Functional Knee Extension Test (FKET): Inter-rater palpatory agreement and visual analysis during a non-weight bearing functional assessment of the knee

SummaryObjectiveThe purpose of this study was to evaluate the inter-rater reliability of the Functional Knee Extension Test (FKET), a non-weight bearing functional assessment of the knee that is utilized within clinical practice.MethodsThe design was a single-session, test-retest reliability study. Active knee extension was assessed and documented by each examiner for each of the visual, palpatory and vastus medialis obliqus (VMO) components of the FKET on fifty-seven healthcare professionals.ResultsThe Kappa (κ) statistic for the inter-rater reliability for the visual, palpatory and VMO variables of the FKET were slight-to-fair (0.13–0.26), fair-to-moderate (0.39–0.50), and moderate-to-almost perfect (0.57–0.93) reliability, respectively. The p-values for all variables, besides ‘Visual RIGHT: TibTubExt’ and ‘Visual LEFT: TibTubExt’ indicated statistically significant evidence of agreement above random guessing. Estimates for κ on the ‘VMO Quantity: No contact’ and ‘VMO Timing: Start then stop’ variables could not be calculated as ratings only existed across one row of the crosstabulation.ConclusionThis study demonstrated that the palpatory and VMO components of the FKET have sufficient reliability to justify utilization within clinical practice. Future research is needed to determine whether the implementation of a functional knee assessment protocol, including the FKET could enhance levels of reliability in clinical decision-making of knee function.