To Örebro University

There is an increasing need for outcome measures in the orthotic and prosthetic field and specifically a lack of outcome measures in Swedish. The Orthotics and Prosthetics Users' Survey (OPUS) was developed in the USA for assessment of the outcome of orthotic and prosthetic interventions, and could potentially also be used for shoe insoles and orthopaedic shoes. The aims of this study were to translate OPUS into Swedish and test the translated version's linguistic validity in a Swedish context. The Orthotic and Prosthetic Users' Survey was translated into Swedish and back-translated into English, following a modified version of the World Health Organization guidelines. After revision of the Swedish version, 39 Swedish clients (12 men, 27 women) answered the OPUS questionnaires and were systematically debriefed afterwards. Most items were understood correctly by the respondents, but some words and expressions had to be changed to avoid misunderstandings or unintended interpretations. The resulting Swedish version of OPUS, OPUS-Swe, showed acceptable linguistic validity and has potential for use in both clinical practice and scientific settings. Nevertheless, before OPUS-Swe can be fully implemented, its psychometric properties need to be evaluated.

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.

Background: The Orthotics and Prosthetics Users' Survey consists of five modules to assess outcomes of orthotic and prosthetic interventions: lower extremity functional status, upper extremity functional status, client satisfaction with device, client satisfaction with services and health-related quality of life.

Objectives: To investigate the test-retest reliability and calculate the smallest detectable difference for all modules of the Swedish Orthotics and Prosthetics Users' Survey.

Study design: Test-retest reliability study design.

Methods: A total of 69 patients at a Department of Prosthetics and Orthotics completed Orthotics and Prosthetics Users' Survey on two occasions separated by a 2-week interval, giving 18 answers on lower extremity functional status, 41 on upper extremity functional status, 53 on client satisfaction with device, 12 on client satisfaction with services and 67 answers on health-related quality of life. Raw scores were converted into Orthotics and Prosthetics Users' Survey units on a 0-100 scale. Intra-class correlation coefficients, Bland-Altman plots, common person linking plots and t-tests of person mean measures were used to investigate the reliability. The 95% confidence level smallest detectable differences were calculated.

Results: The intra-class correlation coefficients ranged from 0.77 to 0.96 for the modules, and no systematic differences were detected between the response occasions. The smallest detectable differences ranged from 7.4 to 16.6 units.

Conclusions: The test-retest reliability was satisfactory for all Orthotics and Prosthetics Users' Survey modules. The smallest detectable difference was large on all modules except the health-related quality of life module.

Clinical relevance: The Orthotics and Prosthetics Users' Survey modules are reliable and, thus, can be recommended for repeated measurements of patients over time. Relatively large changes are needed to achieve statistical significance when assessing individual patients.

Objective: To investigate the cross-cultural validity of the Orthotics and Prosthetics Users’ Survey (OPUS), to investigate differential item functioning (DIF) in the OPUS related to sex, age, amputation level and amputated sides (unilateral or bilateral), and to determine the known-group validity of the OPUS.

Design: Cross-sectional study design.

Setting: 2 outpatient clinics in Sweden and 7 outpatient clinics in the United States.

Participants: A total of 195 Swedish and 126 American adults using lower limb prosthesis.

Interventions: Not applicable.

Main Outcome Measure: 4 modules from the OPUS were used in this study, including the Lower extremity functional status (LEFS), Client satisfaction with device (CSD), Client satisfaction with services (CSS), and Health-related quality of life (HRQoL) modules. Items were scored on 4- or 5-level Likert scales, and a Rasch measure was calculated for each person and module.

Results: The cross-cultural validity was satisfactory. Many items demonstrated DIF related to country and demographic characteristics, but the impact on mean person measures was negligible. The rating scales of the CSD and CSS needed adjustments, and the unidimensionality of the CSD and CSS was weak. The differences between the mean measures of known patient groups were statistically significant for age in the LEFS and for the level of amputation in the CSD.

Conclusions: This study supports the validity of comparing OPUS measures between Sweden and USA and between patient groups with different demographic characteristics. The OPUS can, to some extent, discriminate between patient groups known to be different. The unidimensionality of the CSD and CSS modules is weaker than the other modules and these need further development and evaluation.