Written by Dr. Janesh Ganda with Jana Visser, sonographer and founder of SonoHub Ultrasound.
Musculoskeletal (MSK) ultrasound lets a clinician look at tendons, muscles and ligaments while you're in the room, and watch a needle in real time during an injection. It isn't the answer to every injury, though. Here's what it does well, where it falls short, and what to expect if you need a scan.
What is MSK ultrasound?
An ultrasound probe sends high-frequency sound waves into the body and builds a live picture from the echoes. MSK ultrasound uses this to look at the soft tissues around joints. It is painless and uses no radiation, so it is safe to repeat and suitable for children.
What ultrasound shows well
Ultrasound is good at looking at structures close to the skin:
- Tendons such as the Achilles, patellar, elbow, shoulder and hamstring tendons: thickening, changes in structure, and partial or full tears. Our tendon injuries guide explains how these are managed.
- Muscles: tears and bleeding after a strain.
- Ligaments: for example the ankle after a sprain.
- Fluid and bursae: swelling in a joint, or an inflamed bursa (a small fluid-filled sac near a joint).
- Nerves: some trapped or irritated nerves, such as at the wrist.
Because the picture is live, the scan can be dynamic: you move the joint or tense the muscle to show whether something snaps or catches. Your other side can be scanned for comparison.
What ultrasound can't see
Sound waves don't pass through bone. That means ultrasound can't see:
- inside bones, including most stress fractures early on
- deep structures inside a joint, such as the cartilage inside the knee or the ACL
- much of the meniscus and the deeper parts of the hip and spine
For these, an X-ray or MRI is often the better test, and many injuries need no scan at all: they are diagnosed from your history and examination.
A scan is also only as good as the person doing it. MSK ultrasound takes specific training and experience to perform and interpret.
Two kinds of scan
A quick scan during your consultation. Dr. Ganda may use ultrasound in the consulting room to look at a sore tendon or joint as part of your examination, or to guide an injection.
A formal diagnostic scan. Sometimes a full scan with a written report is more useful, for example to measure a tear, look at several structures in detail or have a record to compare against later. This is done by a sonographer, a health professional trained in ultrasound examinations, and the report goes back to the doctor who referred you to plan your treatment.
The scan is not the whole story
Many people have changes on a scan that cause them no pain at all, especially as we get older, and some people with real pain have a fairly normal scan. So a scan result is always read alongside your symptoms and your examination. Treatment is planned around how you are and what you want to get back to, not around the picture alone.
Ultrasound-guided injections
When an injection is part of a treatment plan, ultrasound shows the needle and the target on screen throughout, which helps place it accurately and avoid nearby nerves and blood vessels. Injections such as cortisone, hyaluronic acid or platelet-rich plasma (PRP) are used alongside rehabilitation, not instead of it, and the evidence for each differs by condition. Our PRP guide explains how PRP works and what the evidence shows.
What to expect at your scan
- A formal diagnostic scan needs a referral from a clinician, such as your doctor or physiotherapist.
- No special preparation is usually needed for an MSK scan. Wear clothing that makes the area easy to reach, such as shorts for a knee or a vest top for a shoulder.
- A water-based gel goes on the skin and the probe is moved over the area. There may be some pressure over a sore spot, and you may be asked to move the joint.
- A scan of one area usually takes about 10 to 20 minutes.
- Bring any previous scans or reports, so changes can be compared.
About Jana Visser
Jana Visser is an HPCSA-registered sonographer and the founder of SonoHub Ultrasound, in the same building as our practice at 55 Scott Road, Observatory. She qualified at the University of Johannesburg in 2016, has worked in Namibia, Gauteng, the North West and Cape Town, and focuses on musculoskeletal and sports imaging.
When to see a sports doctor
Book an assessment if you have:
- pain in a tendon, muscle or joint that hasn't settled after a few weeks
- swelling, or a joint that catches, locks or gives way
- pain that is stopping you from training, working or sleeping
- an injury where you heard a pop or felt something tear
When to go to an emergency unit
Go to your nearest emergency unit straight away if you can't put any weight on the leg, a joint looks deformed, a limb is numb, cold or pale, or a joint is hot, red and swollen and you have a fever.
Getting your injury assessed
At our practice, ultrasound is used when it will help your diagnosis or treatment, alongside a full history, examination and rehabilitation plan. Formal diagnostic scans can be arranged with SonoHub Ultrasound in the same building. For knee problems, see our knee pain guide.