Correlation between smartwatch-measured daily walking steps and patient-reported functional outcomes following total knee arthroplasty: a prospective cohort study
Issued Date
2026-02-09
Resource Type
eISSN
1749799X
Scopus ID
2-s2.0-105033511429
Pubmed ID
41656254
Journal Title
Journal of Orthopaedic Surgery and Research
Volume
21
Issue
1
Rights Holder(s)
SCOPUS
Bibliographic Citation
Journal of Orthopaedic Surgery and Research Vol.21 No.1 (2026)
Suggested Citation
Achawakulthep C., Khattiya S., Chareancholvanich K., Pornrattanamaneewong C., Awirotananon K., Narkbunnam R. Correlation between smartwatch-measured daily walking steps and patient-reported functional outcomes following total knee arthroplasty: a prospective cohort study. Journal of Orthopaedic Surgery and Research Vol.21 No.1 (2026). doi:10.1186/s13018-025-06591-5 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/115914
Title
Correlation between smartwatch-measured daily walking steps and patient-reported functional outcomes following total knee arthroplasty: a prospective cohort study
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Corresponding Author(s)
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Abstract
BACKGROUND: Patient-reported outcome measures (PROMs) are the clinical standard for assessing recovery after total knee arthroplasty (TKA) which reflect patients' perceived function, whereas smartwatch step counts capture real-world activity. Whether their changes align after TKA is uncertain. We therefore assessed correlations between changes in daily steps and changes in PROMs. METHODS: In this prospective single-centre cohort, 86 patients undergoing unilateral primary TKA received a consumer-grade smartwatch (Polar A370™). Daily steps and PROMs were recorded 1 month pre-operatively and at 3 and 6 months post-operatively. PROMs comprised the Oxford Knee Score (OKS; 0-48, higher = better) and the KOOS-Physical Function Short-form (KOOS-PS; 0-28, higher = worse). Change scores were computed so that positive values indicated improvement. Pearson correlations assessed associations between change in steps and change in PROMs; paired t-tests compared pre-operative with 6-month values. RESULTS: Of 96 enrolled patients, 86 (89.6%) completed the 6-month follow-up. At 6 months, functional outcomes improved substantially: OKS increased from 26.4 (6.6) to 38.4 (5.8) (p < 0.001), and KOOS-PS decreased from 14.1 (4.3) to 9.8 (2.7) (p < 0.001). Daily steps increased modestly from 6651 (4,294) to 7807 (4,363) (p = 0.008). Correlations between change in steps and change in PROMs were negligible: OKS r = 0.055 (95% CI - 0.159 to 0.264) and KOOS-PS r = 0.071 (95% CI - 0.143 to 0.279). CONCLUSIONS: Although PROMs improved markedly after TKA, they showed little correlation with smartwatch-measured step counts. Patient-reported outcomes and objective activity data reflect different aspects of recovery and should be interpreted as complementary rather than hierarchical measures. IRB approval: Si COA 582/2022.