Content » Vol 50, Issue 6

Original report

Evaluation of the wear-and-tear scale for therapeutic footwear, results of a generalizability study

Rutger Dahmen, Petra C. Siemonsma, Sandra Monteiro, Geoffrey R. Norman, Maarten Boers, Gustaaf J. Lankhorst, Leo D. Roorda
Rehabilitation, Amsterdam Rehabilitation Research Center | Reade P.O. Box 58271, 1040 HG Amsterdam, The Netherlands. E-mail:
DOI: 10.2340/16501977-2339


Objective: Therapeutic footwear is often prescribed at considerable cost. Foot-care specialists normally assess the wear-and-tear of therapeutic footwear in order to monitor the adequacy of the prescribed footwear and to gain an indicator of its use. We developed a simple, rapid, easily applicable indicator of wear-and-tear of therapeutic footwear: the wear-and-tear scale. The aim of this study was to investigate the intra- and inter-rater reliability of the wear-and-tear scale.
Methods: A test set of 100 therapeutic shoes was assembled; 24 raters (6 inexperienced and 6 experienced physiatrists, and 6 inexperienced and 6 experienced orthopaedic shoe technicians) rated the degree of wear-and-tear of the shoes on the scale (range 0–100) twice on 1 day with a 4-h interval (short-term) and twice over a 4-week interval (long-term). Generalizability theory was applied for the analysis.
Results: Short-term, long-term and overall intra-rater reliability was excellent (coefficients 0. 99, 0. 99 and 0. 98; standard error of measurement (SEM) 2. 6, 2. 9 and 3. 9; smallest detectable changes (SDC) 7. 3, 8. 0 and 10. 8, respectively). Inter-rater reliability between professions, experience and inexperienced raters, and overall was excellent (coefficients 0. 97, 0. 98 and 0. 93; SEM 4. 9, 4. 5, and 8. 1; SDC 13. 7, 12. 4 and 22. 5, respectively).
Conclusion: The wear-and-tear scale has excellent intra-rater, inter-rater, and overall reliability.

Lay Abstract

People with conditions such as diabetes mellitus, rheumatoid arthritis and osteoarthritis often experience foot problems that cause pain and abnormal form and functioning, leading to limitations in standing and walking. In the Netherlands, therapeutic footwear (TF) is part of the usual care prescribed and controlled at the multidisciplinary foot-care clinic by physiatrists and orthopaedic shoe technicians. These professionals judge the wear-and-tear of TF in order to monitor the adequacy of the prescribed footwear, to gain an indicator of its use, and to determine the necessity for a new pair of these expensive TF. The aim of this study was to evaluate a tool for measuring the wear-and-tear of TF: the wear-and-tear scale.

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