Is the Q-angle an absolute or a variable measure? Measurement of the Q-angle over one minute in healthy subjects
Is the Q-angle an absolute or a variable measure? Measurement of the Q-angle over one minute in healthy subjects
Background and Purpose
The quadriceps angle (Q-angle) is currently the only measurement of patellofemoral mechanics available in the clinical situation which does not necessitate the use of sophisticated radiographic equipment. It is generally assumed that for a given subject position and measurement procedure, the Q-angle is an absolute value rather than one which may vary with time. However, this assumption has never been tested. The purpose of this study was to determine whether the Q-angle varies with time.
Methods
The Q-angle of 51 healthy subjects was measured continuously for one minute in the standing position using a video motion analysis system of proven accuracy and reliability.
Results
The Q-angle varied by an average of 3.12° (1.46°-6.97°) over the one minute tested, with a repeatability coefficient of 3.4°.
Conclusion
The data indicate that when measured in the standing position the Q-angle is not an absolute measure, but one which varies with time. It is proposed that when the Q-angle is measured in the clinical situation with a goniometer, the value achieved is not a definitive measurement, but a snapshot in time of the individual's Q-angle within a given range.
q-angle, patellofemoral joint, variability
296 - 302
Wilson, T.
87508743-be38-43b7-93cf-3471dc5152b2
Kitsell, F. K.
36908d2f-bc02-4f5a-af1e-ff9048af3b4b
2002
Wilson, T.
87508743-be38-43b7-93cf-3471dc5152b2
Kitsell, F. K.
36908d2f-bc02-4f5a-af1e-ff9048af3b4b
Wilson, T. and Kitsell, F. K.
(2002)
Is the Q-angle an absolute or a variable measure? Measurement of the Q-angle over one minute in healthy subjects.
Physiotherapy, 88 (5), .
(doi:10.1016/S0031-9406(05)61422-8).
Abstract
Background and Purpose
The quadriceps angle (Q-angle) is currently the only measurement of patellofemoral mechanics available in the clinical situation which does not necessitate the use of sophisticated radiographic equipment. It is generally assumed that for a given subject position and measurement procedure, the Q-angle is an absolute value rather than one which may vary with time. However, this assumption has never been tested. The purpose of this study was to determine whether the Q-angle varies with time.
Methods
The Q-angle of 51 healthy subjects was measured continuously for one minute in the standing position using a video motion analysis system of proven accuracy and reliability.
Results
The Q-angle varied by an average of 3.12° (1.46°-6.97°) over the one minute tested, with a repeatability coefficient of 3.4°.
Conclusion
The data indicate that when measured in the standing position the Q-angle is not an absolute measure, but one which varies with time. It is proposed that when the Q-angle is measured in the clinical situation with a goniometer, the value achieved is not a definitive measurement, but a snapshot in time of the individual's Q-angle within a given range.
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More information
Published date: 2002
Additional Information:
"Lay abstract" - Q-angle is a measurement construct mentioned in 75% of articles on anterior knee pain, a condition affecting up to 25% of the population. This was the first piece of work demonstrating that it is not an absolute measure, as previously thought, but a variable one. As such, it has significant implications for treatment
Keywords:
q-angle, patellofemoral joint, variability
Identifiers
Local EPrints ID: 18113
URI: http://eprints.soton.ac.uk/id/eprint/18113
ISSN: 0031-9406
PURE UUID: 220b6ed9-f602-4c86-9a23-d8e5cbcf9fa2
Catalogue record
Date deposited: 27 Oct 2005
Last modified: 15 Mar 2024 06:02
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Contributors
Author:
T. Wilson
Author:
F. K. Kitsell
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