Intramuscular Rotator Cuff Cysts: Association with Tendon Tears on MRI and Arthroscopy

Rotator cuff tear patterns: MRI appearance and its surgical relevance

A new perspective on rotator cuff anatomy has allowed a better understanding of the patterns of the different rotator cuff tears. It is essential for radiologists to be aware of these different patterns of tears and to understand how they might influence treatment and surgical approach. Our objective is to review the arthroscopy correlated magnetic resonance imaging appearance of the different types of rotator cuff tears based on current anatomical concepts.Critical relevance statement Knowledge of the characteristics of rotator cuff tears improves our communication with the surgeon and can also make it easier for the radiologist to prepare a report that guides therapeutic conduct and serves as a prognosis for the patient.Key points• There is no universally accepted classification for RC tears.• New patterns such as delamination or myotendinous junction tears have been defined.• The most difficult feature to assess in full thickness tears on MRI is the pattern.• Fatty infiltration of the RC tendons is crucial in the prognosis and outcome.• The radiological report is an effective way of communication with the surgeon.

[Lesions of the rotator cuff and biceps tendon]

CLINICAL/METHODOLOGICAL PROBLEM

The rotator cuff is a complex anatomical structure and the integrity is pivotal for the shoulder functionality. The pathologies are often multifactorial, resulting from degenerative, vascular, traumatic and mechanical factors.

RADIOLOGICAL STANDARD PROCEDURES

Radiography, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) form the pillars of radiological diagnostics. Each modality has specific advantages and limitations in the visualization and assessment of pathologies of the rotator cuff and biceps tendon.

METHODOLOGICAL INNOVATIONS

The MR arthrography offers additional insights in unclear cases by enhancing the differentiation between complete and partial tears.

PERFORMANCE

The MRI provides detailed information on tendon quality and associated damages, such as muscle atrophy and fat infiltration, making it the preferred method. The use of MR arthrography can identify defects through increased intra-articular pressure or contrast medium leakage.

EVALUATION

Muscle damage, as induced by edema in acute injuries or fatty degeneration in chronic conditions, can be evaluated using imaging techniques. Special attention is warranted for the infraspinatus, subscapularis and teres minor muscles due to their unique injury patterns and prevalences.

[Partial-Thickness Tear of Supraspinatus and Infraspinatus Tendon Revisited: Based on MR Findings]

The interpretation of MRI of partial-thickness rotator cuff tears can be challenging. This review describes the anatomic considerations for diagnosing partial-thickness tears, especially supraspinatus and infraspinatus tendon and summarizes the classification of partial-thickness rotator cuff tears, as well as provides an overview on partial-thickness tears with delamination.

The Evolving Roles of MRI and Ultrasound in First-Line Imaging of Rotator Cuff Injuries

Rotator cuff tears are the most likely source of shoulder pain in adults and may cause protracted disability. Management of rotator cuff tears is associated with considerable costs. Accurate diagnosis can guide surgical planning and help achieve a favorable clinical outcome. While radiographs remain the initial imaging test for shoulder injury, the roles of MRI and ultrasound (US) as first-line imaging after radiography are evolving. This review leverages current literature and the practical experience of subspecialty musculoskeletal radiologists from different institutions in describing a practical approach to imaging rotator cuff pathology. Both MRI and US are accurate for identifying rotator cuff tears, but each has advantages and shortcomings. As both modalities currently represent reasonable first-line approaches, considerable practice variation has evolved. Given the low cost of US, imagers should strive to optimize the quality of shoulder US examinations and to build referrer confidence in this modality. The roles of direct CT and MR angiography, as well as imaging evaluation of the postoperative rotator cuff, are also considered. Through careful selection among the available imaging modalities, as well as optimal performance and interpretation of such examinations, radiologists can positively contribute to the diagnosis and treatment of patients with rotator cuff injuries.

Arthroscopic Treatment of an Unusual Intramuscular Calcium Hydroxyapatite Crystal Deposit on the Rotator Cuff

Hydroxyapatite crystal deposition disease and its pathophysiology are poorly understood; however, it is known that calcific tendinitis is the most common condition related to this deposition in the upper limb. Movement of the crystals toward the myotendinous junction is rare; to the best of our knowledge, only 19 cases have been described in the literature, one of which was a case of intramuscular deposition without migration. The purpose of this technical note is to describe the technical details of the arthroscopic treatment of intramuscular calcium hydroxyapatite deposits without intratendinous migration.

Patterns of tendon retraction in full-thickness rotator cuff tear: comparison of delaminated and nondelaminated tendons

OBJECTIVE

To analyze full-thickness rotator cuff tears, compare retraction patterns in delaminated and nondelaminated tendons, and correlate retraction distances with anteroposterior tear lengths.

MATERIALS AND METHODS

In 483 MR examinations reported as showing full-thickness cuff tear, two musculoskeletal radiologists independently characterized tendons as delaminated or nondelaminated. Tendon delamination was defined as either horizontal intra-substance splitting of bursal and articular layers by an intervening plane of fluid, or differential retraction of bursal and articular layers. In a subset of 144 shoulders with surgically proven full-thickness cuff tears (45 delaminated, 99 nondelaminated tendons), matched cohorts (n = 45) were further analyzed to compare tendon retraction distance, anteroposterior tear length and retraction ratios (retraction distance/anteroposterior length).

RESULTS

Delamination was present in 13% of 483 total tears, and 31% of 144 operated tears (p = 0.001). In nondelamination and delamination cohorts, mean anteroposterior tear length measured 30.0 and 31.5 mm respectively (p = 0.6). Although nondelaminated tendons showed mean retraction 31.5 mm, articular and bursal layers of delaminated tendons showed mean retractions 36.3 mm and 21 mm respectively (p < 0.0001). Anteroposterior tear length and retraction distance were significantly associated in all cuff tears (p < 0.0001). Retraction ratio for nondelaminated tendons (1.05) was significantly different from retraction ratios for articular (1.21) and bursal (0.70) layers of delaminated tendons (p < 0.0001).

CONCLUSION

In full-thickness rotator cuff tear, delaminated and nondelaminated tendons show significant differences in retraction distances, despite similarities in anteroposterior dimensions. Delaminated tendons are important to identify and report because they are more likely to fail conservative treatments and undergo operative repairs.

Intramuscular migration of calcium hydroxyapatite crystal deposits involving the rotator cuff tendons of the shoulder: report of 11 patients

OBJECTIVE

The intent of the study is to describe an unusual pattern of intramuscular migration of calcific deposits related to hydroxyapatite deposition disease (HADD) involving the rotator cuff, to illustrate the characteristic imaging features of this phenomenon, and to discuss the clinical significance of such migration.

MATERIALS AND METHODS

A series of cases of intramuscular accumulation of calcium hydroxyapatite crystals collected over a 7-year period at multiple hospitals within the same academic institution were retrospectively reviewed.

RESULTS

The patient group was composed of seven men and four women, ranging in age from 51 to 79 years, with a mean age of 63 years. All subjects presented with acute shoulder pain. The majority of subjects reported the spontaneous onset of the symptoms (64%), while others reported weight lifting (27%) and a fall on the arm (9%) as the mechanisms of injury. The right shoulder was affected in 73% of the subjects. The supraspinatus was the most commonly affected muscle (82%), followed by the infraspinatus muscle (36%).

CONCLUSIONS

Knowledge of the imaging features of intramuscular migration of hydroxyapatite deposits is important in order to avoid the erroneous diagnosis of other causes of muscle edema and inflammation such as myotendinous injury, myositis, subacute denervation, and neoplasm.

Delaminated tears of the rotator cuff: prevalence, characteristics, and diagnostic accuracy using indirect MR arthrography

OBJECTIVE. The purpose of this study was to evaluate the prevalence, radiologic characteristics, and accuracy of diagnosing delaminated tears at the supraspinatus tendon-infraspinatus tendon (SST-IST) on indirect MR arthrography. MATERIALS AND METHODS. Of 531 consecutive shoulders that underwent indirect MR arthrography, 231 shoulders with tears at the SST-IST were included. On the MR images, delaminated tears at the SST-IST, defined as intratendinous horizontal splitting between the articular and bursal layers of the SST-IST with or without different degrees of retraction between the two layers, were identified and classified into six types. Other radiologic findings of the SST-IST, such as the presence of intramuscular cysts, were evaluated. We used video records of 127 arthroscopic surgeries to determine the diagnostic accuracy of indirect MRI for the detection of the delaminated tears at the SST-IST. RESULTS. On MRI, 56% (129/231) of shoulders with SST-IST tears had delaminated tears. Articular-delaminated full-thickness tears (n = 58) and articular-delaminated partial-thickness tears (n = 64) were the most common types. Approximately 82% (36/44) of articular-delaminated full-thickness tears occurring at the SST were combined with articular-delaminated partial-thickness tears at the IST. SST-IST footprint tears and intramuscular cysts were significantly more common in the shoulders with delaminated tears. The sensitivity and specificity of indirect MR arthrography for detection of delaminated tears were 92% and 94%, respectively. CONCLUSION. On indirect MR arthrography, approximately half of the shoulders with SST-IST tears had delaminated tears. The diagnostic accuracy of indirect MR arthrography for detection of delaminated tears was high.

MRI findings of rotator cuff myotendinous junction injury

OBJECTIVE

The purpose of this article is to describe the MRI features of rotator cuff myotendinous junction injuries.

MATERIALS AND METHODS

We retrospectively identified MRI cases with myotendinous junction injury of the rotator cuff muscles and reviewed clinical, imaging, and surgical records. MR images were reviewed independently by two musculoskeletal radiologists to grade myotendinous junction injuries (strain, partial tear, or complete tear) and to assess for concurrent tendon tears (partial or full thickness) and bone changes (fracture or contusion).

RESULTS

The final study group comprised 16 subjects. The mean age was 38 years, with a majority of men (56%). The left shoulder was affected in 56% of subjects, with the dominant upper limb affected in 50%. The mean time between symptoms and MRI was 19 days. Subjects reported heavy lifting (19%), landing on the arm after a fall (19%), or prior shoulder therapeutic injection (25%). Myotendinous junction injuries affected the infraspinatus muscle (50%), followed by the supraspinatus (31%), subscapularis (25%), and teres minor (19%) muscles. About one fifth of subjects presented with more than one muscle affected, and 94% did not present with tears of the corresponding tendons. Most myotendinous junction injuries were strains (80%), followed by partial tears (20%). No complete tears were identified. There was no correlation between myotendinous junction injury and the presence of bone changes or the presence of tendon tears (p > 0.05).

CONCLUSION

Rotator cuff myotendinous junction injuries affect mostly the infra-spinatus and supraspinatus muscles, usually in a strain pattern and without tear of the corresponding tendon attachment.

Imaging of tendons

Both magnetic resonance imaging (MRI) and sonography are well suited to tendon imaging. A normal tendon on MRI demonstrates low signal intensity and on sonography, an echogenic fibrillar pattern. MRI is considered the imaging gold standard, providing an anatomic overview and excellent soft tissue contrast. Sonography is a more rapidly performed examination; it has greater resolution than that of MRI; it allows dynamic evaluation of tendons and muscles; and it can guide percutaneous therapeutic procedures. Moreover, the advent of sonographic extended-field-of-view imaging allows the demonstration of the entire length of a tendon, matching MRI’s ability to display a large anatomic region. Sonography should best be considered a focused examination, concentrating on the area of pain and clinical suspicion of pathology, whereas MRI can provide a global assessment of the region of concern. Both modalities demonstrate high accuracy for abnormalities of various tendons. This article reviews normal tendon anatomy and its imaging appearance, as well as the imaging appearances of tendon degeneration and tear.

The aging athlete: part 2, "boomeritis" of the upper extremity

OBJECTIVE

The purpose of this review is to describe the upper extremity injuries that frequently accompany aging, the typical clinical presentations, and the differential diagnoses with an emphasis on the injury most likely encountered with each presentation.

CONCLUSION

Expectation of continued participation in exercise and sports activities by the baby boomer population has presented new challenges to the medical field. The concepts behind factors that predispose older athletes to certain pathologic conditions that affect the muscles, tendons, and bones of the upper extremity must be understood.

Magnetic resonance imaging of rotator cuff disease and external impingement

Magnetic resonance (MR) imaging plays a major role in helping to identify rotator cuff disease and in demonstrating the pathology associated with external impingement. Many surgeons rely on MR imaging to assist in decision making and presurgical planning for patients with rotator cuff pain. This article reviews the etiology of external impingement and rotator cuff tears, and describes the MR imaging appearance of the normal and the pathologic rotator cuffs. It focuses on the supraspinatus tendon because this is the tendon involved in 95% of rotator cuff tears.

A left-sided asymptomatic supraclavicular cystic mass in a 14-year-old girl

A 14-year-old girl was referred to our department with a 3-month history of an asymptomatic swelling in the left cervical triangle. The girl, an active ski jumper, was used to carrying her skis on the left shoulder. There was a history of many minor falls and contusions of her body. The left posterior cervical triangle was enlarged by an elastic, partially fluctuating and clearly delineated swelling with 4-6 cm in diameter. The trapezius was elevated and the overlaying skin was intact. It was clear that the mass was spreading infraclavicularly. Nevertheless, the distal boundaries of the mass were not quite clear (Fig. 1). The infraclavicular spreading was confirmed with an ultrasound examination which revealed a hypoechogenic echo-free mass of the size of 7-10 x 3.6 cm. The mass was sonocompressible, clearly outlined and there were no signs of any infiltrating growth. No internal perfusion was found by colour-coded Doppler investigation. The blood count or biochemical tests did not reveal any pathological findings.

Pitfalls in MR Image Interpretation Prompting Referrals to an Orthopedic Oncology Clinic

Patients referred to the authors' hospital for evaluation on suspicion of a bone or soft-tissue malignancy frequently present to the Orthopaedic Oncology Clinic with magnetic resonance (MR) images that show typical features of nonmalignant or nonneoplastic entities. The purpose of this article is to review the benign entities that may be mistaken by the radiologist for a malignancy and thus lead to needless referral to an orthopedic oncologist. Normal hematopoietic marrow and marrow edema due to a stress reaction may mimic a neoplasm at MR imaging, but knowledge of the typical patterns and locations of these features allows an accurate radiologic interpretation. The MR imaging appearance of osteonecrosis, Paget disease, benign bone lesions, and rheumatologic conditions may be confusing; in such circumstances, radiographic findings may help formulate a correct diagnosis. Knowledge of the common locations and appearances of bursae and ganglia is necessary so that radiologists do not misinterpret these benign entities as soft-tissue sarcomas. Soft-tissue trauma and inflammation also may mimic tumors at MR imaging, but a familiarity with the imaging patterns of nonneoplastic change in muscle allows the avoidance of misinterpretation. The clinical history, as always, is an important component of proper diagnosis. The radiologist can be especially useful to both the clinician and the patient by recognizing entities that are highly unlikely to represent malignancy and by confidently reporting those entities as benign, thereby sparing the patient an unnecessary trip to the orthopedic oncologist.

Advances in musculoskeletal tumor imaging

In the last 2 decades, there has been a dramatic change in the clinical approach to the tumors of the musculoskeletal system. The role of medical imaging in diagnosis, staging,and eventual follow-up of patients who have musculoskeletal neoplasia has expanded. This article presents an overview of the role of imaging, recent advances in technology,and state-of-the-art techniques for evaluating musculoskeletal neoplasms. Conventional imaging modalities, ultrasound, CT, MRI, positron emission tomography, and image-guided interventions are discussed.