The impact of three week's use of below the knee support stocks (Venosan@ 20-30mmHg
graduated compression) on three sam pie groups, nursing statt, catering/cleaning statt
and production workers was determined in a randomised single blinded, cross over trial.
Each participant was randomised to either wearing the support stocks first für 3 weeks
followed by a two week wash out then wearing ordinary work wear or to wearing ordinary
work wear für 3 weeks followed by a two week wash out then wearing support stocks für
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% tor the right
limb and 57% tor the left limb. As a single group nurses showed the most significant
reductions below the knee of 90% tor the right leg and 77% tor 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
sacks were used. Again the single group which showed the most significant improvement
were the nurses. When the impact of the sacks 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 sacks were used although statistical significance was not
attained due to large intra group response variation and sampie size.
Below the knee support sacks seem to have a significant benefit tor 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
Iymphatic system function may, in turn, improve Gell 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 events, although this is yet to be strongly substantiated. Overall, below the knee support
sacks seem to be of significant benefit, most particularly to nursing statt.
Workers who stand für prolonged periods of time are prone to fluid accumulation in the
legs as the valves in both the vascular and Iymphatic 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 für prolonged periods of time are more susceptible to developing venous pathology,
with studies showing a positive association between standing at work and venous
disease2. 3. Although several studies have shown the benefits of support sacks für
standing workers who already have venous disorders4-6, none have examined the
benefits of these sacks in standing workers with no known venous pathology. Therefore
the aim of this study was to investigate the benefits of below the knee support sacks für
workers with no known venous pathology who stood für prolonged periods at work.
Three working populations were investigated; nurses, cleaning/catering statt 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) sacks were investigated, with each participant being randomized using a
randomized number table, into one of two groups:
Group 1: ware below the knee support sacks (BKSS) für 3 weeks, underwent 2 weeks of
wash-out and then ware normal work wear (NWW) für 3 weeks.
Group 2: ware NWW für 3 weeks, underwent 2 weeks of wash-out and then ware BKSS für
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 the allocation. Each participant was instructed not to discuss wh at they were wearing with
the investigators performing the measurements and to remove their sacks before entering
the measurement room so the investigators performing the measurements remained
blinded. Measurements with validated equipment included;
Peromet!y; the perometer (Pero-systems@, Germany) is a previously validated7-S
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 multi-
frequency body and segmental analyser.(5 kHz -500 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 1055 of fluid tram tat and
muscle9. Previous studies have proven the validity of bio-impedance in measuring
body fluids in both healthy adults and patients with limb swelling 10-12.
General auestionnaire; this recorded descriptive data such as age, gender,
employment and exercise history.
Subiective lea svmDtoms: including aching, heaviness, tightness, cramps and tiredness
which were rated on a 10-point likert scale13, where 1 = no problem and 10 = the worst
Bodv 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
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 2 Tempo Services: is a WorkCover insured company which provides support services
such as catering and cleaning tor Flinders Medical Centre. Cleaning/Catering workers
are on their feet and walking around tor the majority ot 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.
All data was analysed using SPSS (v.12). All pre and post measurements were summated
tor each phase and ANOVA analysis was performed.
Activities Undertaken to Meet the Project Tasks
Ethics aDDroval: 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 affiGer 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.
Steerina 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
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 statt 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 Articles about the trial (with an accompanying photo of statt wearing the support
stocks) appeared in the Flinders Medical Centre newsletter (December 2003 issue)
and the Sunday Mail (30/11/03).
Investiaator 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 ent[Y: 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 iourne~: participants were measured before and after a shift twice a week tor 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 tor free tea/coftee and a scone at
the institution's cafe as a gesture of appreciation.
~: 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).
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 sacks. In particular it was hard to recruit people tram 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 feit
that twice a week before and after a shift (especially since same statt started at 6am in
the morning) was tao 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 für 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