Step count as a digital mobility outcome in orthopedics and orthopedic trauma surgery: a scoping review

The need to collect objective outcome parameters digitally is increasing in both clinical practice and research. Step count is a frequently utilized digital mobility outcome (DMO) in orthopedic traumatology; however, its usefulness to monitor the patient recovery process remains unclear. The aim of this scoping review is to investigate the application and utility of daily patient step count as a DMO in musculoskeletal injuries. PubMed and consensus.app were queried. Eligibility criteria included the following: articles published within 20 years including patients with orthopedic trauma conditions and utilizing daily step count as an outcome. The type of study, case numbers, conditions investigated, use/usefulness of step count, duration of assessment, sensor use and location, and data harvesting specifics were assessed. Totally, 40 articles were analyzed, revealing an increasing trend in annual publications. The majority of studies were observational (93%), with a mean of 103 participants (range: 9-666). Proximal femur fractures (n = 7), anterior curciate ligament (ACL) injuries (n = 6), and joint replacement (n = 5) were the most frequently investigated conditions. Overall, 30% of studies used step count to demonstrate an association with patient-reported outcome measures, while 27% employed it to identify differences between study groups. Research-grade accelerometers/inertial measurement units (73%) were the most common sensors, with continuous measurement durations from 4 to 14 days. This review indicates an increasing use of step count as an objective DMO in the orthopedic trauma surgery literature. However, the implementation, application, setup, and data acquisition methodologies remain underexplored. This review highlights current trends and identifies key areas requiring further investigation in future research.