Abnormalities on MRI of the subscapularis tendon in the presence of a full-thickness supraspinatus tendon tear

Irreparable Subscapularis Tears: Current Tendon Transfer Options

PURPOSE OF REVIEW

Irreparable subscapularis tears, especially in younger patients with higher functional demands, present a challenging entity. Pectoralis major and latissimus dorsi tendon transfers are commonly considered for surgical management of this pathology, yet no consensus exists regarding the superior option. The purpose of this article is to review the most current tendon transfer techniques for irreparable subscapularis tears.

RECENT FINDINGS

For decades, transfer of the pectoralis major has been considered the gold standard technique for irreparable subscapularis tears. This transfer was found to reduce pain and improve functional outcome scores, yet range of motion and force of internal rotation were not maintained in long-term follow-up studies. The latissimus dorsi tendon transfer for the same indications has demonstrated biomechanical superiority in recent cadaveric studies with promising short-term results clinically. Both pectoralis major and latissimus dorsi tendon transfers improve outcomes of patients with irreparable subscapularis tears. Future comparative studies are still needed to determine superiority amongst techniques.

Is lesser tuberosity morphology related to subscapularis tears and anterior shoulder instability?

PURPOSE

Although the morphological relationship of the scapula and the humeral head has been claimed to be related to shoulder pathologies, few studies examined the relationship between subscapularis (Ssc) tears and lesser tuberosity (LT)-humeral head (HH) and between Ssc tears and HH-glenoid. This study aims to evaluate the relationship of LT with HH and glenoid in patients with Ssc tears and anterior shoulder instability (ASI). We hypothesized that the glenoid, HH, and their combined relationship with LT may impact Ssc tears and ASI.

MATERIAL AND METHODS

The study included 34 patients with ASI, 28 patients with isolated Ssc tears, and 40 patients as the control group. The radius of HH (Hr), the distance between the center of HH and LT (LTr), and the glenoid radius (Gr) were measured in shoulder magnetic resonance (MR) images. The LTr to Hr (LTr/Hr) ratio was defined as the lesser tuberosity-humeral head index (LTHHI), whereas the LTr to Gr (LTr/Gr) ratio was defined as the lesser tuberosity-glenoid index (LTGI). The three groups were compared regarding LTHHI, LTGI, LTr, Hr, and Gr.

RESULTS

There was a significant difference between each group concerning LTGI (p < 0.001). LTGI values below 1.99 showed 93.1% sensitivity and 93.3% specificity for Ssc tears, while values above 2.24 showed 86.7% sensitivity and 86.2% specificity for ASI. Also, there was a significant difference when the groups were compared for LTHHI (p < 0.001). This rate was lowest for Ssc tears, and LTHHI values below 1.17 showed 82.8% sensitivity and 80.1% specificity.

CONCLUSION

LTGI may be a new predictive factor showing 93.1% sensitivity and 93.3% specificity for Ssc tears and 86.7% sensitivity and 86.2% specificity for ASI. In addition, LTHHI may be a new predictive factor showing 82.8% sensitivity and 80.1% specificity for Ssc tears.

LEVEL OF EVIDENCE

III retrospective comparative study.

Imaging Review of Subscapularis Tendon and Rotator Interval Pathology

As the largest rotator cuff muscle, the subscapularis plays a major role in stabilizing the glenohumeral joint, in conjunction with surrounding rotator cuff structures. Injury to the subscapularis tendon can be isolated, but more commonly is seen in conjunction with supraspinatus tendon pathology. Injury can be associated with biceps pulley instability, superior labral anterior-posterior (SLAP) tears, humeral head subluxation, and anterosuperior and coracoid impingements. The involvement of the rotator interval can lead to what is called “the hidden lesion,” due to its difficulty to diagnose during arthroscopy. Understanding the anatomical relations of the subscapularis tendon with the rest of the rotator cuff and rotator interval, as well as common patterns of injury that involve the subscapularis tendon, can aid in proper diagnosis of these injuries leading to prompt surgical repair. This review describes the anatomy of the subscapularis muscle and tendon, and the magnetic resonance imaging (MRI) patterns of subscapularis tendon injury.

Bilateral coracohumeral distance discrepancy is associated with subscapularis tear in rotator cuff rupture patients

PURPOSE

To describe the bilateral coracohumeral morphological discrepancy in rotator cuff rupture patients with and without subscapularis (SSC) involvement and to investigate its association with SSC tears.

METHODS

Two hundred and thirteen consecutive patients who were scheduled to have arthroscopic rotator cuff repair were prospectively enrolled in the current study. Patients with acute traumatic rotator cuff rupture, glenohumeral osteoarthritis, bilateral rotator cuff rupture, recurrent shoulder instability, systemic inflammatory disease, and previous shoulder surgery history were excluded. Coracohumeral distance (CHD), coracoid overlap (CO), lesser tuberosity index (LTI) and acromiohumeral interval (AHI) were measured bilaterally using CT scans. Based on arthroscopic findings, patients were included in either the SSC tear group (n = 72) or the control group (n = 141).

RESULTS

In the SSC tear group, the affected shoulder possessed a significantly smaller CHD [95% confidence interval (CI) 6.1-7.2 vs. 7.2-8.0 mm, p < 0.0001], larger LTI (95% CI 9.4-9.9 vs. 9.0-9.6 mm, p < 0.0001), and smaller AHI (95% CI 5.0-5.5 vs. 7.1-7.5 mm, p < 0.0001) than the contralateral normal shoulder. In the control group, there was no significant difference between bilateral CHD and CO, and the AHI bilateral discrepancy was less distinct. CO did not differ significantly in the bilateral comparison in either group. Among all evaluated parameters, bilateral CHD discrepancy was the best predictor of SSC tears, with an area under the curve (AUC) of 0.882. A cutoff value of 0.5 mm had a sensitivity of 76.4% and specificity of 99.3% for SSC tears.

CONCLUSION

The CHD values are significantly different between affected and contralateral shoulders in SSC tear patients. Bilateral CHD discrepancy is closely associated with subcoracoid impingement and SSC tears, and its presence warrants specific intraoperative SSC inspection.

LEVEL OF EVIDENCE

Level II.

Predicting the clinically significant subscapularis tendon tear: malposition and tear of the long head of the biceps tendon on shoulder magnetic resonance imaging

BACKGROUND

The diagnostic accuracy of magnetic resonance imaging (MRI) is low for detecting a subscapularis tendon tear.

PURPOSE

To identify MRI findings that may predict the presence of a clinically significant subscapularis tendon tear requiring surgical repair.

MATERIAL AND METHODS

We reviewed shoulder MR images of patients who had undergone arthroscopic rotator cuff repair at our institution between June 2018 and May 2019. Patients were divided into two groups: the study group (n = 51), with an intermediate- to high-grade partial thickness tear of the subscapularis tendon suspected on preoperative MRI and intermediate or higher grade of the tendon tear proven on arthroscopy; and the control group (n = 18), with an intermediate- to high-grade partial thickness tear of the subscapularis tendon suspected on preoperative MRI but no tear or low-grade partial thickness tear of the tendon shown on arthroscopy. Preoperative MR images were retrospectively evaluated by two readers for the size of the subscapularis tendon tear, bone reactions at the lesser tuberosity, and long head of the biceps tendon (LHBT) pathology.

RESULTS

The subscapularis tendon tear measured by reader 2 was larger in the study group than in the control group. The prevalence of a tear (P = 0.006 for reader 1; P = 0.011 for reader 2) and malposition (P < 0.001 for both readers) of the LHBT were significantly greater in the study group.

CONCLUSION

A tear and malposition of the LHBT on MR images may predict the presence of a clinically significant subscapularis tendon tear.

Prediction of the anterior shoulder pain source by detecting indirect signs for partial articular subscapularis tendon tears through conventional magnetic resonance imaging

PURPOSE

To evaluate the diagnostic efficacy of indirect signs for proximal articular-positioned, partial (< 50%), subscapularis tendon tears (facet 1 tears) via conventional magnetic resonance imaging (MRI).

METHODS

A retrospective study was conducted on 67 patients of Yoo's type 1 or 2A tears. Forty-five arthroscopic subacromial decompression and acromioclavicular resection cases served as controls. Indirect signs indicating a facet 1 tear included small defects, superior subscapularis recess (SSR), long head of the biceps (LHBT) configurations, bone edema or cyst formation on lesser tuberosity (LTBEC), and fatty infiltration of subscapularis muscle. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were checked.

RESULTS

SSR was the most sensitive sign (90%). The sensitivities and NPV of LHBT configurations and LTBEC were low (sensitivity: 42.9% and 17.9%, NPV: 56.4% and 44.4%, respectively). The specificities of all indirect signs were relatively high (> 90%). The Chi-squared test and multinomial logistic regression confirmed the significance of small defects, SSRs, and fatty infiltrations for facet 1 tears (p ≤ 0.014). The combined sensitivity and specificity were up to 97.7% and 92.3%, respectively, in the presence of either a small defect or an SSR.

CONCLUSIONS

Conventional MRI alone can detect facet 1 tears through indirect signs (small defects, SSR, and fatty infiltrations of the subscapularis muscle), predicting unspecified anterior shoulder pain due to concealed biceps instability, and facilitating preoperative diagnosis for a facet 1 tear.

LEVEL OF EVIDENCE

III.

Application of virtual touch tissue imaging quantification in diagnosis of supraspinatus tendon injury

OBJECTIVE

To explore the value of virtual touch imaging and quantification (VTIQ) shear wave elastography (SWE) in diagnosis of supraspinatus tendon tear.

METHODS

Eighty patients with unilateral supraspinatus tendon tear underwent shoulder arthroscopy were prospective studied. Tendinopathy, partial-thickness tear or full-thickness tear of supraspinatus tendon were diagnosed according 2D ultrasound examination. Sensitivity, specificity and accuracy of ultrasonic diagnosis of supraspinatus tendon tear were calculated by arthroscopy as the gold standard. VTIQ was applied to measure the shear-wave velocity (SWV) of both normal and affected supraspinatus tendon. The differences of SWV in three types of supraspinatus tendon tear and receiver operating characteristic (ROC) curves were analyzed.

RESULTS

Among 80 patients, there were 20 tendinopathy, 31 partial tears and 29 full-thickness tears diagnosed by shoulder arthroscopy. Sensitivity, specificity and accuracy of 2D ultrasound in diagnosis of tendinopathy, partial tear and full-thickness tear groups were 78%, 90%and 83%; 71%, 86%and 73%; 86%, 88%and 88%, respectively. SWV of 80 supraspinatus tendon tears was 4.59±1.00 m/s, which was lower than that of normal supraspinatus tendon (4.59±1.00 m/s vs. 6.68±1.05 m/s, P < 0.01). SWV of supraspinatus tendon in tendinopathy, partial tear and full-thickness tear groups respectively were 5.66±0.97, 4.66±1.00, and 3.78±0.55 m/s, all lower than that of the contralateral normal supraspinatus tendon (all P < 0.05). In addition, the analysis of variance and pairwise comparison showed that SWV of supraspinatus tendon among three different degree of injury was statistically significant (all P < 0.001). The cutoff thresholds of SWV was 4.83 m/s to identify tendinopathy tear from partial tear and was 4.08 m/s to identify full-thickness tear from partial-thickness tear.

CONCLUSION

VTIQ SWE with SWV might identify degree of supraspinatus tendon tear and improve the value of ultrasonography, which should be further evaluated in large multicenter studies.

Comparison of Functional and Radiological Outcomes of Tears Involving the Subscapularis: Isolated Subscapularis Versus Combined Anterosuperior Rotator Cuff Tears

Background:

Few studies have compared the clinical and radiological characteristics and outcomes in isolated subscapularis (SSC) and combined anterosuperior (AS) rotator cuff tears (RCTs). Furthermore, risk factors for retear after SSC repair and the effect of preoperative fatty degeneration require further evaluation.

Purpose:

To compare the functional and radiological outcomes of isolated SSC with combined AS RCTs after arthroscopic repair and to determine the risk factors for SSC retear in these 2 groups.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Data from 30 patients in the isolated SSC group were compared with data from 110 patients in the combined AS group. All patients underwent primary arthroscopic rotator cuff repair between 2010 and 2016. Clinical outcomes were assessed through use of the visual analog scale for pain, American Shoulder and Elbow Surgeons score, and Simple Shoulder Test at a mean follow-up of 26.7 months (range, 24-96 months). SSC tendon integrity was examined via magnetic resonance imaging, computed tomography arthrogram, or ultrasonography at least 1 year after surgery.

Results:

The isolated SSC group had a greater proportion of males and the patients were younger compared with the combined AS group (both P < .050). The incidence of trauma was high but not significantly different between groups (56.7% vs 40.9%; P = .180). Clinical outcome measures and radiological outcomes in terms of retear were not statistically different between both groups (16.7% vs 8/5%; P = .337). The optimal cutoff values for the risk of SSC tendon retear in both groups were 19-mm retraction and 16-mm superoinferior dimension (P = .048). Unfavorable preoperative fatty degeneration of the SSC muscle (grades 3 and 4) was a significant risk factor for retear (odds ratio, 9.8; P < .001).

Conclusion:

Isolated SSC and combined AS RCTs were comparable except for patient age and sex; both had a high incidence of traumatic history. The current data suggest that the risk factors for retear after SSC repair in RCTs involving the SSC were tear size greater than 19 mm of retraction and unfavorable fatty degeneration (grade 3 or higher) of the SSC muscle.

New predictors for subscapularis tear: Coraco-lesser tuberosity angle, lesser tuberosity angle, and lesser tuberosity height

BACKGROUND

The pathogenesis of degenerative subscapularis (SC) tear is not clear, several mechanisms are involved: intrinsic tendon degeneration or subcoracoid impingement. The aim of this study was to propose new radiographic markers, the coraco-lesser tuberosity angle (CLA), lesser tuberosity angle (LTA) and lesser tuberosity height (LTH). The hypothesis was that higher values of CLA, LTA, and LTH would be associated with a higher likelihood in detecting a SC tear.

METHOD

A total of 114 patients who classified as SC tears through arthroscopic evaluation were retrospectively enrolled in the study from 2016 to 2018. Fifty-seven patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The CLA was measured on an anteroposterior shoulder x-ray image with the arm in neutral rotation, the LTA and LTH were measured on magnetic resonance imaging. Multivariable analyses were used to clarify the potential risks for SC tears. All measurements were calculated by two shoulder surgeons independently measured at 2 different times, 1 month apart.

RESULTS

The intra- and inter-observer reliabilities for radiologic measurements and the interobserver reliability of SC tear classification were almost perfect. The mean CLA value of SC tear group (41.4±4.2°) was significantly larger than that of the control group (38.7±4.0°, p<0.001). The mean LTA value of SC tear group (33.4±4.3°) was significantly larger than that of the control group (31.0±3.9°, p=0.001). Mean LTH value was 9.5±1.9mm in patients and 8.9±1.5mm for controls, there was no statistically significant difference (p=0.054). Multivariable analysis showed that larger CLAs significantly increased the risk of SC tears, with odds ratios of 1.17 per degree. Moreover, larger LTAs also significantly increased the risk of SC tears, with odds ratios of 1.14 per degree.

CONCLUSION

Our findings confirmed associations between new predictors (CLA and LTA) and SC tears. CLA and LTA values were greater in patients with SC tears than in controls, suggesting that they may be independent risk factors for SC tear onset.

LEVEL OF EVIDENCE

IV, retrospective study.

The Volume of Subscapularis Muscle Remains Unaffected by Supraspinatus Tendon Tears: Three-dimensionally Reconstructed Magnetic Resonance Imaging Analysis

Background

This study aimed to compare the subscapularis muscle volume between the intact groups (group I) and supraspinatus tendon tear groups (group T) based on the sex and three different age groups.

Methods

Subjects with a group I and subjects with group T without any other lesions were retrospectively evaluated from among patients who received a magnetic resonance imaging (MRI) scan between January 2011 and December 2013. The MRI scans were studied by a consultant radiologist. The subscapularis muscle volume was compared according to the age and sex; the age groups were categorized as patients in their 40s, 50s, and 60s. The volume of subscapularis muscle was measured by three-dimensional reconstructed images acquired through the axial section of 1.5T MRI.

Results

No statistically significant differences were observed between subscapularis muscle volume of the group I and group T, except for male patients in their 50s (group I: 100,650 mm³ vs. group T: 106,488 mm³) and 60s (group I: 76,347 mm³ vs. group T: 99,549 mm³) (p<0.05). Males had a larger mean volume of subscapularis muscle than females, and the subscapularis muscle volume decreased in a linear manner with increasing age.

Conclusions

Decrease in subscapularis muscle volume was observed with increasing age, and the impact of supraspinatus tear on subscapularis muscle volume is age and sex dependent.

Evaluation of the Subscapularis Tendon Tears on 3T Magnetic Resonance Arthrography: Comparison of Diagnostic Performance of T1-Weighted Spectral Presaturation with Inversion-Recovery and T2-Weighted Turbo Spin-Echo Sequences

Objective

To compare the T1-weighted spectral presaturation with inversion-recovery sequences (T1 SPIR) with T2-weighted turbo spin-echo sequences (T2 TSE) on 3T magnetic resonance arthrography (MRA) in the evaluation of the subscapularis (SSC) tendon tear with arthroscopic findings as the reference standard.

Materials and Methods

This retrospective study included 120 consecutive patients who had undergone MRA within 3 months between April and December 2015. Two musculoskeletal radiologists blinded to the arthroscopic results evaluated T1 SPIR and T2 TSE images in separate sessions for the integrity of the SSC tendon, examining normal/articular-surface partial-thickness tear (PTTa)/full-thickness tear (FTT). Diagnostic performance of T1 SPIR and T2 TSE was calculated with arthroscopic results as the reference standard, and sensitivity, specificity, and accuracy were compared using the McNemar test. Interobserver agreement was measured with kappa (κ) statistics.

Results

There were 74 SSC tendon tears (36 PTTa and 38 FTT) confirmed by arthroscopy. Significant differences were found in the sensitivity and accuracy between T1 SPIR and T2 TSE using the McNemar test, with respective rates of 95.9–94.6% vs. 71.6–75.7% and 90.8–91.7% vs. 79.2–83.3% for detecting tear; 55.3% vs. 31.6–34.2% and 85.8% vs. 78.3–79.2%, respectively, for FTT; and 91.7–97.2% vs. 58.3–61.1% and 89% vs. 78–79.3%, respectively, for PTTa. Interobserver agreement for T1 SPIR was almost perfect for T1 SPIR (κ = 0.839) and substantial for T2 TSE (κ = 0.769).

Conclusion

T1-weighted spectral presaturation with inversion-recovery sequences is more sensitive and accurate compared to T2 TSE in detecting SSC tendon tear on 3T MRA.

Clinico-Radiological Correlation of Subcoracoid Impingement with Reduced Coracohumeral Interval and its Relation to Subscapularis Tears in Indian Patients

INTRODUCTION

Clinically, subcoracoid impingement is characterized by pain at the anterior aspect of the shoulder that is induced by adduction, internal rotation and forward flexion. This position leads to narrowing of the Coraco-Humeral Interval (CHI)-that is, the space between the coracoid process and the lesser tuberosity of the humerus. Structures in the rotator interval are at greatest risk for impingement which includes the Subscorapularis tendon, tendon of the long head of the biceps, and the middle gleno-humeral ligament. This may result in Rotator interval pathologies such as subscapularis tear and long head of biceps tendon subluxation or fraying.

AIM

To study the prevalence of radiological evidence of reduced Coraco-Humeral Interval (CHI) in patients with clinically evident Subcoracoid impingement and to examine the presence of Subscapularis tears in these patients.

MATERIALS AND METHODS

Twenty four patients (6 males, 18 females, average age 52.83 years) were included in this prospective study who were diagnosed to have rotator cuff tears clinically. Nine of these patients were clinically found to have concomitant subcracoid impingement. All patients were subjected to MRI of shoulder. Measurement of the CHI was done in images with humerus in maximal internal rotation. Presence of subscapularis tear was examined intraoperatively. Statistical evaluation of the data was performed using Student's t-test and Fisher's exact test and the results were applied to two cohorts of patients. One cohort consisted of patients who had a CHI value of less than 5.5mm and the other cohort had a CHI value greater than 5.5mm. Average CHI values in patients with and without a subscapularis tear were determined.

RESULTS

Nine patients who had clinical subcoracoid impingement were found to have an average CHI of 5.33mm. All nine of them had an associated tear of subscapularis with long head of Biceps tendon subluxation and/or fraying. Remaining 15 patients had an average CHI of 10.48 and they did not have either signs of Subcracoid impingement or subscapularis tear but had a tear elsewhere (Supraspinatus or Infraspinatus). Difference between these two groups was found highly significant (p-value<0.001). All patients with a CHI value of equal to, or less than 5.5mm had a subscapularis tear, whereas only 11% of patients with a CHI value more than 5.5mm had a tear (p-value<0.001, highly significant).

CONCLUSION

Reduction in the CHI has a significant association with rotator interval pathologies such as subscapularis tears and subluxation or fraying of long head of biceps tendon. Treatment of such patients should include modalities such as coracoplasty or anterior shoulder stabilisation. We recommend that clinical evidence of subcoracoid impingement should lead to further Investigation in the form of MRI and estimation of CHI. A CHI of less than 5.5 mm may indicate subscapulais tear in Indian patients.

Measurement of Coracohumeral Distance in 3 Shoulder Positions Using Dynamic Ultrasonography: Correlation With Subscapularis Tear

PURPOSE

To detect differences between the values of dynamic coracohumeral distance (CHD) measured using ultrasonography (USG) in different shoulder rotations and to investigate its correlation with subscapularis tear.

METHODS

We prospectively enrolled consecutive patients (n = 168) who were scheduled to have arthroscopic rotator cuff repair. Patients with a history of previous shoulder surgery or shoulder fracture and patients with external rotation less than 30° were excluded from the study. Dynamic CHD was measured using USG in 3 different shoulder positions: external rotation, neutral and internal rotation. We evaluated the intrarater reliability with 3 times repetition of measurement. Patients were divided into 1 of 3 groups according to arthroscopic findings: intact subscapularis, partial-thickness tear, and full-thickness tear of the subscapularis. The control group (n = 23) included patients without rotator cuff tears from the outpatient clinic. Subgroup analysis-according to the presence of dynamic subcoracoid stenosis, defined as a CHD less than 6 mm measured in internal rotation-was performed to find the clinical effect of dynamic subcoracoid stenosis.

RESULTS

A partial-thickness tear of the subscapularis tendon was present in 60 patients (35.7%) and a full-thickness tear in 26 patients (15.4%) among 168 patients. The CHD was maximum in external rotation and the narrowest in internal rotation. There were no statistical differences in the CHDs between groups with different subscapularis tear status. According to the presence of dynamic subcoracoid stenosis, patients with dynamic subcoracoid stenosis had a significantly higher incidence of partial-thickness subscapularis tear than those without stenosis (P = .022).

CONCLUSIONS

The CHD values were narrowest in shoulder internal rotation, which is thought to be the pathogenic position. We could not confirm the correlation between CHD and subscapularis tear. However, patients who have dynamic subcoracoid stenosis had significantly higher incidence of subscapularis tear than others without dynamic stenosis.

LEVEL OF EVIDENCE

Level II, prospective prognostic cohort study.

CLINICAL DIAGNOSIS OF SUBSCAPULARIS TENDON TEAR USING THE BEAR HUG SEMIOLOGICAL MANEUVER

Objective: To evaluate the Bear Hug maneuver for clinically diagnosing subscapularis tendon tears, and compare this with other maneuvers described previously (Lift-off, Napoleon and Belly Press). Methods: Forty-nine patients with rotator cuff injuries who had undergone arthroscopy to repair the injury and had previously been assessed using the semiological maneuvers mentioned above were evaluated. Results: The diagnostic values obtained for the Bear Hug test were as follows: sensitivity 75%, specificity 56%, positive predictive value 62%, negative predictive value 70% and accuracy 65%. Conclusion: The highest sensitivity and negative predictive value values were obtained with the Bear Hug test. The highest specificity value was seen with the Lift-off test. The Belly press test gave the greatest specificity, positive predictive and accuracy values.

Cysts within and adjacent to the lesser tuberosity: correlation with shoulder arthroscopy

OBJECTIVE

The purpose of our study was to determine if cysts in and adjacent to the lesser tuberosity are associated with rotator cuff pathology found at arthroscopy.

MATERIALS AND METHODS

A retrospective review was undertaken of the magnetic resonance (MR) imaging of 286 consecutive arthroscopic procedures performed by a single orthopedic shoulder surgeon from February 2001 to June 2009. Images of the shoulders were reviewed by an experienced fellowship-trained musculoskeletal radiologist, reader 1, and a musculoskeletal fellow, reader 2, for the presence and location of lesser tuberosity cysts. Cysts were grouped by their location into those within the lesser tuberosity and those adjacent to the lesser tuberosity. Interreader agreement was calculated using kappa values.

RESULTS

A total of 26 patients (17 men, 9 women; age range 14–84 years; mean of 61 years) had cysts in or adjacent to the lesser tuberosity. For reader 1, patients with cysts located in the lesser tuberosity were found to be significantly older(p=00.03) and more likely to have subscapularis tendon tears(p=00.02) than patients with cysts located adjacent to the tuberosity. No significant difference in any category between patients with a cyst located in the lesser tuberosity and those adjacent to the tuberosity was identified for reader 2. Interreader agreement of imaging findings ranged from fair to near perfect agreement.

CONCLUSION

Cysts located in the lesser tuberosity at the insertion of the subscapularis tendon are suggestive of subscapularis tendon pathology and may occur in older individuals.

The rotator interval and long head biceps tendon: anatomy, function, pathology, and magnetic resonance imaging

The rotator interval is an anatomically defined triangular area located between the coracoid process, the superior aspect of the subscapularis, and the anterior aspect of the supraspinatus. It is widely accepted that the rotator interval structures fulfill a role in biomechanics and pathology of the glenohumeral joint and long head biceps tendon. However, there is ongoing debate regarding the biomechanical details and the indications for treatment. A better understanding of rotator interval anatomy and function will lead to improved treatment of rotator interval abnormalities, and guide the indications for imaging and surgical intervention.

Anterosuperior Glenoid Impingement Syndrome

Anterosuperior glenoid impingement is a well documented cause of shoulder pain. It occurs when there is deep tearing of the subscapularis, with fibers becoming embedded between the anterosuperior glenoid and humeral head. To our knowledge, this has not been described in radiologic literature and we present MRI findings depicting this entity

The subscapularis: anatomy, injury, and imaging

The subscapularis is the largest and most powerful of the rotator cuff muscles and fulfills an important role in glenohumeral movement and stability. The spectrum and implications of subscapularis muscle or tendon injury differ from injury to other rotator cuff components because of its unique structure and function. Diagnosing subscapularis injury is clinically difficult and assessment of subscapularis integrity may be limited during arthroscopy or open surgery. Diagnostic imaging plays an important part in diagnosing and evaluating the extent of subscapularis injury. The radiologist should be aware of the anatomy of the subscapularis, the variations in muscle or tendon injury, and the potential implications for treatment and prognosis.

MRI of impingement syndromes of the shoulder

The diagnosis of shoulder impingement is primarily a clinical one. Imaging has a role in assisting clinicians in developing a treatment strategy by identifying and characterizing the cause of shoulder impingement. In this review, the relevant anatomy, cause/pathomechanics, clinical features, and magnetic resonance imaging (MRI) findings of the different types of impingement syndromes are presented.

Contribution of full-thickness supraspinatus tendon tears to acquired subcoracoid impingement

AIM

To assess the relationship between the severity of full-thickness supraspinatus tendon tears and the development of subcoracoid impingement.

MATERIALS AND METHODS

Fifty-one magnetic resonance imaging (MRI) shoulder examination reports with full-thickness supraspinatus tears were retrospectively identified and reviewed by two dedicated musculoskeletal radiologists. The appearances of the rotator cuff muscles, biceps tendon and the lesser tubercle were recorded. The acromio-humeral distance and the axial coraco-humeral distance were measured. The data were recorded and analysed electronically.

RESULTS

The kappa values for inter-observer agreement were: 0.91 for acromio-humeral distance and 0.85 for coraco-humeral distance measurements. Twenty-six patients had significant retraction of the supraspinatus tendon, 85% (22 cases) of this group had imaging evidence of tear or tendonopathy of the subscapularis tendon. Twenty-five patients had no significant retraction of the supraspinatus, 56% (14 cases) of this group had imaging evidence of a subscapularis tear or tendonopathy. The acromio-humeral distance was significantly less in patients with supraspinatus tears and retraction (p<0.05). The subscapularis tendon was significantly more likely to be abnormal if the supraspinatus was retracted than if no retraction was present (p<0.05). There were no significant differences in coraco-humeral distances between the groups.

CONCLUSION

Subscapularis tendon signal and structural changes are frequently associated with full-thickness supraspinatus tendon tears, particularly if the supraspinatus is significantly retracted. In this static MRI series, the data do not support the occurrence of classical subcoracoid impingement as an aetiology; however, they may support the possibility of a dynamic mechanism, to which future studies could be directed.