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

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.

Management of Shoulder Instability in Patients with Underlying Hyperlaxity

PURPOSE OF REVIEW

Shoulder instability in patients with underlying joint hyperlaxity can be challenging to treat. Poorly defined terminology, heterogeneous treatments, and sparse reports on clinical outcomes impair the development of best practices in this patient population. This article provides a review of the current literature regarding optimal management of patients suffering from shoulder instability with concomitant hyperlaxity of the shoulder, from isolated shoulder joint hyperlaxity to congenital hypermobility spectrum disorders (HSD).

RECENT FINDINGS

Current research shows specialized physiotherapy protocols focused on strengthening of periscapular muscles and improvement of sensorimotor control are a promising non-surgical therapeutic avenue in certain patients, which can be augmented by device-based intervention in select cases. If surgical treatment is warranted, arthroscopic techniques such as pancapsular shift or plication continue to demonstrate favorable outcomes and are currently considered the benchmark for success. The long-term success of more recent innovations such as coracoid process transfers, conjoint tendon transfers, subscapularis tendon augmentation, and capsular reconstruction remains unproven. For patients affected by connective tissue disorders, treatment success is generally less predictable, and the entire array of non-operative and operative interventions needs to be considered to achieve the best patient-specific treatment results. In the treatment of shoulder instability and concomitant hyperlaxity, specialized physiotherapy protocols augmented by device-based interventions have emerged as powerful, non-operative treatment options for select patients. Successful surgical approaches have been demonstrated to comprehensively address capsular redundancy, labral lesions, and incompetence of additional passive stabilizers in a patient-specific fashion, respective of the underlying connective tissue constitution.

Anterior Bankart Repair With Superior Capsular Plication Causes Increased Mean Tension in Posterior Glenohumeral Capsule

Purpose

The purpose of this study is to investigate if a biomechanical difference exists in the prerepair and postrepair states of the posterior inferior glenohumeral ligament (PIGHL) following anterior Bankart repair with respect to capsular tension, labral height, and capsular shift.

Methods

In this study, 12 cadaveric shoulders were dissected to the glenohumeral capsule and disarticulated. The specimens were loaded to 5-mm displacement using a custom shoulder simulator, and measurements were taken for posterior capsular tension, labral height, and capsular shift. We measured the capsular tension, labral height, and capsular shift of the PIGHL in its native state and following repair of a simulated anterior Bankart lesion.

Results

We found that there was a significant increase in the mean capsular tension of the posterior inferior glenohumeral ligament (Δ = 2.12 ± 2.10 N; P = .005), as well as posterior capsular shift (Δ = .362 ± 0.365 mm; P = .018). There was no significant change in posterior labral height (Δ = 0.297 ± 0.667 mm; P = .193). These results demonstrate the sling effect of the inferior glenohumeral ligament.

Conclusion

Although the posterior inferior glenohumeral ligament is not directly manipulated during an anterior Bankart repair, when the anterior inferior glenohumeral ligament is plicated superiorly, some of the tension is transmitted to the posterior glenohumeral ligament as a result of the sling effect.

Clinical Relevance

Anterior Bankart repair with superior capsular plication results in an increased mean tension of the PIGHL. Clinically, this may contribute to shoulder stability.

Ability to Retension Knotless Suture Anchors: A Biomechanical Analysis of Simulated Bankart Lesions

Background:

Knotless suture anchors are gaining popularity in arthroscopic glenohumeral labral repairs. The ability to retension knotless designs after initial anchor placement has been reported; however, no studies have quantified this claim or investigated the biomechanical consequence of retensioning.

Purpose/Hypothesis:

To determine whether knotless and knotted suture anchors have biomechanical or anatomic differences with regard to labral repairs and to determine whether retensioning of knotless suture anchors affects capsular tension, labral height, and capsular shift. We hypothesized that retensioning of knotless anchors would result in improved capsular tension compared with conventional knotted suture anchors.

Study Design:

Controlled laboratory study.

Methods:

A total of 18 fresh-frozen cadaveric shoulders with a mean age of 56 years were dissected to the capsule and disarticulated at the humeral capsular insertion. The scapula was potted and placed in a custom shoulder simulator to tension the capsule via braided sutures localized to the anteroinferior glenohumeral ligament. Specimens were randomized into 3 groups: (1) Knotted (KT), (2) Knotless with end retensioning (KL_end), and (3) Knotless with stepwise retensioning (KL_stepwise). All repairs were completed using all-suture anchors placed at the 5-, 4-, and 3-o’clock positions. KL_stepwise was used to simulate an intraoperative technique. Resultant mean capsular tension under 5 mm of displacement (subfailure loading) was measured for each anchor placement and retensioning step. Labral height and capsular shift were measured using a MicroScribe digitizer.

Results:

The intact, defect, 1-anchor, 2-anchor, and 3-anchor tensions were not significantly different between the KT and KL_end groups. For the latter, retensioning of all knotless anchors increased capsular tension by 2.1 N compared with its 3-anchor state, although this was not statistically significant (P = .081). The KL_stepwise group explored an alternative method to retension the capsule using knotless anchors, with similar final capsular tensions compared with the other groups. All repairs had similar improvements in capsulolabral height and superior capsular shift.

Conclusion:

Knotted and knotless suture anchors provided similar overall restorations in anteroinferior glenohumeral ligament tension. However, knotless devices were capable of small but statistically insignificant improvements in capsular tension with retensioning.

Clinical Relevance:

Retensioning of knotless anchors allows the surgeon to tighten regions of the glenohumeral capsule that remain lax after repair.

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.

Arthroscopic Characterization, Treatment, and Outcomes of Glenoid Labral Articular Disruption Lesions

BACKGROUND

The pathoanatomy of glenoid labral articular disruption (GLAD) lesions has been inconsistently and poorly defined in the literature.

PURPOSE/HYPOTHESIS

The purpose was to characterize GLAD lesions as they pertain to the pathoanatomy of labrum, cartilage, and bony structures, and to correlate findings with patient-reported outcomes (PROs). We hypothesized that greater degrees of bony and cartilaginous involvement would correlate with worse outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All patients with a diagnosis of a GLAD lesion or a reverse GLAD (RGLAD) lesion at the time of diagnostic arthroscopy (January 2006-February 2019) were included in this study. Patients with ≥13.5% bone loss or previous ipsilateral shoulder surgery were excluded. Patient charts and operative reports/photos were used to identify the location of injury, extent of injury (labral, chondral, and bony), associated injuries, demographic factors, and treatment performed. Three injury patterns were identified: small (type 1), with no chondral defect after labral repair; large (type 2), with residual chondral defect after labral repair; and bony (type 3), with associated glenoid bone loss amenable to labral repair. Characterizations were cross-referenced to PROs at a mean follow-up of 5.5 years (range, 2.6-10.5 years): American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation, shortened version of Disabilities of the Arm, Shoulder and Hand, and patient satisfaction.

RESULTS

In total, 50 patients were included, with 40 having GLAD and 10 having RGLAD lesions (mean age, 34.7 and 33.2 years, respectively). There were 14 (35%) type 1, 22 (55%) type 2, and 4 (10%) type 3 GLAD injuries. All PROs improved without any differences in the 3 subgroups postoperatively (ASES, 95.1 vs 91.3 vs 98.8, type 1, 2, and 3, respectively). RGLAD injuries were majority type 2 (7/10; 70%) with the remainder being type 1 (3/10; 30%).

CONCLUSION

With GLAD and RGLAD injuries, 3 distinct injury patterns can be observed correlating with the presence/absence of chondral loss after labral repair or the presence of associated bone loss. This descriptive characterization can facilitate arthroscopic treatment decisions. Future large studies are needed to determine if this is prognostic in nature.

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.

Humeral Avulsion of the Glenohumeral Ligament: Diagnosis and Management

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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.

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

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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.

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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.

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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.