Diagnostic Utility of Ultrasound Versus Physical Examination in Assessing Knee Effusions

A Systematic Review and Meta‐analysis

This publication was made possible by the Johns Hopkins Institute for Clinical and Translational Research (ICTR) which is funded in part by Grant Number UL1 TR003098 from the National Center for Advancing Translational Sciences (NCATS) a component of the National Institutes of Health (NIH), and NIH Roadmap for Medical Research. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the Johns Hopkins ICTR, NCATS, or NIH.


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Knee effusion can be detected by physical examination, ultrasound and MRI, but the utility of each test is unclear. This study aimed to analyze the diagnostic value of physical examination and ultrasound for knee effusion. A systematic literature search of electronic databases was completed. Bivariate mixed‐effects regression modelling was used to estimate sensitivity, specificity and diagnostic odds ratio of physical examination and ultrasound diagnosis of knee effusion. Sensitivity of ultrasound diagnosis of knee effusion was higher than the bulge sign and patellar tap, leading to improved positive and negative predictive values.

First Published on March 5, 2021


Ryan Meyer MD

Christina Lin MD

Gayane Yenokyan PhD

Mark Ellen MD