Magnetic Resonance Imaging of the Shoulder: Interpretation of Common Orthopaedic Injuries

Magnetic resonance imaging (MRI) is frequently obtained to assess for pathology in the setting of shoulder pain and dysfunction. MRI of the shoulder provides diagnostic information that helps optimize patient management and surgical planning. Both general and subspecialized orthopaedic surgeons routinely order and review shoulder MRIs in practice. Therefore, familiarity with the MRI appearance of common shoulder pathologies is important. This document reviews the most common shoulder pathologies using a standardized MRI interpretative approach. Instructional videos demonstrating a musculoskeletal radiologist interpreting normal and abnormal shoulder MRIs are also provided.

Neuropathy Score Reporting and Data System (NS-RADS): A Practical Review of MRI-Based Peripheral Neuropathy Assessment

The Neuropathy Score Reporting and Data System (NS-RADS) is a newly developed MR imaging-based classification that standardizes reporting and multidisciplinary communication for MR imaging diagnosis and follow-up of peripheral neuropathies. NS-RADS classification has shown to be accurate and reliable across different centers, readers' experience levels, and degrees of peripheral neuropathies, which include nerve injury, entrapment, neoplasm, diffuse neuropathy, post-interventional status, and temporal changes in muscle denervation. This article brings a practical review of NS-RADS classification, representative MR cases, and a step-by-step tutorial on how to approach this staging system. Readers can gain knowledge and apply it in their practice, aiming to standardize the communications between specialties and improve patient management.

Predictors of infraspinatus muscle degeneration in individuals with an isolated supraspinatus tendon tear

OBJECTIVE

Determine the demographic and clinical factors that predict infraspinatus muscle degeneration in individuals with an isolated supraspinatus tendon tear.

MATERIALS AND METHODS

A retrospective analysis was performed using the medical records of patients who had a shoulder MRI interpreted by 1 of 3 fellowship-trained musculoskeletal radiologists since the implementation of a standardized MRI 3 T protocol within our healthcare system. Demographic (e.g., age, sex) and clinical data (e.g., tear size, muscle degeneration, co-morbidities) were collected. Patients with an isolated supraspinatus tendon tear (n = 121) were assigned to one of two groups based on whether any infraspinatus muscle degeneration was present. Logistic regression was used to assess the univariate relationships between infraspinatus muscle degeneration and patient and clinical data, while least absolute shrinkage and selector operator (LASSO) logistic regression was used to assess the multivariable relationship.

RESULTS

Of the patients with an isolated supraspinatus tendon tear, 16.5% had evidence of infraspinatus muscle degeneration. The presence of infraspinatus muscle degeneration was independently associated with cardiovascular disease (P = 0.01), supraspinatus muscle degeneration (P < 0.01), and subscapularis muscle degeneration (P = 0.01). When the multivariable relationship is assessed, supraspinatus muscle degeneration emerged as the only variable of significant importance for detecting infraspinatus muscle degeneration (specificity: 87.1%, sensitivity: 80.0%).

CONCLUSION

Infraspinatus muscle degeneration is not uncommon in individuals with an isolated supraspinatus tear and is most associated with concomitant supraspinatus muscle degeneration. These findings highlight the need for clinicians to specifically assess the status of each rotator cuff muscle, even when the tendon itself is intact.

MRI findings in atraumatic shoulder pain-patterns of disease correlated with age and gender

BACKGROUND

The rotator cuff is a group of muscles and tendons which support the shoulder joint. Rotator cuff disease is a frequent cause of morbidity in adulthood.

AIMS

The aims of his study are to determine the prevalence and patterns of rotator cuff derangement in symptomatic patients using MRI and to attempt to correlate identified patterns of disease with age and gender METHODS: Five hundred ninety-seven patients attending for MRI of the shoulder with atraumatic shoulder pain were included for study. Patients' age and gender was recorded. Record was made of the presence or absence of rotator cuff derangement and of degenerative change in the AC and glenohumeral joints. Correlation was made between age and gender.

RESULTS

There were 358 males (60%) and 239 females (40%) with a mean age of 49.4 ± 17.1 years. Subacromial bursitis was identified in 517 patients. A normal supraspinatus tendon was identified in 219 patients and supraspinatus full thickness tearing was identified in 102 patients. A normal AC joint was identified in 267 patients while degenerative AC joint changes were identified in 370 patients. A significant correlation was identified between age and rotator cuff derangement (p < .001) and between age and AC joint derangement (p < .001). No significant difference was identified between gender and patterns of cuff derangement CONCLUSION: The extent of rotator cuff and AC joint derangement increases with ageing. Impingement appears to trigger a cascade of events in sequence, from isolated subacromial bursitis through to supraspinatus tendon tearing. Patterns of rotator cuff derangement are similar in men and women.

Infraspinatus atrophy due to Bennett lesion causing suprascapular nerve palsy

We report the case of a 19-year-old professional volleyball player who presented with right shoulder pain exacerbated during sports activity. On physical examination, infraspinatus atrophy was evident. As the clinical setting suggested suprascapular nerve entrapment syndrome, shoulder MR and later CT were performed. The results showed radiological signs of subacute-chronic infraspinatus muscle denervation and a Bennett lesion of the shoulder, presumably due to chronic repetitive trauma during the classical overhead swing in volleyball. The patient agreed to surgical treatment, and arthroscopic decompression was achieved. After months of rehabilitation, the pain gradually subsided, the infraspinatus muscle recovered its trophism, and the patient progressively returned to her regular sports activity.

Imaging of calcific tendinopathy around the shoulder: usual and unusual presentations and common pitfalls

Rotator cuff calcific tendinopathy (RCCT) is a very common condition, characterized by calcium deposition over fibrocartilaginous metaplasia of tenocytes, mainly occurring in the supraspinatus tendon. RCCT has a typical imaging presentation: in most cases, calcific deposits appear as a dense opacity around the humeral head on conventional radiography, as hyperechoic foci with or without acoustic shadow at ultrasound and as a signal void at magnetic resonance imaging. However, radiologists have to keep in mind the possible unusual presentations of RCCT and the key imaging features to correctly differentiate RCCT from other RC conditions, such as calcific enthesopathy or RC tears. Other presentations of RCCT to be considered are intrabursal, intraosseous, and intramuscular migration of calcific deposits that may mimic infectious processes or malignancies. While intrabursal and intraosseous migration are quite common, intramuscular migration is an unusual evolution of RCCT. It is important also to know atypical regions affected by calcific tendinopathy as biceps brachii, pectoralis major, and deltoid tendons. Unusual presentations of RCCT may lead to diagnostic challenge and mistakes. The aim of this review is to illustrate the usual and unusual imaging findings of RCCT that radiologists should know to reach the correct diagnosis and to exclude other entities with the purpose of preventing further unnecessary imaging examinations or interventional procedures.

Suprascapular nerve entrapment in young kayaker: a case report

Kayaking has become one of the most popular paddle sports throughout the world. The shoulder is the most commonly injured area of the body among kayaking participants as a result of acute traumatic events and chronic overuse injuries. Therefore, kayaking participants may often seek advice for shoulder problems and there is a scarcity of studies regarding shoulder injuries in this population. In this case report, we present a young male recreational whitewater kayaker with a severe suprascapular nerve (SSN) entrapment who presented with shoulder pain and inability to perform his sport. He was initially evaluated elsewhere and was treated with nonsteroidal anti-inflammatory medications and physical therapy for presumptive diagnosis of subacromial impingement. After 5 months of failed non-operative treatment, the patient sought a second opinion with our group. SSN entrapment diagnosis was confirmed by a thorough careful physical examination, magnetic resonance imaging and electrodiagnostic study. Given the failure of non-operative treatment, the patient was treated with arthroscopic SSN decompression and successfully returned to kayaking without symptoms. While SSN entrapment has been reported in a variety of sports, especially those involving overhead movements, this is the first case report of SSN entrapment reported which impaired participation in kayaking. This case report supports the consideration of SSN entrapment in the differential diagnosis of painful shoulder among kayaking participants and highlights the importance of undressing the patient and examining the posterior shoulder for atrophy, winging or deformity.

Nerve and Muscle Abnormalities

Muscle atrophy in shoulders with rotator cuff tendon tears is a negative prognosticator, associated with decreased function, decreased reparability, increased retears after repair, and poorer outcomes after surgery. Muscle edema or atrophy within a neurologic distribution characterizes denervation. Because most nerve entrapments around the shoulder are not caused by mass lesions and show no nerve findings on routine MR imaging sequences, pattern of muscle denervation is often the best clue to predicting location of nerve dysfunction, which narrows the differential diagnosis and guides clinical management. The exception is suprascapular nerve compression in the spinoglenoid notch caused by a compressing cyst.

Ultrasound imaging of nerves in the neck: Correlation with MRI, EMG, and clinical findings

Objective

We evaluated the performance of ultrasound in the detection of neuropathy of the suprascapular nerve (SSN), long thoracic nerve (LTN), spinal accessory nerve (SAN), and phrenic nerve and compared this performance with MRI.

Methods

A retrospective review of 56 patients who had undergone ultrasound imaging of the SSN, LTN, SAN, and phrenic nerve was performed. Diagnoses made by ultrasound, MRI, EMG reports, and clinical and operative notes were recorded.

Results

Ultrasound was successful in visualizing nerves in the neck in the overwhelming majority of cases. Sonographic findings were typically in agreement with MRI and clinical findings.

Conclusion

Ultrasound is effective in the visualization and diagnostic evaluation of the SSN, LTN, SAN, and phrenic nerve.

Classification of evidence

This study provides Class IV evidence that ultrasound can effectively visualize and diagnose neuropathy of the SSN, LTN, SAN, and phrenic nerve in the neck.

MR neurography in Parsonage-Turner syndrome

Background and Aims:

Parsonage Turner Syndrome is a well known clinical entity. Several excellent articles have succinctly described Magnetic Resonance Imaging (MRI) findings in PTS. However, these articles have inferred neural involvement in PTS based on the patterns of denervation of muscles in the shoulder region. The aim of this study is to directly visualize the distribution and extent of abnormality in MR Neurography (MRN) of the brachial plexus in known cases of brachial plexus neuritis or Parsonage-Turner Syndrome (PTS).

Methods:

15 patients who were diagnosed with PTS based on clinical and electrophysiological findings participated in the study. MRN of the brachial plexus was done in a 1.5T system using a combination of T1W (T1-weighted), T2W (T2-weighted) fat-saturated, STIR (Short Tau Inversion Recovery), 3D STIR SPACE (Sampling Perfection with Application Optimized Contrasts) and 3D T2W SPACE sequences. Findings were recorded and assessed.

Results:

The age range of our patients was 7-65 years (mean 37.87 years). Most of the patients had unilateral symptoms. All patients had weakness in shoulder abduction. Other common associated complaints included pain in the shoulder/neck/arm and preceding fever. MRN revealed the percentage of involvement of roots, trunks, cords and terminal branches was 53.3%, 46.7%, 40% and 13.3% respectively. Evidence of muscle denervation in the form of edema, fatty infiltration and atrophy was noted in 8 (53.3%) patients.

Conclusion:

Most of the patients in this study had unilateral involvement on MRN. The roots were the commonest site of involvement followed by the trunks, cords and terminal branches. C5 was the most commonly involved root.

Imaging of Usual and Unusual Complication of Rotator Cuff Repair

Several complications may be encountered after rotator cuff (RC) repair. A thorough knowledge of surgical interventions, normal postoperative findings, and postoperative complications is crucial to provide a timely diagnosis, improving the clinical outcome of patients. Postoperative complications may involve RC, implanted device, osteochondral tissue, surgical-site infection, peripheral nerves, soft tissues, and vascular structures. In this review, we discuss the usual and unusual complications detectable after RC repair.

Neurectomy preserves fast fibers when combined with tenotomy of infraspinatus muscle via upregulation of myogenesis

INTRODUCTION

We evaluated the contribution of denervation-related molecular processes to rotator cuff muscle degeneration after tendon release.

METHODS

We assessed the levels of myogenic (myogenin and myogenic differentiation factor [myoD]) and proadipogenic (peroxisome proliferator-activated receptor γ) transcription factors; the denervation-associated proteins tenascin-C, laminin-2, and calcium/calmodulin-dependent kinase II (CaMKII); and cellular alterations in sheep after infraspinatus tenotomy (TEN), suprascapular neurectomy (NEU), or both (TEN-NEU).

RESULTS

Extracellular ground substance increased at the expense of contractile tissue 16 weeks after surgery, correlating with CaMKII isoform levels. Sheep undergoing NEU and TEN-NEU had exaggerated infraspinatus atrophy and increased fast fibers compared with TEN sheep. The βMCaMKII isoform levels increased with TEN, and myoD levels tripled after denervation and were associated with slow fibers.

DISCUSSION

In sheep, denervation did not affect muscle-to-fat conversion after TEN of the infraspinatus. Furthermore, concurrent NEU mitigated the loss of fast fibers after TEN by inducing a fast-contractile phenotype. Muscle Nerve 59:100-107, 2019.

Comprehensive Shoulder US Examination: A Standardized Approach with Multimodality Correlation for Common Shoulder Disease

Shoulder pain is one of the most common musculoskeletal conditions encountered in primary care and specialty orthopedic clinic settings. Although magnetic resonance (MR) imaging is typically the modality of choice for evaluating the soft-tissue structures of the shoulder, ultrasonography (US) is becoming an important complementary imaging tool in the evaluation of superficial soft-tissue structures such as the rotator cuff, subacromial-subdeltoid bursa, and biceps tendon. The advantages of US driving its recent increased use include low cost, accessibility, and capability for real-time high-resolution imaging that enables dynamic assessment and needle guidance. As more radiologists are considering incorporating shoulder US into their practices, the development of a standardized approach to performing shoulder US should be a priority to facilitate the delivery of high-quality patient care. Familiarity with and comfort in performing a standardized shoulder US examination, as well as knowledge of the types of anomalies that can be evaluated well with US, will enhance the expertise of those working in musculoskeletal radiology practices and add value in the form of increased patient and health care provider satisfaction. This review describes the utility and benefits of shoulder US as a tool that complements MR imaging in the assessment of shoulder pain. A standardized approach to the shoulder US examination is also described, with a review of the basic technique of this examination, normal anatomy of the shoulder, common indications for shoulder US, and characteristic US findings of common shoulder diseases-with select MR imaging and arthroscopic correlation. Online supplemental material is available for this article. ^©RSNA, 2016.

Pathologies of the shoulder and elbow affecting the overhead throwing athlete

The overhead-throwing athlete is susceptible to a variety of predictable disease entities affecting the shoulder and elbow. While the pathophysiology and nomenclature of these diseases are ubiquitous throughout the clinical literature, this information is sparse within the radiology domain. We provide a comprehensive review of these unique injuries with accompanying imaging features in an effort to enhance the role of the radiologist during the management of the overhead thrower. When appropriately recognized and described, the imaging features aid in establishing a diagnosis and ultimately the implementation of appropriate clinical management.

Coracoid Process: The Lighthouse of the Shoulder

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck. Surgeons often refer to the coracoid process as the "lighthouse of the shoulder" given its proximity to major neurovascular structures such as the brachial plexus and the axillary artery and vein, its role in guiding surgical approaches, and its utility as a landmark for other important structures in the shoulder. The coracoid also serves as a critical anchor for many tendinous and ligamentous attachments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and transverse scapular ligaments. Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions. This article will detail the anatomy of the coracoid and its associated structures and review the clinical and radiologic findings of corresponding pathologic conditions in this region with original illustrations and multimodality imaging examples. Highlighted in this article are the coracoclavicular joint, the classification and management of coracoid fractures, subcoracoid impingement, the coracoacromial arch and subacromial impingement, the coracohumeral ligament and the biceps pulley, the coracoclavicular ligament and its surgical reconstruction, adhesive capsulitis, the suprascapular notch and suprascapular notch impingement, subcoracoid bursitis, coracoid transfer procedures, and coracoid tumors. A brief summary of the pathophysiology, potential causes, and management options for each of the pathologic entities will also be discussed. ^©RSNA, 2016.

Beyond the Cuff: MR Imaging of Labroligamentous Injuries in the Athletic Shoulder

Shoulder disease is common in the athletic population and may arise as a consequence of a single traumatic episode or multiple repeated events. Associated labroligamentous injuries can result in substantial disability. Specific athletic and occupational activities result in predictable injury patterns. Imaging in general and magnetic resonance (MR) imaging, in particular, are vital in establishing the correct diagnosis and excluding common mimicking conditions, to ensure timely and appropriate management. In this review, the utility of MR imaging and MR arthrography will be explored in evaluation of shoulder disease, taking into account normal variants of the labroligamentous complex. Subsequently, broad categories of labral lesions and instability, external and internal impingement, as well as nerve entrapment syndromes, will be discussed, while emphasizing their imaging findings in the clinical context and illustrating key features. More recent concepts of internal impingement and secondary subacromial impingement will also be clarified.

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.

What's new in the use of MRI in the orthopaedic trauma patient?

MRI has been established as an essential tool for accurate diagnosis in patients with musculoskeletal trauma. Its major advantages include excellent soft tissue contrast, high spatial resolution and lack of ionizing radiation. Although plain radiographs remain the basic tool for diagnosis and treatment planning in bone fractures assisted by CT in pelvic, spine and large joints injuries, there are specific circumstances that require MRI. For instance, tendinous, ligamentous, intraarticular structures such as the cartilage and menisci, and intramedullary injury are seen mostly with MRI. Volumetric 3D techniques are now commercially available and provide higher spatial resolution which improves anatomic detail, allows multiplanar reformations and reduces the acquisition time. Newer applications on quantitative rather than morphologic imaging, such as relaxometry and diffusion tensor imaging, may be of paramount importance in treatment planning in the near future. Software improvements reduce metal induced artefacts, allowing thus imaging of the postoperative patient with metallic implants. A tendency towards a structured reporting pattern and standardised medical communication needs to be further explored for the benefit of orthopaedic surgeons, radiologists and patients.

Complete Fatty infiltration of intact rotator cuffs caused by suprascapular neuropathy

Suprascapular neuropathy is generally considered to be a diagnosis of exclusion, although it has been described in association with several activities and conditions. To our knowledge, this is the first description of suprascapular neuropathy with complete neurogenic fatty replacement in patients with intact rotator cuff tendons in the absence of traction or compression mechanisms. We present 4 cases of patients who presented with complete fatty infiltration of the supraspinatus (1 patient), infraspinatus (2 patients), and both (1 patient) resulting from suprascapular neuropathy. Each of these patients underwent arthroscopic suprascapular nerve decompression and subsequently had immediate improvement in pain and subjective shoulder value.

MR IMAGING OF SUPRASCAPULAR NEUROPATHIES

Suprascapular neuropathy has become increasingly recognized entity which is often overlooked and mistaken for other causes of shoulder pain and dysfunction like rotator cuff injury, shoulder impingement syndrome, cervical spondylosis and brachial plexopathy. It can be caused by a variety of anatomic and pathologic entities as the nerve courses from the brachial plexus through the suprascapular and spinoglenoid notches to innervate the supraspinatus and infraspinatus muscles. Because of the widespread availability of high-field MRI scanners now it is possible to detect the subtle perineural pathology, thereby excluding the other common causes of shoulder pain. There are scattered case reports and reviews describing suprascapular nerve (SSN) abnormalities using MRI. This article comprehensively reviews different pathologic abnormalities involving the SSN and illustrates their MR features, clinical presentation, correlation with electrophysiologic studies and surgical findings based on a review of 24 cases. We found the different clinical entities which includes trauma and a spectrum of nontraumatic etiology such as idiopathic, mass lesions compressing the nerve, intrinsic lesion like intraneural ganglion cysts of SSN, repetitive overuse, viral neuritis and chemotherapy induced neuropathy.

Imaging evaluation of the rotator cuff

The rotator cuff is a complex network of interwoven tendons that plays a key role in glenohumeral movement and stability. Cuff abnormality is a common source of shoulder pain, but the clinical presentation is often nonspecific and, as a result, diagnostic imaging, especially magnetic resonance imaging, plays a key role in evaluating these patients. This article reviews imaging modalities available for evaluating the cuff, normal cuff anatomy, and common pathologic conditions that affect it.