An anatomic and histologic study of the coracohumeral ligament

Targeting the Sweet Spot: A Systematic Review With Meta-Analysis of Anterior Versus Posterior Glenohumeral Joint Injections for Adhesive Capsulitis

OBJECTIVE

To compare clinical outcomes following steroid injections using the anterior and posterior approaches.

DESIGN

Systematic review with meta-analysis.

SETTING

Embase, Web of Science, and Cochrane Center Register of Controlled Trials were searched for randomized control trials (RCTs) and prospective comparative studies.

PATIENTS

Patients with adhesive capsulitis.

INTERVENTIONS

Glenohumeral steroid injections using either anterior or posterior approach.

MAIN OUTCOME MEASURES

Pain visual analog scale (VAS) and shoulder range of motion (ROM) at 12 weeks, accuracy, and adverse events. Standardized mean difference (SMD) for VAS and weighted mean difference (WMD) for ROMs.

RESULTS

We identified 6 RCTs and one prospective comparative study with a total of 468 patients. While there was no difference in pain VAS at 12 weeks between the 2 approaches (SMD, -0.86; 95% CI, -1.76 to 0.04), the anterior approach resulted in greater improvements in external rotation (WMD, 8.08; 95% CI, 0.79-15.38) and abduction (WMD, 6.76; 95% CI, 3.05-10.48) compared with the posterior approach. Subgroup analysis with RCTs that utilized steroid injection with hydrodilatation for both approaches demonstrated greater reduction in pain VAS at 12 weeks with the anterior approach (SMD, -0.52; 95% CI, -0.98 to -0.07). Overall, procedures were well tolerated without major complications.

CONCLUSIONS

While pain reduction is similar, the anterior approach may be more beneficial in restoring shoulder external rotation and abduction compared with the posterior approach at 12 weeks. Steroid injection combined with hydrodilatation may further improve pain control when performed with the anterior approach at 12 weeks.

Adhesive Capsulitis of the Shoulder: Current Concepts on the Diagnostic Work-Up and Evidence-Based Protocol for Radiological Evaluation

Adhesive capsulitis is an idiopathic and disabling disorder characterized by intense shoulder pain and progressive limitation of active and passive glenohumeral joint range of motion. Although adhesive capsulitis has been traditionally considered a diagnosis of exclusion that can be established based on a suggestive medical history and the detection of supporting findings at the physical exam, imaging studies are commonly requested to confirm the diagnostic suspicion and to exclude other causes of shoulder pain. Indeed, clinical findings may be rather unspecific, and may overlap with diseases like calcific tendinitis, rotator cuff pathology, acromioclavicular or glenohumeral arthropathy, autoimmune disorders, and subacromial/subdeltoid bursitis. Magnetic resonance imaging, magnetic resonance arthrography, and high-resolution ultrasound have shown high sensitivity and accuracy in diagnosing adhesive capsulitis through the demonstration of specific pathological findings, including thickening of the joint capsule and of the coracohumeral ligament, fibrosis of the subcoracoid fat triangle, and extravasation of gadolinium outside the joint recesses. This narrative review provides an updated analysis of the current concepts on the role of imaging modalities in patients with adhesive capsulitis, with the final aim of proposing an evidence-based imaging protocol for the radiological evaluation of this condition.

Dynamic Analysis of the Coracohumeral Ligament Using Ultra-Sonography in Shoulder Contracture

The coracohumeral ligament (CHL) is related to the range of motion of the shoulder joint. The evaluation of the CHL using ultrasonography (US) has been reported on the elastic modulus and thickness of the CHL, but no dynamic evaluation method has been established. We aimed to quantify the movement of the CHL by applying Particle Image Velocimetry (PIV), a technique used in the field of fluid engineering, to cases of shoulder contracture using the US. The subjects were eight patients, with 16 shoulders. The coracoid process was identified from the body surface, and a long-axis US image of the CHL parallel to the subscapularis tendon was drawn. The shoulder joint was moved from 0 degrees of internal/external rotation to 60 degrees of internal rotation at a rhythm of one reciprocation every 2 s. The velocity of the CHL movement was quantified by the PIV method. The mean magnitude velocity of CHL was significantly faster on the healthy side. The maximum magnitude velocity was significantly faster on the healthy side. The results suggest that the PIV method is helpful as a dynamic evaluation method, and in patients with shoulder contracture, the CHL velocity was significantly decreased.

The morphology of the subacromial and related shoulder bursae. An anatomical and histological study

Shoulder bursae are essential for normal movement and are also implicated in the pathogenesis of shoulder pain and dysfunction. The subacromial bursa (SAB), within the subacromial space, is considered a primary source of shoulder pain. Several other bursae related to the subcoracoid space, including the coracobrachial (CBB), subcoracoid (SCB) and subtendinous bursa of subscapularis (SSB), are also clinically relevant. The detailed morphology and histological characteristics of these bursae are not well described. Sixteen embalmed cadaveric shoulders from eight individuals (five females, three males; mean age 78.6 ± 7.9 years) were investigated using macro-dissection and histological techniques to describe the locations, dimensions and attachments of the bursae, their relationship to surrounding structures and neurovascular supply. Bursal sections were stained with haematoxylin and eosin to examine the synovium and with antibodies against von Willebrand factor and neurofilament to identify blood vessels and neural structures respectively. Four separate bursae were related to the subacromial and subcoracoid spaces. The SAB was large, with a confluent subdeltoid portion in all except one specimen, which displayed a distinct subdeltoid bursa. The SAB roof attached to the lateral edge and deep surface of the acromion and coracoacromial ligament, and the subdeltoid fascia; its floor fused with the supraspinatus tendon and greater tubercle. The CBB (15/16 specimens) was deep to the conjoint tendon of coracobrachialis and short head of biceps brachii and the tip of the coracoid process, while the inconstant SCB (5/16 specimens) was deep to the coracoid process. Located deep to the subscapularis tendon, the SSB was a constant entity that commonly displayed a superior extension. Synovial tissue was predominantly areolar (SAB and SSB) or fibrous (CBB and SCB), with a higher proportion of areolar synovium in the bursal roofs compared to their floors. Blood vessels were consistently present in the subintima with a median density of 3% of the tissue surface area, being greatest in the SSB and SAB roofs (4.9% and 3.4% respectively) and least in the SAB floor (1.8%) and CBB roof and floor (both 1.6%). Nerve bundles and free nerve endings were identified in the subintima in approximately one-third of the samples, while encapsulated nerve endings were present in deeper tissue layers. The extensive expanse and attachments of the SAB support adoption of the term subacromial-subdeltoid bursa. Morphologically, the strong attachments of the bursal roofs and floors along with their free edges manifest as fixed and mobile portions, which enable movement in relation to surrounding structures. The presence of neurovascular structures demonstrates that these bursae potentially contribute blood supply to surrounding structures and are involved in mechanoreception. The anatomical details presented in this study clarify the morphology of the shoulder bursae, including histological findings that offer further insight into their potential function.

Association of damage to the coracohumeral ligament with anterosuperior rotator cuff degeneration revealed by anatomical dissection

The coracohumeral ligament (CHL) is an important structure of the biceps pulley which also merges with the rotator cuff. Which role it actually plays in the pathogenesis of rotator cuff degeneration (RCD) and rotator cuff tears (RCT) is still a point of discussion. The hypothesis of this study was, that macroscopic injury to the anterosuperior part of the rotator cuff also includes parts of or the whole CHL. Forty fresh-frozen shoulders were dissected and examined, the morphology of the rotator cuff and the coracohumeral ligament were evaluated and existing lesions documented. 27.5% of the shoulder joints showed an anterosuperior full-thickness RCT. 57.5% of all examined shoulder girdles showed at least a partial rupture of the CHL. A highly significant correlation (p < 0.001, rho = 0.529) between the presence of rotator cuff tears and ruptures of the CHL was found. Cartilage damage within the anterosuperior section of the humeral head was observed in 20% cases. In rotator cuff degeneration and atraumatic rotator cuff tears of the elderly population, the pathomechanism of full-thickness RCT is based on repetitive anterosuperior glenoid impingement. This is especially supported by the identification of a higher frequency of CHL lesions compared to RCT reported in this study. No intact CHL was identified in shoulders with damaged rotator cuff tendons.

The Comma Sign: The Coracohumeral Ligament and Superior Glenohumeral Ligament Exhibit Similar Quantitative Characteristics With Terminal Confluence at the Subscapularis Insertion

Purpose

The purpose of this morphologic cadaveric study was to quantitatively define the composition of the previously described comma tissue along with its relation to the subscapularis tendon insertion.

Methods

Fresh frozen cadaveric shoulder specimens were included for analysis. The coracohumeral ligament (CHL) was exposed at its origin along the base of the coracoid process and freed laterally along its course to the lesser tuberosity adjacent to the bicipital groove. The superior glenohumeral ligament (SGHL) was identified and traced along its course deep to the CHL within the rotator interval with insertion onto the superior aspect of the lesser tuberosity. The midpoint diameters of the SGHL and CHL and their composite insertional diameters on the subscapularis tendon insertion and lesser tuberosity were measured with digital calipers. The mean diameter was determined from 3 measurements taken of each ligament.

Results

Eight specimens were included. With the use of digital calipers, the mean midpoint diameters of the SGHL and CHL were identified as 5.99 mm (range, 5.25-6.91 mm) and 5.13 mm (range, 4.28-5.72 mm), respectively. The composite insertional diameter of the SGHL and CHL on both the lesser tuberosity and humeral insertion of the subscapularis tendon was 9.93 mm (range, 6.69-12.05 mm). At its insertion, the SGHL and CHL comprised 54% and 46% of the comma tissue, respectively. Additionally, all specimens were identified as showing a confluence of the SGHL and CHL composite insertion with the subscapularis tendon at the point of its humeral head insertion.

Conclusions

The comma tissue is a pivotal structure for the identification, mobilization, and repair of retracted subscapularis tendon tears. Therefore, quantitative knowledge of the midpoint diameter, insertional diameter, and composite distribution of the CHL and SGHL provided by this morphologic cadaveric analysis may aid surgeons in their efforts to restore the native anatomy.

Clinical Relevance

Subscapularis tendon tears have often been under-addressed during rotator cuff repair. The comma tissue has been described as an anatomic structure that can aid in the identification, mobilization, and repair of retracted subscapularis tendon tears. Therefore, quantitative knowledge of this important arthroscopic landmark may aid surgeons in their efforts to restore the native anatomy.

The Angular Relationships Between the Coracohumeral Ligament and Adjacent Shoulder Structures Are Variable

Purpose

To describe the arthroscopic anatomy of the coracohumeral ligament (CHL) in relation to visible anatomic reference points to aid in the execution of a more effective arthroscopic medial-lateral rotator interval closure.

Methods

Detailed dissection to identify the CHL was performed in 4 shoulders from 2 fresh-frozen donor cadavers with a deltopectoral approach. The angular relationship between the CHL and the superior border of the subscapularis tendon was determined via gross dissection. Arthroscopic images were used to determine the angular position of the CHL in relation to both the glenoid articular surface and the intraarticular segment of the tendon of the long head of the biceps brachii (LHB).

Results

Analysis of 4 cadaveric shoulders via gross dissection demonstrated the CHL to subtend a mean angle of 29° (range 16° to 39°) with respect to the superior border of the subscapularis tendon. Arthroscopic analysis of 4 cadaveric shoulders demonstrated the CHL to subtend a mean angle of 59° (range 38° to 77°) with respect to the glenoid articular surface. Additionally, arthroscopic analysis of 2 cadaveric shoulders demonstrated the CHL to subtend a mean angle of 29° (range 11° to 47°) with respect to the LHB tendon.

Conclusion

Although the position of the CHL in relation to the subscapularis tendon, glenoid articular surface, and LHB tendon demonstrates a moderate degree of anatomic variability, these structures provide valuable anatomic reference points for the identification of the course of this significant static shoulder stabilizer.

Clinical Relevance

Comprehensive understanding of the angular relationships between the CHL and adjacent shoulder structures may assist with the execution of a more effective arthroscopic rotator interval closure.

Utility of sonoelastography for the evaluation of rotator cuff tendon and pertinent disorders: a systematic review and meta-analysis

OBJECTIVES

Sonoelastography has been increasingly used to investigate musculoskeletal disorders. The aim of this meta-analysis was to investigate the utility of sonoelastography in diagnosing rotator cuff tendon pathology and pertinent disorders.

METHODS

Searching through PubMed and Embase, we systemically reviewed clinical studies in which sonoelastography has been used for imaging rotator cuff tendon pathology and relevant disorders. The primary outcome was the standardized mean difference (SMD) of tendon elasticity between shoulders (or patients) with and without the designated pathological conditions.

RESULTS

A total of 11 cross-sectional studies were included in the meta-analysis. The supraspinatus and infraspinatus tendons assessed by shear wave sonoelastography were likely to be stiffer in shoulders with adhesive capsulitis, with a SMD of 2.103 (95% confidence interval (CI), - 0.151 to 4.357, p = 0.067) and a SMD of 1.548 (95% CI, - 0.032 to 3.127, p = 0.055), respectively. Regarding rotator cuff tendinopathy, there was no significant difference in the elasticity of supraspinatus tendons evaluated by shear wave velocity (SMD = - 0.107; 95% CI, - 0.524 to 0.310, p = 0.615) or strain ratios (SMD = 0.153, 95% CI, - 2.134 to 2.440, p = 0.896). Only one study used shear wave sonoelastography to investigate patients with rotator cuff tendon tears and found tendon that elasticity was similar between diseased and normal shoulders.

CONCLUSION

This meta-analysis revealed that supraspinatus and infraspinatus tendons tended to be stiffer in shoulders with adhesive capsulitis. Furthermore, no significant difference in tendon elasticity could be identified between shoulders with and without rotator cuff tendinopathy or tendon tears.

KEY POINTS

• Supraspinatus and infraspinatus tendons are likely to have decreased elasticity in shoulders with adhesive capsulitis, as assessed by shear wave sonoelastography. • There was no significant difference in tendon elasticity between shoulders with and without rotator cuff tendinopathy or tendon tears when evaluated by strain and shear wave sonoelastography.

Quantitative and Qualitative Analyses of the Glenohumeral Ligaments: An Anatomic Study

BACKGROUND

While several studies have qualitatively described the anatomy of the glenohumeral ligaments, there remains a lack of consensus regarding their quantitative humeral and glenoid attachment sites.

PURPOSE

To quantitatively and qualitatively describe the anatomic humeral and glenoid attachment sites of the glenohumeral ligaments and their relationship to well-established anatomic landmarks.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 10 nonpaired, fresh-frozen human cadaveric shoulders were included in this study. A 3-dimensional coordinate measuring device was used to quantify the location of pertinent bony landmarks and soft tissue attachment areas. All subcutaneous tissues and musculature were removed, with the exception of the rotator cuff (respective muscle bellies cut at their musculotendinous junctions) and the long head of the biceps tendon. The superior glenohumeral ligament (SGHL), middle glenohumeral ligament (MGHL), anteroinferior glenohumeral ligament (AIGHL), posteroinferior glenohumeral ligament (PIGHL), and coracohumeral ligament (CHL) were then transected. Coordinates of points along the perimeters of attachment sites were used to calculate areas, while coordinates of center points were used to determine distances between surgically relevant attachment sites and pertinent bony landmarks.

RESULTS

The mean length of the SGHL humeral attachment along the intra-articular cartilage margin was 9.5 ± 3.2 mm, spanning from 12:55 to 1:40, while the SGHL glenoid attachment to the labrum was 1.9 ± 1.2 mm medial to the most lateral extent of the labral rim, spanning from 12:30 to 12:45. The mean length of the MGHL attachment along the intra-articular cartilage margin was 16.4 ± 3.0 mm, equating to 2:10 to 3:35 on the humeral head clockface, and the glenoid attachment was confluent with the labrum, attaching 1.5 ± 1.0 mm medial to the most lateral extent of the labral rim and thus extending from 1:50 to 2:35 on the glenoid clockface. The mean length of the AIGHL attachment along the intra-articular cartilage margin was 12.0 ± 3.0 mm, spanning from 4:05 to 5:10 on the humeral head clockface. The AIGHL bony footprint on the glenoid neck was 48.4 ± 24.5 mm². The confluent attachment of the AIGHL to the labrum was 1.2 ± 0.9 mm medial to the most lateral extent of the labral rim, corresponding to 3:30 to 4:05 on the glenoid clockface. The mean length of the PIGHL attachment along the intra-articular cartilage margin was 12.0 ± 1.4 mm, spanning from 7:40 to 8:50 on the humeral head clockface. The PIGHL attachment to the labrum was 1.2 ± 0.5 mm medial to the most lateral extent of the labral rim. This attachment to the labrum was calculated to span from 7:35 to 8:50 on the glenoid clockface. The mean length of the CHL origin from the coracoid was 12.9 mm, with its most anterior point located a mean of 14.1 mm from the tip of the coracoid. The mean length of the CHL attachment along the intra-articular cartilage margin was 10.0 ± 4.0 mm, spanning from 11:55 to 12:40 on the humeral head clockface.

CONCLUSION

Glenohumeral ligaments were consistently identified in all specimens with minor anatomic variability for the SGHL, MGHL, AIGHL, and PIGHL. Important landmarks including the cartilage surface of the humerus, the bicipital groove, and the clockface can be utilized intraoperatively when attempting anatomic repair of these structures.

CLINICAL RELEVANCE

There are multiple open and arthroscopic shoulder procedures that rely on anatomic restoration of these static stabilizers to provide optimal shoulder function and prevent recurrent instability. The qualitative descriptions are comparable with current literature; however, this study is the first to quantify the glenohumeral capsular and ligamentous attachments. The data provided allow for reliable landmarks to be established from known bony and soft tissue structures.

Usefulness of intravenous contrast-enhanced MRI for diagnosis of adhesive capsulitis

OBJECTIVES

We aimed to compare the reliability and performance of MRI measures enhanced with intravenous (IV) injection of gadolinium contrast versus non-enhanced MRI measures for the diagnosis of adhesive capsulitis (AC). We also aimed to examine the association between MRI findings and clinical features in patients with AC.

METHODS

MRI of 42 patients with a clinical diagnosis of AC confirmed by arthrography and that of 42 patients in a control group were retrospectively studied by 2 blinded readers. Reliability and performance of MRI findings were compared between IV contrast-enhanced measures and non-enhanced MRI measures in T2-weighted fat-saturated and T1-weighted images. MRI findings were correlated with clinical stage, etiology, and pain.

RESULTS

Sensitivity (97.6%) and specificity (97.6%) of axillary-recess capsule signal enhancement for AC diagnosis were significantly superior (p = 0.02) to hyperintense signals on T2-weighted fat-suppressed images (sensitivity 90.5%, specificity 92.7%). Measures of the intensity signal in the area of the rotator interval were less performant for AC diagnosis but could be improved with joint capsule enhancement. Moreover, we found very high specificity (100%) of enhancement of the coracohumeral ligament signal for AC diagnosis. The early stage of adhesive capsulitis was positively correlated with joint capsule enhancement in the rotator interval. Secondary etiology of capsulitis was correlated with joint capsule hyperintensity signals of the rotator interval on T2-weighted fat-suppressed images.

CONCLUSION

IV contrast injection with MRI can be helpful for AC diagnosis in difficult cases. The stage of AC seems related to joint capsule enhancement in the rotator interval.

KEY POINTS

• IV gadolinium-enhanced MRI can improve the analysis of signal changes in the shoulder synovium and capsule of the shoulder that are related to adhesive capsulitis. • As an original finding, we observed that coracohumeral ligament enhancement had a 100% specificity for the diagnosis of adhesive capsulitis. • The intensity of enhanced signals in the rotator interval seems to be related to the early stage of frozen shoulder.

Evaluating Correlations of Coracohumeral Ligament Thickness with Restricted Shoulder Range of Motion and Clinical Duration of Adhesive Capsulitis with Ultrasound Measurements

OBJECTIVES

The primary objective of this study is to evaluate, using ultrasound measurements, the correlation between coracohumeral ligament (CHL) thickness and restricted shoulder range of motion (ROM) in patients with adhesive capsulitis (AC). The secondary objective is to investigate the correlation between CHL thickness and disease duration.

DESIGN

Prospective cross-sectional survey.

SETTING

Clinical research of a tertiary care hospital.

METHODS

Overall, 65 patients with clinically diagnosed AC were enrolled. Ultrasound measurements of CHL thickness in the axial oblique plane were obtained under maximal external rotation of the glenohumeral joint. Both Shoulder Pain and Disability Index (SPADI) and shoulder ROM were prospectively evaluated by an experienced investigator. CHL thickness was compared with shoulder ROM and SPADI. The association between CHL thickness and disease duration was also investigated.

RESULTS

Simple linear regression analysis showed significant inverse correlation between CHL thickness and shoulder ROM including external rotation (ER) (r = -0.335, P = .006) and internal rotation (IR) (r = -0.409, P = .001). CHL thickness also correlated with disease duration (r = -0.352, P = .004). Multiple linear regression analysis demonstrated that CHL thickness was significantly associated with restricted ER (r = -0.293, P = .02) and IR (r = -0.363, P = .003) after adjusting for age and disease duration. On the other hand, CHL thickness showed no significant correlation with abduction (r = -0.210, P = .09), flexion (r = -0.170, P = .176), or total SPADI score (r = 0.176, P = .16). Moreover, CHL was significantly thicker in patients with disease duration >6 months (P = .004, difference in means: 0.55 mm, 95% confidence interval: -0.922, -0.183).

CONCLUSIONS

CHL was significantly thicker in later-stage AC. CHL thickness correlated negatively with ER and IR of the shoulder. Furthermore, CHL thickening could be observed in the early stage of the disease course. These imaging findings may assist in confirming the diagnosis of AC, leading to early intervention and treatment options.

Optimal Cut-Off Value of the Coracohumeral Ligament Area as a Morphological Parameter to Confirm Frozen Shoulder

BACKGROUND

Thickened coracohumeral ligament (CHL) is one of the important morphological changes of frozen shoulder (FS). Previous research reported that coracohumeral ligament thickness (CHLT) is correlated with anterior glenohumeral instability, rotator interval and eventually FS. However, thickness may change depending on the cutting angle, and measurement point. To reduce measurement mistakes, we devised a new imaging criteria, called the coracohumeral ligament area (CHLA).

METHODS

CHL data were collected and analyzed from 52 patients with FS, and from 51 control subjects (no evidence of FS). Shoulder magnetic resonance imaging was performed in all subjects. We investigated the CHLT and CHLA at the maximal thickened view of the CHL using our picture archiving and communications system. The CHLA was measured as the whole area of the CHL including the most hypertrophied part of the MR images on the oblique sagittal plane. The CHLT was measured at the thickest point of the CHL.

RESULTS

The average CHLA was 40.88 ± 12.53 mm² in the control group and 67.47 ± 19.88 mm² in the FS group. The mean CHLT was 2.84 ± 0.67 mm in the control group and 4.01 ± 1.11 mm in the FS group. FS patients had significantly higher CHLA (P < 0.01) and CHLT (P < 0.01) than the control group. The receiver operator characteristic analysis showed that the most suitable cut-off score of the CHLA was 50.01 mm², with 76.9% sensitivity, 76.5% specificity, and area under the curve (AUC) of 0.87. The most suitable cut-off value of the CHLT was 3.30 mm, with 71.2% sensitivity, 70.6% specificity, and AUC of 0.81.

CONCLUSION

The significantly positive correlation between the CHLA, CHLT and FS was found. We also demonstrate that the CHLA has statistically equivalent power to CHLT. Thus, for diagnosis of FS, the treating physician can refer to CHLA as well as CHLT.

Accuracy of unguided and ultrasound guided Coracohumeral ligament infiltrations - a feasibility cadaveric case series

BACKGROUND

Coracohumeral ligament (CHL) thickening, contracture, and fibroplasia have been identified in glenohumeral idiopathic adhesive capsulitis (GHIAC). The CHL is the main structure responsible for the range of motion limitations. Favorable outcomes have been reported with CHL surgical release. Intra-articular glenohumeral joint corticosteroid infiltrations are utilized to disrupt the inflammatory process and reduce pain in GHIAC. The aim of this study was to investigate whether the CHL could be accurately targeted with a periligamentous infiltration.

METHODS

A convenience sample of 12 unembalmed cadaver shoulders (mean age: 74.5 years, range 66-87 years) without evidence of previous injury or surgery were utilized in this exploratory double factor feasibility cadaveric (unguided and ultrasound (US) guided) case series. Two clinicians trained in musculoskeletal infiltration techniques carried out the infiltrations on each shoulder with colored latex. One clinician infiltrated without guidance, the other with US-guidance. The injecting clinicians were blinded to the others infiltration procedure and the order was randomized. An anatomist blinded to the infiltration order performed a shoulder dissection and recorded the infiltrate location. Percentage calculation for accuracy of infiltration and a chi-square evaluation of the difference between unguided and US-guided infiltrations was applied.

RESULTS

An accuracy of 75% was achieved for unguided infiltration and 80% for US-guided infiltration techniques. Chi-squared indicated there was no significant difference (p = 0.82) between the unguided and US-guided techniques.

CONCLUSION

US-guided and unguided infiltrations achieved good accuracy targeting the CHL, suggesting infiltrations can specifically and accurately target the CHL. In vivo investigation using such infiltration techniques are warranted.

Ectopic tendons of the pectoralis minor muscle as cause for shoulder pain and motion inhibition-Explaining clinically important variabilities through phylogenesis

OJECTIVE

Clinical consequences of ectopic tendons of the pectoralis minor muscle (PMM) for shoulder pain and range-of-motion limitation have been demonstrated. For better understanding the existence of such ectopic tendons, a phylogenetic hypothesis is proposed.

METHODS

Forty-five shoulders of anatomical specimens were dissected and examined. Insertions areas of PMM were measured and occurring aberrant tendons were identified. Their relationship with the coracohumeral ligament (CHL) described and samples of the ligament were collected and histologically stained.

RESULTS

The prevalence of PMM variations was 37.84%. Shoulders with variations showed a statistically significant smaller coracopectoral distance (p<0.001) and larger insertion areas (p<0.003) than shoulders without. A strong negative correlation between these two variables (p<0.001, r = -0.620) was shown.

CONCLUSIONS

The presented results prompted the conclusion that the CHL may be in fact the remnant of the pectoralis minor tendon (PMT), which migrated from the humerus to the coracoid process through the process of phylogenetic evolution. Variations of PMTs are significantly more common than in previous studies. Imaging techniques appear to be insufficiently sensitive for reliably detecting ectopic tendons. Especially in patients experiencing shoulder pain and stiffness in whom the commoner pathologies have been ruled out the possibility of ectopic PMT should be kept in mind and ruled out.

Biomechanics of posterior shoulder instability - current knowledge and literature review

Posterior instability of the shoulder is a rare condition and represents about 10% of shoulder instability. It has become more frequently recognized in the last year, even though it is more difficult to diagnose than anterior shoulder instability. As this form of shoulder pathology is somewhat rare, biomechanical knowledge is limited. The purpose of our study was to perform an extensive literature search, including PubMed and Medline, and to give an overview of the current knowledge on the biomechanics of posterior shoulder instability. The PubMed/Medline databases were utilized, and all articles related to posterior shoulder instability and biomechanics were included to form a comprehensive compilation of current knowledge. A total of 93 articles were deemed relevant according to our inclusion and exclusion criteria. As expected with any newly acknowledged pathology, biomechanical studies on posterior shoulder instability remain limited in the literature. Current biomechanical models are performed in a static manner, which limits their translation for explaining a dynamic pathology. Newer models should incorporate dynamic stabilization of both the rotator cuff and scapulothoracic joint. There is a current lack of knowledge with regards to the pathomechanism of posterior shoulder instability, with no consensus on appropriate treatment regimens. Further investigation is therefore required at both basic science and clinical levels.

Ultrasound-guided coracohumeral ligament release

Long-term follow-up of patients with adhesive capsulitis (AC) reveals that approximately half of them suffer from a limited range of shoulder motion, particularly external and/or internal rotation. We report the surgical technique and short-term clinical outcomes of ultrasound-guided release of the thickened coracohumeral (CH) ligament in 8 patients (9 shoulders) with AC. Passive external rotation with the arm by the side significantly increased from an average of 18° preoperatively to 47° immediately after CH ligament release. VAS and ASES scores were improved at 3months follow-up in all 9 shoulders, and maintained at 6months follow-up in 6 shoulders. No procedure-related adverse events developed over the 6-month follow-up period. Ultrasound-guided release for thickened CH ligament is a reliable and effective minimally invasive surgery for persistent limited external rotation due to AC of the shoulder.

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.

Sonography of the Coracoid Process Region

Sonography is widely known as an accurate imaging tool for assessment of the rotator cuff of the shoulder, the long head of the biceps tendon, and joint disorders, but it is rarely performed to evaluate the coracoid process and the adjacent soft tissues. Nevertheless, sonography can show anatomic details of this region and be used to assess several pathologic conditions. The aims of this pictorial essay are to briefly review the anatomy of the coracoid process region, describe examination technique and normal sonographic appearances, and present the sonographic findings of the main disorders affecting this region.

High-Pressure Balloon-Assisted Stretching of the Coracohumeral Ligament to Determine the Optimal Stretching Positions: A Cadaveric Study

BACKGROUND

The coracohumeral ligament (CHL) is a thick capsular structure and markedly thickened when affected by adhesive capsulitis. Therapeutic stretching is the most commonly applied treatment for adhesive capsulitis, but optimal stretching postures for maximal therapeutic effects on the CHL have not been fully investigated.

OBJECTIVE

To investigate the most effective stretching direction for the CHL by measuring the stretching intensity in 5 different directions and to determine whether the stretching intervention resulted in loosening of the ligament by comparing the changes of CHL tightness before and after stretching.

DESIGN

Biomechanical cadaver study.

SETTING

Academic institution cadaver laboratory.

PARTICIPANTS

Nine fresh frozen cadaveric shoulders.

METHODS

A high-pressure balloon catheter inserted under the CHL and intraballoon pressure was measured, to evaluate CHL tightness without ligament damage as well as to augment and monitor stretching intensity. To find the optimal stretching direction, the glenohumeral joint was stretched from the neutral position into 5 directions sequentially under pressure-monitoring: flexion, extension [EX], external rotation [ER], EX+ER, and EX+ER+adduction [AD] directions.

MAIN OUTCOME MEASUREMENTS

CHL tightness was determined by a surrogate parameter, the additional pressure created by the overlying CHL. The pressure increase (ΔP_str) by a specific directional stretch was considered as the stretching intensity.

RESULTS

ΔP_str by the 5 directions were mean (standard deviation) values of 0.03 ± 0.07 atm, 0.87 ± 1.31 atm, 1.13 ± 1.36 atm, 1.49 ± 1.32 atm, and 2.10 ± 1.70 atm, respectively, revealing the highest ΔP_str by the EX+ER+AD stretch (P < .05). The balloon pressure by the overlying CHL was decreased from 0.45 ± 0.35 atm to 0.18 ± 0.14 atm (P = .012) before and after the stretching manipulation.

CONCLUSIONS

EX+ER+AD of the glenohumeral joint resulted in the greatest increase in balloon pressure, implying that it could be the most effective stretching direction. A series of stretching manipulations assisted with an underlying pressure balloon were capable of decreasing CHL tightness. With further development and modification, high-pressure balloon-assisted stretching can be a potential therapeutic option to release tight CHL, including the advantage of augmenting and monitoring stretching intensity.

LEVEL OF EVIDENCE

II.

Anatomy of the capsulolabral complex and rotator interval related to glenohumeral instability

The glenohumeral joint with instability is a common diagnosis that often requires surgery. The aim of this review was to present an overview of the anatomy of the glenohumeral joint with emphasis on instability based on the current literature and to describe the detailed anatomy and anatomical variants of the glenohumeral joint associated with anterior and posterior shoulder instability. A review was performed using PubMed/MEDLINE using key words: Search terms were "glenohumeral", "shoulder instability", "cadaver", "rotator interval", "anatomy", and "anatomical study". During the last decade, the interest in both arthroscopic repair techniques and surgical anatomy of the glenohumeral ligament (superior, middle, and inferior), labrum, and rotator interval has increased. Understanding of the rotator interval and attachment of the inferior glenohumeral ligament on the glenoid or humeral head have evolved significantly. The knowledge of the detailed anatomy and anatomical variations is essential for the surgeon in order to understand the pathology, make a correct diagnosis of instability, and select proper treatment options. Proper understanding of anatomical variants can help us avoid misdiagnosis. Level of evidence V.

Unilateral ectopic insertion of the pectoralis minor: Clinical and functional significance

During routine dissection of a 70-year-old female, we observed a unilateral ectopic insertion of the left pectoralis minor muscle. The tendon was cord-like and passed through a tendon sheath superior to the coracoid process to insert on the greater tubercle of the humerus. Additionally, an aponeurosis extended from the distal aspect of the muscle's tendon and passed medially to insert near the base of the coracoid process. This is the first report of an additional aponeurosis extending from the tendon of the pectoralis minor and attaching to the coracoid process. We also observed that the pectoralis minor tendon caused an unusually smooth deep indentation on the superior aspect of the coracoid process; considering its insertion on the humerus, we hypothesize that the muscle acted as an abductor of the shoulder along with the supraspinatus. The medial extension of an aponeurotic tendon from the pectoralis minor tendon near its insertion, to the base of the coracoid process further suggests that the muscle provided stability to the glenohumeral joint while acting as an abductor. Pectoralis minor variations have been described since 1897; however, few studies have demonstrated functional or clinical significance. The redundancy of the actions of this muscle along with its long tendon suggests a potential source for autograft.

Elasticity of the Coracohumeral Ligament in Patients with Adhesive Capsulitis of the Shoulder

PURPOSE

To evaluate the elasticity of the coracohumeral ligament (CHL) in healthy individuals and patients with clinical findings suggestive of unilaterally involved adhesive capsulitis of the shoulder (ACS).

MATERIALS AND METHODS

The institutional review board approved this single-institution prospective study, which was performed between November 15, 2012, and July 8, 2014. Informed consent was obtained from all subjects. Measurement of CHL thickness was performed in the axial oblique plane under shoulder maximal external rotation. Shear-wave elastography (SWE) was used to evaluate elasticity of the CHL in healthy individuals (11 men, 19 women aged 22-62 years) and those with clinical findings suggestive of ACS (nine men, 11 women aged 41-70 years). SWE was performed in the shoulder-neutral position and under maximal external rotation. The Wilcoxon signed-rank test was performed to compare the thickness and elastic modulus of the CHL between bilateral shoulders.

RESULTS

In all subjects, the CHL elastic modulus was larger under maximal external rotation than in the neutral position (P < .001 for all). For healthy subjects, there was no significant difference in the CHL elastic modulus between the dominant and nondominant shoulders. For patients presumed to have ACS, the CHL thickness was significantly greater in the symptomatic shoulder than in the unaffected shoulder (P < .001). The CHL elastic modulus of the symptomatic shoulder (median, 234.8 kPa; interquartile range [IQR], 174.4-256.7 kPa) was significantly greater than that of the unaffected shoulder (median, 203.3 kPa; IQR, 144.1-242.7 kPa) in the shoulder-neutral position (P = .004) but not under maximal external rotation (P = .123). When bilateral shoulders were maintained at the same angle of external rotation, the CHL elastic modulus was greater in the symptomatic shoulder than in the unaffected shoulder (P = .005).

CONCLUSION

In patients with clinical findings suggestive of ACS, SWE showed that the CHL is stiffer in the symptomatic shoulder than in the unaffected shoulder.

The anatomy of the coracohumeral ligament and its relation to the subscapularis muscle

BACKGROUND

Only a few reports describe the extension of the coracohumeral ligament to the subscapularis muscle. The purposes of this study were to histo-anatomically examine the structure between the ligament and subscapularis and to discuss the function of the ligament.

METHODS

Nineteen intact embalmed shoulders were used. In 9 shoulders, the expansion of the ligament was anatomically observed, and in 6 of these 9, the muscular tissue of the supraspinatus and subscapularis was removed to carefully examine the attachments to the tendons of these muscles. Five shoulders were frozen and sagittally sectioned into 3-mm-thick slices. After observation, histologic analysis was performed on 3 of these shoulders. In the remaining 5 shoulders, the coracoid process was harvested to investigate the ligament origin.

RESULTS

The coracohumeral ligament originated from the horizontal limb and base of the coracoid process and enveloped the cranial part of the subscapularis muscle. The superficial layer of the ligament covered a broad area of the anterior surface of the muscle. Laterally, it protruded between the long head of the biceps tendon and subscapularis and attached to the tendinous floor, which extended from the subscapularis insertion. Histologically, the ligament consisted of irregular and sparse fibers abundant in type III collagen.

CONCLUSION

The coracohumeral ligament envelops the whole subscapularis muscle and insertion and seems to function as a kind of holder for the subscapularis and supraspinatus muscles. The ligament is composed of irregular and sparse fibers and contains relatively rich type III collagen, which would suggest flexibility.

Arthroscopic anatomy of the subdeltoid space

From the first shoulder arthroscopy performed on a cadaver in 1931, shoulder arthroscopy has grown tremendously in its ability to diagnose and treat pathologic conditions about the shoulder. Despite improvements in arthroscopic techniques and instrumentation, it is only recently that arthroscopists have begun to explore precise anatomical structures within the subdeltoid space. By way of a thorough bursectomy of the subdeltoid region, meticulous hemostasis, and the reciprocal use of posterior and lateral viewing portals, one can identify a myriad of pertinent ligamentous, musculotendinous, osseous, and neurovascular structures. For the purposes of this review, the subdeltoid space has been compartmentalized into lateral, medial, anterior, and posterior regions. Being able to identify pertinent structures in the subdeltoid space will provide shoulder arthroscopists with the requisite foundation in core anatomy that will be required for challenging procedures such as arthroscopic subscapularis mobilization and repair, biceps tenodesis, subcoracoid decompression, suprascapular nerve decompression, quadrangular space decompression and repair of massive rotator cuff tears.

Magnetic resonance imaging in glenohumeral instability

The glenohumeral joint enables tremendous range of motion at the expense of stability. Functional stability is maintained by the synchronous coordination of complex static and dynamic structures. Symptomatic glenohumeral instability most often results from injury to the inferior labral-ligamentous complex, the primary passive stabilizer of the shoulder. This article reviews the structures important in glenohumeral stabilization and illustrates their normal appearances and the abnormalities associated with anterior, posterior, and multidirectional instability. These lesions are discussed in the context of therapeutic decision making.

Arthroscopic anatomy, variants, and pathologic findings in shoulder instability

Shoulder instability is a common diagnosis that often requires surgical treatment. A detailed knowledge of the shoulder anatomy and its stabilizing structures is of utmost importance for successful treatment of shoulder instabilities. Identifying anatomic variants (e.g., sublabral hole, meniscoid labrum, cordlike middle glenohumeral ligament, and Buford complex) and distinguishing them from pathologic findings may be especially difficult, as shown by the high interobserver variability. Over the last decade, basic research and arthroscopic surgery have improved our understanding of the shoulder anatomy and pathology. In the context of shoulder instability, injuries of the glenoid (bony Bankart), injuries of the glenoid labrum superiorly (SLAP) or anteroinferiorly (e.g., Bankart, anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), accompanying cartilage lesions (Hill-Sachs, glenolabral articular disruption), and rotator interval and pulley lesions, as well as signs of dynamic instability impingement (posterior-superior impingement, anterior-superior impingement) can be exactly diagnosed (magnetic resonance imaging with intra-articular gadolinium, arthroscopy) and treated (arthroscopy). Therefore the purpose of this article is to review the current literature concerning shoulder anatomy/pathology related to shoulder stability/instability to improve clinical diagnosis and surgical treatment of our patients.

Biceps pulley: normal anatomy and associated lesions at MR arthrography

The biceps pulley or "sling" is a capsuloligamentous complex that acts to stabilize the long head of the biceps tendon in the bicipital groove. The pulley complex is composed of the superior glenohumeral ligament, the coracohumeral ligament, and the distal attachment of the subscapularis tendon, and is located within the rotator interval between the anterior edge of the supraspinatus tendon and the superior edge of the subscapularis tendon. Because of its superior depiction of the capsular components, direct magnetic resonance arthrography is the imaging modality of choice for demonstrating both the normal anatomy and associated lesions of the biceps pulley. Oblique sagittal images and axial images obtained with a high image matrix are valuable for identifying individual components of the pulley system. Various pathologic processes occur in the biceps pulley as well as the rotator interval. These processes can be traumatic, degenerative, congenital, or secondary to injuries to the surrounding structures. The term hidden lesion refers to an injury of the biceps pulley mechanism and is derived from the difficulty in making clinical and arthroscopic identification. Pathologic conditions associated with pulley lesions include anterosuperior impingement, instability of the biceps tendon, biceps tendinopathy or tendinosis, superior labrum anterior and posterior lesions, and adhesive capsulitis. It is important to be familiar with the normal appearance of the biceps pulley so that abnormalities can be correctly assessed and effectively managed.

Multimedia article. The rotator interval: pathology and management

The rotator interval describes the anatomic space bounded by the subscapularis, supraspinatus, and coracoid. This space contains the coracohumeral and superior glenohumeral ligament, the biceps tendon, and anterior joint capsule. Although a definitive role of the rotator interval structures has not been established, it is apparent that they contribute to shoulder dysfunction. Contracture or scarring of rotator interval structures can manifest as adhesive capsulitis. It is typically managed nonsurgically with local injections and gentle shoulder therapy. Recalcitrant cases have been successfully managed with an arthroscopic interval release and manipulation. Conversely, laxity of rotator interval structures may contribute to glenohumeral instability. In some cases this can be managed with one of a number of arthroscopic interval closure techniques. Instability of the biceps tendon is often a direct result of damage to the rotator interval. Damage to the biceps pulley structures can lead to biceps tendon subluxation or dislocation depending on the structures injured. Although some authors describe reconstruction of this tissue sling, most recommend tenodesis or tenotomy if it is significantly damaged. Impingement between the coracoid and lesser humeral tuberosity is a relatively well-established, yet less common cause of anterior shoulder pain. It may also contribute to injury of the anterosuperior rotator cuff and rotator interval structures. Although radiographic indices are described, it appears intraoperative dynamic testing may be more helpful in substantiating the diagnosis. A high index of suspicion should be used in association with biceps pulley damage or anterosuperior rotator cuff tears. Coracoid impingement can be treated with either open or arthroscopic techniques. We review the anatomy and function of the rotator interval. The presentation, physical examination, imaging characteristics, and management strategies are discussed for various diagnoses attributable to the rotator interval. Our preferred methods for treatment of each lesion are also discussed.

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.

Anatomy of the superior glenohumeral ligament

BACKGROUND

The aim of the present study was to give a detailed, anatomical description of the superior glenohumeral ligament and its relationship with the neighbouring structures in the rotator interval.

METHOD

Twenty-seven cadaveric shoulder specimens were dissected in fine detail to describe superior glenohumeral ligament and additional histologic examination was performed.

RESULTS

The superior glenohumeral ligament is a constant, gross anatomic structure that was present in all of twenty-seven investigated specimens. The fibers of the superior glenohumeral ligament could be divided into two groups - the oblique and direct fibers. The direct fibers of the superior glenohumeral ligament arise from the glenoid labrum, run parallel with the tendon of the long head of the biceps brachii towards the lesser tubercle, which they also partly insert onto. The rest of the direct fibers course into the bottom of the bicipital groove and bridge over it, forming the superior part of the transverse humeral ligament. The oblique fibers arise from the supraglenoid tubercle, run over the intraarticular part of the tendon of the long head of the biceps brachii and insert below the coracohumeral ligament into the humeral semicircular ligament.

CONCLUSION

Due to its anatomic composition and tight connection with the neighboring articular structures, the superior glenohumeral ligament is involved in the stabilizing mechanisms of the intraarticular part of the tendon of the long head of the biceps brachii and plays an important role in the variety of clinical disorders that occur within the rotator interval.