Side comparison for epicondylitis
In epicondylitis, a healthy elbow serves as a standard. The thickness of the extensor tendon in physical workers and athletes is noticeably greater than in office workers, and without comparison it is impossible to say with certainty whether we are talking about pathological thickening or an individual norm. Comparison of symmetrical zones in one person solves this problem.
The practical value of bilateral research is especially great for those whose work or sports load both hands - tennis players, weightlifters, mechanics, massage therapists. In them, degenerative changes in the tendons form on both sides, and pain appears first on the dominant hand. Having detected changes on the “healthy” side, you can adjust the technique and load before a full-fledged pain syndrome develops.
Bilateral examination is mandatory for systemic diseases. Rheumatoid nodules in the olecranon area, gouty tophi and symmetrical synovitis in arthritis require evaluation on both sides, and the result is used to determine disease activity and monitor treatment.
What can be seen on an ultrasound of the joint
Ultrasound, better than any other method, shows the soft tissues surrounding the joint: tendons and their sheaths, ligaments, muscles, synovium, joint capsules and peripheral nerves. It reliably detects free fluid in the joint cavity and bursae, tendon ruptures and tears, cysts, bursitis and tendinitis.
There are also fundamental limitations. Ultrasound does not pass through the bone, so the internal structures - menisci along the entire length, cruciate ligaments, articular cartilage deep in the joint, bone marrow - remain inaccessible. They use magnetic resonance imaging, and X-rays are used to evaluate the bone itself.
The main advantage is exploration in motion
Unlike MRI, which takes a picture of a motionless joint, ultrasound allows you to look at the joint in dynamics. The doctor asks you to bend, straighten or rotate the limb straight during the scan and sees how the tendons and ligaments behave under load.
Many conditions manifest themselves only during movement: tendon subluxation from the groove, impingement, trigger finger, ligament instability. At rest, the picture looks normal, and without functional tests the diagnosis cannot be made.
When to start with ultrasound
Ultrasound is reasonable as the first method for pain and swelling of the joint without injury, for suspected bursitis, tendinitis and cysts, for monitoring the treatment of inflammatory diseases and, if necessary, to induce a puncture or blockade.
If there was a serious injury with a suspected fracture, you need to start with an x-ray. If a torn meniscus or cruciate ligament is suspected, MRI remains the method of choice.