The global profile of individuals undergoing total knee replacement surgery through a PROGRESS-PLUS equity lens: A systematic review.

Background: Osteoarthritis (OA) of the knee is a common, disabling condition influenced by multiple biopsychosocial factors and often requiring a total knee replacement (TKR). However, most rehabilitation programmes are developed in high-income countries, potentially limiting transferability to lower-income settings with distinct health equity challenges. Objectives: This study aimed to describe the demographic and health equity profiles of adults undergoing TKR for primary OA across low-, middle- and high-income countries. Method: A systematic literature search was conducted in PubMed, Scopus, EBSCOhost, Web of Science and ProQuest for peer-reviewed primary research, including observational studies, randomised controlled trials and grey literature published between 2020 and 2024. Studies reporting on individuals undergoing TKR were selected. Data extraction followed the PROGRESS-Plus framework, and a descriptive synthesis of demographic and health equity information was performed. Results: The review included 101 studies with over 3.2 million participants, predominantly from high- and upper-middle-income countries, with no representation from Africa. Although females consistently represented the majority (54% - 86%), key health equity indicators such as socioeconomic status and education were inadequately reported. Clinical characteristics also varied, with a higher mean BMI observed in high-income country studies. Substantial methodological heterogeneity precluded meta-analysis. Conclusion: There is extensive global research on TKR; however, data from lower-income countries is scarce, and health equity factors are poorly reported. Clinical implications: Inconsistent reporting of outcome measures and limited reporting of health equity in global studies limit the implementation of rehabilitation programmes in low-resource settings. These settings would benefit from detailed equity data to adapt interventions to local patient needs. In addition, better integration of social determinants of health into physiotherapy practice can enhance personalised care and fair resource distribution.