Patient-Reported Outcomes After Total Knee Arthroplasty: Comparisons Across TKA Procedures and PRO Domains
Author(s)
Xin Zhang, PhD1, Ling Jie Cheng, PhD2, Qian Yi, PhD3, Wei Loong Barry Tan, PhD4, Nick Bansback, PhD5, Wai San Tam, PhD6, HONGGU HE, PhD6, Hui Hoi Po, PhD4, Melvin Tan, PhD4, Glen Liau, PhD4, Khang Chiang Pang, PhD4, Harish Sivasubramanian, PhD4, Nan Luo, PhD1.
1Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore, 2National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom, 3School of Public Health, Zhejiang University, School of Medicine, Hangzhou, China, 4Department of Orthopaedic Surgery, National University Hospital, Singapore, Singapore, Singapore, 5School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada, 6Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
1Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore, 2National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom, 3School of Public Health, Zhejiang University, School of Medicine, Hangzhou, China, 4Department of Orthopaedic Surgery, National University Hospital, Singapore, Singapore, Singapore, 5School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada, 6Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
OBJECTIVES: To compare patient-reported outcomes (PROs) after Total knee arthroplasty (TKA) across TKA procedures and PRO-domains.
METHODS: We analysed a TKA registry from a Singapore tertiary hospital, including 20 PRO items (12 from Oxford Knee Score, five from EQ-5D-3L, and three from Knee Society Score) collected preoperatively and 6-month, 1-, 2-, and 5-year postoperatively. Postoperative improvement was assessed using proportion improved and Cliff’s δ (averaged across items), to compare across TKA procedures: unilateral, simultaneous bilateral (SimBTKA), and staged bilateral (StaBTKA) with first and second procedure had within 6 months (StaBTKA1≤6M, StaBTKA2≤6M) or beyond (StaBTKA1>6M, StaBTKA2>6M), and across PRO domains. Linear regression examined effects of TKA procedures on PRO improvement, adjusting for covariates including baseline PRO scores, demographic and clinical characteristics.
RESULTS: Analyses included 3,124 unilateral, 109 SimBTKA, 276 StaBTKA1/2≤6M, 857 StaBTKA1/2>6M patients. Unilateral patients had a mean (SD) age of 67.6 (8.1) years, BMI of 27.7 (4.9), and 31.9% were male. Most improvements were reached by 6 months (91% followed up), followed by marginal additional gains. At 6-month, the largest improvements were in pain (83.6%; δ=0.79), followed by physical function (64.0%; 0.56), daily activities (55.5%; 0.53), self-care (47.3%; 0.42), and mental health (13.8%; 0.06). SimBTKA patients experienced the greatest improvement (85.5%; Cliff’s δ=0.80), followed by StaBTKA2≤6M (74.5%; 0.69), unilateral (70.1%; 0.65), StaBTKA2>6M (67.6%; 0.63), StaBTKA1≤6M (66.0%; 0.60), and StaBTKA1>6M (62.7%; 0.59). After adjusting for covariates, compared to unilateral, SimBTKA (β=0.34), StaBTKA2≤6M (β=0.20) and StaBTKA2>6M (β=0.09) showed greater improvement, while StaBTKA1≤6M (β=-0.15) and StaBTKA1>6M (β=-0.16) improved less.
CONCLUSIONS: Findings suggest that post-TKA benefits were greater in physical than mental domains, and outcomes varied by procedures and timing, with SimBTKA and early staged procedures showing better results. Given ongoing debate in the literature about the risks (e.g., complications, readmissions) of SimBTKA versus StaBTKA, this study offers patient-centred insights to facilitate informed surgical decisions on TKA-procedure selection.
METHODS: We analysed a TKA registry from a Singapore tertiary hospital, including 20 PRO items (12 from Oxford Knee Score, five from EQ-5D-3L, and three from Knee Society Score) collected preoperatively and 6-month, 1-, 2-, and 5-year postoperatively. Postoperative improvement was assessed using proportion improved and Cliff’s δ (averaged across items), to compare across TKA procedures: unilateral, simultaneous bilateral (SimBTKA), and staged bilateral (StaBTKA) with first and second procedure had within 6 months (StaBTKA1≤6M, StaBTKA2≤6M) or beyond (StaBTKA1>6M, StaBTKA2>6M), and across PRO domains. Linear regression examined effects of TKA procedures on PRO improvement, adjusting for covariates including baseline PRO scores, demographic and clinical characteristics.
RESULTS: Analyses included 3,124 unilateral, 109 SimBTKA, 276 StaBTKA1/2≤6M, 857 StaBTKA1/2>6M patients. Unilateral patients had a mean (SD) age of 67.6 (8.1) years, BMI of 27.7 (4.9), and 31.9% were male. Most improvements were reached by 6 months (91% followed up), followed by marginal additional gains. At 6-month, the largest improvements were in pain (83.6%; δ=0.79), followed by physical function (64.0%; 0.56), daily activities (55.5%; 0.53), self-care (47.3%; 0.42), and mental health (13.8%; 0.06). SimBTKA patients experienced the greatest improvement (85.5%; Cliff’s δ=0.80), followed by StaBTKA2≤6M (74.5%; 0.69), unilateral (70.1%; 0.65), StaBTKA2>6M (67.6%; 0.63), StaBTKA1≤6M (66.0%; 0.60), and StaBTKA1>6M (62.7%; 0.59). After adjusting for covariates, compared to unilateral, SimBTKA (β=0.34), StaBTKA2≤6M (β=0.20) and StaBTKA2>6M (β=0.09) showed greater improvement, while StaBTKA1≤6M (β=-0.15) and StaBTKA1>6M (β=-0.16) improved less.
CONCLUSIONS: Findings suggest that post-TKA benefits were greater in physical than mental domains, and outcomes varied by procedures and timing, with SimBTKA and early staged procedures showing better results. Given ongoing debate in the literature about the risks (e.g., complications, readmissions) of SimBTKA versus StaBTKA, this study offers patient-centred insights to facilitate informed surgical decisions on TKA-procedure selection.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
PCR182
Topic
Clinical Outcomes, Patient-Centered Research
Topic Subcategory
Patient-reported Outcomes & Quality of Life Outcomes
Disease
Musculoskeletal Disorders (Arthritis, Bone Disorders, Osteoporosis, Other Musculoskeletal)