Dynamic capsuloligamentous anatomy of the glenohumeral joint

Though many anatomic and biomechanical studies have been performed to elucidate capsuloligamentous anatomy of the glenohumeral joint, no previous studies have evaluated capsuloligamentous anatomy during rotator cuff contraction. The purpose of this study was to define and document the orientation and interrelationship between the glenohumeral ligaments during simulated rotator cuff contraction. Six fresh cadaveric shoulders were arthroscoped to document and grade ligamentous anatomy. The superior and middle glenohumeral ligaments and the anterior and posterior bands of the inferior glenohumeral ligament complex were labeled by an arthroscopicassisted technique with a linked metallic bead system. Shoulders were then placed onto an experimental apparatus that simulated rotator cuff function through computer-controlled servo-hydrolic actuators attached to the rotator cuff and biceps by a clamp and cable-and-pulley system. Simulated rotator cuff action and manual placement allowed shoulders to be placed into three positions of rotation (neutral, internal, and external) in three positions of scapular plane abduction (0°, 45°, 90°). Anteroposterior and axillary lateral plane radiographs were taken in each position to document orientation of all four ligaments. Both the superior and middle glenohumeral ligaments were maximally lengthened in 0° and 45° abduction and external rotation and appeared to shorten in all positions of abduction. The anterior and posterior bands of the inferior glenohumeral ligament complex maintained a cruciate orientation in all positions of abduction in the anteroposterior plane, except at 90° abduction and external rotation, where they are parallel. This cruciate orientation is due to the different location of the glenoid origin and humeral insertion of each band and may allow reciprocal tightening of each during rotation. The glenohumeral capsule is composed of discreet ligaments that undergo large charges in orientation during rotation. The superior and middle glenohumeral ligaments appear to complement the inferior glenohumeral ligaments, with the former tightening in adduction and the latter tightening in abduction. This relationship permits the large range of motion normally seen in the glenohumeral joint.     

Anterior shoulder stability: Contributions of rotator cuff forces and the capsular ligaments in a cadaver model

The purpose of this study was to quantify in a biomechanical model the contributions to shoulder joint stability that are made by tensions in the four tendons of the rotator cuff and by static resistance of defined portions of the capsular ligaments. A materials testing machine was used to directly determine anterior joint laxity by measurement of the force required to produce a standard anterior subluxation. Shoulders were tested in external or neutral humeral rotation. Data were analyzed by multiway analysis of variance with regression analysis. This model simulated tensions in the rotator cuff musculature by applying static loads at the tendon insertion sites acting along the anatomic lines of action. A load in any of the cuff tendons resulted in a measurable and statistically significant contribution to anterior joint stability. The contributions between different tendons were not significantly different and did not depend on the humeral rotation (neutral or external). In neutral humeral rotation the superior and middle glenohumeral ligaments together function equally with the inferior glenohumeral ligament as primary stabilizers against anterior humeral translation. The posterior capsule is a secondary stabilizer. The external rotation of the abducted humerus increases anterior stability by more than doubling the stability contribution from the inferior glenohumeral ligament. The stability contribution from the posterior capsule is larger in external rotation than in neutral rotation but is still of secondary magnitude. In external rotation the stability contribution of the anterior capsule, including the superior glenohumeral ligament and the middle glenohumeral ligament, becomes insignificant. The model presented here simulates the combined effect of two major sources of shoulder stability. This versatile model permits the direct measurement of the contributions to anterior shoulder stability that are made by tensions in the rotator cuff tendons and by static resistance of defined capsular zones. The use of multiple regression analysis-a standard statistical technique but one relatively new to the orthopaedic literature-permits quantitative determination of the contribution of each independent variable to the dependent variable, shoulder stability.     

Arthroscopic rotator cuff interval capsular closure

Closure of the rotator cuff interval is an important component of open stabilization techniques in shoulder surgery. This study describes a technique in which the deep layer of the capsule within the rotator cuff interval is closed arthroscopically. The effect of closure of this capsule within the rotator cuff interval on glenohumeral motion also is quantified. Sutures were placed from the superior glenohumeral ligament to the middle glenohumeral ligament and tied intra-articularly in fresh-frozen cadaveric shoulders. Closure of the interval capsule resulted in statistically significant limitation of humeral elevation, external rotation, and extension. Arthroscopic closure of the deep layer of the rotator cuff interval capsule produced a visible superior shifting of the middle and inferior glenohumeral ligaments and imbricated the anterosuperior capsule of the shoulder. In addition, this procedure can be performed in conjunction with arthroscopic capsulolabral reconstruction.     

Incidence of False Positive Rotator Cuff Pathology in MRIs of Patients with Adhesive Capsulitis

The purpose of this study was to compare the incidence of presumed rotator cuff pathology based on radiologist and surgeon interpretation of preoperative magnetic resonance images (MRIs) with actual rotator cuff pathology found intraoperatively in patients undergoing arthroscopic capsular release for adhesive capsulitis.The medical records of 38 consecutive patients who underwent arthroscopic glenohumeral capsular release for adhesive capsulitis between September 2001 and May 2007 were retrospectively reviewed. Radiologist and surgeon predicted status of the rotator cuff by prospective MRI interpretation was compared to the actual status of the rotator cuff intraoperatively. Radiologists' preoperative MRI interpretations predicted a 57.9% incidence of rotator cuff pathology, while operative findings revealed a true incidence of only 13.2% (P<.0001). Radiologists accurately predicted the absence or presence of a rotator cuff tear in 19 of 38 cases (50%), compared to the surgeon, who correctly interpreted 29 of 38 MRIs (76.3%).Interpretations of shoulder MRIs in patients with adhesive capsulitis may provide misleading information regarding rotator cuff pathology. The actual findings of shoulder MRI scans may lead to the appearance of false rotator cuff pathology in this population, and a high percentage of false positive MRI reports of rotator cuff tears was observed in these patients. If MRI is chosen as a diagnostic adjunct in this patient population, careful consideration should be given to its interpretation to avoid unnecessary or possibly aggravating surgical intervention.     

The developmental anatomy of the neonatal glenohumeral joint

The embryologic development of the capsular ligaments, synovial lining, rotator cuff, and bony structures of the shoulder is incompletely understood. The purpose of this study is to report the gross and microscopic anatomy of the developing glenohumeral joint on the basis of dissections of fetal shoulder specimens. After Institutional Review Board approval from our hospital, 51 shoulders in 37 fetal specimens were obtained from cases of fetal demise. The gestation time of these specimens ranged from 9 to 40 weeks. The morphology of the capsule, labrum, and associated ligaments were studied by dissection under a dissecting microscope. High-resolution radiographs were made, and sections were processed for routine histology. There was noted to be minimal variation in the shape and slope of the acromion. The coracoid was much larger in relation to the shoulder than in the mature shoulder. The coracoacromial ligament was grossly evident at this stage of development, with distinct anterolateral and posteromedial bands in this ligament. The inferior glenohumeral ligament was seen as a prominent thickening in the capsule, whereas the middle and superior glenohumeral ligaments were thinner and more difficult to identify as distinct structures. Upon histologic examination, the inferior glenohumeral ligament was seen to consist of several layers of organized collagen fibers. The inferior glenohumeral ligament inserted into the labrum and margin of the glenoid. The capsule was much thinner in the region superior to the inferior glenohumeral ligament. A rotator interval capsular defect was often present, and the coracohumeral ligament was seen as a distinct structure as early as 15 weeks. A bare spot in the glenoid was not observed. This study indicates that some of the important functional elements of the structure of the mature human shoulder are present early in development, including the glenohumeral and coracohumeral ligaments. The coracoacromial ligament plays a significant role in the formation of the coracoacromial arch in the neonatal shoulder. The presence of a capsular rotator interval indicates that this aspect of capsular anatomy is congenital.     

Anterior glenohumeral stabilization factors: Progressive effects in a biomechanical model

The aim of this study was to evaluate the anterior stabilizing factors of the glenohumeral joint over a range of translations. The stabilizers examined included the capsular ligaments, the coracohumeral ligament, the rotator cuff muscles and the long head of the biceps. Simulated muscle forces were applied to eight shoulder specimens to produce 90° of total elevation of the arm in the scapular plane. Stability, defined as the force required to reach a specified subluxation, then was evaluated under varying configurations of capsule cuts, humeral rotation, and muscular loads. The overall force-displacement relationship of the subluxation was found to increase exponentially in external rotation to 239 N at 10 mm of displacement and to level off in neutral rotation to 172 N at 10 mm of displacement. Among the muscles, the biceps was the most important stabilizer in neutral rotation, providing more than 30 N of stabilization: the subscapularis provided the greatest degree of stabilization in external rotation, increasing to approximately 20 N. The subscapularis and supraspinatus were the most consistently important stabilizers in both types of rotation. In external rotation, the superior, middle, and inferior glenohumeral ligaments were the most effective ligamentous stabilizers, and all provided progressively more stabilization as higher displacements were reached. The stability provided by some of the ligaments reached nearly 50 N at 10 mm of displacement.     

Anatomy and function of the glenohumeral ligaments in anterior shoulder instability

The anatomy of the glenohumeral ligaments has been shown to be complex and variable and their function is highly dependent on the position of the humerus with respect to the glenoid. The superior glenohumeral ligament with the coracohumeral ligament was shown to be an important stabilizer in the inferior direction, even though the coracohumeral ligament is much more robust than the superior glenohumeral ligament. The middle glenohumeral ligament provides anterior stability at 45 degrees and 60 degrees abduction whereas the inferior glenohumeral ligament complex is the most important stabilizer against anteroinferior shoulder dislocation. Therefore, this component of the capsule is the most frequently injured structure. An appropriate surgical procedure to repair the inferior glenohumeral ligament complex after shoulder dislocation must be considered. In addition, a detached labrum can lead to recurrent anterior instability and a compromised inferior glenohumeral ligament complex. However, additional capsular injury usually is necessary to allow anterior dislocation.     

Editorial Commentary: Don't Let Cuff Tears With Adhesive Capsulitis Give You the Cold Shoulder

Despite vastly different rehabilitation goals, adhesive capsulitis and a rotator cuff tear of the shoulder can be treated concomitantly with good outcomes. In the face of adhesive capsulitis, rotator cuff tears can be safely repaired with manipulation under anesthesia and/or capsular release without a substantial increase in complication rates compared with patients undergoing rotator cuff repair alone. Adhesive capsulitis pathology causes the cuff to heal rapidly, and we recommend aggressive passive range of motion as part of a traditional but accelerated rehabilitation that can be monitored and thus adjusted on a case-by-case basis.     

Arthroscopic repair of partial-thickness rotator cuff tears and SLAP lesions in professional baseball players

Internal impingement is a primary cause of shoulder pain in throwers; however, instability, internal rotation deficit, scapula muscle dysfunction, and core muscle dysfunction are also important elements of the internal impingement process. Articular surface rotator cuff tears, posterior superior labrum tears, SLAP lesions, anterior capsular ligament attenuation, and posterior capsular ligament contracture are commonly seen in throwers. Each of these conditions must be recognized and appropriately treated to ensure the best possible outcome. There is little potential for spontaneous healing of rotator cuff tears and SLAP lesions after debridement.     

Editorial Commentary: If the Massive Rotator Cuff Tear is Irreparable,Just Fix the Rotator Cable

Large and massive rotator cuff tears are not always reparable and present a difficult clinical problem. If surgery is warranted surgical options range from arthroscopic debridement, partial repairs, degradable spacers, tendon transfers, and more superior capsular reconstruction. The rotator cable is formed by the deep layer of the coracohumeral ligament and the crescent structure running from the anterior insertion site of the supraspinatus to the inferior border of the infraspinatus. The role of the rotator cable is not clear but seems to play a role in reducing tendon stress and influence glenohumeral kinematics. In this laboratory-based cadaver study the anterior cable was reconstructed with semitendinosus allograft treating large “irreparable” rotator cuff defects. Reconstruction resulted in reduced superior migration and subacromial contact forces without inhibiting range of motion.     

Painful Shoulder After Surgery for Rotator Cuff Disease

Persistent shoulder pain after surgery for rotator cuff disease may be caused by conditions that are either extrinsic or intrinsic to the shoulder. Extrinsic causes of persistent shoulder pain include cervical radiculopathy, suprascapular neuropathy, abnormalities of scapular rotation (due to long-thoracic or spinal-accessory neuropathy), and adjacent or metastatic neoplasms. Causes of persistent pain that are intrinsic to the shoulder include both intra-articular conditions (e.g., glenohumeral osteoarthritis, adhesive capsulitis, recurrent anterior subluxation, and labral and bicipital tendon abnormalities) and extra-articular conditions (e.g., persistent subacromial impingement, persistent or recurrent rotator cuff defects, acromioclavicular arthropathy, and deltoid muscle deficiency). Successful management requires an accurate diagnosis, maximal rehabilitation, judicious use of surgical intervention, and a well-motivated patient. The results of revision surgery in patients with persistent subacromial impingement, with or without an intact cuff, are inferior to reported results after primary acromioplasty or rotator cuff repair.     

Intraarticular lesions in primary frozen shoulder after manipulation under general anesthesia

The aim of this study was to find intraarticular lesions after manipulation under general anesthesia in patients with primary frozen shoulder. In a prospective trial conducted between 2001 and 2003 in 30 patients with primary frozen shoulder, the affected shoulders were manipulated while the patients were under general anesthetia. Exclusion criteria were secondary stiffness caused by rotator cuff tears and glenohumeral arthritis. After manipulation, each patient was examined by arthroscopy, and any intraarticular lesions were documented. In all patients, during manipulation, a significant improvement in the range of motion was achieved. Under anesthesia, flexion improved on average from 70 degrees +/- 33 degrees to 180 degrees +/- 15 degrees, abduction from 50 degrees +/- 20 degrees to 170 degrees +/- 25 degrees, and external rotation from -5 degrees +/- 10 degrees to +40 degrees +/- 20 degrees. Arthroscopy revealed hemarthrosis in all patients after manipulation. In 22 patients, localized synovitis was detected in the area of the rotator interval, whereas in 8 patients, disseminated synovitis was observed as a feature of adhesive capsulitis. After manipulation, the capsule was seen to be ruptured superiorly in 11 patients, the anterior capsule was ruptured up to the infraglenoid pole in 24 patients, and 16 patients each had a capsular lesion located posteriorly. In 18 patients no additional joint damage was found after manipulation. In 4 patients, iatrogenic superior labrum anterior-posterior lesions were observed. Further injuries detected were 3 fresh partial tears of the subscapularis tendon, 4 anterior labral detachments (1 with a small osteochondral defect), and 2 tears of the middle glenohumeral ligament. Even though manipulation under anesthesia is effective in terms of joint mobilization, the method can cause iatrogenic intraarticular damage.     

关节镜下盂肱关节前方松解对原发性冻结肩的早期疗效

目的观察应用关节镜进行关节囊前方松解术对原发性冻结肩的治疗效果。 方法2015年3月至2017年3月陕西省人民医院收治的60例原发性冻结肩患者,所有患者经术前MRI检查或术中探查确诊,排除由其余肩部疾病(骨折、肩峰撞击、肩袖损伤、钙化性肌腱炎)引起的继发性冻结肩,所有患者应用关节镜行盂肱关节前方松解术。采集术前及术后的疼痛视觉评分(VAS)、Constant评分、复旦大学肩关节功能评分系统(FUSS),应用单因素重复测量方差分析对结果进行统计学分析评估,对肩关节各方向的被动活动度应用配对t检验方法进行统计学分析。 结果所有患者术后均未出现腋神经损伤或肩关节不稳等并发症。与术前相比,术后12周时患者的VAS评分[(0.7±0.6)vs (8.1±0.7),F ＝38.01]、Constant评分[(93.9±3.0)vs (34.2±3.4),F ＝121.42]及FUSS评分[(93.8±1.3)vs (40.1±2.2),F ＝220.09]差异有统计学意义(均为P <0.01);同时,与术前相比,患肩被动外展[(152±13)° vs (74±9)°,t ＝37.678]、前屈[(156±12)° vs (60±10)°,t ＝46.469]、体侧外旋[(66±11)° vs (8±3)°,t ＝37.762]及内旋在术后12周时明显改善(均为P <0.01)。 结论应用关节镜对盂肱关节囊前方结构进行彻底松解,可有效改善原发性冻结肩患者肩关节功能。     

Reconstruction of the antero-superior shoulder capsule with the subscapularis tendon: A case report

A 14-year-old boy presented with recurrent, anteroinferior, and multidirectional instability of his dominant shoulder. Examination with the patient under anesthesia demonstrated marked anterior and inferior translation when drawer testing was performed in adduction; however, abduction of the shoulder reduced the magnitude of humeral head translation in both these directions. Arthroscopy and open surgical dissection revealed the absence of any capsuloligamentous structures above the anterior band of the inferior glenohumeral ligament complex. This superior capsular defect could not be closed by a capsular shift procedure; therefore it was reconstructed with a portion of the subscapularis tendon. This case provides a clinical correlation of capsular anatomy with laxity on drawer testing. The glenohumeral laxity documented on examination with the patient under anesthesia supports experimental ligament-cutting studies that suggest the inferior glenohumeral ligament complex is the important stabilizer in abduction, whereas the superior and middle glenohumeral ligaments are more important in adduction.     

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.     

Anterior Cable Reconstruction: Prioritize Rotator Cable and Tendon Cord When Considering Superior Capsular Reconstruction

Although distinct in name, the anterior cable of the superior capsule and tendon cord of the supraspinatus are structurally one in the same at the attachment on the greater tuberosity footprint. Force transmission through both structures where they converge and interdigitate at this location is disproportionately high, which has implications on functional impact. Superior capsule reconstruction, and, specifically, the anterior cable of the superior capsule, has been shown to assist in maintaining superior stability and a functional fulcrum of the glenohumeral joint, without overconstraining range of motion. Anterior cable reconstructions have been described for specific indications, including full-thickness tears of the supraspinatus and anterior one-half of the infraspinatus. Cord-like grafts, including long head biceps tendon autografts and semitendinosus allografts, can provide relative technical ease during surgery compared to sheet-like grafts for this indication. Side-to-side sutures between anterior cable reconstruction graft and posterosuperior capsule retension the native capsule to optimize its natural functional role. Accounting for abduction and rotation at the time of fixation and employing “loop-around” fixation sutures (no sutures through the graft), are critical concepts to consider in terms of kinematics and limiting graft failure. With both the biomechanically and clinically based literature demonstrating functionality with maintenance of the superior capsule (and specifically the anterior cable of the capsule), despite rotator cuff tendon insufficiency or irreparability, the anterior cable of the superior capsule should be prioritized when considering full-thickness rotator cuff tears that naturally involve both the capsular cable and the supraspinatus tendon cord.Level of evidenceLevel V (expert opinion).     

盂肱关节不稳定的最新诊治进展

盂肱关节不稳是临床常见病、多发病,是限制人们上肢活动能力的疾病之一。该病的诊断不难,但对关节周围软组织损伤程度的评估却较难判断。随着核磁共振成像技术及关节镜检查的发展,MRA检查成为评估关节盂唇、关节囊、韧带等损伤的金标准。传统的手法复位虽快捷、简单,但常会造成肩袖损伤、韧带松弛、习惯性脱位等不良后果。开放手术可重建关节稳定性,却随着近年来出现的诸多新治疗方法,尤其是关节镜下重建术已逐渐替代开放性手术成为主流趋势,但对于关节囊缩紧术、肩袖间隙闭合术的远期疗效尚不明确,有待进一步跟踪观察。     

Arthroscopic glenohumeral folds and microscopic glenohumeral ligaments: the fasciculus obliquus is the missing link

This study tested the hypotheses that the folds in the inferior glenohumeral capsule appear at the borders and crossings of the underlying capsular ligaments and that embalming may result in misinterpretation of these folds as ligaments. The inferior capsular structures in 80 unembalmed cadaver shoulders were compared with 24 embalmed shoulders. During arthroscopy and dissection, an anteroinferior fold was more prominently seen in internal rotation and was almost obliterated in external rotation. A posteroinferior fold appeared in external rotation and almost disappeared in internal rotation. During dissection, the anteroinferior fold developed at the border of the anterior band of the inferior glenohumeral ligament (ABIGHL) and where this ligament crossed with the fasciculus obliquus (FO). Several patterns of crossing of the ABIGHL and the FO were seen that determined the folding-unfolding mechanism of the anteroinferior fold and the appearance of possible synovial recesses. The axillary part of the IGHL is formed by the FO on the glenoid side and by the ABIGHL on the humeral side. The posteroinferior fold was determined by the posterior band of the IGHL. The folds in the embalmed specimens did not necessarily correspond with the underlying fibrous structure of the capsule. The folds and recesses observed during arthroscopy indicate the underlying capsular ligaments but are not the ligaments themselves. The IGHL complex is formed by its anterior and posterior bands and also by the FO. Both findings are important during shoulder instability procedures because the ligaments need to be restored to their appropriate anatomy and tension. Because the FO may also be involved, Bankart-type surgery may have to reach far inferiorly. Midsubstance capsular shift procedures also need to incorporate this ligament.     

Functional study of glenohumeral ligaments

BackgroundThe glenohumeral ligaments are passive stabilising anatomical structures of the shoulder which, in synergy with the other active and passive stabilising structures, enable joint movement and cohesion. The purpose of this study is to analyse the isolated and synergic function of the glenohumeral ligaments by using a tetrapolar detection system with computer analysis.MethodsIn a study performed on cadavers after anatomical dissection, detector electrodes were positioned on the individual ligaments and recordings were made of bioelectric impedance and, consequently, the resistance, which is an indicator of the state of tension or relaxation of the ligamentous complex. Predefined positions of the upper limb were adopted—neutral adduction, adduction with external rotation, abduction at 45° with neutral and external rotation, and abduction at 90° with neutral and external rotation.ResultsThe superior glenohumeral ligament is important in stabilisation of the glenohumeral joint in adduction and external rotation. The middle glenohumeral ligament is an important stabilising structure in the positions of adduction and external rotation and abduction up to 45° in external rotation. The resistance, and therefore tension, of the inferior glenohumeral ligament, which is negligible in positions of neutral adduction and adduction in external rotation, increases in value for angles between 45° and 90°, indicating the important stabilising function of this ligament in those positions.ConclusionOur experimental study on cadavers, which involved evaluating the resistance of the glenohumeral ligaments by means of tetrapolar detection and computer analysis of the results, contributes to our knowledge of the functional activity of the anterior portion of the joint capsule.