Original article
Reproducibility and Validity of the Dutch Translation of the de Morton Mobility Index (DEMMI) Used by Physiotherapists in Older Patients With Knee or Hip Osteoarthritis

Presented to the Royal Dutch Society of Physiotherapy, November 13, 2009, Amsterdam, The Netherlands.
https://doi.org/10.1016/j.apmr.2011.05.011Get rights and content

Abstract

Jans MP, Slootweg VC, Boot CR, de Morton NA, van der Sluis G, van Meeteren NL. Reproducibility and validity of the Dutch translation of the de Morton Mobility Index (DEMMI) used by physiotherapists in older patients with knee or hip osteoarthritis.

Objective

To examine the reproducibility, construct validity, and unidimensionality of the Dutch translation of the de Morton Mobility Index (DEMMI), a performance-based measure of mobility for older patients.

Design

Cross-sectional study.

Setting

Rehabilitation center (reproducibility study) and hospital (validity study).

Participants

Patients (N=28; age >65y) after orthopedic surgery (reproducibility study) and patients (N=219; age >65y) waiting for total hip or total knee arthroplasty (validity study).

Intervention

Not applicable.

Main Outcome Measures

Not applicable.

Results

The intraclass correlation coefficient for interrater reliability was high (.85; 95% confidence interval, 71–.93), and minimal detectable change with 90% confidence was 7 on the 100-point DEMMI scale. Rasch analysis identified that the Dutch translation of the DEMMI is a unidimensional measure of mobility in this population. DEMMI scores showed high correlations with scores on other performance-based measures of mobility (Timed Up and Go test, Spearman r=−.73; Chair Rise Time, r=−.69; walking test, r=.74). A lower correlation of .44 was identified with the self-report measure Western Ontario and McMaster Universities Osteoarthritis Index.

Conclusions

The Dutch translation of the DEMMI is a reproducible and valid performance-based measure for assessing mobility in older patients with knee or hip osteoarthritis.

Section snippets

Translation

We used the forward-backward translation method recommended by Guillemin et al.12 Two qualified translators independently translated the DEMMI into Dutch. Two other translators independently back-translated each translation into English. All translators were highly educated, translated the DEMMI into their mother tongue, and had no specific knowledge of osteoarthritis. Because physiotherapists are the users of the DEMMI, the Dutch translation subsequently was submitted to 3 physiotherapists

Translation

The 2 forward-backward translations yielded no differences in the description of DEMMI items (see Appendix 1). Some instructions in the protocol for administration of the DEMMI have been described in more detail after consulting the test developer (N.A.d.M.).

Reproducibility

The 2 physiotherapists assessed 28 patients (26 women; mean ± SD age, 73±8y). Fourteen patients underwent total hip replacement, 7 underwent total knee replacement, and 7 underwent other orthopedic surgeries. Nine patients used a walking

Discussion

This was the first study of the reproducibility and validity of the Dutch translation of the DEMMI used by physiotherapists and performed in a population of older people with knee or hip osteoarthritis.

Interrater reliability between 2 physiotherapists was good. There were no systematic differences between the 2 raters. The MDC90 indicated that a patient needs to improve or deteriorate by 7 or more points for a physiotherapist to be 90% confident that a true change in patient condition has

Conclusions

This study provides evidence that the Dutch translation of the DEMMI is a unidimensional, reproducible, valid, and feasible measure of mobility for use by physiotherapists in older patients with knee or hip osteoarthritis. The simplicity and utility of the DEMMI make this instrument easy to fit into usual clinical care.

References (22)

  • M. Cuska et al.

    Simple method for measurement of lower extremity muscle strength

    Am J Med

    (1985)
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    Supported by a National Health and Medical Research Council of Australia (NHMRC) Post Doctoral Fellowship (ID 519555).

    No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.

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