|Year : 2019 | Volume
| Issue : 4 | Page : 208-212
Magnetic resonance imaging diagnosis of rotator cuff tears in subacromial impingement syndrome: A retrospective analysis of large series of cases from a single center
Reddy Ravikanth1, Pooja Majumdar2
1 Department of Radiology, Holy Family Hospital, Thodupuzha, Kerala, India
2 Department of Medicine, INHS Kalyani, Visakhapatnam, Andhra Pradesh, India
|Date of Submission||23-Sep-2019|
|Date of Acceptance||17-Oct-2019|
|Date of Web Publication||12-Dec-2019|
Department of Radiology, Holy Family Hospital, Thodupuzha - 685 605, Kerala
Source of Support: None, Conflict of Interest: None
Background: The most frequent painful shoulder diagnosis is subacromial impingement syndrome. It is important to establish valid diagnostic methods for these patients to potentially improve the management and treatment of this syndrome. Magnetic resonance imaging (MRI) is an excellent modality for imaging of soft tissues of the shoulder joint considering a possibility of multiplanar image acquisition and noninvasive nature of the study. The purpose of this study was to evaluate the prevalence of partial and complete rotator cuff tears in magnetic resonance images of patients with subacromial impingement syndrome and to review the literature on the causes and classification of rotator cuff tears. Materials and Methods: After obtaining institutional ethical committee approval, we retrospectively analyzed the results of 200 shoulder MRI examinations with rotator cuff tears performed in 78 women and 122 men in the department of radiology and diagnostic imaging at a tertiary care hospital between April 2014 and December 2018. Examinations were performed using GE Brivo 1.5T device, including spin echo and gradient echo sequences with T1, T2, and proton-density-weighted as well as fat-saturation sequences in axial, coronal, and sagittal oblique planes. Results: Partial and complete supraspinatus tendon tears were the most frequently reported injuries, with a minority of injuries showing complete tear of subscapularis. Among the 200 patients in the study population, 195 patients suffered from shoulder pain, including 117 patients with a history of trauma. There were 59% men and 41% women among patients with shoulder pain. Posttraumatic shoulder pain was predominantly reported by men, whereas women comprised a larger group of patients with shoulder pain not preceded by injury. Subacromial impingement commonly involved supraspinatus tendon, and supraspinatus tear was the most commonly identified pathology. Subscapularis muscle and infraspinatus tendon tears were less common. Isolated involvement and complete tear most often involved supraspinatus muscle tendon followed by infraspinatus and least often involved subscapularis tendons. Conclusion: Rotator cuff disorders are among the most common causes of shoulder pain and disability encountered, and subacromial impingement syndrome in particular is the most common disorder. Isolated supraspinatus tendon injury or complete tearing is most frequent, rather than in conjunction with injuries to other rotator cuff tendons. Isolated complete tears of infraspinatus and subscapular muscle tendons were rarely encountered in our study.
Keywords: Magnetic resonance imaging, shoulder pain, subacromial impingement syndrome
|How to cite this article:|
Ravikanth R, Majumdar P. Magnetic resonance imaging diagnosis of rotator cuff tears in subacromial impingement syndrome: A retrospective analysis of large series of cases from a single center. Apollo Med 2019;16:208-12
|How to cite this URL:|
Ravikanth R, Majumdar P. Magnetic resonance imaging diagnosis of rotator cuff tears in subacromial impingement syndrome: A retrospective analysis of large series of cases from a single center. Apollo Med [serial online] 2019 [cited 2020 Feb 29];16:208-12. Available from: http://www.apollomedicine.org/text.asp?2019/16/4/208/272824
| Introduction|| |
The supraspinatus outlet is bounded superiorly by the coracoacromial arch, which is made up of the coracoacromial ligament, coracoid process, and the acromion. The supraspinatus tendon and the subacromial subdeltoid (SASD) bursa pass through this narrow outlet. Primary extrinsic subacromial impingement refers to pain caused by contact between the rotator cuff and the coracoacromial arch. The pain is thought to be caused by irritation of the well-innervated SASD bursa. Patients typically present with anterolateral shoulder pain that is essentially produced by impingement of the SASD bursa and supraspinatus tendon between the greater tuberosity of the humerus and the coracoacromial arch during abduction and external rotation or forward elevation and internal rotation of the shoulder. Articular capsule and subacromial bursa are highly innervated, and compression of those structures together with bursitis is considered the main source of pain. It might result from anatomical variations of acromion (rotator cuff tear accompanies type III acromion according to Bigliani classification in 80% of cases), acromioclavicular osteoarthritis with osteophyte formation (osteophytes >3 mm pointed downward are of significance), chronic subacromial bursitis (minute amount of fluid in the bursa is a frequent finding, >3 mm of fluid is considered exudate suggestive of bursitis), posttraumatic deformation of humeral head, and os acromiale, which might also result from abnormal reduction of space between coracoid process and humeral head.
There are many classifications that characterize rotator cuff injuries. Neer  described three stages of injury to rotator cuff tendons, namely, Stage I – edema/bleeding usually in people aged under 25 years; Stage II – fibrosis-tendinitis usually occurs in patients aged between 25 and 40 years of age with thickening and fibrosis of subacromial soft tissues; and Stage III – tendon tear leading to progressive failure of limb motor function which is common in patients aged over 40 years.
Ellman  divided complete rotator cuff injuries into small (<1 cm), moderate (1–3 cm), large (3–5 cm), and massive (>5 cm).
Snyder classified rotator cuff injuries as:
- 0: Normal
- I: Minimal irritation of bursa or synovial membrane or mild damage to articular capsule involving a small surface (<1 cm)
- II: Damage and loss of some rotator cuff fibers, as well as damage to the bursa or capsule (<2 cm)
- III: Damage and fragmentation of tendon fibers, usually involving the entire thickness of a tendon, usually of the supraspinatus muscle (<3 cm)
- IV: Severe damage accompanied by tendon tear and fragmentation often involving more than one tendon.
The southern california orthopaedic institute classification (Snyder) divides rotator cuff injuries into:
- Partial peri-articular tear
- Partial peri-bursal tear
- Complete tear.
The purpose of the study was to assess the frequency of the occurrence of partial and complete rotator cuff muscle tears on MRI among patients with subacromial shoulder impingement syndrome and to review the causes and classification of rotator cuff injuries.
| Materials and Methods|| |
After obtaining institutional ethical committee approval, we retrospectively analyzed the results of 200 shoulder MRI examinations with rotator cuff tears performed in 78 women and 122 men in the department of radiology of a tertiary care hospital between April 2014 and December 2018. The largest group consisted of patients aged 45–70 years – 52% of patients, while patients from the age group of 25–45 years constituted 22% of the studied population, people over 70 years old – 18% of patients. Patients between 15 and 25 years age comprised the smallest studied age group corresponding to 8% of the studied population. Examinations were performed using 1.5-T MR (Brivo 355 inspire, GE Healthcare, Milwaukee, Wisconsin, United States), including spin echo and gradient echo sequences with T1, T2, and proton density (PD)-weighted as well as fat saturation (FS) sequences in the axial, coronal, and sagittal oblique planes.
| Results|| |
In our study group, 200 patients reported shoulder pain, including 58.5% of patients with a history of trauma. A group of patients reporting pain comprised of women in 41% and of men in 59%. Posttraumatic shoulder pain was predominantly reported by men (34.5% of subjects), whereas a larger group of patients with shoulder pain without a history of trauma consisted mainly of women (24.5% of patients) [Table 1]. The most commonly occurring pathologies included partial tear (fibrosis and edema) of supraspinatus muscle tendon (79%), followed by subscapularis muscle tendon (34%) and, less frequently, infraspinatus tendon tears (26%) [Table 2]. Complete tearing usually involved the supraspinatus muscle tendon – 17.5%, more rarely infraspinatus muscle (4%). The least numerous group comprised of patients with complete subscapularis muscle tendon tear – 0.5%. Among partial tears, the most frequent pathology involved isolated supraspinatus tendon injury amounting to 40% of patients. Partial tearing of two muscle tendons was diagnosed in 46% of patients (including supraspinatus and infraspinatus tendons in 18% and supraspinatus and subscapularis tendons in 28%) [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]. No cases of partial injury to infraspinatus and subscapularis muscle tendons were identified in the study without supraspinatus tendon tear. Partial supraspinatus, infraspinatus, and subscapularis muscle tendon tears were identified in 16% of patients. Complete tearing usually involved the supraspinatus muscle tendon in conjunction with the partial tearing of infraspinatus and subscapularis tendons – 6% of patients, followed by complete supraspinatus muscle tendon tear without concomitant injury to other muscle tendons in 7.5% of shoulders. Isolated complete subscapularis or infraspinatus tendon tears were not observed. In the present study, complete tearing of supraspinatus and infraspinatus muscle tendons, complete tearing of supraspinatus and subscapularis tendons, complete tearing of infraspinatus muscle tendon + partial supraspinatus tendon tear, complete supraspinatus and infraspinatus tendon tears + partial subscapular tendon tear, and complete supraspinatus tendon tear + partial infraspinatus muscle tendon tear occurred in 1% of patients (two patients in every group). None of our patients presented with complete tearing of all the three muscle tendons [Table 3].
|Figure 1: Coronal oblique proton-density fat-saturation magnetic resonance image of the left shoulder demonstrating a partial-thickness bursal surface tear of supraspinatus (arrow) in a case of subacromial impingement|
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|Figure 2: Coronal oblique proton-density fat-saturation magnetic resonance image of the right shoulder demonstrating a focal full-thickness tear (orange arrow) at the site of supraspinatus insertion in subacromial impingement. Note the acromioclavicular joint arthropathy (blue arrow) and decreased acromio-humeral distance (green arrow)|
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|Figure 3: Coronal oblique proton-density fat-saturation magnetic resonance image of the right shoulder demonstrating a complex tear of supraspinatus in subacromial impingement. Note the complete articular surface tear with subdeltoid bursitis (red arrow) and partial-thickness intrasubstance tear with subacromial bursitis (green arrow) involving supraspinatus|
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|Figure 4: Coronal Multiple Echo Recombined Gradient Echo magnetic resonance image of the left shoulder demonstrating partial-thickness tear of the subscapularis (arrow) along the course of muscle insertion|
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|Figure 5: Coronal oblique proton-density fat-saturation magnetic resonance image of the right shoulder demonstrating complete tear of the subscapularis (red arrow) with high-grade partial-thickness tear of the infraspinatus (blue arrow)|
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|Figure 6: Coronal oblique proton-density fat-saturation magnetic resonance image of the right shoulder demonstrating severe subacromial impingement (yellow star) with complete tear of the supraspinatus and infraspinatus (blue arrow). Note the severe acromioclavicular joint arthropathy (red star) with Type II acromion (green arrow) and prominent undersurface of coracoacromial ligament (pink arrow) concerning severe subacromial impingement|
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|Table 3: Rotator cuff tendon tears identified on magnetic resonance imaging in the study population|
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| Discussion|| |
Among the analyzed shoulder MRI examinations in rotator cuff injuries, 193 (96.5%) patients had isolated supraspinatus tendon injury or together with the remaining rotator cuff muscles, which is concordant with literature data indicating that supraspinatus muscle tendon is damaged in 95% of rotator cuff pathologies. Literature data indicate that partial tendon tear is more common than complete tear, which was confirmed by our study, which showed partial supraspinatus tendon tear in 158 (79%) patients with diagnosed rotator cuff pathology, whereas complete tear was diagnosed in 35 (17.5%) patients. Similarly, infraspinatus tendon (where complete tear occurred in 52 patients, while 8 patients suffered complete tear) and subscapularis tendon (where 68 patients were diagnosed with partial tear and only 1 with complete tear) were reported. Among all patients with rotator cuff tendon pathology included in our study, 124 (62%) patients were diagnosed with acromioclavicular osteoarthritis, which is concordant with literature data, indicating it as one of the common causes of rotator cuff injury.
Plain X-rays are usually normal in an acute rotator cuff injury. X-rays, however, should form the basis for investigating the painful shoulder and shoulder impingement syndrome. They may demonstrate subacromial spurs or anomalies of the acromion. They are also important in the differential diagnosis of shoulder impingement syndrome and demonstrate calcifying tendinitis, fractures, and neoplasm. Magnetic resonance (MR) arthrography is the most sensitive and specific technique for diagnosing both full- and partial-thickness rotator cuff tears. Ultrasound and MRI are comparable to each other in both sensitivity and specificity in the diagnosis of full-thickness rotator cuff tears. MR arthrography and ultrasound appear to be more accurate for the detection of partial-thickness tears than MRI.
| Conclusion|| |
Subacromial impingement syndromes are a common cause of shoulder pain, and early diagnosis of subacromial impingement can help reduce the risk of progression causing further morbidity to patients in the form of pain, reduced activity, or subsequent partial or even complete rotator cuff tears. The conclusions from our study were in men it was most often caused by trauma, whereas in women, it was more frequently nontraumatic. Subacromial impingement commonly involved supraspinatus muscle tendon. Supraspinatus muscle tendon tear was the most commonly identified pathology, more rarely subscapularis muscle and infraspinatus muscle tendon injuries. Isolated involvement and complete tear most often involved supraspinatus muscle tendon followed by infraspinatus and least often involved subscapularis muscle tendons. None of the patients presented with a complete tear combination of all the three rotator cuff muscle tendons or isolated infraspinatus or subscapularis tendon tears.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3]