Bone loss in patients with posterior gleno-humeral instability: a systematic review

Low Recurrence of Instability and Satisfying Patient-Reported Outcomes Following Various Surgical Treatments of Reverse Hill-Sachs Lesions in the Setting of Posterior Instability: A Systematic Review

PURPOSE

To systematically review the literature and report the outcomes of various surgical treatments for reverse Hill-Sachs lesions (RHSL) in the setting of posterior shoulder instability.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. All studies assessing outcomes of surgical treatment of RHSL from inception to January 2023 were identified in PubMed, Embase, and Cochrane Library. Inclusion criteria consisted of studies reporting outcomes, minimum mean 1-year follow-up, and minimum Level IV evidence. Outcomes were assessed using Forest plots with random effects models using R software.

RESULTS

A total of 29 studies consisting of 291 patients were included with a mean age of 42 years (range 16-88 years), 87% male gender, and mean follow-up of 4.5 years. The mean size of impacted or affected cartilage was 35%, and time from injury to surgery was mean 15 weeks. Nearly all studies were Level IV evidence, and quality of studies was low. Random effect models were performed, and data are presented as range. A low incidence of instability was noted for all surgical techniques with good patient-reported outcome measures. Most studies reported outcomes of the modified McLaughlin procedure (13 studies, 126 patients) with overall Constant-Murley Score of 65 to 92. Trends were seen towards better Constant-Murley Score and external rotation with a shorter delay between injury, and when arthroscopic and joint preserving treatments were performed.

CONCLUSIONS

This systematic review showed low rates of instability recurrence, reproducible range of motion, and favorable patient-reported outcome measures were reported following all treatments for RHSLs with posterior instability. There was a significant association between better outcomes and a shorter delay between injury and surgery. The level of evidence is limited, given the small and retrospective studies which can be explained by the rarity of these injuries. LEVEL OF EVIDENCE: Level IV; systematic review of Level III and IV studies.

Location and size of the reverse Hill-Sachs lesion in patients with traumatic posterior shoulder instability

BACKGROUND

In patients with traumatic posterior shoulder instability, little is known about the precise location and size of the reverse Hill-Sachs lesion.

METHODS

Forty-nine shoulders of 47 patients with traumatic posterior instability were included in this study based on the following inclusion criteria: (1) a primary or recurrent traumatic posterior shoulder dislocation and (2) the initial event being caused by trauma. Patients were excluded if they had (1) no history of trauma, (2) prior shoulder surgery, (3) no computed tomographic (CT) examination, or (4) were seizure cases. Three-dimensional images of the humerus reconstructed from CT images were reviewed using an image analysis software. The location and size of the reverse Hill-Sachs lesion were measured and described on a clock face on the humeral head.

RESULTS

The reverse Hill-Sachs lesion was observed in 25 of 49 shoulders (51%). The reverse Hill-Sachs lesions were located between 1:37 and 2:48. The depth of the reverse Hill-Sachs lesion (mean ± standard deviation) was 5.8 ± 2.2 mm. The extent of the reverse Hill-Sachs lesion was 35° ± 12°. The average orientation of the reverse Hill-Sachs lesion, represented by an angle measured from the 12 o'clock position, was 64° ± 12° and pointing toward 2:09 on a clock face. The mean length and width of reverse Hill-Sachs lesions were 9.7 ± 4.7 mm and 11.1 ± 3.6 mm, respectively.

CONCLUSION

The reverse Hill-Sachs lesion was a semicircular compression fracture located on the anteromedial aspect of the humeral head. Compared with shoulders with anterior shoulder instability, the humeral defect was smaller and located more inferiorly in shoulders with posterior instability.

The Perfect-Circle Technique Demonstrates Poor Inter-Rater Reliability in Measuring Posterior Glenoid Bone Loss on Magnetic Resonance Imaging

Purpose

To evaluate the reliability of the "perfect-circle" methodology for measurement of glenoid bone loss with magnetic resonance imaging (MRI) in patients with posterior glenohumeral instability.

Methods

A prospective chart review was performed on patients who underwent isolated arthroscopic posterior labral repairs in our institution's electronic medical records between January 1, 2021, and June 30, 2021. Inclusion criteria included isolated posterior shoulder instability with posterior labral repair and corroborated tears on MRI. A total of 9 raters, either sports or shoulder and elbow fellowship-trained orthopaedic surgeons, each evaluated the affected shoulder MRI scans twice, at over 2 weeks apart. Measurements followed the "perfect-circle" technique and included projected anterior-to-posterior (AP) glenoid diameter, amount of posterior bone loss, and percentage of posterior bone loss.

Results

Ten consecutive patients between the ages of 17 and 46 years with diagnosed posterior glenohumeral instability were selected. The average age was 28 ± 10 years, and 60% of patients were male. The patient's dominant arm was affected in 40%, and 50% of cases involved the right shoulder. The average glenoid diameter was 29.62 ± 3.69 mm, and the average measured bone loss was 2.8 ± 1.74 mm. The average percent posterior glenoid bone loss was 9.41 ± 5.78%. The inter-rater reliability was poor for the AP diameter and for the posterior glenoid bone loss with intraclass correlation coefficients at 0.30 (0.12-0.62) and 0.22 (0.07-0.54) respectively. The intrarater reliability was poor for AP diameter and moderate for posterior glenoid bone loss, with intraclass correlation coefficients at 0.41 (0.22-0.57) and 0.50 (0.33-0.64), respectively.

Conclusions

Using the "perfect-circle" technique for evaluating posterior glenohumeral bone loss has poor-to-moderate inter- and intrarater reliability from MRI.

Level of Evidence

Level IV, prospective diagnostic study.

How much force is acting on the shoulder joint to create a Hill-Sachs Lesion or reverse Hill-Sachs Lesion?

BACKGROUND

It has not been clarified yet how much force is acting on the shoulder joint to create Hill-Sachs/reverse Hill-Sachs lesions which are commonly observed in patients with anterior or posterior shoulder instability. The purpose of this study was to determine the magnitude of force to create these bony lesions using cadaveric shoulders.

METHODS

Fourteen fresh-frozen cadaveric shoulders were used. Compression tests were performed using the universal testing machine. The specimens were randomly divided into two groups. In group A, the posterior humeral head (the bare area and articular cartilage) was first compressed against the anterior glenoid rim to simulate a Hill-Sachs lesion, followed by the anterior humeral head being compressed against the posterior glenoid rim. In group B, the same procedure was repeated in the reverse order. X-ray microcomputed tomography (microCT) was also performed.

RESULTS

The maximum compression force to create a Hill-Sachs lesion was 771 ± 214 N (mean ± SD) on the articular cartilage of the posterior humeral head, which was significantly greater than the force of 447 ± 215 N to create it on the bare area (P = 0.0086). Regarding the reverse Hill-Sachs lesions, the maximum compression force was 840 ± 198 N when it was created on the articular cartilage of the anterior humeral head, which was significantly greater than the force of 471 ± 100 N when it was created at the footprint of the subscapularis tendon (P = 0.0238). MicroCT showed multiple breakage of the trabecular bone.

CONCLUSION

A force to create a Hill-Sachs lesion or a reverse Hill-Sachs lesion was significantly greater when it was created on the humeral articular cartilage than at the non-cartilage area. Also, the force to create a reverse Hill-Sachs lesion was significantly greater than the one to create a Hill-Sachs lesion.

Modified McLaughlin Procedure Using a Double-Row Suture Anchor for Chronic Locked Posterior Shoulder Dislocation: A Case Report

CASE

A 49-year-old highly active man had a direct fall on the left shoulder, causing a chronic locked posterior shoulder dislocation. Radiographic analysis revealed a reverse Hill-Sachs lesion (RHSL) that affected 31% of the articular surface. He was successfully treated with a modified McLaughlin procedure that included a double-row suture anchor as a novel fixation approach to secure the lesser tuberosity transfer and the subscapularis tenodesis.

CONCLUSION

The reported approach for reconstructing the RHSL provides adequate stability, pain reduction, and functional outcomes. It may be considered as an option for joint preservation in extensive humeral head defects.

Posterior Glenoid Osteotomy With Capsulolabral Repair Improves Resistance Forces in a Critical Glenoid Bone Loss Model

Background:

There is no widespread consensus on the surgical treatment of posterior shoulder instability with critical posterior glenoid bone loss.

Hypothesis:

That opening posterior glenoid wedge osteotomy with soft tissue repair would improve the resistance forces of instability when compared with soft tissue repair alone in the setting of 20% critical bone lose.

Study Design:

Controlled laboratory study.

Methods:

Native glenoid retroversion was measured on 9 shoulders using computed tomography (CT) scans. The humerus was potted in 90° of forward flexion and 30° of internal rotation relative to the scapula, and a posterior dislocation was performed to create a posterior capsulolabral injury model. The specimens were each taken through a fixed sequence of testing: (1) posteroinferior capsulolabral tear, (2) no glenoid bone loss with posteroinferior capsulolabral repair, (3) 20% posterior glenoid bone loss with posteroinferior capsulolabral repair, and (4) 20% glenoid bone loss with posterior glenoid opening wedge osteotomy and posteroinferior capsulolabral repair. Bone loss was created using a sagittal saw. The resultant peak forces with 1 cm of posterior translation were measured. A 1-way repeated-measures analysis of variance was used to compare mean force values.

Results:

After the initial dislocation event, all shoulders had a resultant posterior capsulolabral injury. The resulting labral injury was extended from 6- to 9-o’clock in all specimens to homogenize the extent of injury. Repairing the capsulolabral complex in the 20% posterior glenoid bone loss group did not result in a statistically significant increase in resistance force compared with the labral deficient group (34.1 vs 22.2 N; P = .068). When 20% posterior bone loss was created, the posterior glenoid osteotomy with capsulolabral repair was significantly stronger (43.8 N) than the posterior repair alone both with (34.1 N) and without (31.8 N) bone loss (P = .008 and .045, respectively).

Conclusion:

In the setting of critical posterior glenoid bone loss, an opening wedge posterior glenoid osteotomy with capsulolabral repair improved resistance to posterior humeral translation significantly compared with capsulolabral repair alone.

Clinical Relevance:

The results of this biomechanical cadaveric study may aid in surgical planning for this complex patient population.

Perioperative Botulinum Toxin A in the Surgical Management of Seizure-Related Shoulder Instability: A Case Report

CASE

A 20-year-old woman presented with recurrent bilateral shoulder instability concurrent with severe, treatment-refractory epilepsy. Imaging revealed glenoid bone loss of 25% to 28% and large Hill-Sachs defects bilaterally. Bone graft augmentation of the glenoid and infill of the Hill-Sachs defects was performed bilaterally. Perioperative neuromuscular paralysis of shoulder girdle muscles with botulinum toxin was performed to facilitate recovery. Both shoulders at 2.5 and 4 years, respectively, demonstrate excellent stability and radiographic union despite continued seizure activity.

CONCLUSION

Perioperative neuromuscular paralysis with botulinum toxin may provide early graft protection after the surgical treatment of glenohumeral instability because of seizures.

Anterior and posterior glenoid bone augmentation options for shoulder instability: state of the art

Bony lesions are highly prevalent in anterior shoulder instability and can be a significant cause of failure of stabilisation procedures if they are not adequately addressed. The glenoid track concept describes the dynamic interaction between the humeral head and glenoid defects in anterior shoulder instability. It has been beneficial for understanding the role played by bone defects in this entity. As a consequence, the popularity of glenoid augmentation procedures aimed to treat anterior glenoid bone defects; reconstructing the anatomy of the glenohumeral joint has risen sharply in the last decade. Although bone defects are less common in posterior instability, posterior bone block procedures can be indicated to treat not only posterior bony lesions, attritional posterior glenoid erosion or dysplasia but also normal or retroverted glenoids to provide an extended glenoid surface to increase the glenohumeral stability. The purpose of this review was to analyse the rationale, current indications and results of surgical techniques aimed to augment the glenoid surface in patients diagnosed of either anterior or posterior instability by assessing a thorough review of modern literature. Classical techniques such as Latarjet or free bone block procedures have proven to be effective in augmenting the glenoid surface and consequently achieving adequate shoulder stability with good clinical outcomes and early return to athletic activity. Innovations in surgical techniques have permitted to perform these procedures arthroscopically. Arthroscopy provides the theoretical advantages of lower morbidity and faster recovery, as well as the identification and treatment of concomitant pathologies.

Epidemiology of shoulder instability in Italy: A 14-years nationwide registry study

INTRODUCTION

The aim of this study is to estimate the annual number of shoulder dislocation hospitalizations in Italy from 2001 to 2014, to explore geographical variation in access to hospitalizations between the 3 macro-regions of Italy (North, Centre and South) and to perform statistical projections of hospitalizations volumes and rates based on data from 2001 to 2014.

MATERIALS AND METHODS

Data of the Italian Ministry of Health regarding the National Hospital Discharge records (SDO) were analysed for the period of the survey (2001-2014). These data are anonymous and include the patient's age, sex, domicile, region of hospitalization, length of the hospitalization, and type of reimbursement (public or private).

RESULTS

During the 14-year study period, 92,784 hospitalizations to treat shoulder dislocation were performed in Italy, which represented an incidence of 11.2 hospitalizations for every 100,000 Italian inhabitants. 56,514 patients underwent hospitalization for non-surgical treatment. 36,270 patients underwent hospitalization for surgical treatment. The higher hospitalizations rate was among males from 15 to 64 years of age.

CONCLUSIONS

Increasing rates of surgical hospitalization and decreasing rates of hospitalization for non-surgical treatment of shoulder dislocation are observed over a 14-year period. This study confirms that the socioeconomic burden of shoulder dislocation surgery heavily affects the working population. Most shoulder instability procedures were performed on males. The present study provides a description of the frequency and national distribution of shoulder instability in Italy. This study shows an increase in surgical procedures for shoulder instability in Italy.

Arthroscopic Posterior Glenoid Reconstruction Using a Fresh Distal Tibia Allograft for Recurrent Posterior Instability

Posterior glenohumeral instability is a relatively uncommon cause of shoulder instability. Recurrent posterior instability with static posterior humeral head subluxation is often associated with critical glenoid bone loss. Unlike anterior instability, the amount of bone loss for posterior instability that requires surgical reconstruction remains a topic of debate. Several techniques have been described to treat critical bony defects in patients with recurrent posterior shoulder instability with the use of both autografts and allografts depending on the amount of bone loss present. Open posterior glenoid bone block procedure is associated with increased risk of complications and morbidity to the patient. As such, all-arthroscopic techniques have emerged with the advantage of allowing for the diagnosis and treatment of concomitant glenohumeral pathology and minimizing soft-tissue dissection through the posterior deltoid and rotator cuff muscles. Reported short-term outcomes of arthroscopic posterior bone block stabilization are promising; however, it remains a technically challenging procedure due to intra-articular graft insertion and subsequent fixation congruent to the posterior glenoid articular margin. We describe an all-arthroscopic technique using a fresh distal tibia allograft fixation using 2 partially threaded screws in conjunction with an arthroscopic Latarjet fixation set for a patient with recurrent posterior shoulder instability and associated glenoid bone loss.

Posterior bony Bankart bridge technique results in reliable clinical 2-year outcomes and high return to sports rate for the treatment of posterior bony Bankart lesions

PURPOSE

To introduce the arthroscopic "posterior bony Bankart bridge" repair technique, and to report clinical outcomes, patient satisfaction, recurrent instability rate, and return to sport rate.

METHODS

Patients who were treated for posterior bony Bankart lesions with posterior bony Bankart bridge technique and were at least 2 years out from surgery were included. Clinical outcomes were assessed prospectively by the use of the American Shoulder and Elbow Surgeons (ASES) Score, Single Assessment Numerical Evaluation (SANE) Score, Quick Disabilities of the Arm, Shoulder and Hand (DASH) Score and patient satisfaction. Return to sports rate and complications were reported.

RESULTS

Seven patients with a median age of 23.5 (range 17-43) and a median follow-up of 8 years (range 3-10) were included. Median time from injury to surgery was 15 days (range 3 days-2.2 years). Mean glenoid bone defect was 19% (range 11-31%). At final follow-up the median postoperative outcome scores were: ASES score 100 (range 92-100), SANE score 99 points (range 94-99) and QuickDASH 2.2 points (range 0-9). Median satisfaction of all patients was 10/10 (range 9-10). One patient reported subjective recurrent subluxations, which resolved under physical therapy. No patient underwent further surgery. No complications were noticed. At final follow-up, all patients (100%) reported that their sports participation levels were equal to their pre-injury levels.

CONCLUSION

The arthroscopic posterior bony Bankart bridge technique leads to reliable postoperative shoulder function and restores shoulder stability with high patient satisfaction and low complication rate in this small patient cohort for the treatment of posterior bony Bankart lesions. Also, no recurrent dislocation was observed at a minimum follow-up of at least 3 years, one patient continued to complain of subjective subluxations which resolved under physical therapy. All patients were able to return to their pre-injury sports level.

LEVEL OF EVIDENCE

Case series, Level IV.

Arthroscopic "Bone Block Cerclage" Technique for Posterior Shoulder Instability

Many open and arthroscopic techniques have been described to treat posterior glenohumeral instability. Multifactorial features of posterior shoulder instability pathoanatomy and varied patient characteristics have challenged the understanding of this condition and have led to dissimilar results, without a strong consensus for the most adequate technique to treat it. We describe an arthroscopic anatomical metal-free posterior glenoid reconstruction technique, using a tricortical iliac crest allograft with 2 ultra-high strength sutures (FiberTape Cerclage System; Arthrex, Naples, FL) with concomitant posterior capsulolabral complex reconstruction procedure.

Posterior shoulder instability: a systematic review

INTRODUCTION

This review aims to provide information on outcomes of surgical procedures for soft tissue or bony glenoid and/or humeral abnormalities in case of posterior shoulder instability.

SOURCE OF DATA

A systematic review of the literature according to the PRISMA guidelines was performed. A comprehensive search of PubMed, Medline, CINAHL, Cochrane, Embase, Ovid and Google Scholar databases using various combinations of the keywords 'shoulder', 'posterior instability', 'dislocation', 'reversed bony bankart', 'reversed Hill Sachs', and 'capsulolabral' was performed.

AREAS OF AGREEMENT

A total of 847 shoulders in 810 patients were included. A redislocation event occurred in 33 (8.7%) of 411 shoulders with soft tissue abnormalities and in 12 (9.1%) of 132 shoulders with bony abnormalities of the glenoid, humeral head or both.

AREAS OF CONTROVERSY

The optimal treatment modalities for posterior shoulder dislocation remain to be defined.

GROWING POINTS

Operative stabilization for posterior shoulder instability should be lesion-specific and should correct all components of the posterior instability.

AREAS TIMELY FOR DEVELOPING RESEARCH

Future prospective studies should aim to establish the optimal treatment modalities for posterior shoulder instability.

A new mini-open technique of arthroscopically assisted Latarjet

BACKGROUND

The aim is to describe a new arthroscopically assisted Latarjet technique.

METHODS

We evaluated the clinical and radiological findings of 60 patients with chronic recurrent anterior gleno-humeral instability who underwent, between September 2013 and November 2014, an arthroscopically-assisted Latarjet procedure with double round endobutton fixation. Inclusion criteria were: chronic anterior recurrent instability, Instability Severity Index Score (ISIS) greater than three points, a glenoid bone defect > 15% or a Hill Sachs lesion with concomitant glenoid bone defect > 10%. During surgery the joint capsule and the anterior glenoid labrum were detached. Two drill tunnels perpendicular to the neck of the glenoid were made through a guide. An accessible pilot hole through the glenoid was created to allows the passage of guidewires for coracoid guidance and final fixation onto the anterior glenoid. Through a restricted deltopectoral access a coracoid osteotomy was made. Finally, the graft was prepared, inserted and secured using half-stitches.

RESULTS

The mean follow-up was 32.5 months (range 24-32 months). At a mean follow-up, 56 of the 60 subjects claimed a stable shoulder without postoperative complaints, two (3.3%) had an anterior dislocation after new traumatic injury, and two (3.3%) complained of subjective instability. At the latest follow-up, four subjects complained of painful recurrent anterior instability during abduction-external rotation with apprehension. At 1 year, the graft had migrated in one patient (1.7%) and judged not healed and high positioned in another patient (1.7%). Moreover, a glenoid bony gain of 26.3% was recorded. At the latest follow-up, three patients had grade 1 according to Samilson and Prieto classification asymptomatic degenerative changes. Nerve injuries and infections were not detected. None of the 60 patients underwent revision surgery. Healing rate of the graft was 96.7%.

CONCLUSIONS

This technique of arthroscopically assisted Latarjet combines mini-open and arthroscopic approach for improving the precision of the bony tunnels in the glenoid and coracoid placement, minimizing any potential risk of neurologic complications. It can be an option in subjects with anterior gleno-humeral instability and glenoid bone defect. Further studies should be performed to confirm our preliminary results.

TRIAL REGISTRATION

Trial registration number 61/int/2017 Name of registry: ORS Date of registration 11.5.2017 Date of enrolment of the first participant to the trial: September 2013 'retrospectively registered' LEVEL OF EVIDENCE: IV.

Epidemiology of Paediatric Shoulder Dislocation: A Nationwide Study in Italy from 2001 to 2014

Limited knowledge is accessible concerning the tendencies of hospitalization for skeletally immature patients with episodes of shoulder dislocation. Our research aim was to evaluate annual hospitalizations for shoulder dislocation in paediatric patients in Italy from 2001 to 2014, on the basis of the official data source as hospitalization reports. The second purpose was to investigate geographical diversification in hospitalization for shoulder dislocation in regions of Italy. The last aim was to make statistical predictions of the number of shoulder dislocation hospitalization volumes and rates in skeletally immature patients based on data from 2001 to 2014. An examination of the National Hospital Discharge records (SDO) kept at the Italian Ministry of Health regarding the 14 years of our study (2001 through 2014) was conducted. These data are anonymous and include patient's age, gender, domicile, region and time of hospitalization, and the kind of reimbursement (public or private). In the 14-year study time, 344 hospitalizations for shoulder dislocation of patients aged 0-14 years took place in Italy. The male/female hospitalization ratio varied from a maximum of 3.0 (2001) to a minimum of 1.1 (2013), with a mean average ratio in the 2001-2014 timespan of 2.0. Almost half of the hospitalizations (49.1%) were performed in the South. The mean incidence of hospitalizations in Italy for shoulder dislocation in patients with less than 14 years was 0.3 for every 100,000 inhabitants in the same class of age. The most common treatment was a closed reduction (60.8%), followed by open stabilization (16.6%) and arthroscopic procedures (13.7%). The present registry study shows a low incidence of hospitalization for shoulder dislocation in young patients. The most common treatment for a shoulder dislocation in paediatric patients is a closed shoulder reduction. Regions from the south and the centre of Italy are marked by an inferior number of operations and a higher number of hospitalization for closed shoulder reduction.

Risk Factors for Intra-articular Bone and Cartilage Lesions in Patients Undergoing Surgical Treatment for Posterior Instability

BACKGROUND

Patients with posterior shoulder instability may have bone and cartilage lesions (BCLs) in addition to capsulolabral injuries, although the risk factors for these intra-articular lesions are unclear.

HYPOTHESIS

We hypothesized that patients with posterior instability who had a greater number of instability events would have a higher rate of BCLs compared with patients who had fewer instability episodes.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Data from the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group instability patient cohort were analyzed. Patients aged 12 to 99 years undergoing primary surgical treatment for shoulder instability were included. The glenohumeral joint was evaluated by the treating surgeon at the time of surgery, and patients were classified as having a BCL if they had any grade 3 or 4 glenoid or humeral cartilage lesion, reverse Hill-Sachs lesion, bony Bankart lesion, or glenoid bone loss. The effects of the number of instability events on the presence of BCLs was investigated by use of Fisher exact tests. Logistic regression modeling was performed to investigate the independent contributions of demographic variables and injury-specific variables to the likelihood of having a BCL. Significance was defined as P < .05.

RESULTS

We identified 271 patients (223 male) for analysis. Bone and cartilage lesions were identified in 54 patients (19.9%) at the time of surgical treatment. A glenoid cartilage injury was most common and was identified in 28 patients (10.3%). A significant difference was noted between the number of instability events and the presence of BCLs (P = .025), with the highest rate observed in patients with 2 to 5 instability events (32.3%). Multivariate logistic regression modeling indicated that increasing age (P = .019) and 2 to 5 reported instability events (P = .001) were significant independent predictors of the presence of BCLs. For bone lesions alone, the number of instability events was the only significant independent predictor; increased risk of bone lesion was present for patients with 1 instability event (OR, 6.1; P = .012), patients with 2 to 5 instability events (OR, 4.2; P = .033), and patients with more than 5 instability events (OR, 6.0; P = .011).

CONCLUSION

Bone and cartilage lesions are seen significantly more frequently with increasing patient age and in patients with 2 to 5 instability events. Early surgical stabilization for posterior instability may be considered to potentially limit the extent of associated intra-articular injury. The group of patients with more than 5 instability events may represent a different pathological condition, as this group showed a decrease in the likelihood of cartilage injury, although not bony injury.

Arthroscopic Latarjet for Recurrent Shoulder Instability

Background and Objectives: The all-arthroscopic Latarjet (aL) procedure was introduced to manage recurrent shoulder instability. Our study aimed to report the outcomes of aL procedures with the Rowe, University of California-Los Angeles (UCLA), simple shoulder test (SST) scores, and range of motion (ROM) in external rotation at a minimum follow-up of 2 years. Material and Methods: A total of 44 patients presenting recurrent shoulder instability were managed with aL procedure. Clinical outcomes were assessed at a mean follow-up of 29.6 ± 6.9 months. The postoperative active ROM was measured and compared with the contralateral shoulder. The Rowe, UCLA, and SST scores were administered preoperatively and postoperatively. Results: No patients experienced infections or neuro-vascular injuries. Seven (15%) patients required revision surgery. After surgery, the external rotation was statistically lower compared to the contralateral shoulder, but it improved; clinical outcomes also improved in a statistically significant fashion. Conclusions: The aL produced good results in the management of recurrent shoulder instability, but the complication rate was still high even in the hands of expert arthroscopist.

Editorial Commentary: Unsolved Problems in Shoulder Instability-The Dilemma of Bone Loss!

Bone loss in the setting of shoulder instability is an unsolved problem. Procedures restoring bone stock on the glenoid side vary from minimally invasive arthroscopic techniques of arthroscopic bone block procedures to traditional transposition of the coracoid or bone transplant. These techniques are evolving, and several tips and tricks have been optimized to improve outcomes and to reduce the risk of complications, even though the most terrible complication of transposition of the coracoid remains osteoarthritis in the young adult. The major innovation in the past few years has been the use of remplissage. The aim of our surgical procedures is to restore the anatomy as much as possible. Therefore, gentle handling of bone defects on both the humeral and glenoid sides by means of an arthroscopic bone block and combined remplissage seems to be the future of our surgical procedures.

The role of bone in glenohumeral stability

Shoulder stability depends on several factors, either anatomical or functional. Anatomical factors can be further subclassified under soft tissue (shoulder capsule, glenoid rim, glenohumeral ligaments etc) and bony structures (glenoid cavity and humeral head).

Normal glenohumeral stability is maintained through factors mostly pertaining to the scapular side: glenoid version, depth and inclination, along with scapular dynamic positioning, can potentially cause decreased stability depending on the direction of said variables in the different planes. No significant factors in normal humeral anatomy seem to play a tangible role in affecting glenohumeral stability.

When the glenohumeral joint suffers an episode of acute dislocation, either anterior (more frequent) or posterior, bony lesions often develop on both sides: a compression fracture of the humeral head (or Hill–Sachs lesion) and a bone loss of the glenoid rim. Interaction of such lesions can determine ‘re-engagement’ and recurrence.

The concept of ‘glenoid track’ can help quantify an increased risk of recurrence: when the Hill–Sachs lesion engages the anterior glenoid rim, it is defined as ‘off-track’; if it does not, it is an ‘on-track’ lesion. The position of the Hill–Sachs lesion and the percentage of glenoid bone loss are critical factors in determining the likelihood of recurrent instability and in managing treatment.

In terms of posterior glenohumeral instability, the ‘gamma angle concept’ can help ascertain which lesions are prone to recurrence based on the sum of specific angles and millimetres of posterior glenoid bone loss, in a similar fashion to what happens in anterior shoulder instability.

Cite this article: EFORT Open Rev 2018;3:632-640. DOI: 10.1302/2058-5241.3.180028

Risk of neurological injury in posterior bone block surgery for recurrent glenohumeral instability: a cadaveric study

INTRODUCTION

Recurrent posterior glenohumeral instability poses a challenge for treatment. Bone block procedures have been advocated in cases where a bony defect is present. However, these techniques are not free of complications due to the proximity of neurovascular structures. The aim of this study is to measure the distance to the axillary and suprascapular nerves at the different steps of the procedure.

MATERIALS AND METHODS

Ten frozen human cadavers were used. The bone graft was prepared and placed on the posterior aspect of the glenoid, where it was fixed with two K-wires in different positions: parallel to the articular surface and with 20° of medial angulation. The distance from the entry and exit points of the K-wires to the axillary and suprascapular nerves was measured.

RESULTS

At the exit point, mean distance from the superior K-wire to the axillary nerve was 4.4 mm in the neutral position and 14.4 mm when medially angulated (p = 0.01) and 2.6 mm and 11.5 mm, respectively, for the inferior K-wire (p < 0.01). No differences were found at the entry point (p = 0.7 and p = 0.3). For the suprascapular nerve, mean distance to the entry point of the superior K-wire was significantly greater when it was inserted with 20° of medial angulation than when placed in neutral position (p = 0.04). No differences were found for the inferior K-wire (p = 0.35).

CONCLUSION

Posterior bone block surgery should be performed taking into consideration the possibility of axillary nerve injury anteriorly at the exit point of the K-wires. Wire and screw insertion parallel to the glenoid articular surface may reduce the risk, while increased wire or screw medial angulation with respect to the glenoid surface may heighten risk.

LEVEL OF EVIDENCE

Not applicable (cadaveric study).

Are collision athletes at a higher risk of re-dislocation after an open Bristow-Latarjet procedure? A systematic review and meta-analysis

BACKGROUND

The primary aim of the present study was to review, summarize and compare the redislocation risk for collision athletes and noncollision athletes after an open Bristow-Latarjet procedure. Our secondary aim was to summarize return to sport, satisfaction, pain and complications.

METHODS

We conducted a systematic review in PubMed and EMBASE of articles until 1 July 2016. We included all studies describing Bristow-Latarjet like procedures as a result of glenohumeral instability, mentioning redislocation rates in collision athletes with >2 years of follow-up. We pooled the data using random-effects meta-analysis for redislocation risk-differences (RD) between collision and noncollision athletes, and assessed heterogeneity with I² and Tau² tests.

RESULTS

From 475 titles and abstracts, 11 studies were included and eight studies were meta-analyzed. The pooled RD to develop a postoperative redislocation between collision athletes and noncollision athletes was -0.00 (95% confidence interval: -0.03 to 0.03, p = 0.370). Return to sports rates were high (67-100%), and patients reported high satisfaction scores (93-100% satisfied) and low pain scores (mean visual analogue scale score of 1.6); however, postoperative complication rates varied from 0.8% to 19.2%.

CONCLUSIONS

Collision athletes are not more at risk for redislocation rates after an open Bristow-Latarjet procedure compared to noncollision athletes. Overall postoperative outcomes were good, although numerous complications occurred.

Critical Glenoid Bone Loss in Posterior Shoulder Instability

BACKGROUND

There is currently no consensus regarding the amount of posterior glenoid bone loss that is considered critical. Critical bone loss is defined as the amount of bone loss that occurs in which an isolated labral repair will not sufficiently restore stability.

PURPOSE

The purpose is to identify the critical size of the posterior defect.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eleven cadaveric shoulders were tested. With the use of a custom robot device, a 50-N compressive force was applied to the glenohumeral joint, and the peak force that was required to translate the humeral head posteriorly and the lateral displacement that occurred with translation were measured. The defect size was measured as a percentage of the glenoid width. Testing was performed in 11 conditions: (1) intact glenoid and labrum, (2) simulated reverse Bankart lesion, (3) the reverse Bankart lesion repaired, (4) a 10% defect, (5) the reverse Bankart lesion repaired, (6) a 20% defect, (7) the reverse Bankart lesion repaired, (8) a 30% defect, (9) the reverse Bankart lesion repaired, (10) a 40% defect, and (11) the reverse Bankart repaired.

RESULTS

Force and displacement decreased as the size of the osseous defect increased. The mean peak force that occurred with posterior displacement in specimens with a glenoid defect ≥20% and a reverse Bankart repair (13 ± 9 N) was significantly lower than the peak force that occurred in specimens with an isolated reverse Bankart repair (22 ± 10 N) ( P = .0451). In addition, the mean lateral displacement was significantly less in the specimens with a 20% glenoid defect and a reverse Bankart repair (0.61 ± 0.57 mm) compared with the lateral displacement that occurred in specimens with an isolated reverse Bankart repair (1.6 ± 0.78 mm) ( P = .0058).

CONCLUSION

An osseous defect that is ≥20% of the posterior glenoid width remains unstable after isolated reverse Bankart repair.

CLINICAL RELEVANCE

A bony restoration procedure of the glenoid may be necessary in shoulders with a posterior glenoid defect that is ≥20% of the glenoid width.

[The ABC guide for the treatment of posterior shoulder instability]

BACKGROUND

Posterior glenohumeral instability (PGHI) is an often unrecognized or misdiagnosed type of shoulder instability due to its heterogenic clinical and radiological presentation.

CLASSIFICATION

The ABC classification for PGHI is based on the different pathomechanisms and recommended treatment standards and is therefore a guide to finding the correct diagnosis and therapy for affected patients. There are different types of PGHI: A (first time), B (dynamic), C (static). These groups are further classified based on pathomechanical principles: A1: subluxation, A2: dislocation; B1: functional, B2: structural; C1: constitutional, C2: acquired.

THERAPY

In patients with type 1 PGHI (A1, B1, C1) conservative treatment is recommended while in patients with type 2 PGHI (A2, B2, C2) surgical treatment can be considered based on structural defects, clinical symptoms, chronicity, age, functional demand, and patient-specific health status. In addition it has to be considered, that there is the possibility of coexisting or overlapping subtypes as well as the chance of progression from one category into another over time.

Arthroscopic posterior bone block stabilization-early results of an effective procedure for the recurrent posterior instability

PURPOSE

In the current study the clinical outcome of an arthroscopic posterior bone block augmentation in combination with a posterior capsular repair was investigated.

METHODS

Twenty-four shoulders (18 patients) with unidirectional posterior shoulder instability were treated with an arthroscopic posterior bone block and capsular reconstruction. The mean follow up period was 26 months. The patients were examined pre- and postoperatively using the Constant-Murley score, the Rowe score, Walch-Duplay score and Western Ontario Shoulder index.

RESULTS

At the follow up examination 21 shoulders were classified to be stable, while one patient reported a single redislocation and two further patients reported recurrent posterior subluxation or posterior apprehension. Thus, the recurrence rate was defined to be 12.5%. The Rowe-Score significantly improved from 50 points preoperatively to 75 points postoperatively (p = 0.0003). The WOSI-score significantly improved from 37% preoperatively to 66% postoperatively (p = 0.0001). Revision surgery commonly was required for screw removal.

CONCLUSION

The early clinical results of this arthroscopic bone block augmentation and capsular repair are promising.

LEVEL OF EVIDENCE

IV.

Outcomes of capsulolabral reconstruction for posterior shoulder instability

BACKGROUND

Surgical treatment of isolated posterior shoulder instability-a rare and often misdiagnosed condition-is controversial because of poor outcomes. Failure of physical therapy in symptomatic young athletes requires capsulolabral reconstruction or bone block procedures. The goal of this study was to report the outcomes of patients who have undergone surgical capsulolabral reconstruction and to look for risk factors that contribute to failure of this procedure.

MATERIAL AND METHOD

We analyzed the outcomes of 101 patients who underwent capsulolabral reconstruction: 83 included retrospectively, 18 included prospectively. The procedures were performed alone or in combination with capsular shift, labral repair, closure of the rotator interval and notch remplissage. The primary endpoint was failure of the procedure, defined as recurrence of the instability and/or pain. We also determined the outcomes based on specific (Walch-Duplay, modified Rowe) and non-specific (Constant, resumption of activities) scores of shoulder instability.

RESULTS

The results were satisfactory despite a high failure rate: 35% in the retrospective cohort with 4.8±2.6 years' follow-up and 22% in the prospective cohort with 1.1±0.3 years' follow-up. The various outcome scores improved significantly. Ninety-two percent of patients returned to work and 80% of athletes returned to their pre-injury level of sports. Eighty-five percent of patients were satisfied or very satisfied after the surgery. No risk factors for failure were identified; however, failures were more common in older patients, those who underwent an isolated procedure and those who had unclassified clinical forms.

CONCLUSION

Treatment of posterior shoulder instability by capsulolabral reconstruction leads to good clinical outcomes; however, the recurrence rate is high.

LEVEL OF EVIDENCE

4 - retrospective study.

Arthroscopic Repair of Posterior Bony Bankart Lesion and Subscapularis Remplissage

Posterior shoulder instability with glenoid bone loss has only a fraction of the prevalence of anterior instability. Unlike the latter, there is a paucity of literature regarding the treatment of posterior bony Bankart lesions and even less with concomitant reverse Hill-Sachs lesions. This combination of pathology leads to a difficult situation regarding treatment options. We present our technique for arthroscopic repair of a posterior bony Bankart lesion and reverse Hill-Sachs lesion. The importance of proper portal placement cannot be overstated. By use of the lateral position and strategically placed portals, the posterior bony Bankart lesion and attached labral complex were appropriately mobilized. We reduced the glenoid bone, with the attached capsulolabral complex, to the glenoid rim and performed fixation using a knotless suture anchor. We then placed 2 double-loaded suture anchors into the reverse Hill-Sachs lesion. The sutures were passed creating horizontal mattress configurations that were tied at the end of the procedure, effectively externalizing the humeral head defect. Our technique results in satisfactory fragment reduction, as well as appropriate capsular tension, and effectively prevents the reverse Hill-Sachs lesion from engaging.

ABC classification of posterior shoulder instability

Posterior glenohumeral instability (PGHI) is a commonly under- and misdiagnosed pathology owing to its variety of clinical presentations. In order to facilitate diagnosis and treatment, the simple yet comprehensive ABC classification for PGHI is based on the underlying pathomechanical principles and current standard of treatment. Three main groups of PGHI are distinguished based on the type of instability: A (first time), B (dynamic), C (static). Two subtypes further differentiate these groups in terms of their specific pathomechanism and provide a guideline in the choice of appropriate treatment: A (1, subluxation; 2, dislocation), B (1, functional; 2, structural), C (1, constitutional; 2, acquired). While conservative treatment is warranted in most patients with type 1 PGHI (A1, B1, C1), surgical treatment should be considered on an individual basis in patients with type 2 PGHI (A2, B2, C2), while keeping in mind that the different groups and subtypes can overlap, co-exist, or even progress from one to another over time. Of course the necessity for surgical treatment depends on the extent of the structural defects, on the severity of symptoms, on the chronicity, as well as on patient-specific functional demand, age, and health status. Nonetheless, the ABC classification helps to correctly diagnose the type of PGHI and provides a guideline for the generally recommended type of treatment.

Anatomic Humeral Head Reconstruction With Fresh Osteochondral Talus Allograft for Recurrent Glenohumeral Instability With Reverse Hill-Sachs Lesion

The treatment of recurrent glenohumeral instability, especially with a concomitant bony lesion, remains challenging. This is especially true in the case of posterior instability given its less common incidence. Moreover, the presence of an engaging reverse Hill-Sachs lesion in combination with posterior instability will result in the need for a more aggressive treatment option. In comparison with a Hill-Sachs lesion, a reverse Hill-Sachs lesion features greater chondral deficiency that must be addressed during treatment. We propose the talus allograft as a potential allograft for treatment of an engaging reverse Hill-Sachs lesion. The superior articular surface of the talus may be used to reconstruct the articular surface of the humeral head. In this technical note, we describe our preferred primary technique for treatment of an engaging reverse Hill-Sachs lesion with recurrent glenohumeral instability through use of a fresh osteochondral talus allograft, as well as discuss the advantages and disadvantages of this allograft option.

The J-Shaped Bone Graft for Anatomic Glenoid Reconstruction: A 10-Year Clinical Follow-up and Computed Tomography-Osteoabsorptiometry Study

BACKGROUND

The J-shaped bone graft procedure is one of the recommended methods to reconstruct significant glenoid rim defects.

PURPOSE

To evaluate long-term (minimum 10-year) clinical outcomes and show further details of the remodeling effects on the articular cavity of the glenoid after J-shaped bone grafting.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 14 patients treated with a J-shaped bone graft procedure were observed clinically. Additionally, bilateral preoperative and postoperative follow-up computed tomography (CT) scans were used for CT-osteoabsorptiometry (OAM) to evaluate the bony remodeling processes.

RESULTS

The follow-up rate was 93% at a mean follow-up time of 10.7 years (range, 10.08-11.75 years). Patients exhibited a mean Constant score of 92.5 (range, 80-100) on the clinical evaluation. All patients had free range of motion and were pain free without any recurrence of instability. Based on CT-OAM, comparable and almost anatomically reconstructed, bilaterally equal glenoid cavities were found postoperatively. The distribution patterns of glenoid subchondral mineralization were bilaterally equal in 85.7% of the patients.

CONCLUSION

The surgical treatment of recurrent shoulder instability with a significant bony Bankart lesion using the J-shaped bone graft procedure provided excellent long-term results. This study lends evidence to support the capability of the J-shaped bone graft procedure to restore the normal glenoid shape due to physiological remodeling processes.

Hill-Sachs Off-track Lesions as Risk Factor for Recurrence of Instability After Arthroscopic Bankart Repair

PURPOSE

To evaluate the effect of "off-track" Hill-Sachs lesions, according to the glenoid track concept, as a risk factor for recurrent instability and need for revision surgery after arthroscopic Bankart repair.

METHODS

We retrospectively reviewed 254 patients with anteroinferior glenohumeral instability who were managed with an arthroscopic stabilization procedure between 2006 and 2013. Preoperative magnetic resonance imaging and/or computed tomography scans were available for 100 of these patients to calculate the glenoid track and the presence of "on-track" or off-track Hill-Sachs lesions. Recurrence of instability was evaluated at a mean follow-up of 22.4 months.

RESULTS

Of 100 patients whose magnetic resonance imaging and/or computed tomography scans were available, 88 had an on-track Hill-Sachs lesion and 12 had an off-track Hill-Sachs lesion. Revision surgery for recurrent instability was performed in 5 patients (6%) with an on-track Hill-Sachs lesion and in 4 patients (33%) with an off-track Hill-Sachs lesion (odds ratio, 8.3; 95% confidence interval, 1.85-37.26; P = .006).

CONCLUSIONS

An off-track Hill-Sachs lesion is a significant and important risk factor for recurrence of instability and need for revision surgery after arthroscopic Bankart repair when compared with an on-track Hill-Sachs lesion.

LEVEL OF EVIDENCE

Level IV, prognostic case series.

Humeral Avulsion of the Glenohumeral Ligaments: A Systematic Review

PURPOSE

To analyze clinical outcomes, range of motion, rate of recurrence, and complications after procedures to manage shoulder instability in patients with humeral avulsion of the glenohumeral ligament (HAGL) lesions.

METHODS

A systematic review of the literature according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines with a PRISMA checklist and algorithm was performed. A comprehensive search of PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases using various combinations of the Keywords "shoulder," "HAGL," "treatment," "lesion," "dislocation," "instability," "clinical," "outcome," "Bankart" since inception of databases to 2015 was performed. All the investigators independently extracted the following data: demographics, types of lesions and associated injuries, treatment, outcome measurements, range of motion, recurrent instability, and complications.

RESULTS

Eleven articles were included in which 42 shoulders with HAGL lesions were evaluated. Patients were assessed at a median follow-up period of 25.5 months, ranging from 12 to 54 months. The overall rate of recurrence was 0% (0 of 25) in case of surgery and 90% (9 of 10) in case of nonoperative treatment. The surgical approach was associated with lower rate of recurrence when compared with nonoperative treatment (odds ratio 0.05, 95% confidence interval 0.01 to 0.42, and P = .006). Only 2 papers reported loss of external rotation after surgery. No complications were reported after surgery. Complications after nonoperative treatment were not discussed.

CONCLUSIONS

Recognizing HAGL lesions is important to manage patients with glenohumeral instability. Patients' complaints are often nonspecific. A high index of suspicion is required in patients with prior failed shoulder surgery. HAGL lesions are often associated with other shoulder lesions. Arthroscopic or open repairs of HAGL lesions are associated with good clinical outcomes and a lower rate of recurrence compared with nonoperative treatment.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Management of recurrent shoulder instability in patients with epilepsy

Epileptic seizures can cause dislocation of the shoulder. Recurrent instability is common and occurs soon after the first dislocation. Significant bone loss from the humeral head and glenoid is thought to be responsible for this, and therefore the majority of surgical approaches focus on bone augmentation of the glenohumeral joint. Understanding of the current management strategies and the anatomic lesions associated with seizure-related shoulder instability will guide clinical decision-making. The purpose of this article was to review the pathoanatomy, treatment options, and clinical outcomes of seizure-related shoulder instability.

Bone block procedures in posterior shoulder instability

PURPOSE

Posterior shoulder dislocation is often associated with bone defects. Surgical treatment is often necessary to address these lesions. The aim of the present systematic review was to analyse the available literature concerning bone block procedures in the treatment of bone deficiencies following posterior dislocation. In addition, the methodology of the articles has been evaluated through the Coleman methodology score.

METHODS

A systematic review of the literature was performed using the keywords "posterior shoulder instability", "posterior shoulder dislocation", "bone loss", "bone defect", "bone block", and "bone graft" with no limit regarding the year of publication. All English-language articles were evaluated using the Coleman methodology score.

RESULTS

Fifty-four articles were identified, and 13 articles met inclusion criteria. The initial cohort included 208 shoulders, and 182 were reviewed at an average follow-up of 72.7 months (±55.2). The average Coleman score was 57.2 (±8.0). The most lacking domains were the size of study population, the type of study, and the procedure for assessing outcomes. All the articles showed an increase in the outcome scores. Radiographic evaluation revealed degenerative changes such as osteoarthritis and graft lysis in most of the series.

CONCLUSIONS

This review confirms the lack of studies with good methodological quality. However, bone grafting is a reliable option since significant improvement in all scores is reported. Although a low incidence of recurrence is generally described, there are concerns that the results may deteriorate over time as evidenced by graft lysis and glenohumeral osteoarthritis in up to one-third of patients.

LEVEL OF EVIDENCE

Systematic review, Level IV.

Multidirectional Instability of the Shoulder: A Systematic Review

PURPOSE

To analyze outcomes of surgical and conservative treatment options for multidirectional instability (MDI).

METHODS

A systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. A comprehensive search of the PubMed, MEDLINE, CINAHL, Cochrane, EMBASE, and Google Scholar databases using various combinations of the keywords "shoulder," "multidirectional instability," "dislocation," "inferior instability," "capsulorrhaphy," "capsular plication," "capsular shift," "glenoid," "humeral head," "surgery," and "glenohumeral," over the years 1966 to 2014 was performed.

RESULTS

Twenty-four articles describing patients with open capsular shift, arthroscopic treatment, and conservative or combined management in the setting of atraumatic MDI of the shoulder were included. A total of 861 shoulders in 790 patients was included. The median age was 24.3 years, ranging from 9 to 56 years. The dominant side was involved in 269 (58%) of 468 shoulders, whereas the nondominant side was involved in 199 (42%) shoulders. Patients were assessed at a median follow-up period of 4.2 years (ranging from 9 months to 16 years). Fifty-two of 253 (21%) patients undergoing physiotherapy required surgical intervention for MDI management, whereas the overall occurrence of redislocation was seen in 61 of 608 (10%) shoulders undergoing surgical procedures. The redislocation event occurred in 17 of 226 (7.5%) shoulders with open capsular shift management, in 21 of 268 (7.8%) shoulders with arthroscopic plication management, in 12 of 49 (24.5%) shoulders undergoing arthroscopic thermal shrinkage, and in 11 of 55 (22%) shoulders undergoing arthroscopic laser-assisted capsulorrhaphy.

CONCLUSIONS

Arthroscopic capsular plication and open capsular shift are the best surgical procedures for treatment of MDI after failure of rehabilitative management. Arthroscopic capsular plication shows results comparable to open capsular shift.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.