Transcript Slide 1

Perometer (400T) measurement
of lower limb volume:
development of a standardised
protocol
Fiona Coutts, Andrew Grainger, Dr Cathy Bulley
Queen Margaret University, Edinburgh, UK
Background
• Various musculoskeletal, oncological or vascular
conditions result in increased limb volume
• Limb volume – outcome measures
Fluid displacement
Geometric calculations from limb circumferences
using tape measure
Perometer – optoelectronic imaging device; limb
shape and volume (Pero-System GmbH, Wuppertal,
Germany)
Purpose
• True repeatable
measurement important in
monitoring treatment
efficacy.
• Perometer (400T)
optoelectronic imaging
device used to assess limb
volume. No protocol has
been published to
standardise its use.
Study Design
Rest
Period
(A)
Phase 1
Diurnal
Variation
(A)
Foot
position
on base
plate
(B)
Leg position
(Rotation)
(B)
Phase 2
Speed of
frame
Movement
(C)
Standardised
protocol
End point
of limb
measurement
(C)
Use of
software
(D)
Phase 3
Phase 1A: Diurnal Variation
• Issue: Does limb volume
change through a day?
• Results: Volumes
averaged and %
differences to initial
volume were
calculated. <2%
volume change for
each participant.
• Design: n=2, healthy
participants. 3 volume
measurements @ 3 times
per day, between 09.00
and 18.00.
Tester
Morning –
Afternoon
Morning –
Evening
1
2
1.1% 1.6%
1.8% 1.2%
Phase 1B: Foot position
• Issue: Does the position
of the limb on the base
plate alter measurement
data?
• Results: Four centre squares
(A,B,C,D) demonstrated the
highest repeatability of
measurement. Corner
squares (1,2,3,4) lowest
repeatability.
• Design: Cylinder placed
in each of the 16
squares marked on the
base plate, measured 3
times.
1
4
2
A
B
D
C
3
Phase 1C: End point of limb
measurement
• Issue:
Standardised
landmarks for
measurement of
volume?
• Design: n=4, frame advanced to
comfortable maximum vertical
height, leg marked. Calculated as
% of length Position 1 to 2 (see
below)
• Results: % leg length=
67.6, 69, 79.1, 81.7; 65%
of leg length was max.
height for vertical frame
advancement
Grt Trochanter
(1)
65% Femur
Lat Femoral
Epicondyle
(2)
Lateral
Malleolus
Standardised Protocol 1
• Diurnal variation: keep standardised times
for repeat visits
• Foot position: maintain foot in the centre of
the base plate at all times
• End point of measurement: 65% of
distance from lateral femoral Epicondyle to
Greater Trochanter
Repeatability after phase1
• n= 30 (22F: 8M)
(25.9±3.48yrs,
171.02±6.77cm,
67.32±7.68Kg)
Dominant leg – tested
9 times by a rater on
2 consecutive
occasions
ICC (p<0.001)
95% CI
0.99
0.996-0.999
Upper LOA
185.18 ml
Lower LOA
-193.81 ml
Range
% variation
378.99ml
4.07%
LOA= Limits of Agreement
(Bland & Altman, 1986)
Concerns after phase 1
• Rest period prior to commencement of
measurement
• Axial rotation of the limb in the frame
• Speed of Perometer frame movement
= Phase 2
Phase 2A: Rest Period
• Issue: Stasis of limb
volume prior to
assessment with
perometer
• Results: Volume
change variable until
10 minutes of rest.
After 10 mins. less
variable.
• Design: Pre and post rest
limb volume at : 2.5,
5,10,12.5,15 mins., n=2
healthy participants
% Difference from pre rest
Participant 1
0.02
Participant 2
0.015
0.01
0.005
0
-0.005
2.5
5
10
-0.01
Minutes of rest
12.5
15
Phase 2B: Leg position
• Design: Full size
mannequin limb positioned
10 increments to internal
and external axial rotation
(0 - 50°), 3 times.
• Issue: Does axial limb
rotation cause
measurement error?
• Results: Mean of 3
tests on 2 occasions
shows little variation,
CoV <0.1% in all bar
1 position, <1.2%
overall
MeanCoefficient
Volumne inofaxial
rotation
Variation
(%)(mls)
8000
1.4
1.2
6000
1.0
0.8
4000
0.6
0.4
2000
0.2
0.00
50
50
40
40
30
30
20
20
10
10
00
10
10
20
20
Ext.
Ext.Rot.
Rot. Neutral
Neutal Int.
Int. Rot.
Rot.
3030
40
40
5050
Phase 2C: Speed of frame
• Design: mannequin limb
measured 30 times
Fast speed = 0.37m/s
Slow speed = 0.022m/s
Controlled by a motor
• Issue: Does speed of
movement affect
Perometer
measurement?
Mean Perometer measures at Slow and Fast speeds (n=30)
6720
p<0.00001
6715
6710
mls
• Results: Significant
differences between
slow and fast speeds ,
(p<0.00001)
6725
6705
6700
6695
6690
6685
Motor
1
0.022m/s
Speeds
0.37m/s
Reliability
Intra- & inter-rater reliability, n= 30, 2 raters,
2 occasions
Results:
Rater 1
Session 1
Session 2
9005.53
8993.10
1504.8
1393.9
(p<0.0001)
(p<0.0001)
Rater 2
9088.27
1417.1
9102.10
1452.9
(p<0.0001)
Phase 3: Use of software
• Issue: Software allows
limb measurement length
to change in two screens
• Design: A) reliability study
using independent
measurement of length
B) use of single limb
length measures on 2
occasions
• Results: Variability
A): n=30
B): n=10
Rater 1 = 20%
Rater 2 = 16.3%
Rater 1= 3.8%,
Rater 2 = 5.3%
Conclusions
Protocol reliable if:
1. 10 min rest period before testing with elevated
leg
2. Neutral axial rotation of limb
3. Foot placed in centre of base plate
4. Constant slow speed is maintained
5. Only 1 limb length measurement is taken and
used on repeat visits
Clinical implications
• Use of a standardised protocol will allow
reliable data to be collected on repeated
basis,
• Monitor efficacy of management of
patients with changing limb volume.
Queen Margaret University
Thank You
Acknowledgements
• MSc pre registration Physiotherapy
students:
2007
Francis Burgin
Áine O’Connor
2006
Nicola Dinsmore
Georgina Enderson
MaryAnne Geraghty