Introduction: Access to Total knee replacement arthroplasty (TKA), a life-changing operation has recently been restricted based on body mass index (BMI) due to belief that high BMI may lead to poorer outcomes. Aim of the study is to investigate the associations between BMI and revision surgery, mortality, and pain/function following primary total knee arthroplasty (TKA). Methods: In this retrospective observational cohort study, TKAs registered in the Indian Joint Registry (IJR) between 2005 to 2021 will be investigated for 90-day mortality and 10- year cumulative revision. After adjustment for age, gender, American Society of Anaesthesiologists (ASA) grade, indication for operation, year of primary TKA, and fixation type, patients with high BMI versus normal BMI will be compared with respect to revision surgery, mortality, and patient-reported outcomes after primary knee replacement surgery. Conclusion: Association of BMI and with primary TKA as well as with the predisposition to revision TKA throws light on the need for weight reduction before primary TKA.