Ultrasound in Orthopedic Practice

Point-of-care ultrasound brings great value to patient care in orthopedic practice, especially for soft tissue problems. It offers safe, cost effective, and real-time evaluation for soft tissue pathologies and helps narrow down the differential diagnosis.Pic1

There are variety of soft tissue lesions in orthopedic practice with classic clinical presentation that may not necessitate ultrasound examination for confirmation of diagnosis, for example ganglion cyst. However, there is value in performing an ultrasound scan for these common soft tissue lesions.

Ganglion cyst on the dorsum of the wrist or radial-volar aspect of the wrist are confirmed based on clinical examination and presentation. Adding ultrasound examination can help differentiate classic ganglion cyst from some rare findings like Lipoma, anomalous muscles, or soft tissue tumors. Ultrasound examination may also be helpful in finding the source of the ganglion cyst or the stalk of the ganglion cyst. This can help pre-surgical planning if resection of the ganglion cyst is desired by the patient and recommended by the surgeon, because arthroscopic or traditional surgical approach may be needed based on the location of the stalk or neck of the cyst.

Images 1 and 2 show examples of two different patients with similar presentation of slow growing mass on the digit. Image 1 from patient 1 shows a solid tumor overlying the flexor tendons of the digit, where the mass was palpated. Image 2 from patient 2, shows a cystic mass overlying the tendons of the digit. In both of the cases, masses were painless and slow growing with minimal to no discomfort. Ultrasound is a great tool in differentiating solid vs cystic lesions and can help avoid attempted aspiration of a solid mass when the mass is presented in an area of classic ganglion cyst’s usual presentation.

Another soft tissue problem, where ultrasound is a superior imaging tool is tendon pathology. Ultrasound can help differentiate tendinosis, tenosynovitis, or tendon tears.

In tenosynovitis, tendon by itself shows normal echotexture and uniform appearance but the tenosynovium that surrounds the tendon gets inflamed and appears as hypoechoic halo around the tendon, for example, in image 3, tendons of the first dorsal compartment of the wrist show uniform thickness and fibrillar echotexture, however there is hypoechoic swelling around the tendons, this is an example of tenosynovitis of first dorsal compartment of the wrist.

In tendinosis, tendon loses its fibrillar pattern and appears swollen and may show vascularity on color ultrasound, which is suggestive of neoangiogenesis or angiofibroblastic proliferation. For example, in Image 4, the tendons of the first dorsal compartment of the wrist show focal enlargement, hypoechoic swelling, and loss of normal fibrillar echotexture and tendon appears disorganized with evidence of increased vascularity on color ultrasound. This is an example of tendinopathy or tendinosis.

Focal tendon tears appear as anechoic or hypoechoic focal defects in tendon substance. Image 5 shows partial tear of the triceps tendon from the olecranon process. The partial tear appears as a focal hypoechoic defect in the tendon, which is confirmed in the long and short axis scan of the tendon.

In full thickness tears, the tendon is seen retracted proximally with no fiber attachment at the tendon foot print. Image 6 shows example of a full thickness complete tear of the supraspinatus tendon from its bony attachment at the greater tubercle. The tendon has retracted proximally and the retracted stump is not visible on ultrasound examination.

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Point-of-care ultrasound adds significant value to clinical examination in orthopedic setting. It enhances the understanding of a patient’s problem, increases confidence in care provided, and high patient satisfaction is reported.

 

In what unexpected ways do you find ultrasound to be useful? Do you have additional tips for using ultrasound in orthopedics?  Comment below or let us know on Twitter: @AIUM_Ultrasound.

Mohini Rawat, DPT, MS, ECS, OCS, RMSK, is program director of Fellowship in Musculoskeletal Ultrasonography at Hands On Diagnostics and owner of Acumen Diagnostics. She is ABPTS Board-Certified in Clinical Electrophysiology; ABPTS Board-Certified in Orthopedics; registered in Musculoskeletal Sonography, APCA; and has an added Point-of-Care MSK Soft Tissue Clinical Certificate.

A Future Career Path for the MSK Sonographer

The sonographic community has the opportunity to take advantage of recent orthopedic surgeons’ interest in diagnostic ultrasound. Although much of the interest was prompted by the usefulness of guided injections, sonographers need to fully appreciate and understand the value of the information derived from an ultrasound study, which will ultimately lead the surgeon to better surgical decisions and better patient outcomes. Once you are a part of the orthopedic diagnostic team, you will be able to function as a specialist Physician Assistant member, adding a new dimension to the orthopedic practice and demonstrating the incredible value of diagnostic soft tissue imaging.

I am a Board-Certified Orthopedic Surgeon, with subspecialty in shoulder orthopedics including arthroscopy and open surgery. I incorporated diagnostic shoulder/MSK ultrasound as part of my office practice 20 years ago especially for evaluation of patients presenting with protracted shoulder pain (in addition to the traditional history and physical exam, and occasional MRI).

I have valued diagnostic shoulder imaging in my practice, and determined that all Orthopedic Surgeons should be using ultrasound imaging as part of their usual diagnostic evaluation of patients (especially patients presenting with protracted painful shoulder problems affecting function). In addition, an ultrasound exam with normal findings may be more important than an ultrasound exam that finds some pathology.

I have concluded that the real-time ultrasound examination with comparison to the contralateral side available to the orthopedic surgeon, in most cases, is more valuable than the information obtained from the MRI (especially regarding soft tissue pathology, present or absent).

For example, compare the MRI detail of the supraspinatus with the ultrasound motion clip of the supraspinatus moving under the acromion (see the still MR image below and, at bottom of page, the 1st video, which is the active ultrasound clip of the supraspinatus). MRI is accomplished with arms immobilized at one’s side, and does not benefit from the study being compared to the contralateral side. However, it produces a nice clear image. The ultrasound image in long axis can be a still image or a motion clip viewing the supraspinatus or infraspinatus moving under the acromion and the reaction causing impingement syndrome, spurs along the anterior lateral border of the acromion, dynamic sub acromial bursitis, or a rotator cuff tear, which may be attritional and similarly present on viewing the asymptomatic shoulder.

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The Math

The following statistics help to identify the future vital need for the sonographer to become part of the team working with the surgeon in an orthopedic office practice (Orthopaedic Surgeon Quick Facts, www.aaos.org; 10 Interesting Statistics and Facts About Orthopedic Practice, www.beckersspine.com; Am J Orthop 2016;45(2):66-67; 20 Things to Know About Orthopedics, www.beckershospitalreview.com).

There are approximately 28,000 (2012) orthopedic surgeons in the US, 75% of whom are in private practice, and many are in group practices of 2 or more. The general orthopedic surgeon sees an average of 70-90 patients per week, of which an estimated 12% or more have shoulder problems. This equates to 10 orthopedic shoulder evaluations per week for 1 solo general orthopedic practice, and 20 for a 2-man group (in the same office). Ten to 20 patients (minimum) per week would then benefit from ultrasound imaging information, assisting the surgeon in making a surgical decision.

The following image identifies how important the cross axis image is, as well as describes the degree of rotator cuff injury and approximates the relative number of rotator cuff muscle tendon units thathave been rendered dysfunctional.

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Left, Close to the infraspinatus/supraspinatus interval and insertion site, many fibers are in harm’s way for tendon/fibril tearing. Center, The area for careful X-axis grid examination, looking for possible partial undersurface tearing, fibers losing their connection/attachment to the footplate. Right, Example of an X-axis grid examination of this full thickness tendon tear, which should be accompanied by an x-axis measurement of the width/base of the triangular tear. Real time examination can help to identify the quality of the tissue, which may require repair. Usually, orthopedic surgeons pay more attention to the MRI reading and the coronal views (ultrasound long axis view). (See the 2nd video clip below for real-time imaging of the X-axis rotator cuff tear.) The X-axis view/measurement is the more important image. The wider the tear, the more tendon fibrils are affected and the more dysfunction to the rotator cuff area involved.

This need for diagnostic shoulder ultrasound information could be sufficient and important enough to support an entire career for an MSK sonographer. All the other valuable areas of MSK expertise that come with the MSK sonographer would be an extra bonus to the orthopedic office practice: helping with other ultrasound examinations, diagnosis, and surgical decisions.

Video clip 3 below is an MSK ultrasound examination for CTS identifying median nerve mobility or restriction within the tissue, questioning the presence of scar tissue restricting motion.

 

How have you used ultrasound in orthopedic surgery? What other areas of ultrasound are on the brink of emerging in a new field? Comment below or let us know on Twitter: @AIUM_Ultrasound.

Alan Solomon, MD, is a Board Certified Orthopedic Surgeon and Honorary Staff at the Metro West Medical Center, Natick/Framingham, MA.