SNOWMASS, COLO. — You may be confident that you've got great hands for performing joint injections and aspirations, but the scientific evidence shows that unless you're using sonographic needle guidance, you're not nearly as good as you think.
Numerous studies have demonstrated that even skilled physicians fail to place their needle tip in the intra-articular space 50%–60% of the time when they use palpation to guide injections, Dr. Eric L. Matteson said at a symposium sponsored by the American College of Rheumatology.
“It's a little disconcerting to read these studies showing how ineffective we are. We think we're pretty good, but we don't hit the target as often as we think,” observed Dr. Matteson, professor of medicine and chief of the division of rheumatology at the Mayo Clinic, Rochester, Minn.
To make his point, Dr. Matteson cited data from a recent multicenter randomized trial involving ultrasound- or palpation-guided intra-articular steroid injections of 148 painful joints (mostly knees, wrists, shoulders, hips, elbows, wrists, and ankles).
The ultrasound-guided group had 44% less procedural pain and a 59% greater reduction in pain at the 2-week follow-up than the palpation group. Sonographic guidance also resulted in a 337% increase in the volume of aspirated fluid (J. Rheumatol. 2009;36:892-902).
“There's no question that ultrasound-guided injections are more accurate in certain joints, such as the deeper joints like the hips, the small joints of the hands, and the subacromial bursa,” according to the rheumatologist.
As a practical matter, he is quick to turn to ultrasound guidance in patients who are obese, have failed prior injections or aspirations, have experienced significant pain with prior injections, or have difficulty assuming the proper position for standard injections.
Since taking up musculoskeletal ultrasound half a decade ago, Dr. Matteson said he has become a huge fan. He uses it not only to guide procedures, but also as a dynamic extension of his clinical examination. Dr. Matteson reported that in his experience, musculoskeletal ultrasound is of great assistance in the diagnosis of tendon ruptures, synovitis and tenosynovitis, bursitis, effusions, soft tissue nodules, erosions, and the assessment of disease activity.
“A good ultrasound exam often changes your impression about what's wrong with a patient,” he noted.
The use of office ultrasound to assess the hip joint is particularly noteworthy. This assessment is something that otherwise would often require a referral to radiology.
Another area in which musculoskeletal ultrasound has been a real breakthrough is in assessing the cause of shoulder pain. Ultrasound can readily visualize impingement, biceps tendon dislocation, acromioclavicular and sternoclavicular joint pathology, synovitis, and bursitis, as well as adhesions, calcifications, and rupture of the rotator cuff.
Patients love seeing their anatomy on the ultrasound screen; it turns their office visit into an educational experience, according to Dr. Matteson. Musculoskeletal ultrasound is a great teaching tool for medical professionals, as well.
“It's something that creates excitement among the fellows and medical students and residents who rotate through,” Dr. Matteson said.
Musculoskeletal ultrasound is rather well reimbursed under CPT billing codes 76880 and 76942, which were set by radiologists. Although it's possible to spend $100,000-$200,000 on an ultrasound machine, a very good machine can be purchased for $40,000. The major equipment manufacturers typically sell demonstration models after a year's light use for considerably less.
A single ultrasound probe or probes that cover 5-13 MHz is best for musculoskeletal applications. It provides the required balance between penetration and resolution that permits the imaging of both deep structures like the hip and superficial ones like fingers and toes.
Studies have shown that musculoskeletal ultrasound has an interobserver reliability of 85%–91% in expert hands, depending upon the joint. It's as good as or better than MRI or x-rays in the assessment of erosions. In fact, it's now being used for that purpose in some clinical trials.
“I want to leave you with the message that you can get very good at this. It's like learning to ride a bike or drive a car: You just have to spend a lot of time practicing it. Bring in your wife or husband and kids and just use it. Get familiar with all of the knobs and what they do. You'll find it very gratifying,” Dr. Matteson concluded.
Useful resources in getting started include an intensive, 2-day ACR course to be held Aug. 14-15 in Rosemont, Ill. The European League Against Rheumatism also holds hands-on courses, as do the Mayo Clinic and numerous other medical centers. The U.S. rheumatologist ultrasound interest group is reachable at www.msk-uss.org