Patient Education and Consent
Informed consent must be obtained from the patient prior to the acromioclavicular (AC) joint injection.
Patients should be made aware of the rare, but possible, side effects of AC joint injections, including the following:
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Allergic reaction
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Pain at the injection site or transient increase in pain at the injection site in the days following injection
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Infection
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Bleeding
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Bruising
Patients receiving a steroid injection should be made aware of the possible transient increase in blood sugar levels, as well as the risk of avascular necrosis (AVN), steroid arthropathy, and systemic effects (eg, hot flashes, mood changes, insomnia, psychosis, and adrenal supression). [6] Although these adverse reactions are rare, it is essential that they be disclosed to the patient.
Equipment
AC joint injection is performed with the following equipment:
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Needle, 25 gauge, 1-1.5 in. (~2.5-3.8 cm)
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Syringe, 3-5 mL
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Povidone-iodine swabs or solution
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Gauze pads, 4 × 4 in. (~10 × 10 cm)
No consensus exists on the type or amount of steroids to be used for an AC joint injection. Typically, 0.25-0.5 mL of one of the following steroids is injected [7] :
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Betamethasone sodium phosphate
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Betamethasone acetate
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Methylprednisolone, 40 mg/mL
Patient Preparation
Anesthesia
Typical anesthetics used include 0.5-1 mL of 1-2% lidocaine or 0.25-0.5% bupivacaine. A 2007 survey of western US physicians by Skedros et al found broad variations in the amount of anesthetic injected for painful shoulder conditions, with surgeons using larger volumes. [8]
Positioning
The patient can sit or stand, with the affected arm in a neutral position at the side.
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Acromioclavicular joint anatomy.
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Patient (48-year-old woman with preexisting acromioclavicular [AC] joint arthritis), was hit by motor vehicle, which exacerbated her AC joint arthritis. Video courtesy of James R Verheyden, MD.
