Shoulder Ultrasound for Orthopaedic Surgeons - My Experience
Lennard Funk, 2003

Ultrasound of the shoulder is generally performed by radiologists in the UK and USA, but by surgeons and clinicians on the European mainland. This is purely historical, determined by who adopted the technology first and applied it clinically.

With the advent of small portable devices, such as the Sonosite handheld machine and the rapidly improving visualization technology of ultrasound it is becoming easier for clinicians to use these devices.

Ultrasound is however dependent on the experience of the operator and thorough training in it's use is essential. This can be very difficult for a clinician to acquire. The Nuffield Orthopaedic Centre in Oxford offer a superb course on Musculoskeletal Ultrasound, but hands-on practice is essential under the supervision of an experienced ultrasonographer. Surgeons, however, do have the unique advantage of being able to validate their scans at surgery. Thus, shortening the learning curve substantially.

Office Ultrasound

Office ultrasound of the shoulder, performed at the time of first presentation offers the following advantages:

1. Immediate diagnosis and confirmation of the rotator cuff pathology, allowing:
   1. One stop clinic, avoiding patients being sent away for a scan and then return a few weeks (or months) later with the result.
   2. Management planning and listing for the appropriate surgery at that visit, thus reducing waiting time for surgery.
   3. Patients to know their diagnosis immediately and plan accordingly.
2. Allows therapists treating patient to manage accordingly
3. Patient convenience
4. Surgeon convenience
5. Cheap - avoids cost of MRI and the radiology department costs.
6. Quick
7. Safe - no dangerous radiation
8. Elimination of unnecessary injections - if a patient has a rotator cuff tear I would not inject the subacromial bursa with steroid usually.

This 'One-stop clinic' approach is popular with patients and is excellent for teaching purposes and honing clinical examination skills.

Ultrasound Machine

I currently use both the Sonosite Titan and 180-PLUS machines with a 38mm linear array transducer. It has the following advantages for me:

• Portability:
  • light and easy to transfer between cubicles and rooms in a busy clinic setting.
  • Long life rechargeable battery, so no need to plug-in all the time.
  • Backpack allowing easy transfer between hospital sites
• Quick - starts up quickly and shuts down with the click of a button
• Comfortable and easy to use probe
• Measurement Tools - easy to measure objects
• Easy to enter patient information with keyboard
• Fully digital so images are saved as seen, with all patient and measurement data
• Connectivity to external monitors, TV screen, various printers etc.
• The Titan has the ability to save video sequences and download them to a PC.
• The SiteLink software from Sonosite allows me to save all examinations onto my PC and automatically organises all the examinations in logical files, so they are easy to retrieve.

	Sonosite Titan Handheld Ultrasound Scanner
	Sonosite 180 Plus Handheld Ultrasound Scanner
	38mm linear array transducer - ideal for shoulders

Ultrasound Diagnosis

Ultrasound can reveal many different diseases of the shoulder:

• Subacromial bursitis - when the bursa is too thick (more than 2 mm thick or clearly asymmetric with the asymptomatic shoulder)
• Calcifications in the cuff - These calcifications are of course almost always seen on the plain films. However, in some cases, they are missed because of their location (subscapularis calcifications) or direction of the x-ray beam. The appearance of the calcifications on ultrasound can predict their action on the symptomatology. Thin, long calcifications are often asymptomatic whereas thick, rounded or irregular calcifications give rise to symptoms. The amount of posterior attenuation can also predict the hardness of the calcifications, eventually helping when arthroscopic removal of the calcium deposits is considered for treatment.
• Partial rotator cuff tears can also been depicted, although the accuracy is lower than for complete tears.
• Complete rotator cuff tears are well seen with ultrasound.
  • Direct signs include :
    • flattening of the superficial border of the tendon - the normal tendon is convex.
    • hypoechoic zone separating the tendon edges
    • absence of the normal tendon, replaced by a thin hypoechoic line representing the hypertrophic bursa surrounding the greater tuberosity
    • compression test - compression of the tendon causes flatening as the tendon edges are further pushed apart. The intact cuff cannot be compressed.
  • Indirect signs include :
    • effusion around the long head of the biceps tendon
    • double effusion sign : this sign includes a joint effusion seen around the biceps tendon and subacromial subdeltoid bursitis; it is more specific for a rotator cuff tear; some authors quote a positive predictive value as high as 95%.
    • greater tuberosity erosions : this is a sign of enthesopathy, but this condition is often related to a rotator cuff tear.
    • cartilage interface sign
    • deltoid herniation : the deltoid muscle bulges deeply into the gap of the rotator cuff
    • muscle atrophy : fatty infiltration of the supraspinatus or infraspinatus muscles are seen in their respective fossae; comparison with the other side can help to make this diagnosis; the involved muscles are abnormally hyperechoic; the subscapularis muscle cannot be seen when it goes between the scapula and the chest wall.
  
  

Ultrasound Accuracy

Being an operator-dependent and a device-dependent technique, ultrasound of the shoulder may give very divergent results. A summary is given in the next table.

Generally, the results are as good as those of MR for complete tears. However there might be a discordance between the length of the rupture measured on ultrasound compared with the arthroscopic or open view. This results from the underestimation of the tear on ultrasound. Also, surgeons tend to overestimate the tear size compared to radiologists, as they measure from repairable tissue edges and not from the edges of the tear.

Conclusion

Ultrasound is a quick, easy, cheap imaging process for the diagnosis of soft tissue shoulder diseases.
Performed at the first consultation it offers the advantages of patient and surgeon convenience and shorter waiting times. It is, however, dependent on the skill and experience of the operator who needs to be suitably trained to perform it.

Further Reading:

1.  Milgrom C, Schaffler M, Gilbert S, van Holsbeeck M: Rotator-cuff changes in asymptomatic adults. J Bone Joint Surg. 77-B:296-8. 1995

2. Mack L, Matsen III F, et al: US evaluation of the rotator cuff. Radiology. 157(1):205-9.1985.

3. Middleton W: Ultrasonography of the Shoulder. Rad Clin No Amer. 30(5):927-40.1992

4.  Sonnabend DH, Hughes JS, Giuffre BM, Farrell R: The clinical role of shoulder ultrasound. Aus NZ J Surg. 67:630-3. 1997.

5. Hoy G, Hayes MG et al: Ultrasound imaging and arthroscopic diagnosis of rotator cuff tears. J Bone Joint Surg Br. Suppl. 2:110. 1994.

6. Hodler J, Fretz CJ, Terrier F, Gerber C: Rotator Cuff Tears: Correlation by sonographical and surgical findings. Radiology. 169:791-4. 1988.

Useful Links:

1. Guidelines for Musculoskeletal Ultrasound

2. Shoulder Ultrasound Technique

27/10/2003