Anterior capsular redundancy of the shoulder: congenital or traumatic? An embryological study

The Arthroscopic Trillat Procedure Is a Valuable Treatment Option for Recurrent Anterior Instability in Young Athletes With Shoulder Hyperlaxity

PURPOSE

The purpose of this study is to report the outcomes of the all-arthroscopic Trillat procedure, combined with capsular plication, for the treatment of recurrent anterior instability in young athletes with shoulder hyperlaxity (external rotation >90°).

METHODS

We performed a retrospective evaluation of patients with recurrent anterior instability and shoulder hyperlaxity who underwent an arthroscopic Trillat between 2009 and 2019. Patients with concomitant rotator cuff lesions or voluntary or multidirectional instability were excluded. The osteotomized coracoid was fixed above the subscapularis with a cannulated screw or a suture button; a capsular plication was systematically associated. We followed patients with x-rays, computed tomography scans, and Subjective Shoulder Value, visual analog scale, Walch, Constant, and Rowe scores. Mean follow-up was 56 months (24-145).

RESULTS

Twenty-eight consecutive patients (30 shoulders) with a mean age of 25 years were identified, and all met criteria. The main finding under arthroscopy was a "loose shoulder" with anteroinferior capsular redundancy and no or few (10%) labrum tears, glenoid erosion (13%), or Hill-Sachs lesions (10%). At last follow-up, 90% of the shoulders (27/30) were stable, and 79% (19/24) of the patients practicing sports returned to their preinjury activity level. The Walch-Duplay and Rowe scores improved from 54 (38-68) to 81 (4-100) and 55 (30-71) to 84 (45-100), respectively, P < .001.

CONCLUSIONS

The arthroscopic Trillat is an effective procedure for the treatment of recurrent anterior instability in young athletes with shoulder hyperlaxity but no substantial humeral or glenoid bone loss, allowing return to overhead/contact sports.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Age-Related Changes of Elastic Fibers in Shoulder Capsule of Patients with Glenohumeral Instability: A Pilot Study

Background

Recurrent shoulder dislocations occur much more frequently in adolescents than in the older population but a clear explanation of this incidence does not exist. The aim of the present study was to define the age-related distribution of the elastic fibers (EFs) in the shoulder capsule's extracellular matrix as a factor influencing shoulder instability.

Materials and Methods

Biopsy specimens were obtained from the shoulder capsule of patients divided preoperatively into three groups: Group 1 consisted of 10 male patients undergoing surgery for unidirectional traumatic anterior instability (TUBS); Group 2 consisted of 10 male patients undergoing surgery for multidirectional instability (MDI); Group 3 represents the control, including 10 patients with no history of instability. In addition to the group as a whole, specific subgroups were analyzed separately on the basis of the age of subjects: > 22 or < to 22 years. All the samples were analyzed by histochemical (Weigert's resorcinol fuchsin and Verhoeff's iron hematoxylin), immunohistochemical (monoclonal antielastin antibody), and histomorphometric methods.

Results

Both the elastin density and the percentage of area covered by EFs were significantly higher in younger subjects (<22 years old). Furthermore, the elastin density and the percentage of area covered by EFs were significantly higher in specimens of group of patients affected by multidirectional shoulder instability in comparison to the other two groups.

Conclusion

Data of the present study confirmed the presence of an age-related distribution of EFs in the human shoulder capsule. The greater amount of EFs observed in younger subjects and in unstable shoulders could play an important role in predisposing the joint to first dislocation and recurrence.

Anatomy and Biomechanics of the Unstable Shoulder

PURPOSE

To review the anatomy of the shoulder joint and of the physiology of glenohumeral stability is essential to manage correctly shoulder instability.

METHODS

It was reviewed a large number of recently published research studies related to the shoulder instability that received a higher Level of Evidence grade.

RESULTS

It is reviewed the bony anatomy, the anatomy and function of the ligaments that act on this joint, the physiology and physiopathology of glenohumeral instability and the therapeutic implications of the injured structures.

CONCLUSION

This knowledge allows the surgeon to evaluate the possible causes of instability, to assess which are the structures that must be reconstructed and to decide which surgical technique must be performed.

Multidirectional Instability: Natural History and Evaluation

Background:

Multidirectional instability (MDI) represents a great challenge to the orthopedic surgeon. When treating these patients we must be aware that instability refers to a symptomatic situation, thus multidirectional instability is defined as symptomatic involuntary instability in two or more directions, and should be clearly differentiated from asymptomatic hyperlaxity.

It may be associated with hyperlaxity, either congenital or acquired following repetitive stress, but also may be present without hyperlaxity, which is rare.

Methods:

We searched in the online data bases and reviewed the relevant published literature available.

Results:

Many differences can be seen in the current literature when identifying these patients, unclear definitions and criteria to be included in this patient group are common.

Conclusion:

Understanding the complex shoulder biomechanics as well as being aware of the typical clinical features and the key examination signs, which we review in this article, is of paramount importance in order to identify and classify these patients, allowing the best treatment option to be offered to each patient.

Diagnosis and treatment of anteroinferior capsular redundancy associated with anterior shoulder instability using an open Latarjet procedure and capsulorrhaphy

PURPOSE

There is a paucity of data detailing management of anterior capsular redundancy (ACR) when using the Latarjet procedure for unidirectional instability. This study aimed to describe the surgical management and to assess the clinical profile of patients presenting with anterior capsular redundancy [ACR(+)] with anterior shoulder instability.

METHODS

Seventy-seven patients who had a Latarjet procedure were followed for a 55-month period. Per-operative ACR was assessed during surgery. ACR was considered present if the inferior capsular flap of a Neer T-shaft capsulorrhaphy was able to cover the superior capsular flap with the arm in the neutral position. Patients with ACR(+) received an additional Neer capsulorrhaphy, while patients with ACR(-) did not. This per-operative finding was correlated with demographics, clinical, radiological pre-operative data and surgical outcome.

RESULTS

Patients presenting with a per-operative ACR(+) were significantly associated with a sulcus sign (P < 0.001), a Beighton score >4 (P < 0.01), a low-energy instability history (P < 0.05), a predominant history of subluxations (P < 0.05), fewer Hill-Sachs lesion (P < 0.05) and a female gender (P < 0.05), but not significantly with external rotation >85°. Open standard Latarjet procedures with Neer capsulorrhaphy in ACR(+) patients showed excellent or good results and stability rate of 95 %. All patients except four who presented with a new dislocation after surgery were satisfied with their outcome. Thirteen patients (16 %) had a persistent apprehension sign at the last follow-up. ACR(+) and ACR(-) groups did not show significant difference in the mean values of Rowe, Walch-Duplay and Constant-Murley scores.

CONCLUSION

ACR correlated with a sulcus sign, Beighton score and instability history. In anterior shoulder instability associated with ACR, the Latarjet procedure with a Neer capsulorrhaphy appears a satisfactory treatment alternative to arthroscopic or open capsular shift. It decreased apprehension in comparison with Latarjet procedures without capsular repair.

LEVEL OF EVIDENCE

Cases series, treatment study, Level IV.

Anatomy of the capsulolabral complex and rotator interval related to glenohumeral instability

The glenohumeral joint with instability is a common diagnosis that often requires surgery. The aim of this review was to present an overview of the anatomy of the glenohumeral joint with emphasis on instability based on the current literature and to describe the detailed anatomy and anatomical variants of the glenohumeral joint associated with anterior and posterior shoulder instability. A review was performed using PubMed/MEDLINE using key words: Search terms were "glenohumeral", "shoulder instability", "cadaver", "rotator interval", "anatomy", and "anatomical study". During the last decade, the interest in both arthroscopic repair techniques and surgical anatomy of the glenohumeral ligament (superior, middle, and inferior), labrum, and rotator interval has increased. Understanding of the rotator interval and attachment of the inferior glenohumeral ligament on the glenoid or humeral head have evolved significantly. The knowledge of the detailed anatomy and anatomical variations is essential for the surgeon in order to understand the pathology, make a correct diagnosis of instability, and select proper treatment options. Proper understanding of anatomical variants can help us avoid misdiagnosis. Level of evidence V.

Quantitative analysis of attachment of the labrum to the glenoid fossa: a cadaveric study

PURPOSE

This study investigated the direct and continuous attachment of the labrum to the glenoid fossa, including the fibrocartilaginous tissue, using image-analysis software and histology.

METHODS

Twenty-six cadaveric shoulders (11 male, 15 female; mean age 80.1 years; age range 36-103 years) were used. The glenoid of each specimen was divided into six pie-slice-shaped pieces from the center perpendicular to the articular surface by radial incisions at the 2, 4, 6, 8, 10, and 12 o'clock positions. The general distribution of the labrum, including the fibrocartilage, was assessed in hematoxylin and eosin-, Safranin O- and Azan-Mallory-stained sections. The continuous length of attachment of the labrum to the glenoid was measured using image-analysis software. The width of attachment to the articular surface of the glenoid was assessed in each position.

RESULTS

The labrum attached to both the articular surface and the neck of the glenoid in all shoulders (100 %) in the 4 and 6 o'clock positions. The mean length of the entire attachment to the glenoid was 4.6 mm (range 3.2-6.1 mm). The width of attachment from the bony edge of the glenoid to the edge of the labrum on the articular surface ranged from 0 to 4.3 mm. The length of the entire attachment of the labrum was shortest in the 2 o'clock position (p = 0.229). Additionally, the length of the entire attachment of the labrum was longest in the 4 o'clock position. The width of attachment to the articular surface of the glenoid was greatest in the 4 o'clock position (p < 0.01).

CONCLUSION

In the 4 and 6 o'clock positions, the labrum attached to both the articular surface and neck of the glenoid in all of the shoulders (100 %). The length of the entire attachment to the labrum, including the fibrocartilage, was shortest in the 2 o'clock position. The width of attachment to the articular surface of the glenoid was greatest in the 4 o'clock position (p < 0.01).

Multidirectional instability of the shoulder: biomechanics, clinical presentation, and treatment strategies

Multidirectional instability (MDI) of the shoulder is a condition where the dislocation occurs in more than one direction with minimal or no causative trauma. Its pathoanatomy is complex and characterized by a redundant capsule, resulting in increased glenohumeral joint volume. The fact that several further factors may contribute to symptom onset complicates the diagnosis and hampers the identification of a therapeutic approach suitable for all cases. There is general agreement that the initial treatment should be conservative and that surgery should be reserved for patients who have not responded to an ad hoc rehabilitation program. We review the biomechanics, clinical presentation, and treatment strategies of shoulder MDI.

Attachment of the anteroinferior glenohumeral ligament-labrum complex to the glenoid: an anatomic study

PURPOSE

To determine the morphology of the attachment of the anteroinferior glenohumeral ligament-labrum complex (AIGHL-LC) to the anterior rim of the glenoid.

METHODS

Sixty-six cadaveric shoulders with a mean age of 81 years were studied. The length of the AIGHL-LC attachment in the superoinferior direction and its depth in the mediolateral direction at the 2-, 3-, 4-, and 5-o'clock positions were measured. The radial histologic sections from the center of the glenoid at the 2- and 4-o'clock positions were used for histologic examinations.

RESULTS

The mean length of the AIGHL-LC attachment was 11.7 mm. The mean depth was 4.7 mm (1.6 mm on the articular cartilage and 3.0 mm on the glenoid neck) at the 2-o'clock position, 6.7 mm (2.4 mm and 4.3 mm, respectively) at the 3-o'clock position, 8.4 mm (3.0 mm and 5.4 mm, respectively) at the 4-o'clock position, and 6.8 mm (2.5 mm and 4.3 mm, respectively) at the 5-o'clock position. The depth of the AIGHL-LC attachment was the greatest at the 4-o'clock position (P < .01) and the smallest at the 2-o'clock position (P < .05). Histologically, the AIGHL-LC attached to both the cartilage and bone in 52 shoulders (86.7%) at the 2-o'clock position and in 53 shoulders (88.3%) at the 4-o'clock position.

CONCLUSIONS

The depth of the AIGHL-LC attachment was the greatest at the 4-o'clock position and the smallest at the 2-o'clock position. At the 4-o'clock position, the AIGHL-LC attaches to both the articular cartilage and bone in 88% of shoulders whereas it attaches only to bone in 12%.

CLINICAL RELEVANCE

This study provides fundamental information on the AIGHL-LC attachment. Because healing of the AIGHL-LC to the articular cartilage cannot be expected, the same attachment area as to the bone and cartilage observed in normal shoulders needs to be created on the glenoid neck during Bankart repair to obtain the physiological strength of the AIGHL-LC.

Sequelae of an undiagnosed unilateral congenital fixed anterior shoulder dislocation in a 40-year-old female

Congenital shoulder dislocation is a rare condition. A review of the literature showed that 0.018-0.07% of newborns suffer from shoulder dislocations. There have been only few reports about this entity, clinic and radiologic features, treatment, and etiology of this condition remains unclear. We report a case of undiagnosed unilateral congenital fixed anterior shoulder dislocation in a 40-year-old female, which affected the day quality of life. Pediatrists and orthopaedic surgeons should know this rare condition and the importance of a proper diagnosis in the early childhood when an appropriate treatment could be performed.

An analysis of capsular area in patients with anterior, posterior, and multidirectional shoulder instability

BACKGROUND

Although increased capsular volume has been implicated in shoulder instability, there is a paucity of clinical evidence to quantify the size of the capsule with specific instability conditions of the shoulder.

HYPOTHESIS

Shoulder capsular area, as measured by magnetic resonance arthrography, is increased with specific patterns of shoulder instability.

STUDY DESIGN

Cross-sectional study; Level of evidence, 4.

METHODS

During an 8-month period, all patients with a diagnosis of anterior (n = 19), posterior (n = 14), or multidirectional (n = 13) instability of the shoulder and who were assessed with a magnetic resonance arthrogram were reviewed. A group of 10 control patients without clinical instability were also identified. The magnetic resonance arthrograms of all groups were randomly mixed, and 5 reviewers recorded measures of capsular length and area and determined labral abnormalities. The magnetic resonance arthrogram measurements were compared between groups, and interobserver agreement was determined.

RESULTS

The cross-sectional area of the capsule was increased in patients with posterior (P = .017) or multidirectional instability (P = .021) versus controls, but not in patients with anterior instability. Additionally, the posteroinferior cross-sectional area was increased in patients with posterior (P = .001), multidirectional (P = .003), and anterior (P = .008) instability. In patients with a posterior labral tear, the mean axial (P = .043) and mean posteroinferior sagittal cross-sectional area (P = .011) was increased, but there were no differences in cross-sectional area for those with an anterior labral tear. The overall interobserver reliability was very good (correlation coefficient range, 0.68-0.94).

CONCLUSION

Our results reinforce the concept that capsular elongation and laxity, either preexisting or acquired, play a role in certain instability conditions of the shoulder. Additional work is needed to determine how to correlate surgical decision making with the cross-sectional area measurements demonstrated in this study.

Arthroscopie de l'épaule, installation, voies d'abord et exploration normale

Arthroscopy has been established as a valuable technique in diagnosis and treatment of the injured and deseased shoulder. Arthroscopy is not a new diagnostic tool but offers new approaches to the surgical treatment of shoulder pathology. Shoulder arthroscopy is usally performed under general anesthesia or/with scalene block. The patient is positioned in opposite lateral decubitus position or in beach chair position. Diagnostic arthroscopic is initiated with insertion of the arthroscope from the posterior portal into the gleno humeral joint. Inspection should be organized systematic visualization of the entire joint (articular surfaces of the glenoid and humeral head, glenoid labrum, long head of the biceps tendon, sub scapularis tendon, axillary pouch, capsular ligaments, synovial membrane). Then endoscopic visualization of the subacromail space is a valuable and essential adjunct to the gleno humeral arthroscopy (impingement syndrome, rotator cuff tears, calcific tendinitis, acromio-calvicular joint disorders).

Posttraumatic anterior-inferior instability of the shoulder: arthroscopic findings and clinical correlations

INTRODUCTION

The main purpose of our study was to evaluate intra-articular lesions in glenohumeral-instability with arthroscopy and correlate them with clinical findings as well as history of instability.

MATERIAL AND METHODS

In this prospective multi-centre study, we evaluated arthroscopic findings in 303 patients with posttraumatic anterior-inferior instability of the shoulder. The study cohort was divided into 2 groups: patients with a history of one dislocation (Group 1, n=61, 20.1%) and patients with a history of more than one dislocation (Group 2, n=242, 79.9%).

RESULTS

In Group 1, 37 patients had an IGHL-lesion, 31 a MGHL-lesion and 41 a Hill-Sachs lesion. In Group 2, 182 patients had an IGHL-lesion, 172 a MGHL-lesion and 203 a Hill-Sachs lesion. The percentage of lesions in Group 2 (IGHL-75.2%, MGHL-71.1%, Hill-Sachs-83.9%) was significantly higher than in Group 1 (IGHL-60.7%, MGHL-50.8%, Hill-Sachs-67.2%, P=0.0233, P=0.0026, and P=0.0033, respectively). Within Group 2 we found significantly more Hill-Sachs-lesions with a history of an increasing number of recurrences (P=0.0436). We also found an increase of IGHL- and MGHL-lesions with an increasing number of recurrences, but this difference was not significant. The distribution of lesion types of the anterior labrum-ligament complex showed no significant difference between the two groups, apart from a higher incidence of ALPSA-lesions within Group 2 (34.7% versus 18.0% in Group 1). The results of this study show that recurrences after primary posttraumatic anterior-inferior shoulder dislocation cause increasing ligamental damage as well as increasing Hill-Sachs lesions within the gleno-humeral joint.

CONCLUSION

Thus we conclude that early surgical stabilization after posttraumatic anterior-inferior shoulder dislocation is necessary to prevent increasing damage within the shoulder joint.

Intraarticular lesions in traumatic anterior shoulder instability: a study based on the results of diagnostic imaging

BACKGROUND

Diagnostics of intraarticular lesions is important in the treatment of traumatic anterior shoulder instability.

PATIENTS AND METHODS

We studied 30 patients: 26 men and 4 women. For all patients preoperative examinations involved arthrography, CT arthrography, MR arthrography, and 3D-CT.

RESULTS

The articular capsule adhered to the margin of the glenoid in only 3 cases. In the remaining 27 patients, the joint capsule was detached, showing medial translation. Hill-Sachs lesions were present in 24 cases. Bankart lesions were detected in all cases, and they extended over 2-5 h. Osseous Bankart lesions were detected in 13 cases. MR arthrography revealed the articular labrum in all cases, but AIGHL in only 16 cases. Bankart lesions were found in all cases. When the patients were divided according to the frequency of dislocation, there was a correlation between both distance of the detached joint capsule and visualization of AIGHL and the frequency of dislocation.

INTERPRETATION

From this study, the frequency of dislocation was higher in the patients with severe detachment of the joint capsule, in whom AIGHL could not be visualized by MR arthrography.

Attachment types of the long head of the biceps tendon to the glenoid labrum and their relationships with the glenohumeral ligaments

PURPOSE

To clarify the attachment types of the long head of the biceps tendon to the glenoid labrum and their relationships with the glenoid attachment of the glenohumeral ligaments. TYPES OF STUDY: Anatomic study in cadavers.

METHODS

Using 101 cadaver shoulders, the glenoid attachment types of the biceps tendon and the location of the glenoid origin of the glenohumeral ligaments were assessed macroscopically and then histologically on the sagittal section.

RESULTS

The glenoid attachment types of the biceps tendon were defined as entirely-posterior in 28 shoulders (27.7%), posterior-dominant in 56 shoulders (55.4%), equal in 17 shoulders (16.8%), and entirely anterior in none (0%). In all shoulders, the superior and middle glenohumeral ligaments were attached between 12 and 1 o'clock (average, 12:36 o'clock), whereas the inferior glenohumeral ligament (IGHL) showed greater variation. In the posterior-dominant and equal types, the IGHL was attached relatively high (average 2:49 o'clock for the posterior-dominant type and 1:49 o'clock for the equal type). In the entirely posterior type, the IGHL was attached low, between 4 and 5 o'clock (average, 4:32 o'clock). There was a significant difference between them (P < .001). Histologic examination showed that in the posterior-dominant and equal types, the fibers of the IGHL directly linked to the fibers of the biceps tendon, whereas in the entirely posterior type no such direct connections were observed. However, in all types, the fibers of the biceps tendon were attached to the posterior labrum.

CONCLUSIONS

The labral attachment of the long head of biceps tendon was posterior regardless of its macroscopic appearance. The macroscopic attachment pattern of the biceps tendon resulted from the different attachment height of the IGHL. The attachment site of the IGHL is lower than 4 o'clock in the entirely posterior type, whereas it is higher than 4 o'clock in other types.

CLINICAL RELEVANCE

The present study provides useful information about the original attachment site of the IGHL during Bankart repair.

Arthroscopic study of the shoulder joint in fetuses

PURPOSE

The purpose of this study was to macroscopically examine the fetal shoulder joint using arthroscopy. We attempted to identify and describe the specific characteristics of the fetal shoulder joint, how it evolves during the last few weeks of intrauterine development, and any possible variations with regard to the adult shoulder.

TYPE OF STUDY

Observational anatomic case series.

METHODS

We used 20 frozen fetuses with a gestational age of 24 to 40 +/- 2 weeks, obtained from spontaneous abortions. Examination was performed with standard arthroscopic surgical equipment, using a 2.7-mm optical lens. Whenever possible, we tried to use the standard arthroscopic portals. Images were obtained for comparison with the adult shoulder.

RESULTS

The arthroscopic images of the fetal glenohumeral joint are similar to those of an adult shoulder, with the only differences being those related to the stage of development. In this study we observed no so-called bare spot in the glenoid cavity such as has been described in treatises on the adult shoulder joint. The arthroscopic images of the anterosuperior region of the fetal joint show more highly defined structures than in the adult shoulder, especially the coracohumeral and glenohumeral ligaments.

CONCLUSIONS

To our knowledge, this is the first arthroscopic study to target the fetal shoulder joint. The results indicate minimal differences when compared with the adult shoulder joint; for some structures, particularly in the anterosuperior region, the anatomy observed was easier to discern than what is observed in adult shoulder arthroscopy.

CLINICAL RELEVANCE

Our study obtained clear images of virgin shoulder joints that had never been subjected to deterioration from wear or other distorting forces. The clarity of these images is useful for locating and identifying structures in the adult shoulder.

Reconciling arthroscopic and anatomic morphology of the humeral insertion of the inferior glenohumeral ligament

PURPOSE

To clarify the morphology of the humeral insertion of the inferior glenohumeral ligament (IGHL).

TYPE OF STUDY

Cadaveric and arthroscopic anatomic analysis.

METHODS

The morphology of the humeral insertion was studied in 200 nonembalmed cadavers through open dissection (100 specimens), by arthroscopy (50 specimens), or both (50 specimens). In addition, the morphology was studied in 100 living subjects with stable shoulders undergoing shoulder arthroscopy.

RESULTS

On the humeral side, the insertion of the inferior capsular fibers is usually in the form of a V, the point of which is covered by the tendon of the latissimus dorsi. When viewed intra-articularly, the inferior insertion usually gives a collar-like impression because the capsular recess is filled with frenula capsulae.

CONCLUSIONS

Our description corresponds with that found in the classic literature. Our results are, however, in contrast with those of others who have observed about 50% of V-shaped insertions. This difference may be explained by the method of observation and by the small numbers of specimens studied. The form of the humeral insertion of the IGHL is linked to the formation of a supporting hammock that can accommodate the humeral head during movement as described by several authors.

CLINICAL RELEVANCE

We believe that the difference between arthroscopic and anatomic observation of the humeral insertion may have 2 major clinical implications. An observed tear of the frenula capsulae may not necessarily represent a humeral avulsion of the glenohumeral ligaments (HAGL). In the case of a HAGL, the capsule may have to be reattached in its V-form to adequately retension the inferior capsule.

Arthroscopic findings in atraumatic shoulder instability

PURPOSE

The goal of this study was to evaluate the intra-articular pathology in patients with atraumatic shoulder instability who did not respond to conservative treatment.

TYPE OF STUDY

Prospective case series.

METHODS

Of 226 patients treated for shoulder instability over a 2-year-period, 43 patients (average age, 27.5 years; 26 men and 17 women) were classified as having atraumatic instability. None had responded to physiotherapy. The intra-articular pathology was documented during diagnostic arthroscopy before the definitive surgical procedure.

RESULTS

Three types of lesions of the capsulolabral complex were defined: incomplete labral lesions, pathologic elongation of the capsule or "non-Bankart lesions" (type I), classic Bankart lesions (type II), and complex lesions of the labrum and capsule (type III). Type I was found in 19 patients (44.2%); type II lesions were seen in 13 (30.2%); and type III in 11 (25.6%) patients. Hill-Sachs lesions were found in 26 shoulders (60.5%). Chondral lesions of the glenoid were seen in 10 shoulders (23%); SLAP lesions in 5 (11.7%); and partial, articular-side defects of the supraspinatus tendon in 3 (6.9%) patients.

CONCLUSIONS

Atraumatic onset of shoulder instability does not imply the absence of intra-articular lesions, at least in patients not showing a response to physiotherapy. Arthroscopy is helpful to diagnose the definite intra-articular pathology.

LEVEL OF EVIDENCE

Level IV.

Anterior capsular shift volume reduction: an in vitro comparison of 3 techniques

The anterior capsular shift is a well-established procedure for correction of capsular redundancy. Several different techniques have been developed to reduce capsular volume via a shift or capsulorrhaphy. The purpose of this study was to compare volume reduction objectively among 3 popular capsular shift techniques. Twenty-four fresh-frozen human cadaver shoulders were assigned to one of three groups: a lateral (humeral)-based T-capsular shift (group A), a medial (glenoid)-based T-capsular shift (group B), or a central vertical capsular shift (group C). Initial capsular volume was measured by repeated injection of a viscous fatty acid sulfate solution and recorded for each specimen. A predetermined capsular shift procedure was performed on each cadaver, and repeated measurements were made. All 3 procedures resulted in a significant reduction in capsular volume. The lateral (humeral)-based T-capsular shift resulted in the most reduction (48.9%). This reduction was statistically greater than for the glenoid-based shift (36.8% volume reduction) and approached statistical significance for the vertical shift (40.3% volume reduction, P =.12). Repeated measurements confirmed that the injection technique was valid and reproducible. The lateral (humeral)-based capsular shift results in the most volume reduction and should be considered the preferred procedure for patients with excessive capsular redundancy.

Age-related changes of the glenoid labrum in normal shoulders

A growing number of labral changes are described in the literature. The purpose of this study was to evaluate the glenoid and labrum of normal shoulders at different ages and characterize any apparent age-dependent changes. We analyzed 32 normal cadaveric shoulders with a mean age of 57 years (range, 18-89 years). There were 22 male and 10 female cadavers, with 14 right and 18 left specimens. The shoulders were studied macroscopically, histologically, and radiologically. The radiologic evaluation consisted of an analysis of the subchondral mineralization of the glenoid with the use of computed tomographic osteoabsorptiometry. Macroscopically, there were no statistically significant differences among the age groups. Histopathologically, the labrum showed a significant qualitative and quantitative increase (P <.01) in lesions across all regions with increasing age. In younger individuals, lesions at the 12-o'clock position were the most prevalent, with the incidence increasing with age. The anterosuperior position was the region with the next highest prevalence. This was also the area of the highest stress distribution on the glenoid. Our studies demonstrated clear histopathologic changes of the glenoid labrum that are significantly age-related at specific sites. The earliest changes are seen close to the area of highest stress distribution of the glenoid, which could explain the progressive labral changes with increasing age. Arthroscopically detected changes of the glenoid labrum should be evaluated in the context of age-related changes in normal shoulders.

Variation in the glenoid origin of the anteroinferior glenohumeral capsulolabrum

Restoration of the anteroinferior capsulolabrum, including the labrum and origin of the anterior band of the inferior glenohumeral ligament is crucial during Bankart repair. The purpose of the current study was to describe variations in this anatomy near the glenoid. The histologic and gross anatomy were studied in 10 fresh-frozen glenohumeral joints from adult cadavers. Each joint was placed in the apprehension position of abduction, external rotation, and horizontal abduction because anterior dislocation occurs in this shoulder position. The joints then were sectioned serially in the transverse plane from cephalad to caudad. Three glenohumeral joints were embedded in Techovit 7200 resin, polymerized, and then mounted onto an acrylic slide. Ground sections were prepared by attaching a microscope slide to the face of each and cutting 200 microm-thick sections. The thin sections were ground to a thickness of 30 microm. Finally, sections were stained with 1% toluidine blue zero in 1% sodium tetraborate for light microscopic examination. The other seven glenohumeral joints were frozen in the apprehension position and held with a custom jig while sectioned serially at 3-mm intervals. The surfaces then were recorded with a tabletop computer and a scanning device. Two distinct patterns of the anteroinferior capsulolabrum attachment to the glenoid were identified. In eight joints (80%) it had its major origin from the labrum with some fibers extending onto the glenoid neck, a Type I origin. In two joints (20%), it emanated solely from the glenoid neck, a Type II origin. Failure to repair the glenoid origin of the anteroinferior capsulolabrum, the location of the anterior band of the inferior glenohumeral ligament, because of variations in its anatomy may be a reason for failure after Bankart repair.

Thermal capsulorrhaphy to treat shoulder instability

The contemporary therapeutic approach of glenohumeral instability is directed at the restoration of anatomy. Thermal capsular modification to treat shoulder instability is a relatively recent modality. Early successful clinical applications have led to a wide use of this low demanding technique. Currently, however, the indications for thermal capsulorrhaphy are defined poorly, clinical outcome has not been shown to be superior to conventional stabilization procedures, and long-term effects on joint biology and mechanics are not known. Based on a critical review of the literature and personal clinical experience, the authors conclude that additional experimental and clinical investigations are necessary to add this procedure to the accepted modalities applied for the treatment of shoulder instability.

Anatomy, pathophysiology, and biomechanics of shoulder instability

Instability in the athlete presents a unique challenge to the orthopaedic surgeon. A spectrum of both static and dynamic pathophysiology, as well as gross and microscopic histopathology, contribute to this complex clinical continuum. Biomechanical studies of the shoulder and ligament cutting studies in recent years have generated a more precise understanding of the individual contributions of the various ligaments and capsular regions to shoulder instability. An understanding of the underlying pathology and accurate assessment of degree and direction of the instability by clinical examination and history are essential to developing appropriate treatment algorithms.

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.

Arthroscopic shoulder instability surgery. Complications

Complications associated with arthroscopic shoulder stabilization are relatively common. Excluding recurrence, complications are rarely disabling. Current statistics undoubtedly underestimate the true incidence of complications. Many complications, including neurovascular injuries and articular damage, are preventable and can be minimized through familiarity with anatomy, proper surgical technique and instrumentation, and clinical experience. Nevertheless, despite these efforts, a few complications, including recurrent instability, persist. Despite careful patient selection and attention to labral pathology and capsular laxity, arthroscopic repairs continue to have success rates lower than those achieved through open means. While cautiously proceeding toward a more complete understanding of the instability continuum, surgeons must maintain a high index of suspicion for new techniques that purport to "solve" the problem of arthroscopic shoulder stabilization, lest the history of enthusiastic but ultimately unsubstantiated claims is repeated. Outcomes must withstand the rigors of scientific scrutiny and the test of time. Without this cautious vigilance, the appeal of today's solutions becomes the fodder of tomorrow's articles about the complications of arthroscopic shoulder stabilization.

Role of proprioception in pathoetiology of shoulder instability

Proprioception is a specialized sensory modality that gives information about extremity position and direction of movement. This kind of afferent sensory feedback is probably important in mediating muscular control of the shoulder joint. As this articulation is minimally constrained, such a coordinated dynamic control of muscles about the joint is necessary for stability during arm motion. The authors evaluated proprioception in individuals with normal shoulders, unstable shoulders, and after surgical stabilization, by assessing threshold to detection of passive motion and the ability to passively reposition the arm in space. In normal shoulders there is no difference between the dominant and nondominant shoulder, though in unstable shoulders there is a significantly decreased proprioceptive ability. Surgical stabilization normalizes proprioception of the shoulder.

Technique for selecting capsular tightness in repair of anterior-inferior shoulder instability

Part I of our study consisted of sending a survey questionnaire to all members of the American Shoulder and Elbow Surgeons in which specific questions were asked about their technique of surgical repair in patients with anterior instability who had capsular laxity or injury in conjunction with marked inferior laxity. Part II is a description of the technique and preliminary results in 18 patients of a modified anterior-inferior capsular shift technique that tightens the inferior capsule with the shoulder positioned in abduction and external rotation and the superior capsule with the shoulder in adduction and external rotation. Of the members of the Society of the American Shoulder and Elbow Surgeons who responded to the survey, 80% agreed that preservation of external rotation was important and that shoulder position at the time of capsular repair might influence the ultimate range of motion obtained. However, no more than 50% of the respondents agreed on any one position for the arm when repairing the capsule. The most common responses for each position were flexion 0 degrees (49%) (range, 0 degrees to 40 degrees), abduction 30 degrees (24%) (range, 0 degrees to 80 degrees), and external rotation 30 degrees (37%) (range, 0 degrees to 70 degrees). The average postoperative follow-up period for the 18 patients was 27 months (range, 24 to 39 months). Of the 18 patients, 11 (61%) maintained symmetric motion; the others had minimal loss of external rotation compared with that of the contralateral shoulder. Six of eight patients with repair on the dominant side were able to return to full premorbid recreational throwing or racquet sports, and seven with repair on the nondominant side returned to full participation in overhead sports such as basketball and swimming. We conclude that this method of "selective" capsular repair may be a useful guideline to gauge the degree of capsular tightening in patients who have capsular injury or laxity.

Arthroscopic Bankart repair with the Suretac device. Part I: Clinical observations

Although arthroscopic Bankart repair has become an accepted surgical stabilization technique for anterior shoulder instability, the failure rate remains unacceptably high. Little information is available concerning healing of the Bankart repair. The purpose of this article is to clarify this issue by analyzing a cohort of 15 patients who underwent a "second-look" arthroscopy to evaluate and treat pain or recurrent instability following arthroscopic Bankart repair with the Suretac device (Acufex Microsurgical, Mansfield, MA). "Second-look" arthroscopy was performed at an average of 9 months following the index surgical procedure. The reasons for this second surgery were recurrent instability in 7, pain in 6, and pain and stiffness in 2. In the 7 patients with recurrent instability, the Bankart repair was found to be completely healed in 3 (43%), partially healed in 1 (14%), and had recurred in 3 (43%); however, 6 of 7 were observed to have lax capsular tissue. In 4 of these cases, retrospective review of the index surgical procedure showed that a technical error had been made during the repair. Two cases had biopsy of the repair site on "second-look" at 6 to 8 months, and this showed residual polyglyconate polymer debris surrounded by a histiocytic infiltrate. In the remaining 8 cases with stable shoulders, the Bankart repair had completely healed in 5 cases (62.5%) and partially healed in 3 cases (37.5%). The higher failure rate with this approach compared with open approaches appears to result from improper patient selection and errors in surgical technique. There is some question concerning healing strength of the Bankart repair, although complete healing of the Bankart does not seem to be a prerequesite for shoulder stability. Success of the procedure might be expected to improve by selecting only patients with unidirectional, posttraumatic, anterior instability who are found to have a discrete Bankart lesion and well-developed ligamentous tissue.

The pattern of the collagen fiber bundles of the capsule of the glenohumeral joint

The macroscopic anatomy and the architecture of the collagen fiber bundles were studied in the joint capsules of 43 cadaver shoulders. All the specimens were transilluminoted by polarized light after preparation by Spalteholz' technique. Areas of high-fiber density and complex structure were examined histologically. The macroscopically recognizable ligaments are composed of collagen fiber bundles in several layers of differing thickness and orientation. A simple pattern of radial and circular fibers is found only in the relatively thin posterior capsule. A complex pattern of cross-linking was visible in the superior capsule, and a system of fiber bundles spirally crossing each other was present in the anterior/inferior capsule. The examination under polarized light revealed a continuous transition between the ligamentous reinforcements at the anterior inferior capsule, which radiated obliquely from the glenoid rim and varied greatly in form and orientation. The complicated structure of the joint capsule would suggest that the capsular cylinder has to be regarded as a functional entity and that the current biomechanical concepts must be modified if we want to understand its stabilizing effect. The structural features of the superior capsule present new insight about the pathogenesis of rotator cuff tearing, which can develop as a result of shearing stress between the capsular and tendinous layers.

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.

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.

Arthrotomography of the unstable shoulder

Thirty-seven patients suffering from clinically verified subluxation of the shoulder joint underwent double-contrast arthrotomography. Sixteen of these patients were operated on, 4 of whom after arthroscopy, and 1 patient had only arthroscopy. Arthrotomography readily revealed lesions of the glenoid labrum, most of them small, and also redundancy of the anterior joint capsule. The method can be recommended in the examination of the glenoid labrum in patients suffering from anterior subluxation of the shoulder.