extraarticular joint injection
Extra-articular injections occur when the needle tip is not within the targeted joint during joint injections.
Terminology
Defined by the presence of contrast outside of a joint in fluoroscopic or CT guided procedures, or the lack of direct visualization and resisted flow of intra-articular injectate during ultrasound-guided procedures.
Differential diagnosis
Practical points
- extra-articular injections should be identified when performing image-guided joint injections, to avoid subsequent injection of either arthrogram solution or steroid containing injectate outside of the joint
- during fluoroscopic guided procedures, straight or linear spread during injection of contrast should alert the practitioner to an extra-articular injection
- often extra-articular injections will have resistance and can be uncomfortable for the patient
- adhesive capsulitis can cause resistance and poor joint capsule distension
- the needle tip should be visualized throughout ultrasound-guided procedures to ensure accurate placement
- patient positioning can dramatically change the ease of access into the joint i.e. supinated hand during anterior glenohumeral joint injections
- the benefit of achieving and confirming an intra-articular facet joint injection is debated, as periarticular injections have been shown to have equivalent outcomes as intra-articular injections