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Towards understanding knee joint laxity: errors in non-invasive assessment of joint rotation can be corrected

Towards understanding knee joint laxity: errors in non-invasive assessment of joint rotation can be corrected
Towards understanding knee joint laxity: errors in non-invasive assessment of joint rotation can be corrected
The in vivo quantification of rotational laxity of the knee joint is of importance for monitoring changes in joint stability or the outcome of therapies. While invasive assessments have been used to study rotational laxity, non-invasive methods are attractive particularly for assessing young cohorts. This study aimed to determine the conditions under which tibio-femoral rotational laxity can be assessed reliably and accurately in a non-invasive manner. The reliability and error of non-invasive examinations of rotational joint laxity were determined by comparing the artefact associated with surface mounted markers against simultaneous measurements using fluoroscopy in five knees including healthy and ACL deficient joints. The knees were examined at 0°, 30°, 60° and 90° flexion using a device that allows manual axial rotation of the joint. With a mean RMS error of 9.6°, the largest inaccuracy using non-invasive assessment was present at 0° knee flexion, whereas at 90° knee flexion, a smaller RMS error of 5.7° was found. A Bland and Altman assessment indicated that a proportional bias exists between the non-invasive and fluoroscopic approaches, with limits of agreement that exceeded 20°. Correction using average linear regression functions resulted in a reduction of the RMS error to below 1° and limits of agreement to less than ±1° across all knees and flexion angles. Given the excellent reliability and the fact that a correction of the surface mounted marker based rotation values can be achieved, non-invasive evaluation of tibio-femoral rotation could offer opportunities for simplified devices for use in clinical settings in cases where invasive assessments are not justified. Although surface mounted marker based measurements tend to overestimate joint rotation, and therefore joint laxity, our results indicate that it is possible to correct for this error
knee laxity, fluoroscopy, rotational stability, motion capture, surface mounted markers, soft tissue artefact
1350-4533
889-895
Moewis, P.
9e97e918-0605-4ad5-a760-e296ed40cde4
Boeth, H.
6c2adb2d-3219-46d3-9aac-c09ffc4c98ba
Heller, M.O.
3da19d2a-f34d-4ff1-8a34-9b5a7e695829
Yntema, C.
166d1acc-dc07-496b-9ddf-ad31c262f126
Jung, T.
682b6033-ebca-4a9f-9b71-5f278ed7fe41
Doyscher, R.
5fa1d3b2-c3ca-44da-aa13-5cd7c284a98b
Ehrig, R.
cb1e8040-8e32-4c84-bd40-1665fc616bc5
Taylor, W.R.
4f1cd2b0-4963-4b10-bbde-da586c069e77
Moewis, P.
9e97e918-0605-4ad5-a760-e296ed40cde4
Boeth, H.
6c2adb2d-3219-46d3-9aac-c09ffc4c98ba
Heller, M.O.
3da19d2a-f34d-4ff1-8a34-9b5a7e695829
Yntema, C.
166d1acc-dc07-496b-9ddf-ad31c262f126
Jung, T.
682b6033-ebca-4a9f-9b71-5f278ed7fe41
Doyscher, R.
5fa1d3b2-c3ca-44da-aa13-5cd7c284a98b
Ehrig, R.
cb1e8040-8e32-4c84-bd40-1665fc616bc5
Taylor, W.R.
4f1cd2b0-4963-4b10-bbde-da586c069e77

Moewis, P., Boeth, H., Heller, M.O., Yntema, C., Jung, T., Doyscher, R., Ehrig, R. and Taylor, W.R. (2014) Towards understanding knee joint laxity: errors in non-invasive assessment of joint rotation can be corrected. Medical Engineering & Physics, 36 (7), 889-895. (doi:10.1016/j.medengphy.2014.03.017). (PMID:24780754)

Record type: Article

Abstract

The in vivo quantification of rotational laxity of the knee joint is of importance for monitoring changes in joint stability or the outcome of therapies. While invasive assessments have been used to study rotational laxity, non-invasive methods are attractive particularly for assessing young cohorts. This study aimed to determine the conditions under which tibio-femoral rotational laxity can be assessed reliably and accurately in a non-invasive manner. The reliability and error of non-invasive examinations of rotational joint laxity were determined by comparing the artefact associated with surface mounted markers against simultaneous measurements using fluoroscopy in five knees including healthy and ACL deficient joints. The knees were examined at 0°, 30°, 60° and 90° flexion using a device that allows manual axial rotation of the joint. With a mean RMS error of 9.6°, the largest inaccuracy using non-invasive assessment was present at 0° knee flexion, whereas at 90° knee flexion, a smaller RMS error of 5.7° was found. A Bland and Altman assessment indicated that a proportional bias exists between the non-invasive and fluoroscopic approaches, with limits of agreement that exceeded 20°. Correction using average linear regression functions resulted in a reduction of the RMS error to below 1° and limits of agreement to less than ±1° across all knees and flexion angles. Given the excellent reliability and the fact that a correction of the surface mounted marker based rotation values can be achieved, non-invasive evaluation of tibio-femoral rotation could offer opportunities for simplified devices for use in clinical settings in cases where invasive assessments are not justified. Although surface mounted marker based measurements tend to overestimate joint rotation, and therefore joint laxity, our results indicate that it is possible to correct for this error

Full text not available from this repository.

More information

Accepted/In Press date: 24 March 2014
Published date: July 2014
Keywords: knee laxity, fluoroscopy, rotational stability, motion capture, surface mounted markers, soft tissue artefact
Organisations: Bioengineering Group

Identifiers

Local EPrints ID: 381845
URI: http://eprints.soton.ac.uk/id/eprint/381845
ISSN: 1350-4533
PURE UUID: 397544f0-16ab-4bd0-b82a-82ea2b0ad5e9
ORCID for M.O. Heller: ORCID iD orcid.org/0000-0002-7879-1135

Catalogue record

Date deposited: 16 Oct 2015 09:22
Last modified: 18 Feb 2021 17:19

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