DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 129
Intra- and interrater reliability of pressure pain threshold
in children with orthopedic disorders
Line Kjeldgaard Pedersen, Anders Due Kristensen, Lone Nikolajsen,
Ole Rahbek, Troels Staehelin Jensen, Bjarne Møller Madsen
Ortopædkirurgisk afdeling & Dansk Smerteforsknings Center,
Århus Sygehus
Background: Children undergoing orthopedic surgery are often in pain.
Assessment of pain in children can be difficult and alternative tools for assessing
the threshold for pain in children would be an advantage. Pressure algometry
can be used to assess pain thresholds.
Purpose: It has been documented that children with a history of growing pains
or unspecific abdominal pain have lower pressure pain threshold than healthy
children. This study determines the intra- rater/inter-rater agreement of pressure
pain thresholds in children with orthopedic disorders.
Methods: 50 children aged 4-12 years attending the orthopedic outpatient clinic
at Aarhus University Hospital underwent pressure algometry examination. To
determine both the intra-rater and inter-rater agreement 20 were examined twice
and 20 were examined by two different investigators. Ten children were only
examined once. A Somedic „µ pressure algometer with a rubber surface of 1
cm2 was applied to the skin with a gradually increasing force. Pain pressure
threshold is defined as the minimum pressure applied that can induce pain. The
child was instructed to say ¡¥stop¡ı when the sensation of pressure changed into
a sensation of pain. The thenar of the dominant hand and the back of the calf
were examined.
Findings: The mean age of the children was 8.2 years. The pressure pain threshold
was calculated as the mean of two successive thresholds. Descriptive statistics
was used for demographic data and the Bland-Altman test was used to test
inter-rater and intra- rater reliability. The mean pressure pain threshold was 183
kPa at the thenar and 179 kPa at the leg. Bland-Altman plots revealed very good
intrarater reliability and good interrater reliability between the two examiners.
Pressure pain thresholds were significantly lower both at the leg (difference:
41.4 kPa, SD: 57.5, p< 0.01) and at the thenar (difference: 29.4 kPa, SD: 42.7,
p