Shoulder and Elbow cases acute rotator cuff tears
A 35-year-old male has had left shoulder pain for 4 months, ever since a low-speed motor vehicle accident (MVA). Physical examination demonstrates preserved range of motion but pain and some weakness with Jobe’s testing. His imaging is shown in Figure 2–8.
 |
Figure 2–8 Reproduced with permission from Stadnick ME. Partial Rotator Cuff Tears. MRI Web Clinic. 2007 (Apr).
What is the most likely diagnosis?
-
Partial articular surface tendon avulsion (PASTA)
-
Full-thickness rotator cuff tear
-
Superior labrum anterior to posterior tear (SLAP)
-
Anterior labral periosteal sleeve avulsion (ALPSA)
Discussion
The correct answer is (A). These are best diagnosed on an MRI as seen in the imaging provided; addition of intra-articular contrast can further improve this study. Answer B, full-thickness rotator cuff tear, is incorrect as the bursal side of the tendon can be seen to be in continuity. Answer C, a SLAP lesion, will be visualized as a labral tear on a coronal MRI and will be found at the biceps root. Answer D, an ALPSA lesion, will be most clearly seen on an axial MRI. It is a variant of a Bankart lesion where the labrum is displaced medially and inferiorly rolling down the glenoid neck underneath the periosteum.
Rotator cuff tears are a common reason for shoulder pain and a common reason to obtain shoulder imaging. As a result, numerous different imaging modalities exist offering different pros and cons. Plain films are still the initial imaging modality of choice. These are most useful in ruling out other possible diagnosis but can help with the diagnosis of a rotator cuff tear as well. Changes to the tendon itself
may appear as calcific tendinosis, which would most commonly be seen at the bone–tendon interface. A decrease in the acromiohumeral distance (less than 2 mm) may also be indicative of a cuff tear. In late cases of rotator cuff tears, superior subluxation of the humerus may be evident. Certain variations in acromial anatomy, including spurs or a hook-shaped (type 3) acromions, may be associated with rotator cuff tears as well. With progression of rotator cuff tears, degenerative changes including spurs, cysts, and sclerosis may be evident at the greater tuberosity. In late, massive tears one may see degenerative changes consistent with rotator cuff arthropathy.
Ultrasound has been gaining popularity recently as it is extremely cost effective when compared to MRI and allows a dynamic assessment of the tendons. It has been shown to have greater than 90% specificity and sensitivity when performed by an experienced operator.
MRI remains the most popular imaging modality for diagnosing rotator cuff tears. Normal rotator cuff tendon appears dark on both T1 and T2 sequences. Tears may be noted as being full-thickness, articular-sided, bursal-sided, or intrasubstance. They are visualized as a disruption in the regular contour of the tendon and increased signal intensity on T2 sequences. Occasionally, an MR arthrogram may provide additional information regarding a cuff tear, although this is not routinely ordered.
What MRI sequence and plane is best for viewing supraspinatus rotator cuff tears?
-
T1 coronal
-
T1 sagittal
-
T2 sagittal
-
T2 coronal
-
T2 axial
Discussion
The correct answer is (D). T2 sequence causes most soft tissues, including muscle and tendon, to appear dark and inflammation, such as at the site of a tear, to appear bright. This means that if there is a rotator cuff tear, there will be a bright spot along the course of the dark rotator cuff tendon. This is easiest to pick out in the coronal plane because the tendon runs in this plane, allowing one to view the entire supraspinatus tendon and tear in one cut.
A T1 sequence coronal view (Answer A) would allow you to view the entire
tendon and tear in one cut, but will not provide as much contrast between the tear and tendon as a T2 sequence. A T1 sequence sagittal view (Answer B) would not provide the best sequence or plane for viewing a rotator cuff tear. T1 sequence is useful to visualize Hill–Sachs lesions more than rotator cuff tears. Neither a T2 sequence sagittal view nor a T2 sequence axial view (Answers C and E) would allow one to view a rotator cuff tear in the optimal plane.
What percentage of asymptomatic patients older than 60 year of age will have a rotator cuff tear?
-
0 to 10
-
10 to 30
-
30 to 60
-
60 to 80
-
80 to 100
Discussion
The correct answer is (C). Numerous studies have shown that the rate of asymptomatic rotator cuff tears is between 30% and 60% in patients older than 60 years of age. The frequency of tears tends to increase with advanced age.
A 45-year-old carpenter presents with shoulder pain that has been ongoing for the last 3 months. He denies any significant injury. He describes night pain and significant discomfort at work. His imaging is shown in Figure 2–9. What is the most likely diagnosis?
-
Subscapularis tear
-
Supraspinatus tear
-
Labral tear
-
Anterior labral periosteal sleeve avulsion (ALPSA)
-
Shoulder instability
 |
Figure 2–9 From Shi LL, Mullen MG, Freehill MT, et al. Accuracy of Long Head of the Biceps Subluxation as a Predictor for Subscapularis Tears. Arthroscopy 2015;32(4):615–619.
Discussion
The correct answer is (A). Medial subluxation of the biceps tendon as seen in this MRI is commonly associated with a tear of the subscapularis tendon which attaches to the lesser tuberosity. This patient’s pain may in part be attributable to the subscapular tear and this should be evaluated for during physical examination. Supraspinatus tears (Answer B) cannot be easily visualized on axial views and are not associated with medial biceps subluxations. A labral tear and ALPSA lesion (Answers C and D) are not seen on the images provided. The question stem and MRI are not suggestive of shoulder instability (Answer E).
Objectives: Did you learn...?
Diagnose and treat acute rotator cuff tears?
Acquire advanced imaging at the appropriate time for rotator cuff tears? Use the correct MRI sequence and plane for imaging rotator cuff tears? Diagnose a subscapularis tear based on medial biceps tendon subluxation?