Position the knee in extension or with minimal flexion.
Gently sublux the patella laterally and palpate and mark the posterior edge of the patella.
Prepare the overlying skin with antiseptic solution and place sterile drapes over the area.
Prepare the buffered lidocaine anesthetic solution.
Prepare the MR arthrography contrast solution.
Anesthetize the planned needle tract with buffered lidocaine solution.
Advance the needle (22 or 25 gauge) into the patellofemoral compartment while slightly subluxing the patella.
Advance the needle through the joint capsule and into the patellofemoral compartment.
If there is a suspected joint effusion, consider syringe aspiration of fluid to avoid overdilution of contrast.
After dripping contrast into the needle hub to eliminate air, attach the contrast-filled tubing/syringe.
Inject a small mount of contrast to confirm intra-articular position. Contrast should flow freely away from the needle tip, opacifying the joint capsule. Contrast may pool within the suprapatellar bursa.
After contrast injection, the patient can flex and extend the knee, distributing the contrast.
Document the intra-articular position of your needle and injection with fluoroscopic spot views.
