Execution
- 1Position the patient supine with the knee extended and quadriceps relaxed.
- 2Stroke the medial side of the knee upward from below the joint line toward the suprapatellar pouch to move fluid proximally.
- 3Stroke or taps down the lateral side of the patella toward the lateral joint line.
- 4Observe the medial side of the knee for a returning fluid wave or bulge.
- 5Compare with the opposite knee when the finding is subtle.
Positive outcome
A visible wave or bulge of fluid on the medial side of the knee is positive. The test is intended for minimal effusion and can detect smaller fluid volumes than patellar tap. Absence of a bulge does not exclude moderate or loculated swelling.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Sturgill et al. (2009) | kappa 0.61 (substantial agreement), 73% percent agreement on 5-point grading scale, n=75 | NA | NA | NA | NA |
CommentMagee lists brush, stroke, or bulge testing for minimal swelling. Sturgill 2009 validated the interrater reliability of a 5-point stroke-test grading scale (zero/trace/1+/2+/3+) at kappa 0.61 — substantial agreement among trained physical therapists. The test is useful for small effusions but technique sensitive. A positive result indicates intra-articular fluid, not the cause of the effusion.
Low Clinical Value