Ultrasound In Orthopedics: Using Technology to Help Patients

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Christian T. Andersen, MDby Christian T. Andersen, MD

For years, orthopedic surgeons have counted on x-ray images to assist in diagnosing and treating a variety of musculoskeletal conditions. Over the years, newer technologies have emerged with the advent of digital film. This provides instant images viewable locally, as well as remotely. However, x-ray, although still a clinical necessity in orthopedics, provides a limited portrait of the tissues that may be involved in an injury. If the history and clinical tests raise suspicions of a more serious soft tissue injury, patients are often sent for an MRI. MRI’s provide detailed information, but are extremely expensive and require preauthorization from most insurers. Patients must wait for the MRI preauthorization, schedule the test, and then return to the office for a discussion with their orthopedist to review the result, delaying the diagnosis even further. Recent advances have resulted in a new tool that orthopedic surgeons can use to assess tissue health or localize injection treatments with great accuracy. The new tool is called musculoskeletal ultrasound.

With musculoskeletal ultrasound, a probe with a water-soluble gel is placed onto the skin close to the injured area. Specific settings on the machine allow the image to be adjusted for clarity. The machine uses reflected sound waves that are beyond the hearing capacity of man, similar to sonar, to create live images of a joint and the surrounding tissues. These sound frequencies are quite high. For example, human’s upper limit of hearing is around 20 kHz, cats 30 kHz, dogs 45 kHz, and bats up to 200 kHz. The standard ultrasound machine produces frequencies in the 2,000 to 15,000 kHz range. It is possible for tendons to be dynamically seen to glide, joints to move, or for ligaments to be visualized under stress with ultrasonic testing.

Musculoskeletal ultrasound is a pain-free way for the orthopedic providers at Agility to look at the soft tissues that are not visible through x-rays. If the history and clinical findings raise the specter of a rotator cuff injury, the ultrasound machine can be employed to follow the entire length of the four rotator cuff tendons, as well as the biceps tendon, looking for disruptions as small as a few millimeters. Muscle tears can be visualized, fluid collections identified, loose bodies seen, and ligament injuries diagnosed without having to jump through the MRI “hoops”. The specific locations of swelling and the health of tissues as visualized through the ultrasound images can play an important role in identifying exactly what might be the cause of pain or dysfunction in an extremity. But that is not all that ultrasound can do.

Ultrasound imaging is an incredibly precise way to guide injections into just about any joint in the body. Recent studies in orthopedic journals have indicated that orthopedic surgeons are more accurate with their injections when the injection is guided by ultrasound. Also, studies have demonstrated that patients have faster and more long lasting recoveries if their injections are guided with ultrasound. The needle used to give injections is visible within the real time image created by ultrasound, allowing it to be directed exactly into the location identified as the source of the pain, delivering a variety of medications. A great example of how this technology benefits patients can be found in patients with hip pain. The hip joint is deep and injections into this area have traditionally required fluoroscopic x-ray with its radiation exposure. Nowadays ultrasound has made hip injections possible in the office, typically done during the same appointment. The best part is that patients who have pain do not have to wait for the treatment and do not need to be inconvenienced with having to make an appointment elsewhere for an injection. Once the need is identified, the injection can be made with great accuracy and timeliness.

Often patients come into the clinic with swelling and pain in their knee. Aspirating the fluid can provide pain relief as well as diagnostic clues as to the cause. Additionally, medications can be placed at the same time for treatment. Musculoskeletal ultrasound plays an important role in helping to position the needle in the perfect spot to access the swelling. Fluid accumulations in the joint (called an effusion) are easily identified on the ultrasonic exam. Using ultrasound to guide an aspiration helps to make the procedure a little less uncomfortable for patients as well.

Another use for musculoskeletal ultrasound is a technique known as Hydrodissection. This is a procedure where an injection of dextrose (a sugar based IV fluid) to separate healthy tissues from scar tissues. The classic application for this is in patients with neuropathy, especially from compression (i.e. carpal tunnel syndrome at the wrist). The image of the nerve structure and path, as seen on ultrasound, helps the orthopedic surgeon to locate the exact spot to use the water pressure to break the adhesion or scar tissue. This procedure often provides patients with instant relief to long-standing nerve pain. There is abundant data on the technique of dextrose injection, technically known as “prolotherapy”, used for trigger points, refractory nerve pain, tendon swelling, and other chronic orthopedic conditions. Exciting advances in “regenerative medicine” use ultrasound to instill stem cells from fat or bone marrow, platelet-rich plasma (known as PRP), or viscosupplements for the treatment of a variety of nagging tendon and joint injuries.

The use of ultrasound at Agility Orthopedics has helped us provide better, less expensive, and more immediate care for our patients. It is an important tool to diagnose and treat injuries. If you would like to learn more about the use of musculoskeletal ultrasound at Agility Orthopedics I invite you visit the Agility Learning Center.