Defining and measuring varus thrust in knee osteoarthritis: A scoping review of current evidence and challenges

Objective: This scoping review investigated the definitions, assessment methods, and current applications of varus thrust (VT) in knee osteoarthritis (OA). Methods: Five databases (MEDLINE, EMBASE, CINAHL, SPORTDiscus, and Web of Science Core Collection) were searched in this scoping review for studies assessing VT during walking in adults with knee OA using the terms "varus" and "lateral" in proximity to thrust. Data were extracted and categorized by study characteristics (OA sample, publication year, design, and aim) and VT assessment protocol (method and definition). Results: ​= ​19) methods. Designs included prospective, experimental, cross-sectional, and case series. VT was most often assessed to examine disease severity, progression, surgical outcomes, and symptom associations. Visual VT was commonly defined as dynamic worsening or abrupt onset of varus alignment during weight acceptance. Optical motion capture commonly measured VT as frontal plane knee excursion from foot contact to mid-stance, while inertial methods typically used peak lateral tibial acceleration or angular velocity. Conclusion: Despite growing research interest in VT, inconsistent definitions and measurement protocols limit comparability across studies and hinder broader adoption. Greater standardization and validation are needed to clarify its potential clinical utility in knee OA.