MR arthrography of rotator interval, long head of the biceps brachii, and biceps pulley of the shoulder

Arthroscopic Assessment of the Incidence of Biceps Pulley Lesions Associated With Rotator Cuff Tears: An Observational Study

The shoulder joint houses a stabilizing structure called the biceps pulley. Biceps pulley lesions can trigger anterior shoulder pain and frequently coincide with rotator cuff tears, whose prevalence rises with age. In our study, we aim to assess the incidence of biceps pulley lesions associated with rotator cuff tears in patients undergoing arthroscopic repair, the possible associated factors, and whether MRI findings were correlated with them. This study was a prospective observational one conducted at Al-Hadra University Hospital. The patients aged 40 to 65 years were indicated for arthroscopic repair of a rotator cuff tear. We used IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. to conduct the analysis. A total of 60 patients were enrolled in the study. The mean age was 50.97 ± 6.90. The overall incidence of biceps pulley lesions was 85%. Older age was found to be significantly associated with increased incidence. On the other hand, gender, and the mode of injury (cuff tear) had no significant associations with the incidence. Also, formal MR had no significance in diagnosing biceps pulley lesions. The overall incidence of biceps pulley lesions in the current study was 85%. The older the patient with a cuff tear, the greater the incidence of finding a pulley lesion arthroscopically. Moreover, MRI did not have a significant role in diagnosing the biceps pulley lesions.

Prospective Randomized Clinical Trial of Arthroscopic Repair Versus Debridement for Partial Subscapularis Tendon Tears More Than Half of the Entire First Facet

BACKGROUND

Most outcome studies on subscapularis (SSC) tendon tears have focused on large SSC tears rather than partial SSC tendon tears. Therefore, the optimal treatment for partial SSC tendon tears more than half of the first facet of the entire SSC footprint has not yet been clearly defined.

PURPOSE

To prospectively investigate the clinical and radiological results between the arthroscopic repair group and the debridement group in SSC partial tear (Yoo and Rhee classification, type 2B: SSC tendon tears of more than half of the entire first facet).

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 65 patients with SSC tendon type 2B tears were randomized to arthroscopic debridement (n = 33) or arthroscopic repair (n = 32). Clinical evaluation of the patients was performed on the day before surgery and 6 months, 1 year, 2 years, and 5 years postoperatively using active range of motion measurements and other validated scores (pain visual analog scale scores, function visual analog scale scores, Constant score, American Shoulder and Elbow Surgeons score). In addition, SSC muscle strength was measured using instruments in the belly-press position. Magnetic resonance imaging (upper and lower SSC muscle diameters, Goutallier grades) was performed on the day before operation as well as 6 months and 2 years postoperatively.

RESULTS

There were no clinically or statistically significant differences between the arthroscopic debridement and arthroscopic repair groups with respect to active range of motion, pain visual analog scale scores, function visual analog scale scores, Constant scores, or American Shoulder and Elbow Surgeons scores. There was a statistically significant increase in SSC muscle strength in the repair group compared with the debridement group at 5 years postoperatively (P = .013). Magnetic resonance imaging assessment was also not significantly different between the 2 groups.

CONCLUSION

There were no differences in the patient-reported outcomes of patients with partial SSC tears treated with either arthroscopic debridement or repair, although there was an increase in SSC muscle strength associated with repair, the clinical importance of which may warrant further research.

REGISTRATION

NCT03183466 (ClinicalTrials.gov identifier).

Assessment of Acute Lesions of the Biceps Pulley in Patients with Traumatic Shoulder Dislocation Using MR Imaging

Background: Shoulder dislocations represent common injuries and are often combined with rotator cuff tears and potentially damage to the biceps pulley. Purpose: To assess the occurrence and type of biceps pulley lesions in patients after traumatic anterior shoulder dislocation using 3T MRI. Methods: Thirty-three consecutive patients were enrolled between June 2021 and March 2022 (14 women, mean age 48.0 ± 19 years). All patients underwent MR imaging at 3 T within one week. Images were analyzed for the presence and type of pulley tears, subluxation/dislocation of the LHBT, rotator cuff lesions, joint effusion, labral lesions, and osseous defects. Results: Seventeen patients (52%) with traumatic anterior shoulder dislocation demonstrated biceps pulley lesions. Of those, eleven patients (33%) showed a combined tear of the sGHL and CHL. All seventeen patients with lesions of the biceps pulley showed associated partial tearing of the rotator cuff, whereas three patients showed an additional subluxation of the LHBT. Patients with pulley lesions after dislocations were significantly older than those without (mean age 52 ± 12 years vs. 44 ± 14 years, p = 0.023). Conclusion: Our results suggest an increased awareness for lesions of the biceps pulley in acute traumatic shoulder dislocation, particularly in patients over 45 years.

Audit: sonographic report correlation against surgical findings during elective shoulder surgery

Introduction

Musculoskeletal diagnostic ultrasound is an expanding clinical tool and increasingly used at point of care in clinical practice. Criticism around the accuracy of this modality is often attributed to operator dependence. This study evaluated the accuracy of a sonographer's reporting against shoulder surgery.

Methods

A musculoskeletal sonographer performed same-day ultrasound scans prior to elective shoulder surgery procedures. The sonographer was blinded to clinical history and previous investigations. A brief physical examination of resisted external rotation and resisted abduction strength was performed prior to scanning. Scan results were reported using British Elbow and Shoulder Society (BESS) reporting criteria. The sonographer attended surgery to gain immediate visual feedback. Sonographic reports and magnetic resonance imaging (MRI) reports were graded (1= complete agreement; 2 = minor discrepancy unlikely to alter patient care; 3 = potentially significant discrepancy; 4 = definite, significant discrepancy) against surgical findings. The accuracy of sonographic reporting was correlated with patients' body mass index (BMI).

Results

Fifty-four cases were compared and correlations evaluated. Grade 1 (complete agreement) was reported 87.0% (n = 47), Grade 2 (minor discrepancy) 9.3% (n = 5) and Grade 3 (potentially significant discrepancy) 3.7% (n = 2). Sonographic reports closely correlated (Grade 1 or 2 scores) with surgical findings in 96% of cases.

Conclusions

The musculoskeletal sonographic reporting had a high correlation with surgery findings. Ultrasound was more accurate than MRI in reporting full thickness rotator cuff tears. Clinical weakness in resisted external rotation or abduction did not correlate with imaging. Ultrasound was found to be unreliable in detecting rotator cuff tears in participants with a BMI ≥ 35.

Diagnostic accuracy of magnetic resonance imaging for partial tears of the long head of the biceps tendon in patients with rotator cuff tears

Background

Magnetic resonance imaging (MRI) is useful for diagnosing shoulder diseases preoperatively. However, detection of partial tears of the long head of the biceps tendon (LHBT) using current clinical tests and imaging modalities is difficult. We aimed to evaluate the accuracy of radial-slice MRI for diagnosing partial tears of the LHBT. We hypothesized that radial-slice MRI may be a valuable diagnostic tool for assessing diagnosing tears of the LHBT.

Methods

We retrospectively investigated 118 patients who underwent shoulder arthroscopy for rotator cuff tears. Intraoperative LHBT findings were compared with the identification of partial tears of the LHBT on conventional-slice MRI and radial-slice MRI, using a 3.0-T system. We calculated sensitivity, specificity, accuracy, and positive and negative predictive values for the detection of LHBT tears. Inter- and intraobserver reliability for radial-slice MRI was calculated using kappa statistics.

Results

We diagnosed 69 patients (58%) without any LHBT tears and 49 with partial tears (42%), arthroscopically. Sensitivity, specificity, accuracy, and positive and negative predictive values of conventional-slice MRI for detection of partial tears of the LHBT were 52%, 94%, 78%, 92%, and 58%, respectively. Radial-slice MRI had 84% sensitivity, 90% specificity, 86% accuracy, and 92% positive and 80% negative predictive values for partial tears of the LHBT. Inter- and intraobserver reliability for radial-slice MRI was 0.69 and 0.74, respectively, corresponding to high reproducibility and defined as good.

Conclusion

Radial-slice MRI demonstrated significantly higher sensitivity than conventional-slice MRI. These results indicate that radial-slice MRI is useful for diagnosing LHBT partial tears.

MR arthrography: correlation between anatomic intraarticular variants of the long head of the biceps tendon (long head biceps tendon) and superior labral anterior to posterior (SLAP) lesions

Background

The purpose of this work is to characterize the anatomy of the intraarticular portion of the long head of the biceps tendon (long head biceps tendon) using magnetic resonance (MR) arthrography by investigating whether anatomical variants may facilitate the onset of a supraequatorial lesion (superior labral anterior to posterior, SLAP).

Materials and methods

In 482 shoulder MR arthrographies, we considered the anatomical variants of the intraarticular portion of the long head of the biceps tendon classified according to Dierickx’s arthroscopic classification; lesions of supraequatorial structures were considered in the data analysis. For each anatomical variant, correlation with SLAP and the odd ratio were statistically evaluated, using Fisher’s exact (or chi-squared) test and logistic regression analysis, respectively.

Results

In the mesotenon-type variant, the SLAP frequency was higher than expected [χ² (df = 4) = 14.9, p = 0.005] with a higher risk of developing a type I SLAP (p = 0.0003). In the adherent-type variant, the type II SLAP frequency was higher than expected [χ² (df = 3) = 18.1, p = 0.0004] with a higher risk of developing type II SLAP (p = 0.0001). Two cases of “split” (SPL) long head biceps tendon had III and type IV SLAP, respectively. These patients have a higher risk for type IV SLAP [odds ratio (OR) 19.562, 95% confidence interval (CI) 1.604–238.541, p = 0.001]. An increased risk of developing SLAP type II was calculated for male subjects (OR 3.479, 95% CI 1.013–11.951, p = 0.019).

Conclusions

It is possible that adherence of the long head biceps tendon to the supraspinatus more often predisposes to a lesion of the superior glenoid labrum (SLAP), in view of the close relationships between the fibrocartilage and the bicipital anchor, probably related to the limited excursion of the intraarticular long head biceps tendon.

Anatomical variants of the intraarticular portion of the long head of the biceps tendon should be studied with MR arthrography.

Some anatomical variants are more frequently associated with supraequatorial lesions.

The higher frequency of lesions in the presence of certain anatomical variants is probably related to the limited excursion of the intraarticular long head biceps tendon.

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.

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.

Capsular Injury and Inflammation

The capsular and ligamentous structures of the glenohumeral joint are important for stability of the shoulder. These structures are best evaluated by MR imaging. Familiarity with normal and abnormal appearance of the capsular structures of the shoulder is important to ensure that important pathology is not overlooked. Injury to the capsular structures can occur in the setting of trauma and most commonly involves the inferior glenohumeral ligament and axillary pouch. Adhesive capsulitis is a common inflammatory condition with characteristic imaging features that should be considered in the absence of alternative diagnoses.

Adhesive capsulitis: review of imaging findings, pathophysiology, clinical presentation, and treatment options

Adhesive capsulitis, commonly referred to as "frozen shoulder," is a debilitating condition characterized by progressive pain and limited range of motion about the glenohumeral joint. It is a condition that typically affects middle-aged women, with some evidence for an association with endocrinological, rheumatological, and autoimmune disease states. Management tends to be conservative, as most cases resolve spontaneously, although a subset of patients progress to permanent disability. Conventional arthrographic findings include decreased capsular distension and volume of the axillary recess when compared with the normal glenohumeral joint, in spite of the fact that fluoroscopic visualization alone is rarely carried out today in favor of magnetic resonance imaging (MRI). MRI and MR arthrography (MRA) have, in recent years, allowed for the visualization of several characteristic signs seen with this condition, including thickening of the coracohumeral ligament, axillary pouch and rotator interval joint capsule, in addition to the obliteration of the subcoracoid fat triangle. Additional findings include T2 signal hyperintensity and post-contrast enhancement of the joint capsule. Similar changes are observable on ultrasound. However, the use of ultrasound is most clearly established for image-guided injection therapy. More aggressive therapies, including arthroscopic release and open capsulotomy, may be indicated for refractory disease, with arthroscopic procedures favored because of their less invasive nature and relatively high success rate.

Correlations between Capsular Changes and ROM Restriction in Frozen Shoulder Evaluated by Plain MRI and MR Arthrography

Background:

Evaluation of the Range Of Motion (ROM) is one of the important procedures for shoulder disorders. The purpose of this study was to investigate correlations between capsular changes and ROM restrictions evaluated by both plain magnetic resonance imaging (MRI) and Magnetic Resonance Arthrography (MRA) in the same patients with frozen shoulder.

Methods:

Between March 2015 and June 2016, 24 patients with frozen shoulders (13 male and 11 female patients, mean age 60.5) with severe ROM restriction who underwent both MRI and MRA on the same affected side were evaluated. We evaluated 1) ROM, 2) the coracohumeral ligament (CHL) thickness, 3) the joint capsule thickness in the axillary recess (humeral and glenoid sides), 4) the area of the axillary recess, and 5) the capsular area of the axillary recess.

Results:

Positive correlations were found between the axillary area and forward flexion (FF) (R = 0.43, P = 0.035), lateral elevation (LE) (R = 0.66, P<0.001), external rotation (ER)(R = 0.43, P = 0.035), 90° abduction with external rotation (AER)(R = 0.56, P = 0.004), and hand behind the back (HBB)(R = 0.6, P = 0.002) on MRA. Negative correlations were found between the joint capsule at the glenoid side and ER and HBB in both MRI and MRA.

Conclusion:

The axillary area was significantly correlated with ROM restriction in FF, LE, ER, AER, and HBB on MRA. Thickness of the joint capsule at the glenoid side is an important factor for ROM restriction in frozen shoulder.

Level of Evidence:

Level 3, Study of Diagnostic Test.

Medial Subluxation or Dislocation of the Biceps on Magnetic Resonance Arthrography Is Reliably Correlated with Concurrent Subscapularis Full-Thickness Tears Confirmed Arthroscopically

Background

The purpose of this study was to investigate the relationship between biceps medial subluxation/dislocation on the magnetic resonance arthrography (MRA) imaging and subscapularis full-thickness tear confirmed arthroscopically. We hypothesized that presence of a biceps medial subluxation or dislocation would strongly indicate a subscapularis full-thickness tear.

Methods

A total of 432 consecutive patients who underwent arthroscopic repair for rotator cuff tears with/without subscapularis tears at our institute were retrospectively reviewed. The inclusion criterion of this study was preoperative MRA images taken within 6 months of arthroscopic repair. The presence of medial subluxation/dislocation was evaluated on the preoperative MRA images, and subscapularis tear was confirmed on arthroscopic examination.

Results

Biceps subluxation/dislocation was identified in 46 of the 432 patients on MRA. Forty-five of these 46 patients also had a subscapularis full-thickness tear identified in arthroscopic examination. Among the 386 patients who did not have biceps subluxation or dislocation, 54 patients had a subscapularis full-thickness tear diagnosed arthroscopically. The presence of a biceps subluxation/dislocation could predict a subscapularis full-thickness tear with sensitivity of 45% (45/99), specificity of 99% (332/333), positive predictive value of 98% (45/46), negative predictive value of 86% (332/386), and accuracy of 87% (377(45 +332)/432).

Conclusion

Medial subluxation/dislocation of the biceps on MRA images was highly associated with a concurrent subscapularis full-thickness tear which was confirmed arthroscopically. This association had 99% specificity and 98% positive predictive value. Therefore, if a biceps subluxation/dislocation is identified on MRA images, there is a high chance that a concurrent subscapularis full-thickness tear exists.

Three-dimensional Capsular Volume Measurements in Multidirectional Shoulder Instability

Background

In a previous study undertaken to quantify capsular volume in rotator cuff interval or axillary pouch, significant differences were found between controls and patients with instability. However, the results obtained were derived from two-dimensional cross sectional areas. In our study, we sought correlation between three-dimensional (3D) capsular volumes, as measured by magnetic resonance arthrography (MRA), and multidirectional instability (MDI) of the shoulder.

Methods

The MRAs of 21 patients with MDI of the shoulder and 16 control cases with no instability were retrospectively reviewed. Capsular areas determined by MRA were translated into 3D volumes using 3D software Mimics ver. 16 (Materilise, Leuven, Belgium), and glenoid surface area was measured in axial and coronal MRA views. Then, the ratio between capsular volume and glenoid surface area was calculated, and evaluated with control group.

Results

The ratio between 3D capsular volume and glenoid surface area was significantly increased in the MDI group (3.59 ± 0.83 cm³/cm²) compared to the control group (2.53 ± 0.62 cm³/cm²) (p<0.01).

Conclusions

From these results, we could support that capsular volume enlargement play an important role in MDI of the shoulder using volume measurement.

Radiologic and Histologic Evaluation of Proximal Bicep Pathology in Patients With Chronic Biceps Tendinopathy Undergoing Open Subpectoral Biceps Tenodesis

PURPOSE

To correlate preoperative magnetic resonance imaging (MRI) and intraoperative anatomic findings within the proximal long head biceps tendon to histologic evaluation of 3 separate zones of the tendon in patients with chronic biceps tendinopathy.

METHODS

Sixteen patients with chronic biceps tendinopathy were treated with open subpectoral biceps tenodesis. Preoperative MRI tendon grading was as follows: normal tendon, increased signal, tendon splitting, incomplete/complete tear. The removed portion of the biceps tendon was split into 3 segments: zone 1, 0-3.5 cm from the labral insertion; zone 2, 3.5-6.5 cm; and zone 3, 6.5-9 cm, and was histologically evaluated using the Bonar score. Tenosynovium adjacent to the tendon was assessed histologically using the Osteoarthritis Research Society International score. CD31, CD3, and CD79a immunohistochemistries were conducted to determine vascularization, T-cell infiltrates, and B-cell infiltrates, respectively. Analysis of variance and Pearson correlations were performed for statistical analysis.

RESULTS

Preoperative MRI showed no significant differences in tendon appearance between zones 1-3. Intraoperative findings included nonspecific degenerative SLAP tears or mild/moderate biceps tenosynovitis in all cases. Significantly (P < .001) higher Bonar scores were noted for tendon in zones 1 (7.9 ± 1.8) and 2 (7.3 ± 1.5) compared with zone 3 (5.0 ± 1.1). Cell morphology scores in zone 1 (1.9 ± 0.4) and zone 2 (1.5 ± 0.6) were significantly higher than that in zone 3 (0.8 ± 0.3) (P < .05). Inflammatory tenosynovium showed weak correlation with tendon changes in zone 1 (r = 0.08), zone 2 (r = 0.03), or zone 3 (r = 0.1).

CONCLUSIONS

In patients with chronic long head biceps tendinopathy who underwent open subpectoral tenodesis, MRI and intraoperative assessment did not show significant structural abnormalities within the tendon despite significant histopathologic changes. Severity of tendon histopathology was more pronounced in the proximal and mid-portions of the tendon.

CLINICAL RELEVANCE

Proximal versus distal biceps tenodesis is a subject of frequent debate. This study contributes to the ongoing evaluation of the characteristics of the proximal biceps in this type of pathologic condition.

Imaging of the coracoglenoid ligament: a third ligament in the rotator interval of the shoulder

OBJECTIVE

The coracoglenoid ligament (CGL) forms part of the anterosuperior capsuloligamentous complex of the shoulder. Although it has received attention in the anatomical literature, it has not been investigated on imaging. The purpose of this study is to determine the percentage value and the interobserver agreement of identification and classification of the CGL on MR and MR arthrography (MRA) imaging.

MATERIALS AND METHODS

Retrospectively, 280 MR and 150 MRA examinations were evaluated for detection of the CGL by two musculoskeletal radiologists. On the MRA examinations the CGL configuration in relation to the superior glenohumeral (SGHL) and coracohumeral ligament (CHL) was classified into five types. Additionally, the percentage of intra-articular appearance of the CGL and its mean thickness value were calculated. Finally, a possible correlation between pathological condition and anatomical type was evaluated on MRA.

RESULTS

The CGL could be identified in 56%/54% of MRI and in 76%/77% of MRA examinations. On MRA, the CGL was detected as distinct structures in 37%/35% of cases and it appeared fused (partially or totally) with the SGHL and/or CHL in 39%/42%; it was absent in 12%/12% and it appears undistinguishable in the remaining cases. The interobserver agreement was excellent (κ = 0.98 for detection on MRI; p = 0.927 for classification of anterosuperior anatomy on MRA; κ = 0.873 and 0.978 for identification on sagittal and axial external rotation MRA respectively; κ = 0.943 for classification as intra- or extra-articular on MRA).

CONCLUSIONS

The CGL can be reliably identified on MRI and MRA.

Arthrographic Anatomy of the Biceps Tendon Sheath: Potential Implications for Selective Injection

The purpose of this investigation was to better define the anatomical features of the biceps tendon sheath, including the distance the sheath extends below the inferior margin of the subscapularis tendon and below the termination of the bony bicipital groove. A total of 110 magnetic resonance and computed tomography arthrograms performed during 1-year period at our institution were retrospectively reviewed, and the length of the biceps tendon sheath and distances from the inferior margin of the subscapularis tendon and from the termination of the bicipital groove to the inferior margin of the biceps tendon sheath were measured by 3 radiologists. The mean length of the biceps tendon sheath was 47.5mm. The mean distances from the inferior margin of the subscapularis tendon and from the inferior margin of the bicipital groove to the distal extent of the biceps tendon sheath were 24.5mm and 11.9mm, respectively. The relationships among these 3 anatomical measurements and biological confounders of sex and age were investigated while controlling for measurement variability. The anatomical relationships between the biceps tendon sheath and surrounding structures may have implications for needle placement when attempting to inject into the biceps tendon sheath for diagnostic or therapeutic purposes.

Correlations of coracohumeral ligament and range of motion restriction in patients with recurrent anterior glenohumeral instability evaluated by magnetic resonance arthrography

BACKGROUND

Evaluation of range of motion (ROM) restriction before treatment of shoulder disorders is important for predicting the final functional outcomes. The purpose of this study was to investigate correlations of thickness of the coracohumeral ligament (CHL) and ROM restriction in patients with recurrent anterior glenohumeral instability.

METHODS

Between January 2005 and March 2015, 181 shoulders (137 male and 44 female patients; mean age, 29.3 years) with recurrent anterior glenohumeral instability treated with an arthroscopic Bankart repair were enrolled in this study. We evaluated preoperative ROM, thickness of the CHL, and obliteration of the subcoracoid fat triangle on magnetic resonance arthrography. ROM measurements, including forward flexion (FF), external rotation with the arm at the side (ER), and hand behind the back (HBB), were made in a standing position.

RESULTS

There were significant negative correlations between FF and age (P < .001) and between HBB and age (P < .001) but not between ER and age (P = .11). The thickness of the CHL significantly increased with age (P < .001). FF, ER, and HBB were significantly restricted in patients with obliteration compared with those without obliteration (P < .001, P = .004, P < .001, respectively).

CONCLUSIONS

Obliteration of the subcoracoid fat triangle and the thickness of the CHL positively correlated with ROM restrictions, and these changes were greater with age in patients with recurrent anterior glenohumeral instability.

Detour sign in the diagnosis of subluxation of the long head of the biceps tendon with arthroscopic correlation

OBJECTIVE

To determine whether detection of the detour sign via MRI indicates subluxation of the long head of the biceps tendon (SLBT) in the shoulder joint and to investigate the association of SLBT with the degeneration of the long head of the biceps tendon (LBT) and rotator cuff tears.

METHODS

This retrospective study included 65 patients with shoulder pain who underwent shoulder MRI and arthroscopic surgery. When axial images revealed that the LBT was displaced over the inner rim of the bicipital groove with some remaining contact with the groove (Criterion 1), or demonstrated a "detour sign" of the biceps tendon (Criterion 2), the lesion was diagnosed as an SLBT. Shoulder arthroscopy was used as the reference standard.

RESULTS

Arthroscopy identified SLBT in 18 patients. When the MRI diagnosis was based on Criterion 1 alone, SLBT was diagnosed with a sensitivity of 44.4-55.6% and 75.4-80% accuracy. However, when the MRI diagnosis was based on Criteria 1 plus 2, SLBT was diagnosed with a sensitivity of 83.3-94.4% and 78.5-81.5% accuracy. There was a significant difference (p < 0.05) in the diagnostic sensitivity of Criteria 1 and 2.

CONCLUSION

The detour sign based on axial MRI may be regarded an additional useful anatomical feature that improves the diagnostic performance of MRI in the identification of SLBT lesions. Advances in knowledge: Recognition of the detour sign may enhance the diagnostic performance of the conventional MRI protocol over the MR arthrography protocol for SLBT.

The diagnostic value of magnetic resonance imaging for different types of subscapularis lesions

PURPOSE

To investigate the accuracy of preoperative 1.5 T magnetic resonance imaging (MRI) interpreted with standardized procedure for diagnosing subscapularis (SSC) tears identified by arthroscopy. The diagnostic accuracy of MRI for different types of SSC lesions was also evaluated.

METHODS

Two-hundred and seventy-two consecutive patients with rotator cuff tears identified by arthroscopy were included into this study. All patients had preoperative MRI scans with 1.5 T strength. Totally, seven different signs of SSC tears were evaluated on MRI scans. The diagnostic value of MRI was evaluated, respectively, according to two classifications of SSC lesions. The definitive diagnosis for SSC lesions was based on the arthroscopic findings.

RESULTS

Among the 272 patients in this study, 107 (39 %) had SSC tears confirmed by arthroscopy. The surgeons correctly diagnosed 88 of 107 patients with SSC tears. The overall sensitivity was 82.2 %. The sensitivity of MRI for types I, II, III, IV and V was 70, 82.4, 96, 100 and 100 %, respectively, based on the classification by Lafosse. The sensitivity of MRI for partial-thickness and partial-width, full-thickness and partial-width, full-thickness and full-width tear was 75.3, 96.2, 100 %, respectively, according to the classification by Kim.

CONCLUSIONS

The sensitivity of MRI in predicting SSC tears preoperatively was improved with the current procedure. Understanding of certain MRI characteristics of SSC tears could increase the accuracy for diagnosing SSC lesions. 1.5 T MRI of the SSC was not reliable for predicting partial thickness and especially less than 1/3 width tears.

LEVEL OF EVIDENCE

III.

The Rotator Interval of the Shoulder: Implications in the Treatment of Shoulder Instability

Biomechanical studies have shown that repair or plication of rotator interval (RI) ligamentous and capsular structures decreases glenohumeral joint laxity in various directions. Clinical outcomes studies have reported successful outcomes after repair or plication of these structures in patients undergoing shoulder stabilization procedures. Recent studies describing arthroscopic techniques to address these structures have intensified the debate over the potential benefit of these procedures as well as highlighted the differences between open and arthroscopic RI procedures. The purposes of this study were to review the structures of the RI and their contribution to shoulder instability, to discuss the biomechanical and clinical effects of repair or plication of rotator interval structures, and to describe the various surgical techniques used for these procedures and outcomes.

Long head of the biceps brachii tendon: unenhanced MRI versus direct MR arthrography

OBJECTIVE

We sought to determine the diagnostic accuracy of unenhanced MRI and direct MR arthrography (MRA) for evaluation of the intra-articular long head of the biceps brachii tendon (LHBT) using arthroscopy as the gold standard.

MATERIALS AND METHODS

A retrospective review of patients who underwent shoulder MRI (n = 132) and MRA (n = 67) within 12 months prior to arthroscopy was performed. MR images were independently reviewed by two blinded musculoskeletal radiologists. Routinely recorded arthroscopic photos/videos were reviewed by an orthopedic surgeon. The LHBT was graded as normal, tendinosis, partial thickness tear less or greater than 50%, and complete tear. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for tendinosis and tear detection were calculated.

RESULTS

MRI correctly diagnosed fewer normal LHBTs compared to MRA (39-54% versus 74-84%, respectively; p < 0.005). MRI and MRA did not differ significantly in the diagnosis of tendinosis (18-36% and 15-38%, respectively; p > 0.05) and tears (75-83% and 64-73%, respectively; p > 0.05). For tendinosis, MRI versus MRA showed 18-36% and 15-38% sensitivity, 69-79% and 83-91% specificity, 22-28% and 18-50% PPV, 74-76% and 80-86% NPV, and 61-64% and 70-81% accuracy; respectively. For tears, MRI versus MRA showed 75-83% and 64-73% sensitivity, 73-75% and 82-91% specificity, 66-69% and 41-62% PPV, 82-87% and 92-94% NPV, and 74-78% and 79-88% accuracy; respectively.

CONCLUSIONS

No significant difference was found between unenhanced MRI and direct MRA for the detection of tendinosis and tears of LHBTs.

MRI-Arthroscopy Correlation for Shoulder Anatomy and Pathology: A Teaching Guide

OBJECTIVE

The objectives of the article are to improve the radiologist's understanding of shoulder arthroscopy and see how it correlates with MRI. We review the basic principles of arthroscopy followed by a comparison of its strengths and weaknesses relative to MRI. This discussion is supplemented by a series of cases that show the relationship between arthroscopy and MRI in terms of the visualization of normal and abnormal anatomy in the diagnosis of common shoulder abnormalities.

CONCLUSION

By understanding what our orthopedic colleagues are seeing (and not seeing) during arthroscopic shoulder surgery, we can better understand the strengths and weaknesses of MRI, which provides us the opportunity to improve our imaging interpretations and produce valuable management-guiding diagnostic reports.

Accuracy of long head of the biceps subluxation as a predictor for subscapularis tears

PURPOSE

The aim of this study is to understand the relation between long head of the biceps tendon (LHBT) subluxation and full-thickness tears of the subscapularis.

METHODS

Magnetic resonance imaging (MRI) scans of 94 patients undergoing shoulder arthroscopy were evaluated preoperatively for the presence or absence of LHBT subluxation. Intraoperative pathology of the biceps and subscapularis tendons was recorded. The diagnostic accuracy of LHBT subluxation on preoperative MRI in determining full-thickness subscapularis tendon tears was calculated.

RESULTS

Of the 94 patients in this study, 26 were diagnosed with LHBT subluxation preoperatively. Of these 26 patients, 9 were confirmed to have full-thickness tears of the subscapularis tendon (Lafosse grade 2 or higher). Of the remaining 68 patients who did not appear to have LHBT subluxation preoperatively, 2 were confirmed to have full-thickness tears of the subscapularis tendon. Thus LHBT subluxation on MRI as a predictor for full-thickness subscapularis tears had a sensitivity of 82%, specificity of 80%, positive predictive value of 35%, and negative predictive value of 97%. LHBT subluxation was directly correlated with the severity of the subscapularis tendon tear (P < .001).

CONCLUSIONS

The diagnostic value of subluxation of the LHBT, as seen on an axial MRI scan, lies primarily in its negative predictive value. If the LHBT is not subluxated, it is unlikely that a full-thickness tear of the subscapularis tendon is present. Surgeons should be cautious about relying on biceps subluxation as a primary diagnostic tool in predicting subscapularis tears.

LEVEL OF EVIDENCE

Level IV, study of diagnostic test.

The aponeurotic expansion of the supraspinatus tendon: anatomy and prevalence in a series of 150 shoulder MRIs

OBJECTIVE

To describe the aponeurotic expansion of the supraspinatus tendon with anatomic correlations and determine its prevalence in a series of patients imaged with MRI.

MATERIALS AND METHODS

In the first part of this HIPAA-compliant and IRB-approved study, we retrospectively reviewed 150 consecutive MRI studies of the shoulder obtained on a 1.5-T system. The aponeurotic expansion at the level of the bicipital groove was classified as: not visualized (type 0), flat-shaped (type 1), oval-shaped and less than 50% the size of the adjacent long head of the biceps section (type 2A), or oval-shaped and more than 50% the size of the adjacent long head of the biceps section (type 2B). In the second part of this study, we examined both shoulders of 25 cadavers with ultrasound. When aponeurotic expansion was seen at US, a dissection was performed to characterize its origin and termination.

RESULTS

An aponeurotic expansion of the supraspinatus located anterior and lateral to the long head of the biceps in its groove was clearly demonstrated in 49% of the shoulders with MRI. According to our classification, its shape was type 1 in 35%, type 2A in 10 % and type 2B in 4%. This structure was also identified in 28 of 50 cadaveric shoulders with ultrasound and confirmed at dissection in 10 cadavers (20 shoulders). This structure originated from the most anterior and superficial aspect of the supraspinatus tendon and inserted distally on the pectoralis major tendon.

CONCLUSION

The aponeurotic expansion of the supraspinatus tendon can be identified with MRI or ultrasound in about half of the shoulders. It courses anteriorly and laterally to the long head of the biceps tendon, outside its synovial sheath.

Dynamic high-resolution ultrasound of the shoulder: how we do it

Ultrasonography (US) is an established and well-accepted modality that can be used to evaluate articular and peri-articular structures around the shoulder. US has been proven to be useful in a wide range of rotator cuff diseases (tendon tears, tendinosis, and bursitis) as well as non-rotator cuff abnormalities (instability problems, synovial joint diseases, and nerve entrapment syndromes). Diagnostic accuracy of shoulder US when evaluating rotator cuff tears can reach 91-100% for partial and full thickness tears detection, respectively, having been reported to be as accurate as magnetic resonance imaging in experienced hands. US is cheap, readily available, capable to provide high-resolution images, and does not use ionizing radiations. In addition, US is the only imaging modality that allows performing dynamic evaluation of musculoskeletal structures, that may help to further increase diagnostic performance. In this setting, a standardized imaging protocol is essential for an exhaustive and efficient examination, also helping reducing the intrinsic dependence from operators of US. Furthermore, knowledge of pitfalls that can be encountered when examining the shoulder may help to avoid erroneous images interpretation. In this article we use detailed anatomic schemes and high-resolution US images to describe the normal US anatomy of soft tissues, articular, and para-articular structures located in and around the shoulder. Short video clips emphasizing the crucial role of dynamic maneuvers and dynamic real-time US examination of these structures are included as supplementary material.

Shoulder arthroscopy remains superior to direct MR arthrography for diagnosis of subtle rotator interval lesions

PURPOSE

To assess the sensitivity, specificity and accuracy of MR arthrography, as opposed to shoulder arthroscopy, in diagnosing individual rotator interval (RI) structures lesions at different levels of severity.

MATERIALS AND METHODS

Seventy-five patients were enrolled in a prospective study. All the patients were diagnosed with full-thickness rotator cuff tendon tears on unenhanced MRI and had complimentary MR arthrography to search for obscure RI lesions. All the patients then underwent shoulder arthroscopy. The arthroscopist was blinded about the MR arthrography results.

RESULTS

At arthroscopy, 42 patients (56 %) were found to have RI lesion(s) and represented the study group. The remaining 33 patients represented the control group. The sensitivity, specificity and accuracy of MR arthrography for detecting individual RI lesions varied widely depending on the location and severity of the lesions. MR arthrography showed intermediate sensitivity of 67-80 %, specificity of 83-89 % and accuracy of 89-92 % for diagnosing subtle RI lesions; and perfect (100 %) sensitivity, specificity and accuracy for diagnosing biceps long head tendon dislocation. For the rest of RI lesions, MR arthrography showed high sensitivity, specificity and accuracy. Inter-observer agreement was found to be almost perfect (K = 0.81-1.0).

CONCLUSION

Shoulder arthroscopy remains the gold standard for diagnosing subtle RI lesions. Although MR arthrography has proved to be a valuable tool for diagnosing established RI lesions, it is of intermediate sensitivity for diagnosing subtle RI lesions resulting in early insufficiency of the biceps pulley system.

In vivo evaluation of the kinematics of the long head of the biceps tendon within the pulley: a 3 T MRI motion analysis

INTRODUCTION

To evaluate the kinetic amplitude and direction of the long head of the biceps tendon (LHB) within the pulley and the proximal bicipital groove, we performed a 3T-magnetic resonance-throwing motion analysis.

MATERIALS AND METHODS

This prospective study was performed on a 3T-MRI scanner. A T2-weighted-3D sequence in three specific positions of throwing motion of the dominant shoulder was performed under isometric 5 N loading conditions or without loading, respectively. Measurements were performed in high (140°) abduction/external rotation, medium (110°) abduction/external rotation and low (45°) adduction-flexion/internal rotation. Multiplanar rotational reconstructions along the LHB in the bicipital groove allowed for the localization of the LHB including the degree of motion in the three most proximal slices.

RESULTS

12 healthy volunteers (age 22–34 years) were enrolled. Adduction led to an anterior deviation of the LHB within the bicipital groove. Loading conditions in medium (110°) elevation/external rotation furthermore led to a significant anterior deviation of the LHB. Conclusion Our findings support the thesis that pulley lesions result from movements of the LHB especially in extreme positions during throwing/overhead activities. Load application in the medium (110°) elevation/external rotation position might enable a better evaluation of patients with dedicated pulley lesions. These results need further evaluation in larger study cohorts and in patients with dedicated rotator cuff lesions, which will be the focus of ongoing studies.

Posterior dislocation of long head of biceps tendon following traumatic anterior shoulder dislocation: imaging and intra-operative findings

A case of posterior dislocation of the long head of biceps tendon, a rare occurrence following traumatic anterior glenohumeral dislocation, along with complete rotator cuff rupture and large haemarthrosis is presented with imaging and intra-operative findings. The interposed tendon prevented complete reduction. Appearances at MRI were diagnostic and directed the surgical approach.

Long head of the biceps tendon and rotator interval

The term "biceps brachii" is a Latin phrase meaning "two-headed (muscle) of the arm." As its name suggests, this muscle has two separate origins. The short head of biceps is extraarticular in location, originates from the coracoid process of the scapula, having a common tendon with the coracobrachialis muscle. The long head of biceps tendon (LBT) has a much more complex course, having an intracapsular and an extracapsular portion. The LBT originates from the supraglenoid tubercle, and in part, from the glenoid labrum; the main labral attachments vary arising from the posterior, the anterior of both aspects of the superior labrum (Bletran et al. in Top Magn Reson Imaging 14:35-49, 2003; Vangsness et al. in J Bone Joint Surg Br 76:951-954, 1994). Before entering the bicipital groove (extracapsular portion), the LBT passes across the "rotator cuff interval" (intracapsular portion). Lesions of the pulley system, the LBT, and the supraspinatus tendon, as well as the subscapularis, are commonly associated (Valadie et al. in J Should Elbow Surg 9:36-46, 2000). The pulley lesion can be caused by trauma or degenerative changes (LeHuec et al. in J Should Elbow Surg 5:41-46, 1996). MR arthrography appears to be a promising imaging modality for evaluation of the biceps pulley, through the distention of the capsule of the rotator interval space and depiction of the associated ligaments.

MR-arthrography in superior instability of the shoulder: correlation with arthroscopy

PURPOSE

This study was undertaken to evaluate magnetic resonance (MR) arthrography in the detection and classification of lesions that may cause superior instability.

MATERIALS AND METHODS

Forty-two consecutive patients with clinical signs of chronic superior instability of the shoulder underwent MR arthrography followed by arthroscopic surgery. For each patient we retrospectively reviewed the MR arthrography and surgical findings.

RESULTS

We detected 31 superior labral anterior posterior (SLAP) lesions, all confirmed on arthroscopy with three cases of underestimation: in the detection of SLAP lesions, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of MR arthrography were 100%; in the evaluation of the type of SLAP lesion, sensitivity was 100%, specificity was 78.5%, accuracy was 92.8%, PPV was 71.7% and NPV was 100%. All cases of capsular laxity (13/42) and biceps tendon lesions (3/42) were confirmed on arthroscopy with sensitivity, specificity, accuracy, PPV and NPV of 100%. Eleven cuff lesions were detected on MR arthrography, 10 of which confirmed at arthroscopy: sensitivity was 100%, specificity was 96.8%, accuracy was 97.6%, PPV was 90.9% and NPV was 100%. Associated lesions were found in 38/42 patients.

CONCLUSIONS

Superior instability is frequently associated with different anatomical variants or pathological conditions, such as SLAP lesions. The role of MR arthrography is to describe the key features of lesions affecting the superior portion of the shoulder, including location, morphology, extent, and associated injuries and leanatomical variants and to correlate these features with clinical symptoms.

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.

Long head of the biceps pathology combined with rotator cuff tears

The long head of the biceps tendon (LHBT) is an anatomic structure commonly involved in painful shoulder conditions as a result of trauma, degeneration, or overuse. Recent studies have pointed out the close correlation between LHBT lesions and rotator cuff (RCT) tears. Clinicians need to take into account the importance of the LHBT in the presence of other shoulder pathologies. This paper provides an up-to-date overview of recent publications on anatomy, pathophysiology, diagnosis, classification, and current treatment strategies.

MRI of selected abnormalities at the anterior superior aspect of the shoulder: potential pitfalls and subtle diagnoses

OBJECTIVE

MRI has proven to be a helpful tool in the detection and description of pathologic changes of the rotator cuff, biceps tendon, and glenoid labrum and has thus become a mainstay in the evaluation of patients with shoulder pain. This review seeks to illustrate some of the more subtle abnormalities that can be detected on shoulder MRI and to highlight some normal anatomic variants that may mimic pathologic processes, concentrating on structures at the anterior superior aspect of the shoulder.

CONCLUSION

Shoulder MRI can provide a very accurate evaluation of shoulder pathologic processes and can assist in elucidating abnormalities that can be difficult to diagnose clinically. Awareness of the known anatomic variants and the sometimes subtle potential pain generators at the anterior superior aspect of the shoulder will allow a more accurate interpretation and can therefore increase the diagnostic yield of shoulder MRI.

A systematic approach for diagnosing subscapularis tendon tears with preoperative magnetic resonance imaging scans

PURPOSE

To determine and propose a systematic approach to evaluating magnetic resonance imaging (MRI) scans for subscapularis tears and compares preoperative MRI interpretations with findings of the same shoulders at arthroscopy.

METHODS

The study was composed of 202 patients who underwent shoulder arthroscopy by 1 of 5 orthopaedic surgeons during a 3-month period. All patients had MRI scans performed within 6 months before arthroscopy.

RESULTS

Of the 202 patients, 82 had subscapularis tendon tears confirmed at the time of arthroscopy. The orthopaedic surgeons correctly diagnosed 60 of 82 patients (73%) with subscapularis tendon tears on preoperative MRI that were subsequently identified by arthroscopy. The orthopaedic surgeons correctly diagnosed 113 of 120 patients (94%) as not having subscapularis tendon tears. This resulted in an overall sensitivity of 73%, specificity of 94%, positive predictive value of 90%, negative predictive value of 84%, and accuracy of 86%. The frequency of subscapularis tears was highest when the long head of the biceps was displaced from the groove (88%), a combined supraspinatus/infraspinatus tear existed (71%), or the long head of the biceps tendon was torn (69%).

CONCLUSIONS

Preoperative MRI scans of the shoulder interpreted by orthopaedic surgeons with the described systematic approach resulted in improved accuracy in diagnosing subscapularis tendon tears compared with previous studies. A consistent finding is that larger subscapularis tendon tears are more easily detected using MRI scans whereas smaller tears are more frequently missed.

LEVEL OF EVIDENCE

Level III, development of diagnostic criteria with universally applied reference (nonconsecutive patients).

Lesions of the biceps pulley as cause of anterosuperior impingement of the shoulder in the athlete: potentials and limits of MR arthrography compared with arthroscopy

PURPOSE

This study aimed to evaluate the diagnostic possibilities of MR arthrography in the correct identification of complex tears of the biceps pulley and their possible correlation with anterosuperior impingement (ASI) development.

MATERIALS AND METHODS

MR arthrography examinations of 23 athletes with clinical suspicion of ASI were reviewed. All examinations were obtained with a 1.5-T unit (Signa Horizon, GE Healthcare). The shoulders were studied with a dedicated surface coil with the patient's arm in the neutral position and in internal and external rotation. In five patients, images in abduction-external rotation (ABER) were obtained. Within 2 month after MR arthrography, the athletes underwent arthroscopic surgery.

RESULTS

MR arthrography images showed a spectrum of tears that, according to the Habermeyer classification, were subdivided into four groups: type 1 in three patients; type 2 in five; type 3 in seven; type 4 in eight. At arthroscopic evaluation, one patient presented type 1 lesion, five type 2, five type 3 and ten type 4. During arthroscopic dynamic manoeuvres, ASI signs were observed in three patients with type 3 lesion and in ten with type 4 lesion.

CONCLUSIONS

MR arthrography is the imaging modality of choice for evaluating lesions of the rotator interval structures, and only complex lesions of the biceps pulley are related to the development of ASI.

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.

Shoulder US: anatomy, technique, and scanning pitfalls

The accuracy of shoulder ultrasonography (US) is largely dependent on the US examination technique. It is essential that the individual performing the US examination has an understanding of pertinent anatomy, such as bone surface anatomy and tendon orientation. It is also important to be familiar with imaging pitfalls related to US technique, such as anisotropy. In this article, shoulder US scanning technique, as well as related anatomy and scanning pitfalls, will be reviewed. The use of a protocol-driven shoulder US examination is important to ensure a comprehensive and efficient evaluation. An on-line video tutorial demonstrating a shoulder US also accompanies this article.

Unusual variation of the rotator interval: insertional abnormality of the pectoralis minor tendon and absence of the coracohumeral ligament

OBJECTIVE

To evaluate the anomalous insertion of the pectoralis minor tendon with absence of the coracohumeral ligament on MR arthrography and to demonstrate the associated findings seen with this anatomical variation.

MATERIALS AND METHODS

We retrospectively reviewed the 335 MR arthrograms of the shoulder joint (mean age 37.8 years) performed from March 2000 to February 2008. Images were evaluated with attention to anomalous insertion of the pectoralis minor tendon and the coracohumeral ligament.

RESULTS

Anomalous insertion of the pectoralis minor tendon was demonstrated in 5 out of 335 shoulders (1.5%). The pectoralis minor tendons crossed over the coracoid process and attached directly to a glenohumeral joint capsule, and the coracohumeral ligament was absent in these 5 patients. In these patients, injected contrast material was noted to extend over the coracoid process along the course of the pectoralis minor tendon. Among 5 patients, 3 patients (60%) were diagnosed with SLAP (superior labrum anterior to posterior) lesions.

CONCLUSION

Anomalous insertion of the pectoralis minor tendon to the glenohumeral joint capsule and associated absence of the coracohumeral ligament is well demonstrated on MR arthrography. It is an unusual variant of the pectoralis minor muscle insertion, and may be a possible contributing factor in the development of a SLAP lesion.