Development, Usability, and Feasibility of a #Pain-Stratified Smartphone-Based Home Intervention System for Patients With Adhesive Capsulitis: Exploratory Feasibility and Usability Trial
Background: Frozen shoulder causes prolonged #Pain and restricted range of motion that impair daily function. Home exercise is an indispensable part of self-management, but adherence is often suboptimal under traditional printed or verbal instruction because of the lack of objective monitoring and individualized progression. Existing #Rehabilitation apps offer sensor-based assessment and feedback but generally lack an adaptive mechanism that tailors the exercise prescription to a patient’s dynamically changing clinical status. Objective: This #Study aimed to develop a personalized, #Pain-stratified tele#Rehabilitation app for patients with frozen shoulder; to evaluate its usability, feasibility, and safety as an add-on to usual care; and to explore the system’s clinical outcomes on a descriptive basis. Methods: An Android app integrating smartphone sensor-based range of motion self-assessment, #Pain-based exercise stratification, usage records, and exercise reminders was developed. In an exploratory, assessor-blinded, randomized controlled feasibility trial, 10 patients with frozen shoulder were randomly allocated to an app group (n=5) or a handout group (n=5), and both underwent a 4-week home exercise intervention with identical content. Primary outcomes included system usability (System Usability Scale) and feasibility (retention and exercise adherence). Secondary outcomes focused on the exploratory clinical signs included #Pain and function (Shoulder #Pain and Disability Index) and range of motion (measured by goniometer). Given the small sample size, continuous variables were analyzed nonparametrically and interpreted strictly as descriptive clinical trends without inferential hypothesis testing. Results: All 10 participants completed the trial (attrition rate 0%). The mean System Usability Scale score in the app group was 87.5 (SD 5.86), corresponding to an “excellent” usability rating. Over the 28-day intervention, the app’s usage logs objectively documented a mean of 18.0 (SD 5.0) of 28 exercise days (18/28, 64.3%) in the app group, demonstrating the feasibility of objective home monitoring. Both groups improved in Shoulder #Pain and Disability Index scores and range of motion. Notably, all participants in the app group achieved a descriptive within-group improvement in the clinically challenging shoulder external rotation, whereas the handout group showed smaller marginal gains; however, between-group comparisons across all parameters were interpreted descriptively without significance testing due to the sample size. On the other clinical outcomes, the handout group showed numerically comparable or larger improvements. Conclusions: This #Study shows that a #Pain-stratified, personalized tele#Rehabilitation app is highly usable and feasible as an add-on mobile health intervention for patients with frozen shoulder and that it provides objective home monitoring of exercise adherence that traditional handouts cannot. These exploratory findings highlight the need for a fully powered confirmatory trial. To robustly evaluate clinical efficacy, future #Study designs must include a common objective adherence measure, stratification variables, and an extended follow-up period.