Variability of the capsular anatomy in the rotator interval region of the shoulder

Prevalence of the anterosuperior capsulolabral anatomical variations and their association with pathologies of the glenoid labrum: a systematic review and meta-analysis

PURPOSE

Differentiating the anatomical variations of the anterosuperior portion of the glenoid labrum from pathologies is important to avoid unnecessary iatrogenic complications resulting from inaccurate diagnosis. Additionally, the presence of several variations was reported to be conductive to lesions involving the glenoid labrum. Thus, the aim of this study was to state the prevalence rates of the sublabral recess, sublabral foramen, and the Buford complex, and to verify their association with labral lesions.

METHODS

Systematic search of electronic databases was conducted to gain potentially eligible literature. Suitable studies were selected in a two-round screening, and relevant data were subsequently extracted. Calculation of the pooled prevalence estimates, including sub-analyses on cohort size, study type, and geographical variance, was conducted. Pooled analysis of risk ratios (RR) was used to assess the conductive nature of the discussed variants to superior labrum anterior to posterior (SLAP) lesions.

RESULTS

The screening resulted in selection of 20 studies investigating the morphological features of the glenoid labrum, consisting of 7601 upper limbs. On the bases of random-effects meta-analysis the sublabral recess, sublabral foramen and Buford complex occur with a pooled prevalence of 57.2% (95% CI 30.0-84.4%), 13.5% (95% CI 8.2-18.9%), and 3.0% (95% CI 1.5-4.5), respectively. Moreover, individuals with Buford complex have RR 2.4 (95% CI 1.3-4.7) of developing SLAP lesions, especially type II (95.5%; 95% CI 86.1-100%), whereas such risk for sublabral recess and sublabral foramen was not statistically significant.

CONCLUSION

Morphological variants of the glenoid labrum posing diagnostic confusion are frequently observed. Gradually, the Buford complex may be a predisposing factor for sustaining a SLAP lesion.

The middle glenohumeral ligament: a classification based on arthroscopic evaluation

BACKGROUND

Although middle glenohumeral ligament (MGHL) variations have been shown in the literature, their clinical effect and relationship with intra-articular pathologies have yet to be revealed, except for the Buford complex. This study was designed to classify MGHL and to reveal its relationship with clinical pathologies.

METHODS

A total of 843 consecutive shoulder arthroscopies were evaluated retrospectively, and a classification system was proposed for MGHL with regard to its structure and its relation to the anterior labrum. The associations of each MGHL type with superior labrum anterior-posterior (SLAP) lesions, subscapularis tears, and anterior instability were investigated.

RESULTS

MGHL variations were grouped into 6 types according to the classification. A significant difference in favor of type 6 MGHL (Buford complex) was observed in the distribution of SLAP lesions (P < .001). There was no significant difference between MGHL types and the distribution of anterior instability history (P = .131) and subscapularis tears (P = .324).

CONCLUSION

SLAP lesions accompany type 6 MGHLs (Buford complex) significantly more frequently than other types. There is also a negative relation between the anterior instability and thicker MGHL variants.

The Buford complex: prevalence and relationship with labral pathologies

BACKGROUND

This study aimed to determine the prevalence of the Buford complex and to investigate its association with labral pathologies (superior labrum anterior-posterior [SLAP] lesion and anterior, posterior, or multidirectional instability) using a very large patient database. Furthermore, the prevalence of the Buford complex in patients without any labral pathology was also determined.

METHODS

A total of 3129 consecutive shoulder arthroscopy procedures were retrospectively evaluated for the presence of the Buford complex and coexisting labral pathologies. The relationships between the Buford complex and SLAP lesions, as well as instability, were evaluated statistically.

RESULTS

The Buford complex was observed in 83 shoulders (2.65%). SLAP lesions were significantly more frequent in patients with the Buford complex than in those without it (81.9% vs. 33.1%, P < .001) Shoulders with the Buford complex presented a lower frequency of anterior instability (10.8% vs. 19.3%, P = .052) and a higher frequency of posterior instability (1.2% vs. 0.9%, P = .789). The prevalence of the Buford complex in patients with and without labral pathologies was 4.6% and 0.3%, respectively (P < .001).

CONCLUSIONS

This study, to our knowledge, includes the largest cohort in the literature reporting the prevalence of the Buford complex (2.65%). In the 1461 patients without labral tears or multidirectional instability, the prevalence of the Buford complex was 0.3%. This result suggests that the real prevalence of the Buford complex might be lower than that reported previously. In addition to the aforementioned conclusions, the identification of the Buford complex should prompt a thorough evaluation for concomitant SLAP lesions.

[Research progress of indication and treatment of graft in shoulder superior capsular reconstruction for rotator cuff tear]

Objective

To review the research progress of indication and treatment of graft in shoulder superior capsular reconstruction (SCR) for rotator cuff tear (RCT).

Methods

The literature related to shoulder SCR in recent years was extensively reviewed, and the anatomy, biomechanics, surgical indications, and treatment of graft in SCR were summarized.

Results

Superior capsule plays a role as a functional complex with rotator cuff, ligament, and whole capsule. SCR can effectively restore the superior stability of the shoulder. The indications of SCR include the irreparable massive RCT, massive RCT combined with pseudoparalysis shoulder, medium/large RCT with severe degenerative rotator cuff tissue, and dual-layer RCT. In order to achieve a better healing of tendon-bone in graft and decrease the rate of long-term graft retearing, it is essential to select an appropriate thickness graft, fix the graft in right intensity, and get a better capsular continuity.

Conclusion

The technique of SCR advanced to SCR for reinforcement and it is indicated from substantial massive RCT to severe degeneration of rotator cuff tissue. Graft treatment is the key step for a successful SCR.

[Short-term effectiveness of arthroscopically capsular vertical mattress suturing for shoulder recurrent anterior dislocation combined with joint laxity]

Objective

To evaluate the short-term effectiveness of arthroscopically capsular vertical mattress suturing for shoulder recurrent anterior dislocation combined with joint laxity.

Methods

A retrospective analysis was performed on 6 shoulder recurrent anterior dislocation patients combined with joint laxity treated with arthroscopically capsular vertical mattress suturing between January 2017 and December 2018. There were 5 males and 1 female with an average age of 20.8 years (range, 19-24 years). The number of shoulder dislocation was 3-18 times, with an average of 9.5 times. The disease duration ranged from 2 to 60 months, with an average of 25.3 months. The preoperative Beighton score was 4-7, with an average of 5.8; the Instability Severity Index Score (ISIS) was 2-5, with an average of 3.5. There were 5 cases of simple Bankart injury and 1 case of bony Bankart injury. The range of motion of shoulder joint (including active flexion and lifting, external rotation, abduction and external rotation, and internal ratation) was recorded before operation and at last follow-up; Oxford shoulder instability score, Rowe shoulder instability score, and Simple Shoulder Test (SST) score were used to evaluate shoulder joint function before operation, at 6 months after operation, and at last follow-up, and complications were recorded.

Results

All patients were followed up 16-28 months (mean, 19.3 months). During the follow-up, all patients had satisfactory motor function, and no re-dislocation and postoperative neurovascular complications occurred. At last follow-up, the activities of active external rotation and abduction and external rotation were significantly improved when compared with those before operation ( P<0.05); the activities of active flexion and lifting and internal rotation were not limited before and after operation, and the difference was not significant ( P>0.05). The Oxford shoulder instability score, Rowe shoulder instability score, and SST score at 6 months after operation and at last follow-up were significantly improved when compared with those before operation ( P<0.05); there was no significant difference between at 6 months after operation and at last follow-up ( P>0.05).

Conclusion

The treatment of shoulder recurrent anterior dislocation combined with joint laxity by arthroscopically vertical matress suturing can achieve good short-term effectiveness.

Arthroscopic anatomy of the middle glenohumeral ligament. A series of 300 cases

PURPOSE

The anatomy of the middle glenohumeral ligament (MGHL) is seldomly described during arthroscopy. The aim of this study was to determine the arthroscopic variants concerning the anatomy of the MGHL.

METHODS

A prospective, observational, single-center study was conducted between June 2016 and June 2017. All patients undergoing a first-time arthroscopy of the shoulder and with no history of prior surgery or trauma of the same shoulder were consecutively enrolled. The variations of the MGHLs shape and of its glenoid and distal insertions were documented during surgery.

RESULTS

A total 300 patients were included. Surgeries included rotator cuff sutures, tenotomy/tenodesis of the long head of the biceps tendon (LHBT) and subacromial decompression in respectively 31%, 32.7% and 35.5% of cases. The MGHL was absent in 12% of cases, presented a flat structure in 72% of cases, a cord-like shape in 14% and a Buford complex was observed in 1%. Its glenoid insertion was located on the labrum between the superior (SGHL) and inferior (IGHL) in 43% of cases, presented a combined insertion with the LHBT in 7%, with the SGHL in 29% and with both the SGHL and LHBT in 9%. The distal insertion was located in 67% of cases on the subscapularis tendon (SCCT) or the capsule covering it, and on the humeral bone in 21%.

CONCLUSION

This study confirms and details the anatomic variants of the MGHL, notably describing the lesser-known variants of its distal insertion, yet arises the question of the exact nature and function of this so-called ligament.

Rotator cable and rotator interval: anatomy, biomechanics and clinical importance

The rotator cable and rotator interval are among the most recent topics of interest in current shoulder literature. Most of the research has been published in the last two decades and our understanding about the importance of these anatomical structures has improved with biomechanical studies, which changed the pre- and intra-operative approaches of shoulder surgeons to rotator cuff tears in symptomatic patients.

The rotator cable is a thick fibrous bundle that carries the applied forces to the rotator cuff like a ‘suspension bridge’. Tears including this weight-bearing bridge result in more symptoms. On the other hand, the rotator interval is more like a protective cover consisting of multiple layers of ligaments and the capsule rather than a single anatomical formation like the rotator cable.

Advances in our knowledge about the rotator interval demonstrate that even basic anatomical structures often have greater importance than we may have understood. Misdiagnosis of these two important structures may lead to persistent symptoms.

Furthermore, some distinct rotator cuff tear patterns can be associated with concomitant rotator interval injuries because of the anatomical proximity of these two anatomical regions. We summarize these two important structures from the aspect of anatomy, biomechanics, radiology and clinical importance in a review of the literature.

Cite this article: EFORT Open Rev 2019;4:56-62. DOI: 10.1302/2058-5241.4.170071.

Outcomes After Arthroscopic Rotator Interval Closure for Shoulder Instability: A Systematic Review

PURPOSE

(1) To systematically assess the clinical outcomes of arthroscopic rotator interval closure (RIC) procedures for shoulder instability and (2) to report the different technical descriptions and surgical indications for this procedure.

METHODS

Two independent reviewers searched 4 databases (PubMed, Embase, Web of Science, and Cochrane) from database inception until October 15, 2017. The inclusion criteria were studies that reported outcomes of shoulder stabilization using arthroscopic RIC as an isolated or adjunctive surgical procedure. The methodologic quality of studies was assessed with the Methodological Index for Non-Randomized Studies tool and Grading of Recommendations Assessment, Development and Evaluation system for randomized controlled trials.

RESULTS

Fifteen studies met our search criteria (524 patients). Of the studies, 12 were graded Level IV evidence; 2, Level III; and 1, Level II. Six different RIC technique descriptions were reported, with 2 studies not defining the details of the procedure. The most common method of RIC was arthroscopic plication of the superior glenohumeral ligament to the middle glenohumeral ligament (8 of 15 studies). The most commonly used patient-reported outcome measure was the Rowe score, with all studies reporting a minimum postoperative score of 80 points. The rate of return to preinjury level of sport ranged from 22% to 100%, and the postoperative redislocation rate ranged from 0% to 16%.

CONCLUSIONS

The indications for RIC were poorly reported, and the surgical techniques were inconsistent. Although most studies reported positive clinical results, the heterogeneity of outcome measures limited our ability to make definitive statements about which types of rotator interval capsular closure are warranted for select subgroups undergoing arthroscopic shoulder stabilization.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II through IV studies.

Arthroscopic anatomy of the middle glenohumeral ligament

PURPOSE

The middle glenohumeral ligament (MGHL) has seldom been studied and its function is unknown. The aim of this study was to describe its anatomical presentations.

METHODS

A prospective study was conducted of MGHL anatomy in 107 arthroscopies, with a description of its shape and superior and inferior insertion in the articular surface of the subscapularis tendon. The MGHL was investigated dynamically during internal rotation of the glenohumeral joint.

RESULTS

Sixty-three percent (68/107) of the MGHLs were found to be leaf-like, and 27% (28/107) cord-like, 5.5% (6/107) vestigial, and 2% (2/107) had several strands. The MGHL was absent for 2% of patients (2/107). The inferior insertion point of the MGHL was lateral, masked by the humeral head, in 34% of cases (36/105), intermediate, in front of the glenohumeral joint line, in 57% of cases (60/105), and medial, in front of the labrum, in 9% of cases (9/105). During internal rotation, 46% (48/105) of the MGHLs were observed to retract medially, the subscapularis tendon moving away from the anterior glenoid rim, while 54% (57/105) remained visible in front of the glenohumeral joint and came into contact with the articular surface of the subscapularis tendon.

CONCLUSIONS

The MGHL has many anatomical variations.

The Rotator Cuff and the Superior Capsule: Why We Need Both

Tears of the rotator cuff are frequent. An estimated 250,000 to 500,000 repairs are performed annually in the United States. Rotator cuff repairs have been successful despite fatty infiltration and atrophy of the rotator cuff muscles. Although the emphasis in rotator cuff repair has historically focused on re-establishing the tendon attachment, there is growing interest in and understanding of the role of the superior capsule. The superior capsule is attached to the undersurface of the supraspinatus and infraspinatus muscle-tendon units, and it resists superior translation of the humeral head. Herein, we propose that it is the defect in the superior capsule that is the "essential lesion" in a superior rotator cuff tear, as opposed to the defect in the rotator cuff itself. We propose that rotator cuff repair must restore the normal capsular anatomy to provide normal biomechanics of the joint and thus a positive clinical outcome.

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

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