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Toni Talks about PT Today

New on the Horizon: Musculoskeletal Ultrasound

Published February 26, 2009 8:21 AM by Toni Patt
I learned something new this week.  My class in radiology is looking at ultrasound.  Before I did the reading I thought it would be the same old, same old.  Everyone knows about US.  I was wrong.  We're not studying the therapeutic US we use in our clinics.  We're studying musculoskeletal US which is a diagnostic procedure.   I had no idea anything like this even existed much less the implications for PT.

First I need to provide some background information.  Musculoskeletal US or rehabilitative ultrasound imaging (RUSI) works on the same principle as the US we're familiar with. It uses sound waves to create images similar to the way ECHO cardiograms and prenatal pictures are created.  RUSI is used to measure different aspects of muscle morphology including thickness, cross-sectional area and volume. It shows the relationship of the muscle under study to the tissues surrounding it.   RUSI creates a real-time picture of what the muscle is doing when the image is created.  RUSI is also used in research. The research can have continuous images of a muscle before, during and after contraction.  Compared to X-ray, CT and MRI, RUSI has the advantages of being less expensive, less time consuming and doesn't involve exposure to radiation.  The machines are similar to those used for ECHOs so it is also portable.

Most of the research I saw involved images of the shoulder, although it can be used on any superficial structure such as a joint or on deeper structures such as organs.   One study looking at rotator cuff repairs found RUSI had an 86% accuracy rate for correct diagnosis as determined by surgery.  The same study found MRI to have an 82% accuracy.  All of the research concluded that RUSI was excellent for diagnosing rotator cuff repairs.

So, what does this mean for PT?   Some of the same individuals who are pushing for direct access and the ability to order X-ray also believe PTs should be able to perform RUSI examinations in the clinic.   Interpretation of RUSI images requires two things.  One is a thorough knowledge of the anatomy being studied.  The second is a thorough knowledge of neuromuscular and musculoskeletal disorders.  Not only do PTs have both, but their knowledge is significantly greater than that of a radiologist when it comes to superficial joints and surrounding tissues.   Giving PTs this ability would also be cost effective. 

The argument has already been made that direct access would be cost effective as would permitting us to order X-rays.  The same argument applies to RUSI with an additional bonus.  A PT who is able to perform RUSI could do so at the initial visit and diagnosis a rotator cuff tear the same visit.  That patient could then be referred to a physician for medical management minus the expense of multiple x-rays and other studies, a few weeks of pain and ineffective therapy and with a diagnostic image that reveals the injury.  The same PT could then use RUSI post-operatively for muscle re-education by showing the patient in real-time what happened when he or she contracted a muscle.

Other than lacking true direct access, the biggest drawback to RUSI is the long learning curve.  All the literature I reviewed talked about introductory courses of 3 to 5 days followed by up to 2 years of supervised study, including performing up to 50 or 60 one-on-one scans.  Completion of the programs results in certification to perform the examinations.  Currently the courses are open to MDs, MDs in training and retired MDs.  I saw one course open to sonographers.  That certification means the person is competent to perform RUSI of any structure, not just the superficial joints that would interest a PT.   A PT would need much less training to perform scans of the shoulder, hips, knees and ankles.

For anyone interested, here are some articles to reference.  I found these using CINHAL which can be accessed through Open Door on the APTA Website.

Robertson, D., Brown, J. (2007) An introduction to musculoskeletal ultrasound in sports and exercise medicine.  Sportex Medicine, 33, pgs. 20-26.

Robertson, D.  (2007)  The clinical applications of musculoskeletal ultrasound in primary care.  Sportex Medicine, 34, pgs. 21-26.

Sullivan, O., Bentman, S, Bennett, K., Stokes, M. (2007) Rehabilitative ultrasound imaging of the lower trapezius muscle: Technical description and reliability.  Journal of Orthopedic & Sports Physical Therapy, 37, pg. 620-626.

Whitake, S., Teyhan, D., Elliot, J., Cook, K., Languin, H. Dahl, H., Stokes, M. (2007)  Rehabilitative ultrasound imaging.  Understanding the tecnnology and its applications.  Journal of Orthopedic & Sports Physical Therapy, 37, pgs 434-449.

posted by Toni Patt

2 comments

do you know any training sites or workshops on musculoskeletal US for PTs? thank you.

Maria Chang, DPT December 31, 2012 6:03 PM

You are right, most of the studies about diagnostic US in MSK medicine have been focused on the shoulder.  However, I look at it like this:

Even with the US imaging, the correlation between findings and pain is still poor.  I see a trend of moving away from understanding the pathoanatomic diagnosis...the fact is, that they often don't correlate.  Research is showing time and time again that we can successfully treat patients without knowing the specific "pain generator"...we have to base it on their neurological and mechanical presentation.

Partial thickness tear and even small full thickness tears of the RTC are prevelant as much as 50% in the pain free population over the age of 50.  So what does the US imaging buy us?  In my opinion, not much.  Rather, it's their clinical presentation that of more importance.  In the case of suspected RTC tear, I suppose it would be beneficial in someone who is unable to raise their arm over their head but has full PROM...then again, we know right away that this person really should be seeing a surgeon when you consider that 90% of people with such a presentation will not be able to regain that motion via conservative care.  I'd be much more likely to refer them to the surgeon without any imaging so the surgeon can perform the imaging of their choice.  

Final case point, I've had numerous patients with partial and even full thickness RTC tears (albiet, usually small) make complete recoveries.  Their treatment was based on mechanical presentation and understanding of connective tissue healing.  

In the end, it's their presentation that was more important to me.  The added costs and training, in my opinion, are not worth it.

Christie , PT February 26, 2009 11:42 AM
Streamwood IL

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