Can a mobile app support recovery after hip or knee replacement? A feasibility study of patient engagement and usability

Brief name: Digital rehabilitation support platform (SimpliMove) integrated with usual physiotherapy care Participants undergoing total hip replacement (THR) or total knee replacement (TKR) will receive usual physiotherapy care in addition to access to a digital rehabilitation support platform (SimpliMove), delivered via a mobile device. Participants with THR and TKR will be analysed as a single cohort for this feasibility study. However, the exercise programs provided within the digital intervention are tailored to the type of surgery (hip or knee replacement) and reflect condition-specific rehabilitation pathways consistent with usual care. The digital platform provides standardised rehabilitation content and includes: Pre-operative and post-operative exercise programs (0–2 weeks, 3–6 weeks, and 7–12 weeks post-operatively), delivered via video, images, and written instructions Educational materials (PDF resources) covering recovery expectations, precautions, and rehabilitation guidance Automated daily reminders/notifications to support exercise adherence Contact information for the treating physiotherapy department The exercise and educational content are not developed specifically for this study. They are based on existing physiotherapy protocols routinely provided by Armidale Rural Referral Hospital (ARRH) and are delivered via the SimpliMove platform in a digital format. Examples of exercises included in the intervention: Hip replacement: ankle pumps, quadriceps sets, gluteal sets, heel slides, sit-to-stand practice Knee replacement: knee flexion/extension range of motion exercises, quadriceps strengthening, straight leg raises, sit-to-stand practice The intervention is delivered remotely via a patient-facing mobile application, accessed through a secure link sent via SMS or email following consent. Participants are instructed to use the platform 2–3 times per day, with each session taking approximately 20–30 minutes. Adherence to the intervention is assessed through: Participant self-reported completion of exercises via study surveys Usage data from the mobile application (e.g. logins and program access) The platform does not provide real-time clinical monitoring, clinician-directed progression, or emergency support. Usual Physiotherapy Care: Usual care at Armidale Rural Referral Hospital (ARRH) includes: Post-operative physiotherapy only (no routine pre-operative physiotherapy) Weekly physiotherapy-led group classes (hip and knee replacement class) Duration: approximately 60 minutes per session Frequency: once per week for 4–6 weeks post-operatively Mode of delivery: face-to-face group-based sessions Participants are also expected to complete independent home exercises outside of these sessions. Examples of exercises prescribed in usual care: Hip replacement: mobility exercises, strengthening (e.g. gluteal and quadriceps exercises), functional tasks such as sit-to-stand Knee replacement: range of motion exercises, strengthening (quadriceps-focused), functional retraining including sit to stand and stairs There is no routine one-to-one outpatient physiotherapy provided as part of usual care for these patients.