Position and anatomical landmarks
Intra-articular injection of the acromioclavicular joint is applied with the patient in a supine position. The lateral end of the acromion is identified at the top of the shoulder (most cephalad portion). The joint cleft can be palpated 2.5 cm medially of this point.
After sterile preparation, 1 ml bupivacaine 0.25% with 40 mg depot corticosteroid is injected (under ultrasound guidance). There should be some resistance when injecting since it involves a relatively small intra-articular space. If there is substantial resistance, the tip of the needle is probably situated inside the connective tissue layers of the joint capsule. With too little resistance, the intra-articular space is possibly no longer intact and an MRI should be performed.
Directly after a well-performed infiltration of the acromioclavicular joint, the passive shoulder abduction has to be normalised.
- The most serious complication after the injection is infection.
- Small subcutaneous bleedings may result in a temporary increase in pain after the injection.