Validity evidence for a modified version of the Orthotics and Prosthetics Users’ Survey

Abstract

Purpose: To evaluate the validity of a modified version of the Orthotics and Prosthetics Users’ Survey (OPUS) with persons using different prosthetic and orthotic (P&O) devices.Method: Two-hundred-and-eighty-two adults using prosthesis, orthosis, shoe insoles or orthopaedic shoes completed OPUS. OPUS comprises five modules - Lower and Upper Extremity Functional Status, respectively (LEFS and UEFS), Client Satisfaction with Device and Services, respectively (CSD and CSS), and, Health-Related Quality of Life (HRQoL). Eight new items were added to LEFS and six to UEFS. Rasch analysis was used for data analyses.Results: Rating scales functioned satisfactory after some modifications. All modules demonstrated a ceiling effect. Unidimensionality was satisfactory after deleting some items and dividing HRQoL into two subscales, although somewhat weak on CSD and CSS. Item reliability was excellent for all modules and person reliability good for all but CSD and CSS. Some items demonstrated differential item functioning related to sex and age, but the impact on person measures was small.Conclusions: This study supports the validity of a modified version of OPUS for persons using different P&O devices, but also reveals limitations to be addressed in future studies. OPUS could be useful in clinical rehabilitation and research to evaluate P&O outcomes.

Implications for Rehabilitation

• The rehabilitation of individuals with musculoskeletal dysfunction often includes prosthetic or orthotic devices.

• There is a need for validated instruments to assess the outcomes of prosthetic and orthotic (P&O) interventions.

• This study provides validity evidence in support of using the Orthotics and Prosthetics Users’ Survey (OPUS) as an outcome measure for P&O interventions.

Keywords::

• Activities of daily living
• artificial limbs
• orthotic devices
• patient satisfaction
• quality of life
• treatment outcome
• validation studies

Acknowledgements

The authors acknowledge Britt-Marie Engwall, Inga-Lill Freijd, Emma Rosander and Kenneth Karlsson, at the Department of Prosthetics and Orthotics, Örebro County, Örebro, Susanne Löfstedt, Josefin Hjälte, and Ulla Ekholm, registered occupational therapists, at the Department of Rheumatology, and Christina Carlsson, Eva Karlsson-Schagerström, and Cathrine Fredsdal, registered occupational therapists, at the Department of Hand Surgery, Örebro University Hospital, Örebro, Sweden, for help with the data collection. The authors thank Anders Kottorp, PhD, at the Division of Occupational Therapy, Department of Neurotec, Karolinska Institutet, Stockholm, Sweden, for valuable comments on the analysis. The authors also thank all clients participating in this study.

Declaration of Interest: The authors report no conflicts of interest. This study was supported by the Centre for Rehabilitation Research and the Research Committee, Örebro County Council, Sweden and the Norrbacka-Eugenia Foundation, Sweden.

Appendix 1.  Items deleted from Orthotics and prosthetics users’ survey

Appendix 2.  Item calibration of the modified Lower extremity functional status module

Appendix 3.  Item calibration of the modified Upper extremity functional status module

Appendix 4.  Item calibration of the modified Client satisfaction with device module

Appendix 5.  Item calibration of Client satisfaction with services module

Appendix 6.  Item calibration of Health-related quality of life module, Restrictions subscale

Appendix 7.  Item calibration of Health-related quality of life module, Emotional reactions subscale