Accelerometry-based functional outcomes across total and partial knee and hip replacement: a propensity-matched UK biobank study
File(s)
Accepted version
Author(s)
Glynou, Sevasti
Musbahi, Omar
Sousi, Sara
Cobb, Justin
Type
Journal Article
Abstract
Aims
To evaluate objectively measured physical activity after hip and knee arthroplasty using accelerometry, by comparing bone-preserving procedures with total replacements and benchmarking both against non-arthritic controls.
Methods:
This observational study was conducted within the UK Biobank. Adults aged 40–69 years with total knee replacement (TKR), unicompartmental knee replacement (UKR), total hip replacement (THR), or hip resurfacing (HR) were identified through linked hospital records
and completed 7-day wrist-worn accelerometry (Axivity AX3). Outcomes included adjusted daily step count (primary), peak cadence, moderate-to-vigorous physical activity (MVPA), and Euclidean Norm Minus One (ENMO). Surgical groups were propensity score–matched to non
arthritic controls on demographics, lifestyle factors, and comorbidities. Direct comparisons between procedure types were examined using both propensity-matched analyses and complementary multivariable regression and adjusted for demographic and clinical covariates..
Subgroup analyses considered ≤12 months and >12 months post-surgery.
Results
A total of 2,283 participants were included (TKR = 860, UKR = 162, THR = 1,168, HR = 93). Compared with matched controls, TKR and THR patients showed persistently lower activity, while UKR and HR achieved levels similar to controls. In the knee cohort, UKR patients walked significantly more steps/day than TKR (9,150 vs 8,151; +12%, p<0.001) with higher cadence; these differences persisted after matching and across time strata. In the hip cohort, HR patients outperformed THR (10,112 vs 9,253 steps/day; +9%, p=0.04) and demonstrated higher peak cadence, and HR remained comparable to controls. All groups fell within the
“somewhat active” to “active” step-count range (7,500–12,499 steps/day).
Conclusion
UKR and HR are associated with higher postoperative activity compared with total arthroplasty (TKR, THR). Accelerometry provides an objective, scalable assessment of functional recovery, highlighting procedure-specific differences that should be considered alongside implant longevity when selecting surgical options.
To evaluate objectively measured physical activity after hip and knee arthroplasty using accelerometry, by comparing bone-preserving procedures with total replacements and benchmarking both against non-arthritic controls.
Methods:
This observational study was conducted within the UK Biobank. Adults aged 40–69 years with total knee replacement (TKR), unicompartmental knee replacement (UKR), total hip replacement (THR), or hip resurfacing (HR) were identified through linked hospital records
and completed 7-day wrist-worn accelerometry (Axivity AX3). Outcomes included adjusted daily step count (primary), peak cadence, moderate-to-vigorous physical activity (MVPA), and Euclidean Norm Minus One (ENMO). Surgical groups were propensity score–matched to non
arthritic controls on demographics, lifestyle factors, and comorbidities. Direct comparisons between procedure types were examined using both propensity-matched analyses and complementary multivariable regression and adjusted for demographic and clinical covariates..
Subgroup analyses considered ≤12 months and >12 months post-surgery.
Results
A total of 2,283 participants were included (TKR = 860, UKR = 162, THR = 1,168, HR = 93). Compared with matched controls, TKR and THR patients showed persistently lower activity, while UKR and HR achieved levels similar to controls. In the knee cohort, UKR patients walked significantly more steps/day than TKR (9,150 vs 8,151; +12%, p<0.001) with higher cadence; these differences persisted after matching and across time strata. In the hip cohort, HR patients outperformed THR (10,112 vs 9,253 steps/day; +9%, p=0.04) and demonstrated higher peak cadence, and HR remained comparable to controls. All groups fell within the
“somewhat active” to “active” step-count range (7,500–12,499 steps/day).
Conclusion
UKR and HR are associated with higher postoperative activity compared with total arthroplasty (TKR, THR). Accelerometry provides an objective, scalable assessment of functional recovery, highlighting procedure-specific differences that should be considered alongside implant longevity when selecting surgical options.
Date Acceptance
2026-06-01
Citation
Bone & Joint Research
ISSN
2046-3758
Publisher
The British Editorial Society of Bone & Joint Surgery
Journal / Book Title
Bone & Joint Research
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
License URL
Publication Status
Accepted
Date Publish Online
2026-06-17