Background

Open joint injuries are skin and soft-tissue injuries that penetrate the joint space. Like open fractures, open joint injuries require timely diagnosis, exploration, and irrigation to minimize long-term morbidity and mortality. The procedure of intra-articular injection of methylene blue is an easy and safe way to identify disruption of the joint capsule and may facilitate early intervention.

Intra-articular injection of methylene blue that demonstrates extravasation of dye from the wound site is highly suggestive of open joint injury. In the absence of dye extravasation, open joint injury may still be present; therefore, an orthopedic consultation is recommended for all patients with a suspected open joint injury.^[1]

The literature is inconclusive in regard to the sensitivity of this procedure for detection of joint-capsule injuries, with reported sensitivities ranging from 31% to 99%. Some authors have suggested that the diagnostic accuracy of the saline-load test is unacceptably low; others have suggested that the test is still clinically relevant, in that patients with a negative test result and no clinical or imaging evidence of an arthrotomy appear to have an infection rate of 0% with nonoperative management.^{[2, 3, 4]}

For more information on aspiration techniques, see Surgical Treatment of Septic Arthritis.

Indications

Indications for methylene blue injection include soft-tissue injury associated with at least one of the following:

Periarticular fracture
Visible joint capsule
Proximity to a joint

Contraindications

No absolute contraindications exist for intra-articular joint injection, though the following situations are strongly suggestive of open joint injury and therefore necessitate joint exploration and irrigation regardless of the results of intra-articular joint injection:

Open fracture with obvious joint involvement on plain radiographs
Intra-articular air or foreign bodies on plain radiographs

In July 2011, the US Food and Drug Administration (FDA) warned against the concurrent use of methylene blue with serotonergic psychiatric drugs, unless it is indicated for life-threatening or urgent conditions. Methylene blue may increase serotonin levels in the central nervous system (CNS) as a result of monoamine oxidase A (MAO-A) inhibition, increasing the risk of serotonin syndrome.^{[5, 6]}

Periprocedure

Collins DN, Temple SD. Open joint injuries. Classification and treatment. Clin Orthop Relat Res. 1989 Jun. 48-56. [QxMD MEDLINE Link].
Nord RM, Quach T, Walsh M, Pereira D, Tejwani NC. Detection of traumatic arthrotomy of the knee using the saline solution load test. J Bone Joint Surg Am. 2009 Jan. 91 (1):66-70. [QxMD MEDLINE Link].
Metzger P, Carney J, Kuhn K, Booher K, Mazurek M. Sensitivity of the saline load test with and without methylene blue dye in the diagnosis of artificial traumatic knee arthrotomies. J Orthop Trauma. 2012 Jun. 26 (6):347-9. [QxMD MEDLINE Link].
Konda SR, Howard D, Davidovitch RI, Egol KA. The saline load test of the knee redefined: a test to detect traumatic arthrotomies and rule out periarticular wounds not requiring surgical intervention. J Orthop Trauma. 2013 Sep. 27 (9):491-7. [QxMD MEDLINE Link].
FDA Drug Safety Communication: Serious CNS reactions possible when methylene blue is given to patients taking certain psychiatric medications. US Food and Drug Administration. Available at http://www.fda.gov/Drugs/DrugSafety/ucm263190.htm. July 26, 2011; Accessed: April 12, 2021.
FDA Drug Safety Communication: Updated information about the drug interaction between methylene blue (methylthioninium chloride) and serotonergic psychiatric medications. US Food and Drug Administration. Available at https://www.fda.gov/Drugs/DrugSafety/ucm276119.htm. October 20, 2011; Accessed: April 12, 2021.
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Patzakis MJ, Dorr LD, Ivler D, Moore TM, Harvey JP Jr. The early management of open joint injuries. A prospective study of one hundred and forty patients. J Bone Joint Surg Am. 1975 Dec. 57 (8):1065-70. [QxMD MEDLINE Link].
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