Sensitivity of the saline load test with and without methylene blue dye in the diagnosis of artificial traumatic knee arthrotomies.
OBJECTIVE
To determine whether methylene blue dye significantly improves the sensitivity of the saline load test for detection of a traumatic arthrotomy of the knee.


METHODS
Randomized, prospective.


METHODS
Orthopaedic department, tertiary care medical center.


METHODS
Subjects scheduled for elective outpatient knee arthroscopy were prospectively enrolled and randomized to a normal saline group or a methylene blue group. A total of 58 subjects were enrolled (methylene blue 29, normal saline 29).


METHODS
In the course of routine elective knee arthroscopy, a standard inferior lateral arthrotomy was created and then normal saline or methylene blue solution was injected while observing for fluid outflow from the arthrotomy site.


METHODS
The volume of fluid injected at the time of outflow was recorded with 180 mL set as the maximum injection volume.


RESULTS
The false-negative rate was 67% (methylene blue 69%, normal saline 66%). In patients with a positive test, mean volume of injected fluid at outflow was 105 mL in the methylene blue group and 95 mL in the normal saline group (P = 0.61).


CONCLUSIONS
The sensitivity of the saline load test is unacceptably low. The addition of methylene blue does not improve the diagnostic value of the saline load test. Therefore, these results indicate that the saline load test, regardless of the inclusion of methylene blue, is not an accurate test for diagnosing small traumatic knee arthrotomies.


METHODS
Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.
Department of Orthopaedic Surgery, Naval Medical Center San Diego, San Diego, CA 92134, USA. paul.metzger@med.navy.mil
Paul
P
Metzger
Joseph
J
Carney
Kevin
K
Kuhn
Kermit
K
Booher
Michael
M
Mazurek
D000293:Adolescent; D000328:Adult; D000556:Ambulatory Surgical Procedures; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008751:Methylene Blue; D008875:Middle Aged; D011446:Prospective Studies; D016059:Range of Motion, Articular; D016037:Single-Blind Method; D055815:Young Adult
D008751:Methylene Blue