If you need a steroid injection into the hip for pain from osteoarthritis, there’s only a 50-50 chance the agent will actually reach its intended destination. That’s the conclusion of this study from Turkey. Using anatomical landmarks to position and advance the needle is called a blind injection. Using this technique with any success is like tossing a coin and shouting heads or tails and then being right (or wrong).
What can the physician do to increase his or her accuracy? Use some type of imaging to guide the needle. That could include magnetic resonance imaging (MRI), ultrasound (US), fluoroscopy (real-time 3-D X-rays), computerized tomography (CT scans), or arthrography. Arthrography is a tool doctors use to find the source of patients’ symptoms. By injecting a special substance or contrast dye into a painful joint, doctors can see soft tissues and joint structures to find out what may be causing pain and other symptoms.
In this study, physicians used fluoroscopy to guide and place the needle into the hip joint. Injecting a joint like this is called an intra-articular injection. They found that even with the special X-rays to guide them, placement was still only accurate in three out of four patients. To ensure complete accuracy for all patients, it was necessary to use arthrography. The contrast medium showed conclusively whether or not the needle had gained entrance into the joint cavity.
Physicians may be interested to know that using the backflow method of blind injection isn’t reliable or accurate either. Backflow refers to the way physicians check blind injections for accuracy. After advancing the needle into what the surgeon thinks is the joint cavity, a small amount of saline solution is spurted into the joint and then aspirated (drawn back out) as proof that the joint cavity has been reached.
The physician who performed all of the injections in this study had 10 years of experience doing these types of intra-articular injections. But after doing a blind injection with backflow, fluoroscopy was used to confirm placement. There was almost a 20 per cent rate of backflow (one out of five patients) when the physician wasn’t really inside the joint.
In summary, intra-articular injections of the hip joint can be helpful in alleviating painful symptoms from osteoarthritis. Careful technique is required on the part of the physician performing the injection. Blind injections are less expensive than injections performed with imaging. Blind injections can be done right in the physician’s office. And the patient isn’t exposed to radiation. But blind injections are not advised. For complete accuracy, imaging and arthrography are required.
With the increasing popularity of intra-articular interventions, studies are needed to find the absolute best way to accomplish these injections. This study kept its focus on comparing fluoroscopy versus arthrography. Similar studies are needed to compare the results with all available imaging tools to find the most accurate and reliable method of injection. The authors also suggest studies are needed to compare the two directions injections are given from (the front of the hip or the side of the hip). Degenerative changes from arthritis can change the structure of the hip making needle placement even more challenging than on a normal, healthy hip.