# Digital home-based physical activity promotion for older adults after total hip arthroplasty: protocol for the randomized controlled iPATH trial

## TL;DR

This study tests a digital home exercise program to boost physical activity in older adults after hip replacement surgery.

## Contribution

The iPATH trial introduces a novel digital home-based intervention with or without personal caching to increase post-surgery physical activity in older adults.

## Key findings

- The trial will assess the efficacy of a digital exercise program on increasing physical activity in older adults post-THA.
- Advanced monitoring tools will track outcomes like daily step count and walking distance over six months.
- The study aims to determine if digital interventions can be implemented as routine post-rehabilitation care.

## Abstract

Total hip arthroplasty (THA) effectively alleviates pain and improves physical function. However, an increase in patients’ physical activity (PA) is often not observed after surgery. This paradox may result from short rehabilitation periods and persistent sedentary habits and be further influenced by methodological limitations of previous PA monitoring approaches. Digital home-based exercise programs and personal caching (PC) using behavioral change techniques for PA promotion, together with recent advances in PA monitoring, may offer new opportunities to address these challenges. The aim of the iPATH study is to evaluate the efficacy of two novel post-rehabilitation interventions, consisting of a digital home-based physical exercise program with or without PC, compared with usual care, for increasing PA in older adults following THA using advanced PA monitoring approaches.

In this monocentric, three-arm randomized controlled trial, 213 older THA patients (≥ 65 years) will be assigned in a 1:1:1 ratio post-rehabilitation to a 12-week digital home-based exercise program (“Keep On Keep Up”) with or without additional PC for PA promotion, or usual care. The primary outcome is the mean daily step count at six months post-THA; mean daily walking distance serves as a subordinated primary outcome. Both outcomes will be collected preoperatively, post-rehabilitation, and at six months postoperatively using a body-fixed inertial measurement unit (AX6, Axivity Ltd.) combined with newly validated processing algorithms (Mobilise-D computational pipeline). Secondary outcomes include other digital and self-reported mobility outcomes, physical capacity, hip pain and function, psychological factors, falls, intervention acceptability, and health-related resource use. Primary analyses will follow the intention-to-treat principle.

The digital home-based interventions are expected to increase PA compared with usual care. If effective, they have the potential to enhance patient health, reduce morbidity and mortality risk, and be implemented as routine post-rehabilitation care for older adults recovering from THA.

ClinicalTrials.gov (NCT07135843); prospectively registered on August 22, 2025.

The online version contains supplementary material available at 10.1186/s12877-026-07013-9.