Iterative Development and Usability Evaluation of an Open-Source Rehabilitation Follow-Up Platform: User-Centered Development Study.

BACKGROUND: Rehabilitation frequently extends beyond supervised clinical settings, creating a demand for scalable digital tools to support structured follow-up. We propose a novel open-source telerehabilitation platform. OBJECTIVE: We describe the iterative, user-centered development of an open-source rehabilitation follow-up platform and report findings from an initial formative usability evaluation with patients, health care professionals, and additional end users. METHODS: The platform was developed through repeated cycles of stakeholder engagement, prototyping, and evaluation within the rehabilitation department of Insel Group, University of Bern. A formative usability evaluation was conducted with 24 participants (8 health care professionals, 9 patients, and 7 additional participants; mean age 41.1, SD 12.9 y) using a task-based protocol. Perceived usability was assessed with the System Usability Scale (scored 0-100) and the Post-Study System Usability Questionnaire (scored 1-7; higher is better). Open-ended written responses were processed by one researcher using rapid content analysis. RESULTS: A web-based telerehabilitation platform enables therapists to manage patient caseloads, assign and track personalized rehabilitation interventions, and monitor patient progress through Fitbit activity data and rehabilitation plan adherence. It supports multiclinic workflows with role-based access, REDCap patient importing (Vanderbilt University), automated background processing via Celery, and multilingual content. Its mean System Usability Scale score was 82.8 (SD 14.1), placing the platform in the "excellent" usability range. The mean Post-Study System Usability Questionnaire overall score was 6.02 (SD 0.77), with all 3 subscales scoring above 5.7. Most participants (20/24, 83%) rated the task set as easy or very easy; no participant rated any task as difficult. Among health care professionals, 7 out of 8 (88%) reported an intention to use the platform in practice. Qualitative themes highlighted the value of a rehabilitation plan overview, structured intervention scheduling, and progress tracking. CONCLUSIONS: The platform, released as open-source (Massachusetts Institute of Technology [MIT] License), demonstrated promising perceived usability across both patient and clinician user groups in a formative evaluation. These findings provide preliminary support for the platform's perceived usability and justify further evaluation in real-world rehabilitation settings. Future work will evaluate deployment in real-world outpatient settings and assess clinical effectiveness.