Testing for effusion
This is best done by using a sweep test. To perform this the patient lies in a supine position with the knee fully extended. Using a firm stroke the examiner sweeps up the medial side of the knee (towards the supra patella region) and then using a firm stroke sweeps down the lateral side of the knee, looking for any bulge or “re-fill” of fluid on the medial aspect of the knee. This can be subtle and the test may need to be repeated several times to confirm the results. See the attached video clip.