Functional study of glenohumeral ligaments

Role of middle glenohumeral ligament in external shoulder rotation

Background

The middle glenohumeral ligament (MGHL) is one of the three ligaments that stabilize the anterior capsule of the shoulder. Recent work suggests that it inserts distally into the deep layer of the subscapularis tendon. The role of the MGHL remains debated. The hypothesis of this study was that the MGHL plays a significant functional role in limiting external rotation of the shoulder while allowing a wide range of motion through its distal insertion into the subscapularis rather than directly onto the humerus.

Methods

In a cadaveric study performed on 20 shoulders (10 subjects), the MGHL and the other anterior structures of the shoulder were successively cut according to a standardized protocol. At each stage, the external rotation range of the shoulder was measured with the arm at the side (ER 1) and in 90° abduction (ER 2) using a goniometer. After dissection, the structure of the MGHL and its distal insertion were analyzed.

Results

Cutting the MGHL led to significant increases in ER 1 but not in ER 2. Shoulder range of motion in ER 1 increased on average by 15 ± 5° (P < .001) after cutting the MGHL and by 21 ± 11° (P < .001) after subscapularis peel. The range of motion in ER 2 increased by 3 ± 4° (P = .048) after cutting the MGHL, by 4 ± 6° (P = .02) after subscapularis peel and by 25 ± 8° (P < .001) after cutting the inferior glenohumeral ligament. The MGHL was present in all dissected shoulders. It was leaf-like in 12 cases, cord-like in 6 cases and had a vestigial appearance in 2 cases. The distal insertion was in all cases in the deep layer of the subscapularis in a thickening of the anterior capsule in the superior part of the muscle, except for two cases in which the tendinous part of the subscapularis was also involved.

Conclusion

The MGHL limited shoulder external rotation by a similar amount as the subscapularis muscle. Further studies are required to understand the clinical relevance of these findings, notably for the treatment of shoulder stiffness.

Posterior Humeral Avulsion of the Glenohumeral Ligament: A Critical Analysis Review

➢

Posterior humeral avulsions of the inferior glenohumeral ligament represent an increasingly recognized but likely underdiagnosed source of posterior shoulder instability and pain.

➢

Injuries are commonly reported in athletic individuals who have sustained injury by either traumatic or atraumatic mechanisms; the ligament is most susceptible to injury with the shoulder in flexion, adduction, and internal rotation.

➢

Posterior humeral avulsions of the glenohumeral ligament often occur in the setting of concurrent injuries to the posterior or inferior labrum.

➢

Diagnosis is often challenging due to nonspecific symptoms and physical examination findings; a magnetic resonance arthrogram generally is utilized to identify avulsion from the humeral attachment; however, a definitive diagnosis is often made at the time of arthroscopic evaluation.

➢

In patients with persistent discomfort and limitations following nonoperative management, operative fixation, primarily utilizing arthroscopic techniques, can be performed to restore motion and glenohumeral stability.

Anatomical, functional and biomechanical review of the glenoid labrum

The glenohumeral joint is the most mobile joint in the human skeleton, supported by both active and passive stabilisers. As one of the passive stabilisers, the glenoid labrum has increasingly been recognised to play an important role in stability of the glenohumeral joint, acting to maintain intraarticular pressure, centralise the humeral head and contribute to concavity-compression stability. Several studies have investigated the macro- and micro-anatomical features of the labrum as well as its biomechanical function. However, in order to better understand the role of the labrum and its mechanics, a comprehensive anatomical, functional and biomechanical review of these studies is needed. Therefore, this article reviews the current literature detailing anatomical descriptions of the glenoid labrum, with an emphasis on its function(s) and biomechanics, as well as its interaction with neighbouring structures. The intimate relationship between the labrum and the surrounding structures was found to be important in glenohumeral stability, which owes further investigation into the microanatomy of labrum to better understand this relationship.

Humeral Avulsion of the Glenohumeral Ligament: Diagnosis and Management

»

The most common type of humeral avulsion of the glenohumeral ligament (HAGL) is a purely ligamentous avulsion involving the anterior inferior glenohumeral ligament (IGHL), but other variants are seen, including posterior lesions and those with an osseous avulsion.

»

A central lesion between the intact anterior and posterior bands of the IGHL is gaining recognition as a distinct clinical entity.

»

HAGL lesions are most commonly seen in patients with anterior instability without a Bankart tear or in those with persistent symptoms despite having undergone a Bankart repair.

»

Magnetic resonance imaging is the most sensitive imaging modality. An arthrogram is helpful with subacute and chronic lesions when the joint is not distended. Arthroscopy is the gold standard for diagnosis.

»

While some have reported success with nonoperative management, surgical repair with either arthroscopic or open techniques has provided a high rate of successful outcomes; however, the literature is limited to mostly Level-IV and V evidence.

An Arthroscopic Technique for Release of the Middle Glenohumeral Ligament and the Effect on External Rotation of the Shoulder

The middle glenohumeral ligament (MGHL) is well recognized as a primary stabilizer of the shoulder. Its role in shoulder pathologies such as adhesive capsulitis, subscapularis tendon tear, and glenohumeral arthritis is less understood. Biomechanically, the MGHL plays an important role in range of motion, specifically involving normal and pathologic external rotation in less than 45° of abduction. In this Technical Note, we present a technique for arthroscopic release of the MGHL in the setting of a stable shoulder with preoperative loss of external rotation and a patient at risk for postoperative restriction of external rotation.

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.

Surgical management of complex proximal humeral fractures: pinning, locked plate and arthroplasty : Clinical results and functional outcome on retrospective series of patients

PURPOSE

The aim of the study was to compare the clinical results and related complications of four different surgical treatments of complex proximal humeral fractures according to their classification and features of patients.

METHODS

Between 2007 and 2011, 92 consecutive patients with diagnosis of three-four-part displaced fractures, fractures with head dislocation and head-splitting fractures were evaluated postoperatively with Constant-Murley score, disability of arm, shoulder and hand score and simple shoulder test.

RESULTS

All the treatment modalities showed from optimal to good mean functional results. The statistical analysis comparing each treatment group showed better outcomes scores (p < 0.05) for: locked plating versus HA, locked plating versus RSA and RSA versus HA. No differences between postoperative range of motion, complication rate and overall revision rate of the treatment groups were found at the end of follow-up (p > 0.05). Overall complication rate of surgical treatment of complex PHF was 31.5% (29 patients) with overall revision rate of 14.1%. Among patients with complications 77.8% of HA (7 of 9) required revision surgery (p < 0.05).

CONCLUSIONS

The treatment of complex PHF is nowadays a challenge even for skilled shoulder surgeons. The several viable operative options give good results whenever used for the correct indication. The range of reported complications from 18.2 to 37.5% remains concerning, but most of them did not affect clinical outcome in this series. Accurate preoperative characterization of the fracture pattern is necessary, and high surgical skills of the different operative techniques, including arthroplasty, are recommended to meet the increased functional expectations of patients.

LEVEL OF EVIDENCE

Therapeutic series, Level IV.

Anterior glenohumeral instability: a pathology-based surgical treatment strategy

The glenohumeral joint is the most frequently dislocated major joint, and most cases involve an anterior dislocation. Young male athletes competing in contact sports are at especially high risk of recurrent instability. Surgical timing and selection of surgical technique continue to be debated. Full characterization of the injury requires an accurate history and physical examination. Diagnostic imaging assists in identifying the underlying anatomic lesions, which range from no discernible lesion to significant bone loss of the glenoid or humeral head and/or capsulolabral stretching or avulsion from the glenoid or humerus. Historically, open Bankart repair has been considered to be the standard method of managing capsulolabral injuries, but comparable results have been achieved with arthroscopic techniques. In the setting of anterior glenoid bone loss >20% of the articular surface, iliac crest bone grafting or coracoid transfer via the Bristow or Latarjet procedures has demonstrated satisfactory outcomes. Favorable results have been reported with bone grafting or remplissage for engaging Hill-Sachs lesions and those that affect >30% of the humeral circumference.