Use the methylene blue challenge to find out if there’s more damage beneath the surface.
24 year old male presents with laceration to the right elbow after rollover MVC. He has stable vital signs and no other injuries. Plain films reveal no fracture or dislocation and no foreign bodies. He has full ROM and is neurovascularly intact. Your intern suggests local infiltration of Lidocaine for analgesia, copious irrigation and primary closure. You consider the option, but are concerned about elbow joint involvement. You suggest performing a methylene blue challenge to determine if the laceration communicates with the joint space.
Intra-articular involvement of the laceration requires urgent orthopedic consultation and thorough irrigation to prevent intra-articular infection. By instilling 20 mL of a sterile colored solution (such as methylene blue) into the joint, the provider can look for leakage of fluid out of the laceration, which would indicate intra-articular involvement. If no dye leaks through the wound, the provider can be comfortable closing the wound in the emergency department without further intervention.
The elbow joint is formed by the articulation of the humerus, radius, and ulna. A lateral approach is used for elbow arthrocentesis to avoid the ulnar nerve, which is located medially. The provider should palpate for three landmarks, which form a triangle and identify the appropriate approach. These landmarks are the lateral epicondyle of the humerus, the radial head, and the olecranon (image 2 above).
- Sterile gloves
- Sterile drape
- 20 mL syringe
- 5 mL syringe
- 22 gauge, 1.5 inch needle
- 27 gauge needle
- Methylene blue vial
- Normal Saline, 500 mL
- Cleansing solution (iodine or chlorhexidine)
The patient should have the elbow flexed at 90 degrees and in neutral position with the ulna and base of the 5th metacarpal resting on his or her thigh or a bedside table. The landmarks should be palpated and marked prior to starting the procedure.
As stated earlier, the provider should take a lateral approach through the triangle created by the radial head, lateral humeral epicondyle and olecranon. The needle is directed medially towards the medial epicondyle (image 3 above).
After palpating the landmarks and marking the appropriate triangle, the provider should prep the elbow with iodine or chlorhexidine. The elbow should be placed on a sterile drape and a sterile field should be created. The methylene blue solution is created in a sterile fashion by adding 2 mL methylene blue to a 500 mL NS bottle.
The provider should place all required items on the sterile field and then put on his or her sterile gloves. Local infiltration of Lidocaine is typically done using a 5 mL syringe and 27 gauge needle. The provider should then use the 20 mL syringe and 22 gauge needle as an assistant holds the pre-mixed methylene blue/NS solution at an angle to aid in filling of the syringe under sterile conditions. The contents may also be poured into a sterile bowl and the provider can fill the syringe from the container (images 4-5 left & image 6 below).
The needle should be advanced into the soft tissue triangle created by the three landmarks described above. Steady negative pressure should be applied to the syringe. Once in the joint cavity, the syringe should draw back, filling with synovial fluid.
During typical arthrocentesis, this fluid will appear yellow-clear; however, it will be difficult to see this as the syringe is filled with methylene blue. If the needle contacts bone, it should be pulled back and redirected at a slightly different angle. When the needle tip is in the synovial cavity, the methylene blue solution should flow easily. If the provider notes difficulty when instilling the solution, he or she is unlikely to be in the appropriate space and should redirect the needle. Approximately 20 mL of solution should be injected into the joint space while looking for leakage of fluid out of the wound. Sterile 4x4 gauze can be placed over the wound to look for blue discoloration, which will be very apparent against the white gauze.
If there is leakage of solution through the wound, the procedure should be terminated and orthopedics should be consulted for probable intra-articular invasion of the wound and prompt operative irrigation. If there is no leakage of solution, but the provider has a high suspicion for intra-articular extension of the wound, some authors recommend performing full range of motion of the elbow to look for leakage. This will increase sensitivity of the methylene blue challenge, as will instilling additional solution into the joint.
If there is no leakage of fluid, the provider should attempt to remove as much of the methylene blue solution as possible. If he or she is unable to do so, the body will reabsorb this fluid, but in the meantime it will cause minor discomfort by distending the joint capsule. If the methylene blue challenge is negative and no solution is seen leaking from the wound, then typical wound care can be performed.
Our methylene blue challenge was negative in this patient. His wound was further anesthetized, irrigated, and closed with simple interrupted sutures. He was placed in a sling for comfort. He returned to the emergency department eight days later for suture removal and was doing well with no signs of intra-articular infection.
- Feathers T, Stinner D, Kirk K et al. Effectiveness of the Saline Load Test in Diagnosis of Traumatic Elbow Arthrotomies. J Trauma. 2011;71(5): E110-E113.
- Parillo S, Morrison D, Panacek E. (2010). Arthrocentesis. Roberts and Hedges Clinical Procedures in Emergency Medicine. Philadelphia: Saunders Elsevier.
- Keese GR, Boody AR, Wongworawat MD, Jobe CM. The accuracy of the saline load test in the diagnosis of traumatic knee arthrotomies. J Orthop Trauma. Aug 2007;21(7):442-3.
- Perron A. Elbow Injuries. (2005). Hardwood-Nuss’ Clinical Practice of Emergency Medicine. Philadelphia: Lippincott Williams & Wilkins.
Dr. Erik Adler and Dr. Samantha Mauck are 3rd year Emergency Medicine Residents at the Denver Health Emergency Medicine Residency Program. Dr. Peter Pryor is a faculty member at Denver Health, an Assistant Professor of Emergency Medicine at the University of Colorado School of Medicine and has an academic focus in medical photography.