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The variability of goniometric measurements in ambulatory children with spastic cerebral palsy
B C McDowell1, V Hewitt, A Nurse
1Rehabilitation Sciences Research Group, University of Ulster, BT37 OQB, Newtownabbey, UK. bc.mcdowell@ulst.ac.uk
Insights
Goniometric measurements in children with cerebral palsy (CP) show significant measurement error, especially on different days. This highlights the need for caution in clinical decision-making based on these joint range assessments.
Area of Science:
- Pediatric Physical Therapy
- Biomedical Engineering
- Clinical Measurement
Background:
- Cerebral palsy (CP) management relies on accurate joint range assessments.
- Goniometric measurements are standard tools for evaluating joint mobility in children with CP.
- Variability in these measurements can impact clinical decisions and treatment efficacy.
Purpose of the Study:
- To quantify the measurement error of commonly used goniometric assessments in children with CP.
- To identify sources of variability in repeated goniometric measurements.
- To inform the reliable use of goniometry in pediatric physical therapy.
Main Methods:
- Six goniometric joint measurements were performed on 12 children with spastic CP by three experienced pediatric physiotherapists.
- Measurements were taken consecutively on the same day and repeated one week later.
- A randomized, blinded procedure was employed, with generalizability theory used for analysis.
Main Results:
- Same-day measurement error ranged from +/-10-14 degrees for hip measurements (foot/thigh angle, abduction, internal rotation).
- Different-day measurement error increased significantly for ankle dorsiflexion and popliteal angles, ranging from +/-18-28 degrees.
- Child-assessor interaction and systematic differences between days were identified as major error sources.
Conclusions:
- Goniometric measurements in children with CP exhibit considerable variability, particularly when taken on different days.
- Clinicians should exercise caution when interpreting goniometric data for clinical decision-making, especially for tone-dependent muscles.
- Standardized protocols and awareness of measurement error are crucial for reliable CP assessment.
Abstract:
This study assessed the variability of six goniometric measurements commonly used in the assessment of children with cerebral palsy (CP). Three experienced paediatric physiotherapists recorded three consecutive measurements of six joint ranges from 12 children with spastic CP. A fourth measurement was recorded 1 week later. The order of measurement with regards to both joint measurement and tester, was randomised to ensure a balanced experimental design. A blinded procedure was adopted with masked goniometers and a second assessor present to record the measurement. Results, analysed using generalizability theory, showed same day and different day measurement error of +/-10-14 degrees (95% confidence limits) for the foot/thigh angle, abduction and internal rotation of the hip. The source of this was child-assessor and residual error. For ankle dorsiflexion and the popliteal angles, same day measurement error was similar. However, for joint ranges recorded on different days, error ranged from +/-18-28 degrees. The major source of this was systematic differences in measurements recorded on different days. Results show a need for caution when using goniometric measurements in clinical decision making, particularly in the more tone dependent biarticular muscles after an initial assessment.
