Intra-articular Methylene Blue Injection
- Author: Gil Z Shlamovitz, MD, FACEP; Chief Editor: Erik D Schraga, MD more...
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 for 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.
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 suggest that the diagnostic accuracy of the saline-load test is unacceptably low; others suggest 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 Aspiration Techniques and Indications for Surgery, Septic Arthritis.
Indications for methylene blue injection include soft-tissue injury associated with at least one of the following:
Visible joint capsule
Proximity to a joint
No absolute contraindications exist for intra-articular joint injection, though the following situations are strongly suggestive of open joint injury and therefore require 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
The US Food and Drug Administration (FDA) warns 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.
Equipment used for intra-articular injection of methylene blue includes the following:
Sterile preparation solution and surgical scrubs
Normal saline bottle (approximately 500 mL)
Sterile methylene blue or fluorescein dye
Syringes, 12-mL and 20- or 30-mL
Needles, 18- and 21-gauge
Local anesthetic solution
Sterile 4 X 4 gauze pads
For anesthesia, inject a local anesthetic agent such as 1% lidocaine subcutaneously until a skin wheal appears before entering the joint space. For more information, see Local Anesthetic Agents, Infiltrative Administration.
Positioning varies according to the joint that is to undergo injection. ↵
Intra-articular injection of dye requires the ability to create enough dye pressure to distend the joint capsule and maximize the chances to visualize dye extravasation from the wound. An 18-gauge needle is the recommended gauge for injection or aspiration of most adult joints.
This is a painful procedure that involves distention of the joint capsule (similar to arthroscopy); therefore, both parenteral analgesia and local anesthesia are indicated.[8, 9]
Select a joint injection approach that is as far as possible from the skin wound. Make sure to avoid any neurovascular structures. Aspirate back as much fluid as possible before withdrawing the needle.
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. Extravasation of contrast from an open joint injury necessitates immediate administration of intravenous (IV) antibiotics and emergency (≤6 hours) orthopedic evaluation for exploration and irrigation of the joint.
An alternative technique that can be used in patients who are allergic to methylene blue is injection of sterile fluorescein in normal saline solution into the joint space.[6, 7] The authors recommend that the fluorescein solution and normal saline solution be tested for fluorescence with a Wood lamp before injection into the joint.
Injection of methylene blue into joint
Obtain informed consent from the patient.
On a sterile drape, open the sterile bowl, syringes, and needles. Pour the sterile normal saline solution into the sterile bowl, and add 1-2 mL of methylene blue to create a dark solution (see the image below). Fill at least one 20- or 30-mL syringe with the dark solution.
After providing appropriate parenteral analgesia, cleanse a wide field by scrubbing the affected joint with a sterile preparation or a surgical scrub in circular motions, starting from within the wound and working outward (see the image below). Repeat the scrubbing process at least two more times. Cover the joint with sterile drapes to create a sterile field.
Select a joint injection approach that is as far as possible from the skin wound (see the image below). Make sure to avoid any neurovascular structures.
Elevate a skin wheal of local anesthetic using a 25-gauge needle (see the image below).
Switch to a 21- or 18-gauge needle, and continue to inject lidocaine into the subcutaneous and deeper soft tissues until the joint space is entered (see the image below). Entry into the joint space can be confirmed by increased ease of injection and by aspiration of joint fluid (which is likely to appear bloody rather than its normal straw color).
Once the joint capsule is entered, secure the needle in the joint space with the nondominant hand while using the dominant hand to switch to the 20- to 30-mL syringe that contains the normal saline and dye solution (see the image below).
Inject the solution into the joint until it is fully distended. (The volume required to distend a joint fully varies among different joints and patients.) Watch the wound site for contrast extravasation (see the image below).
Aspirate back as much fluid as possible and withdraw the needle.
Clean the skin and wound with remaining preparation solution, and apply a sterile dressing over the wound and injection site. Extravasation of contrast from an open joint injury calls immediate administration of IV antibiotics and emergency orthopedic evaluation for exploration and irrigation of the joint.
The procedure is depicted in the video below.
Potential complications of intra-articular injection of methylene blue include the following:
Bleeding or nerve injury - Proper technique and awareness of normal anatomy should minimize the chances of injuring a neurovascular structure
False-negative result from injection - Small open defects in a joint capsule or failure to inject enough dye into the joint to allow dye extravasation might lead to a false-negative intra-articular dye injection result; consultation with an orthopedic surgeon is recommended in all cases of suspected open joint injury
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