Testing the usability and acceptability of the NON-STOP app for children with Perthes’ disease

Aims

Perthes’ disease is a childhood hip condition that requires prolonged management, which often includes physiotherapy and education. Families and clinicians have highlighted a need for optimized self-management. The NON-STOP app was developed as a digital self-management intervention. The app incorporates exercises, educational content, and a reward system including a customisable avatar to motivate children to engage. This study assessed the usability and acceptability of the NON-STOP app in preparation for a definitive clinical trial.

Methods

A mixed-methods study was undertaken, involving an observational before-and-after study, with a nested focus group study. Children with Perthes’ disease from three UK NHS centres were recruited and used the Non-Surgical Treatment of Perthes’ (NON-STOP) app for six weeks. Quantitative data included app engagement metrics, quality of life and function (for follow-up completion rates), physical activity levels (Children’s Physical Activity Questionnaire), and app-usability (Health Information Technology Usability Evaluation Scale (Health ITUES)). Following this, focus groups with participating families explored their experiences to explore usability and acceptability in more detail and also inform refinement of the app.

Results

A total of 31 children were recruited, 20 of whom completed post-trial data. Health ITUES scores demonstrated high usability, with particularly high scores in ‘perceived ease of use’ and ‘usefulness’. Engagement was highest in the first three weeks, with a decline thereafter. Focus group participants described the app as more engaging than previous self-management tools (e.g. paper handouts), citing rewards, avatars, and a user-friendly layout as positive elements. Suggested improvements included further personalization and inclusion of videos in the education section of the app.

Conclusion

The NON-STOP app was found to be both usable and acceptable by children with Perthes’ disease and their families. Insights from this study have informed further refinements to the app in preparation for its integration in Op NON-STOP trial, the first randomized clinical trial comparing surgical and non-surgical treatment in Perthes’ disease.