing group. All members of all groups had (as far as we could ascertain and they were aware) normally functioning lymphatic and vascular systems. While some had very poor skin integrity or very dry skin, none of the other detected conditions in the members of the groups entered into the study had any significant problem that would impact on the lymphatic or vascular system function. The major parameter of concern is that of the extracellular fluid volumes. While these consist of the true extracellular fluid, which is between the cells, the other components of it such as the intravascular and intra-lymphatic space must be considered. It is likely the use of external compression has an impact on all three components of the extracellular fluid volume in the limb, but with the current equipment it is difficult to separate out the impact of this compression on these three separate compartments. It is moderately well evidenced however that external compression will reduce intravascular volume (especially of the veins 19

20 as these are capacitance vessels), and that it does reduce the exudation from the blood vessels into the tissues. Due to the delicate nature of the lymphatic collectors it s also likely that this space will also be reduced. The changes in fluids we are measuring thus are likely to be related to changes in all three compartments. Bio-impedance Due to the lack of significant difference between the groups on the major parameter (ie: duration of standing) the groups were combined for the first pass analysis. In the right limbs of the untreated groups over the 3 week period of measurement the normal limbs increased by 207 mls, between the pre shift and post shift measurement. However, with the use of the below the knee support socks the volume increase was 140 mls the difference of 67 mls of which represented a borderline statistically significant reduction of p = This represented a 32% reduction in accumulated fluids over the control group. In terms of the left limb, there was a slightly greater increase of 211 mls in the control (non compression) group and a slightly better control of the increase in the treatment (compression) group of 109 mls, with the difference of 102 mls being statistically different (p =.001). This represented a 48% reduction in the accumulated fluids over the control group. Why this difference existed between the limbs is uncertain, but is possibly related to a differing effect of the external stocking pressure on the lymph system on the left limb in that the pathway of lymph from this limb is shorter than from the right and less likely to be constrained by abdominal influences (such as high levels of abdominal fat) as it crosses this area. In terms of how the three groups responded individually, the right leg of the nursing group showed a non statistically significant reduction of 115mls (45%) while the left leg showed a statistically significant (p = 0.010) reduction of 120 mls (60%). The right leg of the catering/cleaning group showed a non significant reduction of 38 mls (23%) and the left leg a borderline non significant reduction of 112 mls (52%). In the production workers group the right leg showed a non significant reduction of 31 mls (18%) while the left leg showed a significant reduction of 85 mls (38%) Again as per the combined group, the impact of the below the knee support stocking is greater statistically, biologically and certainly practically for the left leg. 20

21 Perometry Perometry measurements were only made up as far as the distal patella. For this reason changes are of a lesser magnitude of difference than for the whole limb as determined by bio-impedance. It should also be noted that while bio-impedance measures total fluids, perometry measures volumes as calculated by circumferences measured at 4 mm intervals. Again from the whole group perspective for both the left and right limbs there was a statistically significant volume reducing effect of the below the knee compression socks. For the right leg below the knee this represented a statistically significant reduction (p= 0.017) of 67% of the increased volume without the stocking and for the left below the knee a statistically significant (p = 0.004) reduction of 62%. An examination of the changes in the separate groups showed the greatest and most statistically significant reductions of 90% (p =0.045) for the right leg and 77% (p = 0.018) for the left leg. The catering/cleaning group showed reductions of 25% (ns) for the right limb and 84% (ns) for the left limb, while the production workers showed reductions of 35% (ns) and 34% (ns) for the right and left legs respectively. The major reasons for the lack of statistically significant changes in these latter two groups seemed to be primarily the result of the large spread of changes within the groups. Subjective Findings While objective findings such as the above are important, it is the influence of these on how the person feels which is crucial. When the whole group subjective comments were considered the wearing of support socks resulted in a statistically significant reduction in limb aching (43%, p = 0.011), limb heaviness (56% p = 0.001), limb tightness (66%, p = 0.004) and limb tiredness (39% p = 0.006). While cramps reduced, it was not statistically significant. Whole group findings were mirrored by the three sub group findings but statistical significance was not achievable except in the nursing group where there was a 60% (p = 0.011) reduction in aching, a 63% (p = 0.001) reduction in heaviness and a 53% (p = 0.005) reduction in tiredness. 21

22 Body Part Discomfort Changes in body part discomfort may occur as the day progresses, usually in the lower back, and legs. Generally accompanying this are increased levels of fatigue. In the whole group, the use of below the knee support socks significantly reduced neck and shoulder discomfort by 66% (p = 0.041), and lower back discomfort by 85% (p = 0.017). Left and right arm, upper back discomfort and level of fatigue were also reduced but not significantly. They are likely to be practically significant, however this remains to be determined. The individual group changes in body part discomfort were not statistically significant although larger sample sizes would see this. Other Subjective Comments Forty four of the participants commented on the support socks, with 24 (55%) of them stating that the socks had an overall beneficial effect and or felt good and 14 (32%) reported them to be comfortable to wear. Ten (23%) indicated their legs felt less tired at the end of the day. However, 12 (27%) reported them to be difficult to get on/off and 8 (18%) indicated them to be too long. Other difficulties reported were problems with their tightness, hotness, itchiness and the making of ridges on the legs; however it seems clear that their benefits significantly outweighed the negatives for most people. 22

23 General Conclusion In all cases, it s likely that reductions in extracellular fluids achieved by the below the knee support socks over each and every day will have a significant effect on the cellular and tissue health in the lower limb (Tuchsen et al 2000). While the end point of this remains to be explored, it is hypothesised that this change alone may result in a reduced risk of varicosities of the lower limb and of venous oedemas. The major reason for this is likely to be as a consequence of the additional external pressure on the venous system and its effect on their distension and on the exudation of materials from them as well as their clearance from the area. Another important reason is the impact of a more efficient use of the calf muscle pump when supported by external pressure over and above that normally provided by the natural elasticity of the skin. A third reason is the benefits of this compression on tissue pressures and the impact that has on the ability to load the lymphatic system and to clear fluids, waste products and toxins from the tissues. Practical implications This study has shown that the wearing of below the knee light compression garments is beneficial in terms of leg fluid and volume reduction and in improving how the legs and general body feel. This is the case in a working population that stand for long periods of time and who have no known venous or lymphatic pathologies. As the literature has already established a link between standing for long periods and venous pathology, the wearing of support garments by workers may over the long term prevent or slow the onset of venous disorders (ie: varicose veins) and hopefully lead to a happier, healthier and more productive worker. The garments were well tolerated by most participants and provide an easy to implement initiative for those who due to the nature of their work, stand for long periods. These sorts of findings may also be generalisable to other standing occupations such as the hospitality and supermarket industries. This sort of study provides evidence for enterprise bargaining for the work groups involved, especially the nursing group who previously (but not currently) were supplied with support stocks as a part of a standard uniform. 23

24 EVALUATION The majority of the aims of this study were met, the study design demonstrated that support stocks were superior to wearing normal work wear in terms of reducing fluid accumulation and increase in below the knee leg volume plus improving subjective symptoms, body part discomfort and fatigue. The only target not met was the projected recruitment numbers for each work group, if the withdrawal/drop out numbers are considered then the required numbers would have been achieved. The project was managed well, each investigator completed all measurements required and the trial was completed in a timely fashion. The results have been disseminated to the managers of each work group and a pamphlet outlining the trial and its results has been prepared for the workers. There was a slight delay in the original time line due to a delay in availability of measurement equipment from overseas and an unforseen shutdown/ maintenance period in the middle of the year at Bridgestone T G Australia. All the milestones of the trial, except for recruitment numbers (see explanation above) were achieved. All measurements in terms of the trial (ie: general questionnaire, bioimpedance, perometry, subjective leg symptoms and body discomfort questionnaires) were achieved. Analysis and final write up of the results was also achieved. The quality of the outcomes were good, the equipment used was able to demonstrate that the support socks were beneficial for workers who stand for long periods, both objectively (less fluid accumulation and volume increase) and subjectively (less subjective leg symptoms and body discomfort). The impact of this study is that it is an easy to implement initiative which in the short term improves worker comfort and in the long term may prevent or slow venous pathology onset and improve productivity. 24

25 COMMUNICATION The results of this study (to date) have been disseminated in the following ways: The leader(s) of each work group and the steering committee members have been sent a summary of the results (with alterations recommended by Work Cover see appendix I) for their own record, this included: Dr Jack Walsh Vascular Surgeon/Specialist, Flinders Medical Centre Mr Rob Hull Nurse Clinical Educator & Australian Nursing Federation Representative, Flinders Medical Centre Ms Wendy Robertson Manager of Tempo Catering Services, employed by Flinders Medical Centre Ms Shelley Short Occupational Health & Safety Manger, Flinders Medical Centre Mr Jeff Benham Occupational Health & Safety Officer, Bridgestone TG Australia General Management Bridgestone TG Australia The preliminary results of this trial were presented at the 6th International Congress on Work Injuries Prevention, Rehabilitation & Compensation (WorkCongress6). Rome, Italy. The results specifically pertaining to the nursing group with a general overview of the results of the tempo and factory production groups have been posted on the Flinders Medical Centre website: and in the FMC newspaper (Feb 05). A pamphlet which outlines the trial, where to purchase the support socks, in an easy to read style has been completed and will be distributed to the individual work sites involved in the study. The research team are being interview about the trial and its results by Channel 7 news and the southern messenger newspaper on Wednesday 9 th of February Articles are currently being prepared for submission to the Australian Nursing Journal (distributed to all Australian Nursing Federation members) and the Ergonomics journal. 25

26 EXTENSION OF RESULTS Managers of each work group involved in the study will be encouraged to give all current and new employees the developed pamphlet so each worker is aware of the benefits of below the knee support socks. A meeting is being organized with Mr Jeff Benham (OH&S Officer, Bridgestone T G Australia) and his representatives and a member of WorkCover and our key members with a view to attempting to facilitate further use of these support socks. Union members will be encouraged to approach their organisation regarding the permanent implementation of these support socks. The primary investigators will endeavour to present these findings at relevant and appropriate conferences. RECOMMENDATION The recommendation of this trial is that below the knee support socks (probably in combination with isotonic and isometric leg exercises) be implemented for all workers who stand for long periods of time and that this information be disseminated in the above mentioned ways. Ideally the best way to implement this initiative would be to incorporate the below the knee support socks as part of the workers standard uniform. Further studies could be beneficial in the populations of workers in both the hospitality and supermarket areas particularly as these are generally younger persons and the introduction of documented outcomes through the wearing of the support socks in these groups might encourage their use and importantly, lead to better health maintenance awareness in these younger groups A longer term study on a subgroup might be very interesting in terms of the documentation of the effects of below the knee support socks on the incidence/ prevalence of other lower limb issues such as varicose veins which affect a significant proportion of older populations. Evidence suggests these might be in part be preventable, but there are certainly opportunities to be better able to be manage them in their early stages through awareness and obviously some gentle external compression. 26

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