Wearable sensor-based measures of step-up transfers are supplementary to patient-reported outcome measures following total joint arthroplasty

Disabil Rehabil. 2023 Jun 5:1-8. doi: 10.1080/09638288.2023.2219066. Online ahead of print.


Purpose: This study investigated the longitudinal assessment of step-up performance in patients undergoing total joint arthroplasty (TJA) and correlation with subjective patient reported outcome measures (PROMs).

Methods: In this sub-analysis of the ADAPT study, PROMs were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Block step-up (BS) transfers were assessed by wearable-derived measures of time. 76 patients undergoing TJA were included. Subgroups were formed isolating the worst performing quartile (low functioning (LF)) from the high functioning (HF), and outcomes were compared.

Results: One-year post-surgery, WOMAC function demonstrated strong correlations to WOMAC pain (Pearson's r = 0.67-0.84) and moderate correlations to BS performance (Pearson's r = 0.31-0.54). Both WOMAC and BS significantly improved with a larger effect size for the HF subgroup (0.62 vs. 0.43; p < 0.05). Patients designated to the LF subgroup at 3 months had increased odds of representing the LF subgroup at 12 months (WOMAC = 19; BS = 4). WOMAC defined 18 LF patients at 12 months follow-up. BS performance identified 9 additional LF patients.

Conclusions: WOMAC function scores seem pain dominated. Measures of BS performance allow assessment of otherwise hidden residual functional impairment. Lower functioning 3 months post-surgery is predictive of longer-term impairment.

Keywords: Arthroplasty; WOMAC; outcome assessment; patient reported outcome measures; performance-based test.

Plain language summary

Severe hip or knee osteoarthritis is a disabling condition which not only impacts patients’ mobility but restricts quality of life due to constant pain and consequential lifestyle changes.Total joint arthroplasty (TJA) has developed into a successful intervention for patients with advanced hip or knee osteoarthritis.Some patients are dissatisfied after TJA due to residual functional impairment and the inclusion of performance-based tests in the post-operative evaluation and rehabilitation allows for the assessment of otherwise hidden residual impairment.Early detection of functional impairment using the repeated block step-up (BS) transfers allows to facilitate more targeted rehabilitation for better functional outcomes.