US Appearance of the Rotator Cable with Histologic Correlation: Preliminary Results

An interexaminer agreement and reliability study on cadavers with musculoskeletal ultrasound of the shoulder performed by physiotherapists and radiologists compared with dissection

STUDY DESIGN

A cross-sectional inter-examiner agreement and reliability study on fresh frozen cadaver shoulders.

BACKGROUND

Musculoskeletal ultrasound (MSU) is frequently used by physical therapists and radiologists to improve specific diagnosis in rotator cuff related pathology. The evaluation of the rotator cable seems to be important as stabilizing structure when cuff tears occur.

OBJECTIVES

To evaluate the inter-examiner agreement and reliability of MSU of the shoulder to detect rotator cuff-pathology and the involvement of the rotator cable in comparison to "dissection".

METHODS

Physical therapists, a radiologist and an orthopedic surgeon (dissection) investigated 40 fresh frozen cadaver shoulders in order to detect shoulder pathology including rotator cable involvement. Examiners were blinded to each other's findings.

RESULTS

We found a strong and significant agreement between the raters: PTs, the radiologist and the dissector in this cadaver study for all rotator cuff, the long head of the biceps pathologies and in detecting abnormalities of the rotator cable. The kappa value was substantial to (almost) perfect agreement for all diagnostic outcome categories.

CONCLUSIONS

This study shows that among a limited group of physical therapists, one radiologist and a dissector a strong level of agreement with kappa values from substantial to (almost) perfect in finding subacromial pathology.

[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.

A 5-Year Follow-up of Patients Treated for Full-Thickness Rotator Cuff Tears: A Prospective Cohort Study

Background:

The evidence in support of operative versus nonoperative management of rotator cuff tears (RCTs) is limited, based primarily on observational studies of lower scientific merit.

Purpose:

To (1) compare the efficacy of operative versus nonoperative management of full-thickness RCTs across time and (2) detect variables that predict success within each group.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

We included patients with symptomatic full-thickness RCTs who were enrolled in an institutional shoulder registry. Patient enrollment began in 2009 and continued until early 2018. The following outcome measures were collected at baseline, then 6 months, 1 year, and annually up to 5 years postoperatively: Western Ontario Rotator Cuff Index (WORC), American Shoulder and Elbow Surgeons (ASES) score, Veterans RAND 12-Item Health Survey (VR-12) mental and physical component subscales (MCS and PCS, respectively), 100-point Single Assessment Numeric Evaluation (SANE) rating, and 100-point visual analog scale (VAS) for pain and for patient satisfaction. We performed regression models for all outcome variables across all 5 years of follow-up and included the following predictor variables: treatment type (operative vs nonoperative), sex, age, symptom duration, smoking status, diabetes status, injury side, and obesity status.

Results:

A total of 595 patients were included. Longitudinal mixed-effects regression revealed that patients who received operative treatment did better across time on all outcomes. Women (n = 242; 40.7%) did not fare as well as did men on the ASES, WORC, or VR-12 PCS. Older patients tended to improve less on the VR-12 PCS and more on the VR12-MCS. Patients with longer symptom duration at baseline had better scores across time on the ASES, WORC, VAS for pain, and SANE. Current or recent smokers and patients with diabetes tended to have lower scores on all measures across time. For changes in scores from baseline, patients in the operative group improved to a larger degree out to 3 years compared with those in the nonoperative group.

Conclusion:

Patients with RCTs tended to improve regardless of whether they received operative or nonoperative treatment, but patients who underwent operative treatment improved faster. There appear to be several predictors of improved and worsened outcomes for patients with RCTs undergoing operative or nonoperative treatment.

Interobserver reliability of the rotator cable and its relationship to rotator cuff congruity

BACKGROUND

This study evaluated the presence of the rotator cable intraoperatively and compared its prevalence according to both patient age and rotator cuff integrity. The study hypothesis was that the cable would be more prevalent in older patients and patients with partial-thickness tears.

METHODS

Patients who were undergoing shoulder arthroscopy and were aged at least 16 years were included in this study, whereas those who had a cuff tear of more than 1 tendon or who had a video with poor visualization of the rotator cuff insertion were excluded. Intraoperative videos were collected, deidentified, and distributed to 7 orthopedic surgeons to define rotator cable and cuff tear characteristics.

RESULTS

A total of 58 arthroscopic videos (average patient age, 46 years; range, 16-75 years) were evaluated. The observers were in the most agreement on identifying the presence of a cable, with a κ coefficient of 0.276. Patients with the rotator cable were significantly older than those without it (mean age, 52.1 years vs. 42.5 years; P = .008), and a positive and significant correlation was found between rotator cable presence and increasing patient age (r = 0.27, P = .04). A significant association was noted between tear degree and cable presence (P = .002). There was no significant association with cable presence in patients with a full-thickness tear.

CONCLUSIONS

In this study, an intraoperative analysis was performed to define the presence of the rotator cable and correlate this with both patient age and rotator cuff integrity. The hypothesis was confirmed in that patients older than 40 years had a significantly higher rotator cable prevalence.

Recent Issues in Musculoskeletal Anatomy Research and Correlation with MRI

MRI 영상은 관절 내 질환의 평가에 중요한 검사기법이며, 관절 MRI 영상의 해석을 위해선 견고한 해부학적 지식이 바탕이 되어야 한다. 관절의 해부학 분야에서는, 새로운 구조물이 발견되기도 하며, 과거에 보고되었으나 기능을 알지 못하던 구조물이 새롭게 주목을 받기도 한다. 본 종설에서는 최근 십여 년간 활발하게 연구되어온 견관절 회전근개 케이블(rotator cable) 및 상관절막(superior capsule), 슬관절의 후외측(posterolateral corner) 및 전외측 인대 복합(anterolateral ligament complex), 발목관절의 원위부 경비골 인대결합(distal tibiofibular syndesmosis) 등의 최근 연구 결과를 소개하고, 이를 MRI 영상을 통해 확인해 보았다.

Rotator cable and rotator interval: anatomy, biomechanics and clinical importance

The rotator cable and rotator interval are among the most recent topics of interest in current shoulder literature. Most of the research has been published in the last two decades and our understanding about the importance of these anatomical structures has improved with biomechanical studies, which changed the pre- and intra-operative approaches of shoulder surgeons to rotator cuff tears in symptomatic patients.

The rotator cable is a thick fibrous bundle that carries the applied forces to the rotator cuff like a ‘suspension bridge’. Tears including this weight-bearing bridge result in more symptoms. On the other hand, the rotator interval is more like a protective cover consisting of multiple layers of ligaments and the capsule rather than a single anatomical formation like the rotator cable.

Advances in our knowledge about the rotator interval demonstrate that even basic anatomical structures often have greater importance than we may have understood. Misdiagnosis of these two important structures may lead to persistent symptoms.

Furthermore, some distinct rotator cuff tear patterns can be associated with concomitant rotator interval injuries because of the anatomical proximity of these two anatomical regions. We summarize these two important structures from the aspect of anatomy, biomechanics, radiology and clinical importance in a review of the literature.

Cite this article: EFORT Open Rev 2019;4:56-62. DOI: 10.1302/2058-5241.4.170071.

Rotator cable in pathological shoulders: comparison with normal anatomy in a cadaveric study

The rotator cable is a semicircular thickening of the glenohumeral joint capsule. It travels between tubercles of the humerus and interweaves with the supra- and infraspinatus muscle tendons. The rotator cable anchors these tendons to the tubercles, playing the role of a suspension bridge. However, little is known about the modifications of this cable that result from pathologies to the rotator cuff tendons. Thus, we aim to compare the morphology of the normal rotator cable with cables in specimens with rotator cuff injuries. The glenohumeral joint was dissected in 30 cadaveric shoulders. The supra-, infraspinatus and teres minor muscles were inspected for injuries and the rotator cable was visualised. The cables course was determined and the width, length and thickness were measured. The rotator cable was found present in all cadavers dissected. In three specimens there was a partial injury of the supraspinatus tendon (two from capsular side and one from bursal side). The rotator cable was thickened in the cases of capsular tears. In another two specimens the supraspinatus and infraspinatus muscles were torn completely and in these cases the rotator cable was blended with retracted stumps and elongated to the level of the glenoid rim. The rotator cable creates a functional complex with the supra- and infrasinatus muscles. The morphology of the cable differs in cases of rotator cuff injury.

The Rotator Interval - A Link Between Anatomy and Ultrasound

Shoulder pathologies of the rotator cuff of the shoulder are common in clinical practice. The focus of this pictorial essay is to discuss the anatomical details of the rotator interval of the shoulder, correlate the anatomy with normal ultrasound images and present selected pathologies. We focus on the imaging of the rotator interval that is actually the anterosuperior aspect of the glenohumeral joint capsule that is reinforced externally by the coracohumeral ligament, internally by the superior glenohumeral ligament and capsular fibers which blend together and insert medially and laterally to the bicipital groove. In this article we demonstrate the capability of high-resolution musculoskeletal ultrasound to visualize the detailed anatomy of the rotator interval. MSUS has a higher spatial resolution than other imaging techniques and the ability to examine these structures dynamically and to utilize the probe for precise anatomic localization of the patient's pain by sono-palpation.

Sonographic Visualization of the Rotator Cable in Patients With Symptomatic Full-Thickness Rotator Cuff Tears: Correlation With Tear Size, Muscular Fatty Infiltration and Atrophy, and Functional Outcome

OBJECTIVES

To assess the prevalence of sonographic visualization of the rotator cable in patients with symptomatic full-thickness rotator cuff tears and asymptomatic controls and to correlate rotator cable visualization with tear size, muscular fatty infiltration and atrophy, and the functional outcome in the patients with rotator cuff tears.

METHODS

Fifty-seven patients with rotator cuff tears and 30 asymptomatic volunteers underwent shoulder sonography for prospective assessment of the rotator cable and rotator cuff tear and responded to 2 functional outcome questionnaires (shortened Disabilities of the Arm, Shoulder, and Hand [QuickDASH] and Constant). In the patients with rotator cuff tears, appropriate tests were used to correlate rotator cable visualization with the tear size, functional outcome, muscular fatty infiltration, and atrophy.

RESULTS

The patients with rotator cuff tears included 25 women and 32 men (mean age,57 years; range, 39-67 years), and the volunteers included 13 women and 17 men (mean age, 56 years; range, 35-64 years). The rotator cable was identified in 77% (23 of 30) of controls and 23% (13 of 57) of patients with rotator cuff tears. In the patients, nonvisualization of the rotator cable correlated with larger tears (P < 0.001) and higher grades of supraspinatus atrophy (P = .049) and fatty infiltration (P = .022). There was no significant correlation with functional outcome scores (QuickDASH, P = .989; Constant, P = .073) or infraspinatus fatty infiltration (P = .065).

CONCLUSIONS

Nonvisualization of the rotator cable was more prevalent in patients with symptomatic rotator cuff tears than asymptomatic controls and was associated with a larger tear size and greater supraspinatus fatty infiltration and atrophy. Diligent assessment of the supraspinatus muscle should be done in patients with rotator cuff tears without a visible rotator cable, as the integrity of these anatomic structures may be interdependent.

Pilot Study to Determine Accuracy of Posterior Approach Ultrasound for Shoulder Dislocation by Novice Sonographers

Introduction

The goal of this study was to investigate the efficacy of diagnosing shoulder dislocation using a single-view, posterior approach point-of-care ultrasound (POCUS) performed by undergraduate research students, and to establish the range of measured distance that discriminates dislocated shoulder from normal.

Methods

We enrolled a prospective, convenience sample of adult patients presenting to the emergency department with acute shoulder pain following injury. Patients underwent ultrasonographic evaluation of possible shoulder dislocation comprising a single transverse view of the posterior shoulder and assessment of the relative positioning of the glenoid fossa and the humeral head. The sonographic measurement of the distance between these two anatomic structures was termed the Glenohumeral Separation Distance (GhSD). A positive GhSD represented a posterior position of the glenoid rim relative to the humeral head and a negative GhSD value represented an anterior position of the glenoid rim relative to the humeral head. We compared ultrasound (US) findings to conventional radiography to determine the optimum GhSD cutoff for the diagnosis of shoulder dislocation. Sensitivity, specificity, positive predictive value, and negative predictive value of the derived US method were calculated.

Results

A total of 84 patients were enrolled and 19 (22.6%) demonstrated shoulder dislocation on conventional radiography, all of which were anterior. All confirmed dislocations had a negative measurement of the GhSD, while all patients with normal anatomic position had GhSD>0. This value represents an optimum GhSD cutoff of 0 for the diagnosis of (anterior) shoulder dislocation. This method demonstrated a sensitivity of 100% (95% CI [82.4–100]), specificity of 100% (95% CI [94.5–100]), positive predictive value of 100% (95% CI [82.4–100]), and negative predictive value of 100% (95% CI [94.5–100]).

Conclusion

Our study suggests that a single, posterior-approach POCUS can diagnose anterior shoulder dislocation, and that this method can be employed by novice ultrasonographers, such as non-medical trainees, after a brief educational session. Further validation studies are necessary to confirm these findings.

Assessment of the rotator cable in various rotator cuff conditions using indirect MR arthrography

BACKGROUND

The rotator cable is an important structure providing stress shield to the rotator cuff, similar to the mechanism of suspension bridge.

PURPOSE

To evaluate the visibility and appearance of the rotator cable in various conditions of the rotator cuff, using indirect magnetic resonance (MR) arthrography.

MATERIAL AND METHODS

Indirect MR arthrography images from 27 patients (age range, 20-63 years) with normal rotator cuffs, and 47 (age range, 20-73 years) with tendinosis, 32 (age range, 49-71 years) with partial-thickness tears, and 55 (age range, 44-75 years) with full-thickness tears in the supraspinatus and infraspinatus tendons (SST-ISTs) were included in this study. In these various rotator cuff conditions, the visibility and appearance (thickness and width) of the rotator cable and the relationships between the rotator cable appearance, rotator cuff tear size, rotator cuff thickness, and patient's age were assessed.

RESULTS

On the sagittal MR images, all rotator cables were visible in the normal rotator cuffs and tendinosis/partial-thickness tears of SST-ISTs. In the order of normal cuff, tendinosis, partial-thickness tear, and full-thickness tear of SST-ISTs, the rotator cable tended to become thicker (1.07, 1.27, 1.32, and 1.59 mm, respectively) and narrower (12.1, 10.68, 10.90, and 8.55 mm, respectively). The thickness of the rotator cable was significantly positively correlated with the rotator cuff thickness in the normal rotator cuffs (coefficient, 0.49; P = 0.010) and tendinosis of SST-ISTs (coefficient, 0.53; P < 0.001), but was not correlated with patients' age.

CONCLUSION

On sagittal plane of indirect MR arthrography, most rotator cables were visible. The appearance of the rotator cable changed according to the rotator cuff condition.

Magnetic resonance anatomy of the superior part of the rotator cuff in normal shoulders, assessment and practical implication

OBJECTIVES

The superior part of the rotator cuff consists of the anterior (SSa) and posterior (SSp) parts of the supraspinatus tendon, the infraspinatus (IS) tendon plus the articular capsule. An overlap of the distal SSp tendon by the anterior part of the IS one has been anatomically demonstrated; the insertion area of the IS is more anterior than currently believed. The aim of our study was to assess this complex architecture through standard MRI scans.

METHODS

Twenty-five healthy volunteers underwent a shoulder MRI. Three planes T2 fat saturation sequences were read in consensus by two radiologists. The SSa, the SSp, the IS tendons and the articular capsule were assessed for visibility. The patterns of demarcation of each structure from adjacent ones were assessed. The width and the thickness of each tendinous band were measured on sagittal images.

RESULTS

The SSa, the SSp and the IS tendons were distinguishable in all patients. The anterior part of the IS tendon overlapped the SSp tendon to reach a quite anterior insertion into the greater tuberosity of the humerus. The SSa, the SSp and the IS tendons were 6.5-3.4, 15.1-2.8 and 26.8-2.2 mm wide and thick, respectively.

CONCLUSION

MR images of the normal superior rotator cuff are consistent with latest anatomical descriptions. The distal superposition of the IS over the SSp tendon should be considered regarding the linear increased signal areas and the commonly named "partial thickness ruptures" of the superior rotator cuff as well as the fatty infiltration of the IS muscle.

Stitch positioning influences the suture hold in supraspinatus tendon repair

PURPOSE

This study was designed to compare the pull-out strength of simple suture stitches in human supraspinatus tendons with respect to the position of the rotator cable.

METHODS

Fifty-four tests were performed on 6 intact, human supraspinatus tendons, to assess the cutout strength of a simple suture configuration in different positions; medial to, lateral to, or within the rotator cable. Tendon thickness was measured and correlated for each positioned suture.

RESULTS

Suture positioning lateral to or in the rotator cable showed significantly lower suture retention properties compared with positioning the suture medial to the cable (p = 0.002). In all tested specimens, the central stitch in the row medial to the rotator cable provided the optimum retention properties (mean: 191 N; SD: ± 44; p < 0.01), even after correcting for tendon thickness.

CONCLUSION

This study shows that it is desirable to identify the rotator cable and to pass sutures just medial to it, close to the middle of the tendon, which provided highest possible suture retention properties.

Ultrasonography of the shoulder with arthroscopic correlation

Ultrasonography is a well-established and widely accepted modality for the evaluation of rotator cuff tears and injury to the biceps brachii tendon. Ultrasonography and magnetic resonance imaging have comparable sensitivity and specificity for diagnosing both full-thickness and partial-thickness rotator cuff tears. This article addresses the ultrasonographic diagnosis of abnormalities of the rotator cuff, rotator interval, and biceps brachii, with magnetic resonance imaging and arthroscopic correlation. Characteristic ultrasonographic findings as well as imaging pitfalls are reviewed.

Margin convergence anchorage to bone for reconstruction of the anterior attachment of the rotator cable

PURPOSE

The purpose of this study was to compare the biomechanical characteristics of a massive L-shaped retracted rotator cuff tear repaired with either soft-tissue side-to-side sutures or margin convergence anchorage to bone.

METHODS

Eight matched pairs of cadaveric shoulders were used. The supraspinatus and infraspinatus were secured in a clamp at 30° of glenohumeral abduction. The subscapularis was secured in a separate clamp, and a constant load was applied. A massive L-shaped rotator cuff tear of the supraspinatus and infraspinatus tendon was created. In all specimens the posterior aspect of the tear was repaired by a transosseous-equivalent technique. In 1 group we placed 2 margin convergence sutures between the supraspinatus and the rotator interval. In the comparison group, a suture anchor was inserted at the anterior attachment of the rotator cable. Margin convergence anchorage to bone was then performed between the supraspinatus and the rotator interval. Each specimen was tested with an Instron machine (Instron, Canton, MA) and a video digitizing system. A paired t test was used for statistical analysis.

RESULTS

Margin convergence anchorage to bone decreased gap formation at cycle 1, cycle 30, and yield load across the entire footprint (P < .05). In both constructs the anterior gap was greater than the posterior gap at cycle 1, cycle 30, and yield load (P < .05). Margin convergence anchorage to bone decreased hysteresis and increased stiffness during the first cycle and increased yield load (P < .05).

CONCLUSIONS

Using margin convergence anchorage to bone to restore the anterior attachment of the rotator cable decreased gap formation across the entire footprint and improved biomechanical properties for cycle 1 and yield load compared with soft-tissue margin convergence for massive rotator cuff repairs.

CLINICAL RELEVANCE

Repairing the anterior rotator cuff with margin convergence anchorage to bone may improve clinical outcomes of an L-shaped massive tear repair.

Preliminary ultrasound evaluation of the rotator cable in asymptomatic volunteers()

PURPOSE

To characterize the rotator cable high-resolution ultrasound appearance in asymptomatic shoulders of volunteers of different age.

MATERIALS AND METHODS

IRB approval and volunteers' written consent was obtained. Excluding subjects with known shoulder affections, we screened 24 asymptomatic volunteers. Supraspinatus and infraspinatus tendons high-resolution ultrasound evaluation was performed according to standard scan protocols, further excluding shoulders with partial/full-thickness cuff tears. Thus, we studied 24 shoulders in 12 young volunteers (age range 21-39 years, mean age 33 ± 8 years) and 21 shoulders in 11 elderly volunteers (age range 62-83 years, mean age 75 ± 45 years). For each shoulder, we noted rotator cable visibility and its thickness and width. Fisher's and U Mann-Whitney statistics were used.

RESULTS

Rotator cable was less frequently detected in young than in elderly volunteers (5/24 vs. 11/21 shoulders; P = 0.034). When detected, rotator cable was significantly thicker in young (range 1.2-1.5 mm, mean thickness 1.3 ± 0.1 mm) than in elderly (range 0.9-1.4 mm, mean thickness 1.2 ± 0.1 mm) volunteers (P = 0.025), while its width was not significantly different in young (range 4.5-7.1 mm, mean 5.6 ± 1.1 mm) compared to elderly (range 2.5-7.1 mm, mean 4.2 ± 1.4 mm) volunteers (P = 0.074) although a tendency can be highlighted.

CONCLUSIONS

Ultrasound demonstrated the different consistency of rotator cable in young and elderly asymptomatic patients, with high interobserver reproducibility.

Ultrasound assessment of the rotator cuff cable: comparison between young and elderly asymptomatic volunteers and interobserver reproducibility

Our aim was to characterize rotator cable ultrasound appearance in shoulders of different-aged asymptomatic volunteers, also estimating interobserver reproducibility. We studied 83 shoulders in 42 young volunteers (mean age 26 ± 7.0 years, range 21-35 years) and 66 shoulders in 36 elderly volunteers (65-81 years, 73 ± 4.9 years), noting rotator cable visibility and its minimum thickness and width. Interobserver reproducibility was tested in elderly volunteers by two blinded observers. χ(2), U Mann-Whitney, t-test, Bland-Altman, and κ statistics were used. Rotator cable was less frequently detected in younger than elderly volunteers (25/83 vs. 36/66 shoulders; p = 0.002). Young subjects had thicker (1.5 ± 0.2 mm, range 1.3-1.8 mm vs. 1.1 ± 0.1 mm, 0.9-1.3 mm; p < 0.001) and wider rotator cable (5.8 ± 0.7 mm, 4.5-7.1 mm vs. 4.0 ± 1.2 mm, 2.5-7.1 mm; p < 0.001) than elderly volunteers. Thickness and width reproducibility index were 89% and 94%, respectively; κ = 0.87. Ultrasound demonstrated different rotator cable consistency in younger and elderly asymptomatic patients, with high interobserver reproducibility.

Shoulder ultrasound

Ultrasound is used increasingly in the investigation of the rotator cuff. It is as accurate as magnetic resonance imaging in the detection of rotator cuff tears and the assessment of tear size and can demonstrate atrophy and fatty infiltration in the rotator cuff muscles. This article reviews the anatomy and technique of shoulder ultrasound, the ultrasound findings in rotator cuff disease, the accuracy of ultrasound and magnetic resonance imaging in the assessment of rotator cuff tears and the role of interventional ultrasound of the shoulder.

Rotator cable at MR imaging: considerations on morphological aspects and biomechanical role

PURPOSE

The rotator cable (RC) is a thickening of the coracohumeral ligament. It extends from the coracohumeral ligament to the inferior border of the infraspinatus tendon, with fibres running perpendicularly to the rotator cuff fibres. According to some authors, the RC tends to thicken with age, thus allowing some individuals with a cuff lesion to preserve normal shoulder function. We evaluated the RC with magnetic resonance (MR) imaging and investigated its possible role in the biomechanics of the shoulder affected by cuff lesions.

MATERIALS AND METHODS

Between November 2007 and May 2008, we performed shoulder MR examinations for shoulder pain or disability on 94 patients (46 males, 48 females; age range 16-79 years; mean age 54.09 ± 15.09 years) for a total of 104 shoulders (62 right, 42 left).

RESULTS

RC was more easily detectable in oblique coronal scans where it appeared as a crescent-shaped, regularly marginated structure adjacent to the articular surface of the supraspinatus tendon and medial to the insertion point of this tendon on the greater tuberosity. Its thickness was 2.8 ± 0.3 mm. The structure was identified in 62% of cases (mean patient age 55.3 ± 14.9 years). No statistically significant difference in age was found between patients with and without evidence of RC (Student's t test=0.05; p=0.82). Among patients with partial- or full-thickness supraspinatus tendon lesions at MR imaging, no statistically significant difference was found between the presence or absence of RC and disability on Jobe's test (χ(2)=1.17; p>0.05).

CONCLUSIONS

RC can be observed at MR imaging in >60% cases. In our sample it did not seem to influence shoulder function in patients with cuff lesions.

Transverse thickening along the articular surface of the rotator cuff consistent with the rotator cable: identification with MR arthrography and relevance in rotator cuff evaluation

OBJECTIVE

The purposes of this study were to describe the imaging appearance of transverse thickening along the articular surface of the supraspinatus and infraspinatus tendons presumed to represent the rotator cable on MR arthrographic images obtained with the shoulder in abduction and external rotation (ABER) and in the non-ABER position and to assess the role of the rotator cable in the diagnosis of rotator cuff tears.

MATERIALS AND METHODS

The study group comprised 54 patients who underwent arthroscopy of the shoulder and preoperative MR arthrography in which ABER images were obtained. Two blinded reviewers independently examined the ABER and non-ABER images for the presence of the rotator cable and rotator cuff tears.

RESULTS

In intact rotator cuffs, the presumed rotator cable was not well visualized on non-ABER images. In one case of prominent rotator cable, MR arthrography showed no tear on non-ABER images, but at arthroscopy, a partial-thickness undersurface tear was found. On non-ABER images, both readers readily visualized the rotator cable in eight and 10 of 18 cases (44% and 56%) of partial-thickness undersurface tear and four of five cases (80%) of full-thickness tear. On ABER images, both readers readily visualized the rotator cable in 15 and 17 of 31 cases (48% and 55%) of intact cuff, 14 and 15 of 18 cases (78% and 83%) of undersurface tear, and four and five cases (80% and 100%) of full-thickness tear. Interobserver agreement on cable visualization was almost perfect (kappa = 0.86).

CONCLUSION

On non-ABER MR arthrographic images, thickening along the articular side of the supraspinatus and infraspinatus tendons presumed to represent the rotator cable suggests the presence of a partial-thickness rotator cuff tear. On ABER images, the cable is well defined in intact and torn rotator cuffs.

Shoulder ultrasound imaging-integrating anatomy, biomechanics and disease processes

This article brings together the anatomy, biomechanics and the imaging of shoulder disease using ultrasound to enable a better understanding of the strengths and weaknesses of ultrasound when imaging the shoulder.