What is Musculoskeletal (MSK) Ultrasound?
MSK is the use of sophisticated ultrasound imaging to evaluate muscle, tendon, ligaments and joints to aid in the accurate diagnosis of painful injuries that can happen at sport, work or play. Ultrasound is a safe imaging technique that uses no ionizing radiation like x-ray and Computed Tomography (CT). Further, it has advantages over MRI as high frequency transducers produce images with higher resolution than MRI for some musculoskeletal structures. Another advantage is that MSK uses real time motion of these tissues to see functionally how these structures are injured. MRI is a static study with no dynamic component, thereby allowing many injuries to go undiagnosed. By moving the injured tissue while using diagnostic ultrasound the defect or tear can be visualized. We feel strongly that functional ultrasound, in most injuries, is the study technique of choice for making the correct diagnosis.
MSK ultrasound is a standard of care in many countries around the world as it’s convenient, accessible and cost effective. MSK ultrasound typically costs 4 -5 times less than MRI. MSK is underutilized in the United States because of the considerable profits that MRI imaging brings to many hospitals or clinics. Although MRI is especially suited for spinal imaging, MSK ultrasound has comparable imaging capabilities for many musculoskeletal injuries. In several comparison studies looking at rotator cuff tears, MRI and Ultrasound were found to have the same sensitivity and specificity of about 92-93%. Only MR arthrogram (adding an injected dye into the shoulder) had better sensitivity and specificity of about 95%.
By providing our patients with better resolution of soft tissue than MRI, convenient in-office service, no exposure to ionizing radiation and the ability to perform a dynamic study to the injured area, we believe we provide our patients with the best quality medical care for musculoskeletal injuries. For those injuries that require penetration of bone or to see deeper structures our services also include digital radiology services, MRI and CT referrals.
Why do we use ultrasound guided injections?
Many studies have shown that the accuracy of joint injects by physicians are not what you would think. Even under the careful guidance of orthopaedic surgeons, the targeted tissue is often not injected. Recent studies have compared ultrasound guided injections versus experienced surgeons using standard injection techniques. Similar results have been found in several other studies and although an injection without imaging is less expensive, it may not be cost effective.
Below are the percentage of correct injection placement using unguided and Ultrasound guided injections using meta-analysis.
|Joint||Standard Technique||Ultrasound Guidance|
|Shoulder: AC Joint||45%||100%|
|Knee: Superiolateral Joint||79%||99%|
We also know that injections that are unusually painful have frequently been injected into the tendononous structures or the meniscus of the knee. By injecting cortisone (steroid) into the tendon, the steroid may act to weaken the tendon and increase the risk of tendon rupture and or failure to improve.
When injecting visco-supplements such as Hyalgan or Synvisc, we frequently recommend ultrasound guidance for Synvisc one (single 6cc injection). We do recommend ultrasound guidance as there is a 20% chance that an unguided injection won’t inject over $600.00 worth of medication into the wrong compartment. The technical challenges of unguided injections also increases with patients weight and arthritis. If you are considering joint replacement and a visco-supplement is the last determining factor, consider having it done under guidance to ensure the medicine is getting into the right place. That way, if the injection doesn’t help you, you’ll have the confidence to move forward with surgery knowing that the injection was placed correctly.
If you have any other questions, please do not hesitate to ask. You can click here to contact us.