Consensus statement on shoulder instability

Shoulder Proprioception: A Review

The purpose of this review is to provide a comprehensive resource for shoulder proprioception assessment and its integration into clinical decision making as well as targeted rehabilitation protocols. Data for this review were acquired from peer-reviewed articles from computerized online databases, namely PubMed and Medline, published between 1906 and 2021. The development of digital/smart phone goniometers can improve shoulder joint range of motion (ROM) measurements and demonstrate comparable measurement accuracy to the universal standard goniometer. The inclinometer offers a portable and cost-effective method for measuring shoulder joint angles and arcs of motion in the vertical plane. Two types of dynamometers, the computerized isokinetic machine and the handheld hydraulic dynamometer, are reliable tools for objective shoulder rotator cuff strength assessment. Motion analysis systems are highly advanced modalities that create three-dimensional models of motion arcs using a series of cameras and reflective beads, offering unparalleled precision in shoulder proprioception measurement; however, they require time-consuming calibration and skilled operators. Advancements in wearable devices and compact mobile technology such as iPhone applications may make three-dimensional motion analysis more affordable and practical for outpatient settings in the future. The complex interplay between proprioception and shoulder dysfunction is not fully understood; however, shoulder proprioception can likely both contribute to and be caused by shoulder pathology. In patients with rotator cuff tears, glenohumeral osteoarthritis, and shoulder instability, clinicians can track proprioception to understand a patient's disease progression or response to treatment. Finally, rehabilitation programs targeting shoulder proprioception have shown promising initial results in restoring function and returning athletes to play.

Assessing the use of the frequency, etiology, direction, and severity classification system for shoulder instability in physical therapy research - A scoping review

OBJECTIVE

The aim of this study is to review the implementation of the Frequency, Etiology, Direction, and Severity (FEDS) classification for shoulder instability by the physical therapy scientific community since its publication in 2011.

METHODS

A systematic search was conducted on January 10, 2024 in the MEDLINE, EMBASE, SPORTDiscus, Scopus, Web of Science, Cochrane, and SciELO databases, as well as Google Scholar. Studies investigating physical therapy interventions in people with shoulder instability, and reporting selection criteria for shoulder instability were considered eligible. A narrative synthesis was conducted.

RESULTS

Twenty-six studies were included. None reported using the FEDS classification as eligibility criteria for shoulder instability. Only 42% of the studies provided data of all four criteria of the FEDS classification. The most reported criterion was direction (92%), followed by etiology (85%), severity (65%), and frequency (58%). The most common reported descriptor for profiling shoulder instability was "dislocation" (83.3%), followed by "first-time" (66.7%), "anterior" (62.5%), and "traumatic" (59.1%). Regarding other instability classifications, only one study (4%) used the Thomas & Matsen classification, and two (8%) the Stanmore classification.

CONCLUSIONS

The FEDS classification system has not been embraced enough by the physical therapy scientific community since its publication in 2011.

The internal rotation and shift-test for the detection of superior lesions of the rotator cuff: reliability and clinical performance

Background

Using reliable and valid clinical tests are essential for proper diagnosis and clinical outcomes among injuries involving the rotator cuff. The addition of a new clinical examination test could improve the clinical diagnosis and informative value of the sensitivity and specificity of pathology. This study of diagnostic accuracy evaluated the use of a new rotator cuff test, called the internal rotation and shift-test (IRO/shift-test), to determine its reliability and clinical performance (sensitivity, specificity, positive (PPV)/negative predictive value (NPV)). Clinical diagnostic outcomes were confirmed with radiological findings (MRI).

Methods

100 patients from a specialized shoulder unit participated (64 male, 36 female, mean age: 55 ± 13.5 years). A single-blinded (no knowledge of prior clinical or technical diagnostics) study design was used with two experienced physicians performing the IRO/shift-test. For clinical performance, all clinical testing was compared with MRI.

Results

The intra-rater (ICC = 0.73, 95% CI: 60-82) and inter-rater (ICC = 0.89, 95% CI: 81-94) coefficients for the IRO/shift-test showed good-to-excellent reliability. 75% of the patients showed a positive IRO/shift-test, while 65% had a radiologically diagnosed superior rotator cuff tear. 60% of these patients had both a positive IRO/shift-test and objective rotator cuff tear via MRI. The sensitivity of the IRO/shift-test to detect superior rotator cuff lesions based on MRI diagnosis was calculated at 92% (95% CI: 86-99%), while specificity was 67% (95% CI: 50-84%). Predictive values were also found to be high with 86% PPV (95% CI: 78-94%) and 80% NPV (95% CI: 64-96%).

Conclusion

Our results demonstrate that the IRO/shift-test is a reliable and valid tool for assessing superior rotator cuff pathology. With good-to-excellent intrarater and inter-rater reliability and strong sensitivity and specificity this test should be considered a valuable addition to clinicians' cadre of clinical evaluation tools.

Kinematics and biomechanical validity of shoulder joint laxity tests as diagnostic criteria in multidirectional instability

BACKGROUND

Clinical laxity tests are commonly used together to identify individuals with multidirectional instability (MDI). However, their biomechanical validity in distinguishing distinct biomechanical characteristics consistent with MDI has not been demonstrated.

OBJECTIVE

To determine if differences in glenohumeral (GH) joint laxity exist between individuals diagnosed with multidirectional instability (MDI) and asymptomatic matched controls without MDI.

METHODS

Eighteen participants (9 swimmers with MDI, 9 non-swimming asymptomatic matched controls without MDI) participated in this observational study. Participants were classified as having MDI with a composite laxity score from three laxity tests (anterior/posterior drawer and sulcus tests). Single plane dynamic fluoroscopy captured joint motion with 2D-3D joint registration to derive 3D joint kinematics. Average GH translations occurring during the laxity tests were compared between groups using an independent sample's t-test. The relationship of composite laxity scores to overall translations was examined with a simple linear regression. Differences of each laxity test translation between groups were analyzed with a two-way repeated measures ANOVA.

RESULTS

Mean composite translations for swimmers were 1.7 mm greater (p = 0.04, 95% Confidence Interval (CI): 0.1, 3.3 mm) compared to controls. A moderate association occurred (r² = 0.40, p = 0.005) between composite laxity scores and composite translation. Greater translations for the posterior drawer (-2.4 mm, p = 0.04, 95% CI: -0.1, -4.6) and sulcus tests (-2.7 mm, p = 0.03, 95% CI: -0.3, -5.0) existed in swimmers compared to controls.

CONCLUSION

Significant differences in composite translation existed between symptomatic swimmers with MDI and asymptomatic control participants without MDI during GH joint laxity tests. The results provide initial biomechanically based construct validity for the clinical criteria used to identify individuals with MDI.

Evaluation of variations of the glenoid attachment of the inferior glenohumeral ligament by magnetic resonance arthrography

Objective

To evaluate the anatomical variations of the attachment of the inferior glenohumeral ligament (IGHL) to the anterior glenoid rim.

Materials and Methods

This was a retrospective review of 93 magnetic resonance arthrography examinations of the shoulder. Two radiologists, who were blinded to the patient data and were working independently, read the examinations. Interobserver and intraobserver agreement were evaluated. The pattern of IGHL glenoid attachment and its position on the anterior glenoid rim were recorded.

Results

In 50 examinations (53.8%), the glenoid attachment was classified as type I (originating from the labrum), whereas it was classified as type II (originating from the glenoid neck) in 43 (46.2%). The IGHL emerged at the 4 o'clock position in 58 cases (62.4%), at the 3 o'clock position in 14 (15.0%), and at the 5 o'clock position in 21 (22.6%). The rates of interobserver and intraobserver agreement were excellent.

Conclusion

Although type I IGHL glenoid attachment is more common, we found a high prevalence of the type II variation. The IGHL emerged between the 3 o'clock and 5 o'clock positions, most commonly at the 4 o'clock position.

Dynamic contact area ratio in shoulder instability: an innovative diagnostic technique measuring interplay of bony lesions

PURPOSE

The hypothesis of this study is that Dynamic Contact Area Ratio of the humerus and glenoid, measured with CT scans, is significantly reduced in patients with anterior shoulder instability compared to the Dynamic Contact Area Ratio in a control group of people without shoulder instability.

METHODS

Preoperative CT scans of patients who underwent surgery for anterior shoulder instability were collected. Additionally, the radiologic database was searched for control subjects. Using a validated software tool (Articulis) the CT scans were converted into 3-dimensional models and the amount the joint contact surface during simulated motion was calculated.

RESULTS

CT scans of 18 patients and 21 controls were available. The mean Dynamic Contact Area Ratio of patients was 25.2 ± 6.7 compared to 30.1 ± 5.1 in healthy subjects (p = 0.014).

CONCLUSION

Dynamic Contact Area Ratio was significantly lower in patients with anterior shoulder instability compared to controls, confirming the hypothesis of the study. The findings of this study indicate that calculating the Dynamic Contact Area Ratio based on CT scan images may help surgeons in diagnosing anterior shoulder instability.

LEVEL OF EVIDENCE

III.

Instability severity index score values below 7 do not predict recurrence after arthroscopic Bankart repair

PURPOSE

To evaluate the efficacy of the Instability Severity Index Score (ISIS) in predicting an increased recurrence risk after an arthroscopic Bankart repair.

METHODS

Retrospective review of a cohort of patients operated in three different centres. The inclusion criteria (recurrent anterior instability [dislocation or subluxation] with or without hyperlaxity, arthroscopic Bankart repair) and the exclusion criteria (concomitant rotator cuff lesion, acute first-time dislocation, surgery after a previous anterior stabilization, surgery for an unstable shoulder without true dislocation or subluxation; multidirectional instability) were those used in the study that defined the ISIS score. The medical records and a telephone interview were used to identify the six variables that define the ISIS and identify recurrences.

RESULTS

One hundred and sixty-three shoulders met the inclusion and exclusion criteria. Of these, 140 subjects (22 females/118 males; mean age 35.5 ± 7.9) with 142 (89.0%) shoulders were available for follow-up after 5.3 (1.1) (range 3.1-7.4) years. There were 20 recurrences (14.1%). The mean (SD) preoperative ISIS was 1.8 (1.6) in the patients without recurrence and 1.8 (1.9) in the patients with recurrence (n.s.). In the 117 subjects with ISIS between 0 and 3 the recurrence rate was 12.8%; in the 25 with ISIS 4 to 6 the rate was 20% (n.s.).

CONCLUSION

For subjects with anterior shoulder instability in which an arthroscopic Bankart repair is being considered, the use of the ISIS, when the values obtained are ≤ 6 was not useful to predict an increased recurrence risk in the midterm in this retrospectively evaluated case series. The efficacy of the ISIS score in defining a group of subjects with a preoperative increased risk of recurrence after an arthroscopic Bankart instability repair is limited in lower risk populations (with ISIS scores ≤ 6).

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Epidemiology of the Frequency, Etiology, Direction, and Severity (FEDS) system for classifying glenohumeral instability

HYPOTHESIS

The purpose of this multicenter epidemiologic study was to determine the distribution of patients within the Frequency, Etiology, Direction, and Severity (FEDS) classification system to determine which categories are of clinical importance.

METHODS

Shoulder instability patients were identified using International Classification of Diseases, Ninth Revision coding data from 3 separate institutions from 2005-2010. Data were collected retrospectively. Details of instability were recorded in accordance with the FEDS classification system. Each patient was assigned a classification within the FEDS system. After all patients were assigned to a group, each group was individually analyzed and compared with the other groups.

RESULTS

There are a total of 36 possible combinations within the FEDS system. Only 16 categories were represented by at least 1% of our patient population. Six categories captured at least 5% of all patients with shoulder instability. Only 2 categories represented greater than 10% of the population: solitary, traumatic, anterior dislocation, with 95 patients (24.8%), and occasional, traumatic, anterior dislocation, with 63 patients (16.4%).

CONCLUSIONS

There are 16 categories within the FEDS classification that are clinically significant. Solitary, traumatic, anterior dislocation and occasional, traumatic, anterior dislocation were the most frequently observed in our cohort.

Surgical treatment outcomes after primary vs recurrent anterior shoulder instability

INTRODUCTION

The aim of this study is to compare the outcomes of surgical management after primary anterior shoulder dislocation to the outcomes of patients who have surgical stabilization after recurrent anterior shoulder instability.

METHODS

A Medline (PubMed) search was performed in November of 2016 using the following key terms: shoulder, labrum, Bankart, instability, repair, outcome, recurrent. In May 2017 a Cochrane search was performed using similar key terms to ensure we included all studies. Only level I and II studies were included.

RESULTS

There were three studies that compared primary repair to delayed repair. In all three studies, the rate of recurrence was higher in group R than group S. When pooled, there was not a statistically significant difference between these groups, but there was a slightly higher odds of recurrence in group R (pooled OR 2.08, CI 0.69-6.26, p = 0.19). No significant differences were appreciated in functional outcomes or complications in these two groups.

CONCLUSION

Further level I and level II studies to compare surgical treatment after first time and recurrent instability are needed. This study failed to find a statistically significant difference in recurrence rates in patients who had stabilization acutely after a single episode compared to patients with recurrent instability events, although results suggest there may be a small benefit in primary stabilization.

Arthroscopic Findings in Anterior Shoulder Instability

Background:

In the last years, basic research and arthroscopic surgery, have improved our understanding of shoulder anatomy and pathology. It is a fact that arthroscopic treatment of shoulder instability has evolved considerably over the past decades. The aim of this paper is to present the variety of pathologies that should be identified and treated during shoulder arthroscopy when dealing with anterior shoulder instability cases.

Methods:

A review of the current literature regarding arthroscopic shoulder anatomy, anatomic variants, and arthroscopic findings in anterior shoulder instability, is presented. In addition, correlation of arthroscopic findings with physical examination and advanced imaging (CT and MRI) in order to improve our understanding in anterior shoulder instability pathology is discussed.

Results:

Shoulder instability represents a broad spectrum of disease and a thorough understanding of the pathoanatomy is the key for a successful treatment of the unstable shoulder. Patients can have a variety of pathologies concomitant with a traditional Bankart lesion, such as injuries of the glenoid (bony Bankart), injuries of the glenoid labrum, superiorly (SLAP) or anteroinferiorly (e.g. anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), and accompanying osseous-cartilage lesions (Hill-Sachs, glenolabral articular disruption). Shoulder arthroscopy allows for a detailed visualization and a dynamic examination of all anatomic structures, identification of pathologic findings, and treatment of all concomitant lesions.

Conclusion:

Surgeons must be well prepared and understanding the normal anatomy of the glenohumeral joint, including its anatomic variants to seek for the possible pathologic lesions in anterior shoulder instability during shoulder arthroscopy. Patient selection criteria, improved surgical techniques, and implants available have contributed to the enhancement of clinical and functional outcomes to the point that arthroscopic treatment is considered nowadays the standard of care.

Are radiologists superior to orthopaedic surgeons in diagnosing instability-related shoulder lesions on magnetic resonance arthrography? A multicenter reproducibility and accuracy study

BACKGROUND

We compared the diagnostic reproducibility and accuracy of musculoskeletal radiologists with orthopaedic shoulder surgeons in 2 large medical centers in assessing magnetic resonance arthrograms (MRAs) of patients with traumatic anterior shoulder instability.

METHODS

Forty-five surgically confirmed MRAs were assessed by 4 radiologists, 4 orthopaedic surgeons, 2 radiologic teams, and 2 orthopaedic teams. During MRA assessment and surgery, the same 7-lesion scoring form was used. κ Coefficients, sensitivity, specificity, and differences in percentage of agreement or correct diagnosis (P < .05, McNemar test) were calculated per lesion and overall per the 7 lesion types.

RESULTS

The overall κ between the individual radiologists (κ = 0.51, κ = 0.46) and orthopaedic surgeons (κ = 0.46, κ = 0.41) was moderate. Although the overall percentage of agreement between the radiologists was slightly higher than that between the orthopaedic surgeons in both centers (80.0% vs 77.5% and 75.2% vs 73.7%), there was no significant difference. In each medical center, however, the most experienced orthopaedic surgeon was exceedingly more accurate than both radiologists per the 7 lesion types (81.9% vs 72.4%/74.6% and 76.5% vs 67.3%/73.7%). In 3 of 4 cases, this difference was significant. Overall accuracy improvement through consensus assessment was merely established for the weakest member of each team.

CONCLUSION

Experienced orthopaedic surgeons are more accurate than radiologists in assessing traumatic anterior shoulder instability-related lesions on MRA. In case of diagnosis disagreement, these orthopaedic surgeons should base their treatment decision on their own MRA interpretation.

Approach to the treatment of primary anterior shoulder dislocation: A review

Glenohumeral joint dislocation is common among younger, active patients. Anterior dislocation is the most common direction of instability following a traumatic event. Due to a high rate of recurrence following primary traumatic anterior shoulder dislocation, an evidence-based approach is necessary to determine the best treatment regime for a patient presenting with this problem. A history, physical examination, and radiographic imaging can help guide treatment recommendations by determining the extent of soft tissue damage following dislocation. Controversies in the treatment of the first-time dislocator include the length and position of immobilization following dislocation, and the role of initial surgical stabilization. This article outlines the treatment options for the first-time glenohumeral dislocator, with an emphasis on the available evidence in the literature. Where applicable, the criteria known as the Strength of Recommendation Taxonomy were used to summarize the strength of evidence available for recommendations.

Strength training and shoulder proprioception

CONTEXT

Proprioception is essential to motor control and joint stability during daily and sport activities. Recent studies demonstrated that athletes have better joint position sense (JPS) when compared with controls matched for age, suggesting that physical training could have an effect on proprioception.

OBJECTIVE

To evaluate the result of an 8-week strength-training program on shoulder JPS and to verify whether using training intensities that are the same or divergent for the shoulder's dynamic-stabilizer muscles promote different effects on JPS.

DESIGN

Randomized controlled clinical trial.

SETTING

We evaluated JPS in a research laboratory and conducted training in a gymnasium.

PATIENTS OR OTHER PARTICIPANTS

A total of 90 men, right handed and asymptomatic, with no history of any type of injury or shoulder instability.

INTERVENTION(S)

For 8 weeks, the participants performed the strength-training program 3 sessions per week. We used 4 exercises (bench press, lat pull down, shoulder press, and seated row), with 2 sets each.

MAIN OUTCOME MEASURE(S)

We measured shoulder JPS acuity by calculating the absolute error.

RESULTS

We found an interaction between group and time. To examine the interaction, we conducted two 1-way analyses of variance comparing groups at each time. The groups did not differ at pretraining; however, a difference among groups was noted posttraining.

CONCLUSIONS

Strength training using exercises at the same intensity produced an improvement in JPS compared with exercises of varying intensity, suggesting that the former resulted in improvements in the sensitivity of muscle spindles and, hence, better neuromuscular control in the shoulder.

Does the experience level of the radiologist, assessment in consensus, or the addition of the abduction and external rotation view improve the diagnostic reproducibility and accuracy of MRA of the shoulder?

AIM

To prospectively evaluate the influence of observer experience, consensus assessment, and abduction and external rotation (ABER) view on the diagnostic performance of magnetic resonance arthrography (MRA) in patients with traumatic anterior-shoulder instability (TASI).

MATERIALS AND METHODS

Fifty-eight MRA examinations (of which 51 had additional ABER views) were assessed by six radiologists (R1-R6) and three teams (T1-T3) with different experience levels, using a seven-lesion standardized scoring form. Forty-five out of 58 MRA examination findings were surgically confirmed. Kappa coefficients, sensitivity, specificity, and differences in percent agreement or correct diagnosis (p-value, McNemar's test) were calculated per lesion and overall per seven lesion types to assess diagnostic reproducibility and accuracy.

RESULTS

Overall kappa ranged from poor (k = 0.17) to moderate (k = 0.53), sensitivity from 30.6-63.5%, and specificity from 73.6-89.9%. Overall, the most experienced radiologists (R1-R2) and teams (T2-T3) agreed significantly more than the lesser experienced radiologists (R3-R4: p = 0.014, R5-R6; p = 0.018) and teams (T2-T3: p = 0.007). The most experienced radiologist (R1, R2, R3) and teams (T1, T2) were also consistently more accurate than the lesser experienced radiologists (R4, R5, R6) and team (T3). Significant differences were found between R1-R4 (p = 0.012), R3-R4 (p = 0.03), and T2-T3 (p = 0.014). The overall performance of consensus assessment was systematically higher than individual assessment. Significant differences were established between T1-T2 and radiologists R3-R4 (p<0.001, p = 0.001) and between T2 and R3 (p<0.001/p = 0.001) or R4 (p = 0.050). No overall significant differences were found between the radiologists' assessments with and without ABER.

CONCLUSION

The addition of ABER does not significantly improve overall diagnostic performance. The radiologist's experience level and consensus assessment do contribute to higher reproducibility and accuracy.

Shoulder rotator strength and torque steadiness in athletes with anterior shoulder instability or SLAP lesion

OBJECTIVES

To investigate shoulder rotator strength and steadiness in athletes with anterior instability and superior labrum anterior posterior (SLAP) lesion.

DESIGN

Cross-sectional laboratory study.

METHODS

Athletes with anterior shoulder instability (instability group, n=10) and a SLAP lesion (SLAP group, n=10) were compared with healthy athletes matched by age, anthropometrics and sport (control group for shoulder instability, n=10 and control group for SLAP, n=10). Torque steadiness was evaluated with three 10s submaximal isometric contractions (35% of peak torque) with the arm at 90° of shoulder abduction and 90° of external rotation. The mean isometric torque, standard deviation and coefficient of variation were measured from the steadiness trials. To evaluate shoulder rotator strength, concentric isokinetic tests (90°/s, 180°/s) were performed at the 90-90° position and peak torque to body mass and shoulder external to internal rotation ratio variables were analyzed. The variables were tested with the instability and control groups with respect to shoulder instability and between the SLAP and control groups for SLAP lesion using the Mann-Whitney test.

RESULTS

The SLAP group presented a higher coefficient of variation than the SLAP control group (p=0.003). Regarding shoulder strength, the internal and external shoulder rotators were weaker in the instability group than in the instability control group (p<0.05).

CONCLUSIONS

Athletes with anterior shoulder instability presented shoulder rotation weakness, while athletes with a SLAP lesion showed higher torque fluctuation during internal rotation. These results indicate that there are different alterations to strength and sensory motor control in each condition.

Anterior shoulder instability: correlation between magnetic resonance arthrography, ultrasound arthrography and intraoperative findings

The purpose of the present study was to determine ultrasound (US) arthrography diagnostic accuracy in patients with recurrent shoulder dislocation by comparing US arthrography and magnetic resonance arthrography (MRA) with intraoperative findings. Fifty-six consecutive patients with diagnosis of chronic anterior instability of the shoulder were evaluated for assessment of bone and soft tissue lesions by three radiologists. Twenty-five cases were confirmed by surgery. Sensitivity, specificity, inter- and intraobserver agreement were calculated. Ultrasound sensitivity ranged from 20% to 100% and specificity from 25% to 90%. MRA sensitivity ranged from 80% to 100% and specificity from 50% to 100%. Interobserver agreement was good for MRA (0.54-0.70) and fair for US arthrography (0.19-0.40). Despite a higher interobserver variability for US arthrography than for MRA, our results indicate that US is capable of demonstrating bone and soft tissue lesions related to chronic instability of the shoulder in the presence of intra-articular fluid.

A biomechanical evaluation of bicortical metal screw fixation versus absorbable interference screw fixation after coracoid transfer for anterior shoulder instability

PURPOSE

The purpose was to evaluate the load to failure of 2 coracoid fixation techniques after transfer of the coracoid to the anterior glenoid neck.

METHODS

Ten cadavers (mean age, 87 years; range, 74 to 96 years) underwent the Bristow conjoined tendon tenodesis technique as described by Boileau et al. (bioabsorbable interference screw fixation of a coracoid bone plug) in 1 shoulder and the Latarjet-Patte coracoid transfer popularized by Walch (fixation with 2 screws through a larger piece of the coracoid) in the opposite shoulder. The force on the conjoined tendon required to pull the coracoid off of the anterior glenoid was recorded, along with the mode of construct failure.

RESULTS

The median ultimate failure load was 110 N (range, 35 to 170 N) in the interference screw group and 202 N (range, 95 to 300 N) in the bicortical screw group (P = .002). The mode of failure of the interference screw technique was complete avulsion of the bone plug from the socket in 6 cases (60%) and fracture of the bone plug in 4 (40%). The mode of failure of the bone block technique was a vertical fracture through both screw holes in 7 cases (70%), a horizontal fracture through the distal screw hole in 2 (20%), and an intratendinous rupture of the conjoined tendon in 1 (10%).

CONCLUSIONS

Fixation of a coracoid bone block to the anterior glenoid neck with 2 bicortical metal screws is stronger than fixation of a coracoid bone plug with an absorbable interference screw.

CLINICAL RELEVANCE

These data may influence surgeons' decisions regarding coracoid fixation as well as postoperative rehabilitation after coracoid transfer.

Arthroscopic anatomy, variants, and pathologic findings in shoulder instability

Shoulder instability is a common diagnosis that often requires surgical treatment. A detailed knowledge of the shoulder anatomy and its stabilizing structures is of utmost importance for successful treatment of shoulder instabilities. Identifying anatomic variants (e.g., sublabral hole, meniscoid labrum, cordlike middle glenohumeral ligament, and Buford complex) and distinguishing them from pathologic findings may be especially difficult, as shown by the high interobserver variability. Over the last decade, basic research and arthroscopic surgery have improved our understanding of the shoulder anatomy and pathology. In the context of shoulder instability, injuries of the glenoid (bony Bankart), injuries of the glenoid labrum superiorly (SLAP) or anteroinferiorly (e.g., Bankart, anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), accompanying cartilage lesions (Hill-Sachs, glenolabral articular disruption), and rotator interval and pulley lesions, as well as signs of dynamic instability impingement (posterior-superior impingement, anterior-superior impingement) can be exactly diagnosed (magnetic resonance imaging with intra-articular gadolinium, arthroscopy) and treated (arthroscopy). Therefore the purpose of this article is to review the current literature concerning shoulder anatomy/pathology related to shoulder stability/instability to improve clinical diagnosis and surgical treatment of our patients.

Evaluation and treatment of shoulder instability

The shoulder joint has a wide range of motion as a result of a complex interplay of soft tissue and bone structures. It is also the most frequently dislocated joint in the body. Shoulder dislocations are generally classified as traumatic and nontraumatic. There are many specific causes, each of which necessitate individualized treatment modalities. Accurate diagnosis requires a careful history and physical examination. Arthroscopic surgery and advances in imaging have expanded our understanding of anatomy and pathology relevant to shoulder instability and its treatment. Surgery is the treatment of choice for recurrent traumatic instability. Surgery may also be indicated in some first-time traumatic dislocations in young contact athletes, whereas rehabilitation is the initial treatment of choice in older patients with initial instability and in those with nontraumatic dislocations. Results of arthroscopic capsulolabral repair now equal those of open capsulolabral repair and have become the surgical treatment of choice for most patients. However, in cases of recurrent instability and significant bone deficiency of either the glenoid or humeral head, open bone reconstructive procedures are often necessary to ensure successful outcomes.