Detailed MRI-anatomic study of the lateral epicondyle of the elbow and its tendinous and ligamentous attachments in cadavers

Anatomy and Sonographic Examination for Lateral Epicondylitis: EURO-MUSCULUS/USPRM Approach

OBJECTIVE

The aim of the study is to define a standardized comprehensive sonographic approach for evaluating the different histoanatomical compartments of the lateral elbow.

DESIGN

Using high-frequency ultrasound probes, we tried to match the anatomical features of the lateral elbow and its different sonographic patterns in patients with the diagnosis of lateral epicondylitis. Moreover, high-sensitive color/power Doppler assessments have also been performed to evaluate the microcirculation.

RESULTS

Modern ultrasound equipment seems to provide an extremely detailed sonographic assessment of the different anatomical layers located in the lateral compartment of the elbow. Moreover, high-sensitive color/power Doppler imaging allows for clear visualization of the perfusion patterns in pathological conditions.

CONCLUSIONS

In clinical practice, high-frequency B-mode and high-sensitive color/power Doppler imaging can be integrated with the clinical findings to better define the pain generator(s) for optimizing the management of patients with lateral epicondylitis.

Individual Evaluation of the Common Extensor Tendon and Lateral Collateral Ligament Improves the Severity Diagnostic Accuracy of Magnetic Resonance Imaging for Lateral Epicondylitis

The effectiveness of magnetic resonance imaging for diagnosing lateral epicondylitis severity is controversial. We aimed to verify whether individual evaluations of the common extensor tendon and lateral collateral ligament would improve the severity diagnostic accuracy of magnetic resonance imaging for lateral epicondylitis. We obtained coronal images of the lateral elbow in three groups: healthy, clinically mild, and clinically severe. We used our scoring system for evaluation using combined and individual methods. We developed the receiver operating characteristic curve for diagnosis using the scores of the healthy and mild groups and that for severity diagnosis using the scores of the mild and severe groups. The scores, in decreasing value, were those of the severe, mild, and healthy groups, with a significant difference in both methods. The curve for diagnosis showed an area under the curve of 0.85 for the combined evaluation and 0.89 for the individual evaluation, without a significant difference between the methods (p = 0.23). The curve for severity diagnosis showed an area under the curve of 0.69 for combined and 0.81 for individual evaluation, with a significant difference between the methods (p = 0.046). Individual evaluation of the common extensor tendon and lateral collateral ligament improved the severity diagnostic accuracy of lateral epicondylitis.

How to Report: Elbow MRI

The elbow is the least common of the main joints examined with magnetic resonance imaging (MRI), thus radiologists may be less familiar with writing these reports. This article addresses the main pathologies encountered in and around the elbow, emphasizing the specific features that need reporting and providing examples of terminology to use when describing these abnormalities.

Acute Ligament Injuries of the Elbow

Ulnar collateral, radial collateral, lateral ulnar collateral, and annular ligaments can be injured in an acute trauma, such as valgus stress in athletes and elbow dislocation. Recognizing normal anatomy in magnetic resonance imaging and ultrasonography studies is important to identify ligamentous abnormalities in these imaging modalities.

Imaging Evaluation of Medial and Lateral Elbow Pain: Acute and Chronic Tendon Injuries of the Humeral Epicondyles

Medial and lateral elbow pain are often due to degenerative tendinosis and less commonly due to trauma. The involved structures include the flexor-pronator tendon origin in medial-sided pain and the extensor tendon origin in lateral-sided pain. Multimodality imaging is often obtained to verify the clinically suspected diagnosis, evaluate the extent of injury, and guide treatment decisions. Image-guided procedures can provide symptom relief to support physical therapy and also induce tendon healing. Surgical debridement and repair are typically performed in refractory cases, resulting in good to excellent outcomes in most cases. In this article, we review and illustrate pertinent anatomical structures of the distal humerus, emphasizing the structure and contributions of the flexor-pronator and extensor tendon origins in acute and chronic tendon abnormalities. We also discuss approaches to image-guided treatment and surgical management of medial and lateral epicondylitis.

Radiocapitellar incongruity of the radial head in magnetic resonance imaging correlates with pathologic changes of the lateral elbow stabilizers in lateral epicondylitis

OBJECTIVE

Post-traumatic posterolateral rotatory instability (PLRI) can be shown as radiocapitellar incongruity or posterior translation (PT) of the radial head in magnetic resonance imaging (MRI). We aimed to evaluate whether PT correlated with pathologic changes of lateral elbow stabilizers in patients with lateral epicondylitis.

MATERIALS AND METHODS

In MRIs of 160 patients with lateral epicondylitis, we measured PT of the radial head in the sagittal images. We qualitatively graded five lesions of the lateral elbow structures that included common extensor tendon (CET) lesion (grade 1-3), lateral collateral ligament complex (LCLC) insufficiency (grade 0-2), and absence or presence of bone marrow signal change, osteochondral lesion, and calcification. We analyzed whether the PT correlated with pathologic changes of the lateral elbow stabilizers and evaluated the diagnostic value of the PT for severe lesions.

RESULTS

The average PT was 1.9 mm. The PT correlated with both the CET lesion (p < 0.001) and LCLC insufficiency (p < 0.001). The optimal cutoff values of the PT for grade 3 CET lesion and grade 2 LCLC lesion were 2.6 and 2.8 mm, respectively. When potential PLRI was defined as the PT of > 3.4mm as suggested for post-traumatic PLRI, 21 patients had potential PLRI. The positive predictive values of the PT > 3.4mm were 76% for grade 3 CET lesions and 67% for grade 2 LCLC insufficiency.

CONCLUSION

This study demonstrates that PT of the radial head correlates with pathological changes of the lateral elbow stabilizers. As radiocapitellar incongruity is easy to measure quantitatively, it can be used for screening potential PLRI in patients with lateral epicondylitis.

Practical ultrasonographic technique to precisely identify and differentiate tendons and ligaments of the elbow at the level of the humeral epicondyles: anatomical study

OBJECTIVES

To develop a practical step-by-step technique to precisely identify and differentiate tendons and ligaments attaching to the humeral epicondyles, to confirm through gross anatomical study the accurate structure identification provided by this technique and to determine the frequency at which each structure can be identified in healthy volunteers.

MATERIALS AND METHODS

First, ten fresh frozen cadavers (6 men, age at death = 58-92 years) were examined by two musculoskeletal radiologists and a step-by-step technique for the identification of tendons and ligaments at the level of humeral epicondyles was developed. Second, the accurate identification of structures was confirmed through gross anatomical study including anatomical sections on five specimens and layer-by-layer dissection technique on five others. Finally, 12 healthy volunteers (6 men, average age = 36, range = 28-52) were scanned by two radiologists following the same technique.

RESULTS

An ultrasonographic technique based on the recognition of bony landmarks and the use of ultrasonographic signs to differentiate overlapping structures was developed and validated through gross anatomical study. In healthy volunteers, most tendons and ligaments were identified and well-defined in ≥ 80% of cases, except for the extensor carpi radialis brevis and extensor digiti minimi tendons on the lateral epicondyle (having common attachments with the extensor digitorum communis) and the palmaris longus tendon on the medial epicondyle (absent, or common attachment with the flexor carpi radialis).

CONCLUSION

A step-by-step approach to the ultrasonographic assessment of tendons and ligaments at the humeral epicondyles allowed accurate identification of and differentiation among these structures, in particular those relevant to pathological conditions.

Magnetic resonance imaging of the elbow

Elbow pain can cause disability, especially in athletes, and is a common clinical complaint for both the general practitioner and the orthopaedic surgeon. Magnetic resonance imaging (MRI) is an excellent tool for the evaluation of joint pathology due to its high sensitivity as a result of high contrast resolution for soft tissues. This article aims to describe the normal imaging anatomy and biomechanics of the elbow, the most commonly used MRI protocols and techniques, and common MRI findings related to tendinopathy, ligamentous and osteochondral injuries, and instability of the elbow.

Optimal Elbow Positions for Identification of the Radial Collateral Ligament Using Ultrasonography

BACKGROUND

The standard position for examining the lateral elbow with ultrasonography is an "extended" or "slightly flexed" position. However, because the radial collateral ligament (RCL) is more deeply attached on the lateral epicondyle than the common extensor tendon, an anisotropic artifact of the RCL could be observed in the conventional positions, making it difficult to fully visualize the RCL.

OBJECTIVES

To determine optimal elbow positions for accurate identification of the RCL and to explore the relevant landmarks in ultrasonography.

DESIGN

Prospective study.

SETTING

Tertiary university hospital.

PARTICIPANTS

Forty healthy elbows of 20 participants.

METHODS

The RCL was evaluated using ultrasonography in six elbow flexion positions (0°, 30°, 60°, 90°, 120°, and 140°). The relative depth, defined as the depth of the capitellum subtracted by the depth of the radial head under ultrasonography, was measured at each angle. The rates of successful identification of ultrasonographic landmarks for localizing the RCL were calculated. After ultrasonography, the optimal elbow position for identifying the RCL was determined by group consensus.

MAIN OUTCOME MEASUREMENTS

Relative depth between radial head and capitellum, rates of successful identification of ultrasonographic landmarks, and consensus-based determination of the optimal angle.

RESULTS

The relative depth significantly decreased with an increase in the flexion angle (P for trend <.001), approaching zero at the angles of 90° and 120°. The rates of successful identification of the superior tubercle, hyperechogenic line, and anterior and posterior tubercles were 100%, 100%, 90%, and 80%, respectively. In the group consensus, the 90° and 120° flexion angles were selected with the highest frequency (90%; 36/40).

CONCLUSION

Our findings suggest that elbow flexion at 90° or 120° is optimal for visualization of the RCL with the least possibility of anisotropy under ultrasonography, suggesting that the elbow should be flexed considerably beyond the conventional extended or slightly flexed position.

Lateral epicondylitis: Associations of MR imaging and clinical assessments with treatment options in patients receiving conservative and arthroscopic managements

OBJECTIVES

We assessed the implications of MR imaging with clinical history in lateral epicondylitis management by evaluating imaging and clinical features in patients with lateral epicondylitis treated conservatively or operatively.

METHODS

Sixty patients with lateral epicondylitis treated conservatively (n = 38) or operatively (n = 22) from 2011-2015 were included. MR imaging findings of common extensor tendon (CET), lateral collateral ligament (LCL) complex, muscle oedema, ulnar nerve and elbow joint were reviewed. Clinical data recorded were frequency, duration and intensity of pain, history of trauma and injection therapy, range of motion.

RESULTS

MRI-assessed CET and LCL complex abnormalities, muscle oedema, radiocapitellar joint widening, joint effusion/synovitis, pain frequency and intensity differed significantly between the two groups (p < .05) with increased severity in operative group. Persistent pain (OR 12.2, p < .01), CET abnormality on longitudinal plane (OR 7.5, p = .03 for grade 2; OR 22.4, p < .01 for grade 3) and muscle oedema (OR 6.7, p = .03) were major factors associated with operative treatment. Area under the ROC curve of predicted probabilities for combination of these factors was 0.83.

CONCLUSION

MR imaging, combined with clinical assessment, could facilitate appropriate management planning for patients with lateral epicondylitis.

KEY POINTS

• MRI can reflect different disease severity between patients treated conservatively/operatively. • CET abnormality, muscle oedema were major MRI findings with operative treatment. • Patients in operative group were more likely to experience persistent pain. • MRI plus clinical symptoms could facilitate appropriate management for lateral epicondylitis.

Radial collateral ligament of the elbow: sonographic characterization with cadaveric dissection correlation and magnetic resonance arthrography

OBJECTIVES

An abnormality of the radial collateral ligament (RCL) in the setting of lateral epicondylitis can indicate a poor clinical outcome; therefore, accurate assessment is important. The purpose of this study was to characterize the proximal RCL attachment, or footprint, as seen on sonography using cadaveric dissection correlation and magnetic resonance arthrography.

METHODS

For the first part of this study, 4 cadaveric elbow specimens were imaged with sonography before and after dissection to characterize the RCL. After Institutional Review Board approval with consent waived, 26 consecutive magnetic resonance (MR) arthrograms of the elbow were identified. The sonograms and MR arthrograms were retrospectively reviewed to measure the length of the RCL footprint and its percentage of the combined RCL and common extensor tendon (CET) humeral footprints.

RESULTS

The mean RCL footprint length and percentage of the combined RCL and CET footprints were 8.4 mm (range, 7.4-10.0 mm) and 54% as measured from the elbow specimen sonograms and 9.1 mm (range, 6.4-12.5 mm) and 54% as measured from the MR arthrograms. The mean RCL footprint length combining data from specimens and MR arthrograms was 8.9 mm (range, 6.4-12.5 mm), covering 54% of the combined RCL and CET footprints.

CONCLUSIONS

The RCL can be differentiated from the CET on sonography with knowledge of the RCL humeral footprint extent, which measured 8.9 mm in length and comprised 54% of the combined RCL and CET footprints.

Ultrasound assessment of the lateral collateral ligamentous complex of the elbow: imaging aspects in cadavers and normal volunteers

OBJECTIVE

The Lateral Collateral Ligamentous complex (LCL) is an important stabiliser of the elbow. It has a Y-shaped structure with three components. In this study, we sought to describe the ultrasound aspect of the individual components of this ligamentous complex and to evaluate the performance of ultrasound in both cadavers and in normal subjects.

METHODS

Ten cadaveric elbow specimens underwent high-frequency ultrasound. Two specimens were sliced and two were dissected for anatomical correlation. Ten elbows of normal subjects were also evaluated by ultrasound. The findings were compared.

RESULTS

The three components of the LCL could be visualised in all specimens and normal subjects with the exception of the proximal portion of one specimen. In 80% of the specimens and 100% of the healthy volunteers the proximal portion of the LCL could be separated from the extensor tendons.

CONCLUSION

High-resolution ultrasound can assess all components of the LCL of the elbow and can distinguish them from surrounding structures.