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

Contribution of the Bony Bankart in Calculating Glenoid Bone Loss

Background

Determining the magnitude of glenoid bone loss in patients with anterior shoulder instability is an important step in guiding management. Most calculations to estimate the bone loss do not include the bony Bankart fragment. However, if it can be reduced and adequately fixed, the estimation of bone loss may be decreased.

Purpose

To derive a simple equation to calculate the surface area of the bony fragment in Bankart fractures.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 26 patients suspected of having clinically significant bone loss underwent computed tomography imaging preoperatively, and the percentage of glenoid bone loss (%BL) was approximated with imaging software using a freehand region of interest area measurement with and without the inclusion of the bony Bankart fragment. By assuming this bony fragment as a hemi-ellipse with height, H, and thickness, d, we represented the surface are of the bony piece (Abonefragment=πHd4), and subtracted it from the overall %BL. They compared this value with the one found using imaging software.

Results

Without the inclusion of the bony Bankart, the overall %BL by the standard true-fit circle measured using imaging software was 23.8% ± 9.7%. When including the bony Bankart, the glenoid %BL measured using imaging software was found to be 12.1% ± 8.5%. The %BL calculated by our equation with the bony Bankart included was 10% ± 11.1%. There was no statistically significant difference between the %BL values measured using the equation and the imaging software (P = .46).

Conclusion

Using a simple equation that approximates the bony Bankart fragment as a hemiellipse allowed for estimation of the glenoid bone loss, assuming that the fragment can be reduced and adequately fixed. This method may serve as a helpful tool in preoperative planning when there are considerations for incorporating the bony fragment in the repair.

Predictive Factors for Failure of Intraarticular Injection in Management of Adhesive Capsulitis of the Shoulder

Intraarticular (IA) corticosteroid injections have been demonstrated to be an effective management for adhesive capsulitis in both the short- and mid-term. Yet, certain patients fail to improve both subjectively and clinically. This study aims to identify predictive factors for treatment failure of IA injections in management of adhesive capsulitis. A retrospective review found 533 patients undergoing IA corticosteroid or IA NSAID injection for adhesive capsulitis between June 2015 and May 2020 at a single healthcare institution. Patient demographics characteristics, comorbidities, pain scores, and range of motion were compared. Treatment failure was defined as need for subsequent IA injection within 6 months or progression to surgical management within 12 months. 152 patients (28.52%) experienced treatment failure of IA corticosteroid injection. Pre-injection pain scores were greater for those who experienced treatment failure (5.40 vs. 4.21, p < 0.05). Post-injection pain scores were greater for those who experienced treatment failure (3.77 vs. 2.17, p < 0.01). Reduced post-injection external rotation in abduction also predicted treatment failure (56.88° vs. 70.22°, p < 0.01). IA corticosteroid injections are associated with increased rates of failure and progression to surgical management when patients present with increased pain levels as well as with less improvement in pain levels and ROM following injection.

Imaging Review of Subscapularis Tendon and Rotator Interval Pathology

As the largest rotator cuff muscle, the subscapularis plays a major role in stabilizing the glenohumeral joint, in conjunction with surrounding rotator cuff structures. Injury to the subscapularis tendon can be isolated, but more commonly is seen in conjunction with supraspinatus tendon pathology. Injury can be associated with biceps pulley instability, superior labral anterior-posterior (SLAP) tears, humeral head subluxation, and anterosuperior and coracoid impingements. The involvement of the rotator interval can lead to what is called “the hidden lesion,” due to its difficulty to diagnose during arthroscopy. Understanding the anatomical relations of the subscapularis tendon with the rest of the rotator cuff and rotator interval, as well as common patterns of injury that involve the subscapularis tendon, can aid in proper diagnosis of these injuries leading to prompt surgical repair. This review describes the anatomy of the subscapularis muscle and tendon, and the magnetic resonance imaging (MRI) patterns of subscapularis tendon injury.

Low grade of osteoarthritis development after Latarjet procedure with a minimum 5 years of follow-up: a systematic review and pooled analysis

PURPOSE

The purpose of this systematic review and pooled analysis was to evaluate incidence and risk factors for glenohumeral osteoarthritis (OA) in patients who underwent Latarjet procedure with a minimum of 5-year follow-up.

METHODS

The PRISMA guidelines were followed to perform this systematic review. PubMed and EMBASE were searched up to February 29, 2020 for English, human in vivo studies that evaluated glenohumeral OA in patients undergoing Latarjet procedure at least 5 years after surgery. A pooled analysis on the included databases sent by authors was performed to evaluate the risk factors influencing the development or progression of dislocation arthropathy after the Latarjet procedure.

RESULTS

Four studies, including a total of 280 patients (213 males and 67 females), were analysed. In our study population, the median age at surgery was 25.0 years (range 20.8-32.6 years). and 92.1% were athletes. In 90% of the cases, the number of dislocations before surgery were fewer than 5. The recurrence of instability after Latarjet procedure was observed only in seven patients (2.5%). The position of the bone graft resulted flush to the anterior glenoid rim in 238 cases (85.3%), medial in 8 (2.9%) and overhanging in 33 (11.8%). Radiological signs of development or progression of shoulder OA were observed in 25.8% of the patients, of which 88.6% presented a grade 1 of OA according to Samilson and Prieto classification. The overhanging position of the bone graft resulted statistically significant for onset or worsening of OA. The age at surgery, the number of dislocations before surgery and the Hill-Sachs lesion were not significantly associated with joint degeneration. Instead, hyperlaxity showed a prevention role in the development of OA after open Latarjet procedure.

CONCLUSION

The Latarjet procedure is a valid and safe surgical treatment in recurrent anterior shoulder instability with a low risk of developing moderate or severe OA also at long-term follow-up. The overhanging position of the bone graft represents the principal risk factor of joint degeneration, whereas the hyperlaxity seems to be protective. Finally, age, gender, time between first dislocation and surgery, and number of dislocations do not seem to affect the onset of OA after Latarjet procedure. Therefore, an accurate execution of the Latarjet procedure can be considered a valid treatment even in young and athletes thanks to the low recurrence rates and the low development of major long-term complications.

LEVEL OF EVIDENCE

IV.

Permeable spaces between glenohumeral ligaments as potential gateways for rapid regional anesthesia of the shoulder

Shoulder pain is a highly prevalent condition, often resulting in major life limitations, and requiring effective treatments. In this work, we explore the anatomical basis of a proposed approach to the regional anesthesia of the shoulder through a single injection under the subscapularis muscle. Bilateral experimental injections in shoulders from body donors (Radiolar ® and Methylene-Blue) under the subscapular muscle (n = 11) and cadaveric systematic dissections of other 35 shoulders from body donors were performed. Injectate spread was then qualitatively assessed. Long axis of permeable foramina in the anterior aspect of the shoulder joint capsule was measured in centimeters using a digital caliper. More than 40% of specimens had at least one permeable space (Weitbrech and/or Rouvière foramina) communicating the subscapular bursa and the articular space. We further demonstrate that an ultrasonography-guided injection under the subscapularis muscle allows the spread of the injectate through the anterior, inferior and posterodorsal walls of the articular capsule, the subacromial bursa, and the bicipital groove, as well as into the articular space for some injections. The odds of accidental intraarticular injection decrease when injecting with low volumes. This anatomical study provides a detailed description of foramina between glenohumeral ligaments. Furthermore, the data shown in this work supports, as a proof of concept, a safe alternative for rapid and specific blockade of terminal sensory branches innervating the shoulder joint capsule.

Arthroscopic Soft Tissue Stabilization With Selective Augmentations for Traumatic Anterior Shoulder Instability in Competitive Collision Athletes

BACKGROUND

Many surgeons prefer bony stabilization including Bristow or Latarjet procedures for shoulder instability in collision athletes, even though several potential complications have been reported. There has been a limited number of studies on the midterm outcomes of arthroscopic soft tissue stabilization for anterior shoulder instability in competitive collision athletes.

PURPOSE

To assess the outcomes of arthroscopic soft tissue stabilization in combination with selective augmentation procedures for collision athletes with traumatic anterior shoulder instability.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively assessed rugby or American football players (<40 years old) who underwent arthroscopic Bankart or bony Bankart repair with selective augmentations (rotator interval closure and/or Hill-Sachs remplissage) for traumatic anterior shoulder instability between January 2012 and March 2017. Shoulders that required other bony procedures were excluded. Recurrence, complications, return to sport, and functional scores (Rowe score and Subjective Shoulder Value sports score) were investigated.

RESULTS

This study included 113 shoulders in 100 patients with a mean age of 20 years (range, 15-36 years) at surgery. Rotator interval closure was performed on 36 shoulders in addition to Bankart repair, and rotator interval closure and Hill-Sachs remplissage were performed on 77 shoulders. The mean follow-up period was 44 months (range, 24-72 months). Of the 113 shoulders, 4 (3.5%) experienced postoperative dislocation, but there were no complications. A total of 93 athletes (93%) attained complete or near complete preinjury sports activity levels. The mean Rowe score significantly improved from 36 (range, 10-75) at presurgery to 96 (range, 35-100; P = .003) at postsurgery. The mean Subjective Shoulder Value sports score significantly improved after surgery, from a mean preoperative score of 22 (range, 0-50) to a postoperative score of 92 (range, 64-100; P = .002).

CONCLUSION

Our treatment strategy, where arthroscopic soft tissue stabilization was combined with selected augmentations, provided good clinical outcomes for competitive collision athletes in terms of low rates of recurrence and complication, a high rate of return to sports, and good shoulder function.

Medial Dislocation of the Long Head of the Biceps without Concomitant Subscapularis Tear: A Case Report

Introduction

Medial dislocation of the long head of the biceps tendon (LHBT) is classically known as a pathognomonic finding for a subscapularis or at least a rotator cuff (RC) injury. However, this case report outlines a young active individual with symptomatic medial dislocation of the long head of the biceps with associated posterior instability, without a corresponding RC injury.

Case Report

An 18-year-old male complained of the left shoulder pain and crepitus after a shoulder injury while playing hockey a year prior. Magnetic resonance imaging demonstrated medial dislocation of the LHBT without subscapularis or supraspinatus tendon injury. The patient complained of instability in the shoulder and exam findings supported posterior instability of the glenohumeral joint. Arthroscopic debridement of the glenohumeral joint with arthroscopic posterior capsulorrhaphy and open biceps tenodesis was performed. The patient regained full and painless range of motion at 2-year follow-up.

Conclusion

Medial dislocation of the LHBT can occur without injury to the subscapularis tendon. Furthermore, a capsulorrhaphy with open biceps tenodesis and closure of the rotator interval may provide a successful outcome for this rare injury pattern.

Capsular Injury and Inflammation

The capsular and ligamentous structures of the glenohumeral joint are important for stability of the shoulder. These structures are best evaluated by MR imaging. Familiarity with normal and abnormal appearance of the capsular structures of the shoulder is important to ensure that important pathology is not overlooked. Injury to the capsular structures can occur in the setting of trauma and most commonly involves the inferior glenohumeral ligament and axillary pouch. Adhesive capsulitis is a common inflammatory condition with characteristic imaging features that should be considered in the absence of alternative diagnoses.

Treatment of Adhesive Capsulitis of the Shoulder

Adhesive capsulitis presents clinically as limited, active and passive range of motion caused by the formation of adhesions of the glenohumeral joint capsule. Radiographically, it is thickening of the capsule and rotator interval. The pathology of the disease, and its classification, relates to inflammation and formation of extensive scar tissue. Risk factors include diabetes, hyperthyroidism, and previous cervical spine surgery. Nonsurgical management includes physical therapy, corticosteroid injections, extracorporeal shock wave therapy, calcitonin, ultrasonography-guided hydrodissection, and hyaluronic acid injections. Most patients will see complete resolution of symptoms with nonsurgical management, and there appears to be a role of early corticosteroid injection in shortening the overall duration of symptoms. Surgical intervention, including manipulation under anesthesia, arthroscopic capsular release both limited and circumferential, and the authors' technique are described in this article. Complications include fracture, glenoid and labral injuries, neurapraxia, and rotator cuff pathology. Postoperative care should always include early physical therapy.

Coracohumeral Ligament Reconstruction for Patients With Multidirectional Shoulder Instability

Coracohumeral ligament pathology arises from acute trauma, capsular thickening, or congenital connective tissue disorders within the glenohumeral joint. Recent studies have highlighted the significance of this pathology in multidirectional shoulder instability because insufficiency of the rotator interval has become increasingly recognized and attributed to failed shoulder stabilization procedures. The diagnosis and subsequent treatment of coracohumeral ligament pathology can be challenging, however, because patients usually present with a history of failed surgical stabilization and persistent laxity. At the time of presentation, most patients have undergone failed nonoperative treatments and are indicated for surgical intervention. One of the options for the treatment of coracohumeral ligament pathology is reconstruction. The purpose of this Technical Note is to describe our preferred surgical technique for the reconstruction of the coracohumeral ligament. Research was performed at the Steadman Philippon Research Institute.

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.

Glenoid and rotator interval dimension in patients older than 40 years after traumatic anterior shoulder dislocation

INTRODUCTION

The number of patients above 40 years suffering an anterior shoulder dislocation for the first time has recently increased. This study investigated the role of glenoid version, inclination and rotator interval dimension in patients older than 40 years with an anterior shoulder dislocation. We hypothesize that the rotator interval plays a more important role than the osseus alignment in older patients.

MATERIALS AND METHODS

Patients aged older than 40 years with a traumatic shoulder dislocation were compared with patients who had undergone magnetic resonance imaging (MRI) for a different reason. The MRIs of 61 dislocation group patients were compared with MRIs of 73 comparison group patients. Two shoulder surgeons measured glenoid version, inclination, height and width, rotator interval (RI) height, base (width) and area. The study and comparison group consisted of 61 patients with a mean age of 59 ± 9 years and 73 patients with a mean age of 57 ± 12, respectively.

RESULTS

The mean glenoid version of the dislocation group was - 4.9° ± 4.4° (retroversion) and mean inclination was 9.8° ± 8° (reclination). Mean rotator interval base, height and the rotator interval area was 46 ± 6 mm, 14 ± 5 mm and 33 ± 14 mm², respectively. The comparison group had a mean glenoid version of - 5.4° ± 5.4° and a mean inclination of 10.8° ± 6.2°. The rotator interval base was 41 ± 6 mm, the height was 16 ± 4 mm and the area was 34 ± 11 mm². The between-group differences were statistically significant for rotator interval height and base (p < 0.0001). A significant difference was revealed for the height-width ratio of the glenoid (p = 0.0001).

CONCLUSIONS

In patients older than 40 years who have suffered anterior shoulder dislocation, the shape of the glenoid rather than its spatial position is of significance. A wide and high rotator interval promotes anterior shoulder dislocation in these patients.

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.

Editorial Commentary: Rotator Interval Closure of the Shoulder Continues to Be a Challenge in Consensus on Treatment

In discussions of repair or plication of rotator interval capsular tissue and the respective surgical techniques, there is great variability in the procedures used to accomplish this, as well as a lack of consensus in defining rotator interval closure and the complex associated anatomy. The concept of rotator interval closure and how it is performed has shown wide variation and numerous definitions. In the future, it is recommended that one truly define what type of closure is performed, what tissues are imbricated, and where these tissues are imbricated, because both medial and lateral imbrications around the joint can have significant differences in terms of rotation, stability, and overall efficacy. Through this work, we can improve diagnostic capabilities, as well as examination capabilities, and better delineate the overall rotator interval closure procedure based on diagnostic and clinical findings. In this manner, we will be better able to define when rotator interval closure is necessary and most beneficial to patients. In our opinion, clinical indications for rotator interval closure are as follows: (1) multidirectional instability with increased capsular volume, (2) anterior instability-and especially a failed arthroscopic instability repair-that could benefit from imbrication of the coracohumeral ligament, (3) a sulcus that persists in external rotation in the setting of symptomatic instability, and (4) posterior instability with a multidirectional component.

What Are the Effects of Capsular Plication on Translational Laxity of the Glenohumeral Joint: A Study in Cadaveric Shoulders

BACKGROUND

Surgical treatment for shoulder instability generally involves labral repair with a capsular plication or imbrication. Good results are reported in both open and arthroscopic procedures, but there is no consensus on the amount or location of capsular plication that is needed to achieve stability and anatomic anterior, posterior, and inferior translation of the joint.

QUESTIONS/PURPOSES

(1) What are the separate and combined effects of increasing plication magnitude and sequential additive plications in the anterior, posterior, and inferior locations of the joint capsule on glenohumeral joint translation in the anterior, posterior, and inferior directions? (2) What plication location and magnitude restores anterior, posterior, and inferior translation to a baseline level?

METHODS

Fourteen cadaveric shoulders were dissected down to the glenohumeral capsule and underwent instrumented biomechanical testing. Each shoulder was loaded with 22 N in anterior, posterior, and inferior directions at 60° abduction and neutral rotation and flexion and the resulting translation were recorded. Testing was done over baseline (native), stretched (mechanically stretched capsule to imitate a lax capsule), and 5-mm, 10-mm, and 15-mm plication conditions. Individually, for each of the 5-, 10-, and 15-mm increments, plications were done in a fixed sequential order starting with anterior plication at the 3 o'clock position (Sequence I), then adding posterior plication at the 9 o'clock position (Sequence II), and then adding inferior plication at the 6 o'clock position (Sequence III). Each individual sequence was tested by placing 44 N (10 pounds) of manual force on the humerus directed in an anterior, posterior, and inferior direction to simulate clinical load and shift testing. The effect of plication magnitude and sequence on translation was tested with generalized estimating equation models. Translational differences between conditions were tested with paired t-tests.

RESULTS

Translational laxity was highest with creation of the lax condition, as expected. Increasing plication magnitude had a significant effect on all three directions of translation. Plication location sequence had a significant effect on anterior and posterior translation. An interaction effect between plication magnitude and sequence was significant in anterior and posterior translation. Laxity in all directions was most restricted with 15-mm plication in anterior, posterior, and inferior locations. For anterior translational laxity, at 10-mm and 15-mm plication, there was a progressive decrease in translation magnitude (10-mm plication anterior only: 0.46 mm, plus posterior: 0.29 mm, plus inferior, -0.12 mm; and for 15-mm anterior only: -0.53 mm, plus posterior: -1.00 mm, plus inferior: -1.66 mm). For posterior translational laxity, 10-mm and 15-mm plication also showed progressive decrease in magnitude (10-mm plication anterior only: 0.46 mm, plus posterior: -0.25 mm, plus inferior: -1.94; and for 15-mm anterior only: 0.14 mm, plus posterior: -1.54 mm, plus inferior: -3.66). For inferior translational laxity, tightening was observed only with magnitude of plication (anterior only at 5 mm: 0.31 mm, at 10 mm: -1.39, at 15 mm: -3.61) but not with additional plication points (adding posterior and inferior sequences). To restore laxity closest to baseline, 10-mm AP/inferior plication best restored anterior translation, 15-mm anterior plication best restored posterior translation, and 5 mm posterior with or without inferior plication best restored inferior translation.

CONCLUSIONS

Our results suggest that (1) a 10-mm plication in the anterior and posterior or anterior, posterior, and inferior positions may restore anterior translation closest to baseline; (2) 10-mm anterior and posterior or 15-mm anterior plications may restore posterior translation closest to baseline; and (3) 5-mm anterior and posterior or anterior, posterior, and inferior plications may restore inferior translation closest to baseline. Future studies using arthroscopic techniques for plication or open techniques via a true surgical approach might further characterize the effect of plication on glenohumeral translation.

CLINICAL RELEVANCE

This study found that specific combinations of plication magnitude and location can be used to restore glenohumeral translation from a lax capsular state to a native state. This information can be used to guide surgical technique based on an individual patient's degree and direction of capsular laxity. In vivo testing of glenohumeral translation before and after capsular plication will be needed to validate these cadaveric results.

Prevention and management of post-instability glenohumeral arthropathy

Post-instability arthropathy may commonly develop in high-risk patients with a history of recurrent glenohumeral instability, both with and without surgical stabilization. Classically related to anterior shoulder instability, the incidence and rates of arthritic progression may vary widely. Radiographic arthritic changes may be present in up to two-thirds of patients after primary Bankart repair and 30% after Latarjet procedure, with increasing rates associated with recurrent dislocation history, prominent implant position, non-anatomic reconstruction, and/or lateralized bone graft placement. However, the presence radiographic arthrosis does not predict poor patient-reported function. After exhausting conservative measures, both joint-preserving and arthroplasty surgical options may be considered depending on a combination of patient-specific and anatomic factors. Arthroscopic procedures are optimally indicated for individuals with focal disease and may yield superior symptomatic relief when combined with treatment of combined shoulder pathology. For more advanced secondary arthropathy, total shoulder arthroplasty remains the most reliable option, although the clinical outcomes, wear characteristics, and implant survivorship remains a concern among active, young patients.

Shoulder Problems Motivate Innovative Solutions

Shoulder arthroscopic and related surgeons may require expertise in use of the 70° arthroscope, biologic patch augmentation, repair of massive rotator cuff tears, the Latarjet procedure and related glenoid bone augmentation, and reverse total shoulder arthroplasty.