The prevalence of a large Hill-Sachs lesion that needs to be treated

From Labral Tears to Bone Loss: Imaging the Spectrum of Shoulder Instability

Glenohumeral instability results from disruptions in dynamic and static stabilizers of the glenohumeral joint, leading to dislocation, subluxation, or chronic apprehension. Although anterior glenohumeral instability is the most common form, posterior instability represents a distinct and often underrecognized condition with unique biomechanical and clinical characteristics. Imaging plays a critical role in evaluating shoulder instability, guiding diagnosis, and informing treatment decisions. Radiographs, computed tomography, and magnetic resonance imaging help assess structural abnormalities, such as labral tears, capsuloligamentous injuries, and osseous defects. Advanced imaging techniques, such as three-dimensional computed tomography and zero echo time magnetic resonance imaging, offer improved assessment of bone loss; magnetic resonance arthrography enhances the detection of soft tissue pathology. This article offers a comprehensive review of the imaging spectrum of glenohumeral instability, covering labral pathology, capsuloligamentous injuries, and bone loss. It highlights the critical role of precise imaging assessment in guiding optimal management strategies for both anterior and posterior instability patterns.

CT-Like MRI for Assessing Shoulder Bone and Ligament Injuries

Introduction This study investigates the use of "CT-like imaging" derived from a 3D multi-echo gradient-recalled echo (GRE) MRI sequence to assess the morphology of bones and ligaments in the shoulder joint. Methods CT-like images were produced using a 3D multi-echo GRE sequence with optimized imaging parameters, including a 5° flip angle and the combination of two echo acquisitions. A monopolar readout gradient was employed to minimize ligament blurring, and subtraction processing was applied to enhance the visualization of both bone and ligament structures. Results In a clinical case of anterior shoulder dislocation, the CT-like images successfully revealed bone injuries with clarity comparable to that of conventional CT. In addition, this MRI-based technique provided superior visualization of ligament structures. Conclusions This radiation-free imaging approach offers particular advantages for radiosensitive patients. However, further validation in multicenter studies across various age groups is necessary to establish its broader clinical utility.

The Radiologic Evaluation and Clinical Significance of Glenohumeral Bone Loss in Anterior Shoulder Instability

Glenoid and humeral bone loss is associated with a high incidence of recurrent shoulder instability and failure of arthroscopic stabilization procedures. However, the radiographic evaluation of bony Bankart and Hill-Sachs injuries continues to pose a diagnostic challenge, and a universally accepted optimal method of measurement is lacking. The purpose of this review is to summarize the advantages and disadvantages of various techniques and imaging modalities available for measuring glenoid bone loss in shoulder instability, including conventional roentgenography, 2-dimensional and 3-dimensional computed tomography (CT), and magnetic resonance imaging (MRI). We also review the concepts of engaging "on-track" and "off-track" Hill-Sachs lesions. Finally, we highlight the clinical importance of obtaining accurate determinations of bone loss by the various methods available, as it can affect surgical decision making and the appropriate procedure required to ensure shoulder stability is adequately restored.

Glenoid track revisited

The risk of Hill-Sachs lesion (HSL) to cause instability depends not only on the HSL but also on the glenoid size. Clinically, the only method to assess the risk of instability considering the dynamic interaction of both, the HSL together with the glenoid bone loss, is the glenoid track concept. Since it was introduced in a cadaveric study, its clinical efficacy and validity have been reported in the literature. Sometimes, the medial margin of the footprint (lateral margin of the glenoid track) is difficult to identify when a HSL is overriding the footprint. In such cases, we propose a method to draw an imaginary line connecting 2 landmarks. Although 3-dimensional computed tomography is the most accurate and widely used method to assess on/off-track lesions, our interest gradually is shifting toward magnetic resonance imaging (MRI), which has no radiation concern. The current magnetic resonance method is still under way. There are various risk factors influencing the recurrent instability after surgery. The glenoid track concept deals with only 1 of these factors, that is, instability caused by bony lesions. Therefore, the following 2 issues are important: 1) how to assess the glenoid track precisely and 2) how to incorporate other risk factors into consideration. The former can be achieved by obtaining the custom-made glenoid track width using not the fixed value of 83%, but more individualized value obtained by measuring the active horizontal extension angle of the opposite shoulder in the sitting position. At the same time, the gray zone (peripheral-track lesion) needs to be clearly defined. The latter can be achieved by incorporating the risk factors other than the bony lesions. One example is the Glenoid Track Instability Management Score (GTIMS), a combination of the glenoid track concept and the instability severity index score. This new scoring system is expected to increase the predictive potential of the scoring system, and accordingly to enhance clinical decision-making.

Management of bone loss in anterior shoulder instability

Bone defects are frequently observed in anterior shoulder instability. Over the last decade, knowledge of the association of bone loss with increased failure rates of soft-tissue repair has shifted the surgical management of chronic shoulder instability. On the glenoid side, there is no controversy about the critical glenoid bone loss being 20%. However, poor outcomes have been described even with a subcritical glenoid bone defect as low as 13.5%. On the humeral side, the Hill-Sachs lesion should be evaluated concomitantly with the glenoid defect as the two sides of the same bipolar lesion which interact in the instability process, as described by the glenoid track concept. We advocate adding remplissage to every Bankart repair in patients with a Hill-Sachs lesion, regardless of the glenoid bone loss. When critical or subcritical glenoid bone loss occurs in active patients (> 15%) or bipolar off-track lesions, we should consider anterior glenoid bone reconstructions. The techniques have evolved significantly over the last two decades, moving from open procedures to arthroscopic, and from screw fixation to metal-free fixation. The new arthroscopic techniques of glenoid bone reconstruction procedures allow precise positioning of the graft, identification, and treatment of concomitant injuries with low morbidity and faster recovery. Given the problems associated with bone resorption and metal hardware protrusion, the new metal-free techniques for Latarjet or free bone block procedures seem a good solution to avoid these complications, although no long-term data are yet available.

Minimum 10-year follow-up outcomes of arthroscopic Bankart's repair with metallic anchors: Reliable results with low redislocation rates

BACKGROUND

With stiff competition from alternative albeit more expensive counterparts, it has become important to establish the applicability of metallic anchors for shoulder instability in the modern era. This can be accomplished, in part, by analysing long-term outcomes.

AIM

To analyse minimum 10-year outcomes from 30 patients following arthroscopic anterior stabilisation using metallic anchors.

METHODS

Prospectively collected data from arthroscopic Bankart repairs performed using metal anchors during 2007P-2010 were retrospectively analysed in this single-surgeon study. Comprehensive data collection included historical and clinical findings, dislocation details, operative specifics, and follow-up radiological and clinical findings including shoulder scores. The primary outcomes were patient-reported scores (Constant, American Shoulder and Elbow Surgeons [ASES], and Rowe scores) and pain and instability on a visual analogue scale (VAS).

RESULTS

A 3% recurrence rate of dislocation was noted at the final follow-up. Total constant scores at 10 years postoperatively measured between 76 and 100 (mean 89) were significantly better than preoperative scores (mean 62.7). Congruous improvements were also noted in the Rowe and ASES scores and VAS at the 10-year review.

CONCLUSION

Reliable long-term outcomes with metallic anchors in surgery for shoulder instability can be expected. Our results provide additional evidence of their continued, cost-effective presence in the modern scenario.

Treatment of Shoulder Cartilage Defects in Athletes

Articular cartilage defects in the glenohumeral joint may be found in laborers, the elderly, and young athletes, among others. Various factors can contribute to cartilage damage, including prior surgery, trauma, avascular necrosis, inflammatory arthritis, joint instability, and osteoarthritis. There is a wide variety of treatment options, from conservative treatment, injections, and surgical options, including arthroscopic debridement, microfracture, osteochondral autograft transfer, osteochondral graft transplantation, autologous chondrocyte implantation, and the newly emerging techniques such as biologic augmentation. There is a challenge to determine the optimal treatment options, especially for young athletes, due to limited outcomes in the literature. However, there are many options which are viable to address osteochondral defects of the glenohumeral joint.

Glenoid track and subcritical Hill-Sachs lesion

Background

We have proposed the concept of glenoid track ("on-track/off-track" lesion) to evaluate the risk of engagement of the Hill-Sachs lesion with the glenoid after arthroscopic Bankart repair. This concept has been widely used and many clinical validation studies have been reported. To measure the glenoid track width, we have recommended to use 3-dimensional computed tomography (CT) images. However, the CT method has the issue of radiation exposure and involves time and effort to make 3-dimensional CT images from 2-dimensional images. For these reasons, there are several reports describing the measurement method using magnetic resonance imaging. Recently, the threshold of the critical glenoid bone loss becomes lower. A zone of bone loss below the critical size is called "subcritical bone loss", which might be related to deterioration of quality of life and bone grafting is recommended. We applied the concept of "subcritical bone loss" to the glenoid track. Patients with "on-track" lesions can be divided into 2 subgroups: those with a "peripheral-track" lesion (most medial 1/4) and those with a "central-track" lesion (the rest 3/4). More recently, similar evaluation methods to evaluate the risk of "off-track" lesions have been reported: ''distance to dislocation'' and "Hill-Sachs interval/glenoid track ratio". Also, similar concept to "peripheral-track" lesion, "near-track" lesion was reported. The concept of "peripheral-track" lesion is a concept of assessing an "on-track" lesion which is very close to the medial margin of the glenoid track (subcritical bone loss).

Methods

Similar evaluation methods to evaluate the risk of "off-track" or "peripheral-track" lesions were proposed in the literature. A review was performed by searching PubMed. Journal articles published between January 2014 and January 2023 were taken into account. They were compared and their differences were explained.

Results

The "near-track" lesion concept is similar to "peripheral-track" lesion. However, the cutoff value is different: Hill-Sachs occupancy ≥ 75% is the "peripheral-track" lesion, whereas "distance to dislocation" < 8 mm is the "near-track" lesion.

Conclusion

We introduced update of the glenoid track concept including the evaluation method, peripheral-track lesion, and its clinical application.

Controversies in surgical management of anterior shoulder instability. State of the Art

Arthroscopic Bankart repair (ABR) has been accepted as a standard procedure for anterior shoulder instability with a minimum or no glenoid bone loss and an on-track Hill-Sachs lesion if present. However, several controversies exist in the surgical treatment of anterior shoulder instability. This article will discuss some of these controversies in, "simple," dislocations (without bone loss) as well as, "complex," (with critical bone loss). Determining which patients will benefit from an arthroscopic procedure depends on multiple factors including age, activity level, adequate determination of bone loss, performed with feasible and reliable imaging techniques. In the absence of concomitant significant bony and soft tissue pathology, ABR alone can provide satisfactory clinical results on a long-term basis. Controversies, including whether to remove cartilage from the edge of the glenoid, knotted versus knotless anchors, and routine rotator interval closure, still exist. In cases with significant bone loss, several bone restoring procedures have been described, such as, the Latarjet procedure, iliac crest bone graft, arthroscopic anatomic glenoid reconstruction with a frozen distal tibial allograft, and fresh distal tibial allograft reconstruction. This article will address these controversies and provide guidance based on available published data.

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.

Utility of Talus Osteochondral Allograft Augmentation for Varying Hill-Sachs Lesion Sizes: A Cadaveric Study

Background

Humeral head reconstruction with fresh osteochondral allografts (OCA) serves as a potential treatment option for anatomic reconstruction. More specifically, talus OCA is a promising graft source because of its high congruency with a dense cartilaginous surface.

Purpose

To analyze the surface geometry of the talus OCA plug augmentation for the management of shoulder instability with varying sizes of Hill-Sachs lesions (HSLs).

Study Design

Controlled laboratory study.

Methods

Seven fresh-frozen cadaveric shoulders were tested in this study. The humeral heads were analyzed using actual patients' computed tomography scans. Surface laser scan analysis was performed on 7 testing states: (1) native state; (2) small HSL; (3) talus OCA augmentation for small HSL; (4) medium HSL; (5) talus OCA augmentation for medium HSL; (6) large HSL; and (7) talus OCA augmentation for large HSL. OCA plugs were harvested from the talus allograft and placed in the most medial and superior aspect of each HSL lesion. Surface congruency was calculated as the mean absolute error and the root mean squared error in the distance. A 1-way repeated-measures analysis of variance was performed to evaluate the effects of the difference in the HSL size and associated talus OCA plugs on surface congruency and the HSL surface area.

Results

The surface area analysis of the humeral head with the large (1469 ± 75 mm2), medium (1391 ± 81 mm2), and small (1230 ± 54 mm2) HSLs exhibited significantly higher surface areas than the native state (1007 ± 88 mm2; P < .001 for all sizes). The native state exhibited significantly lower surface areas as compared with after talus OCA augmentation for large HSLs (1235 ± 63 mm2; P < .001) but not for small or medium HSLs. Talus OCA augmentation yielded improved surface areas and congruency after treatment in small, medium, and large HSLs (P < .001).

Conclusion

Talus OCA plug augmentation restored surface area and congruency across all tested HSLs, and the surface area was best improved with the most common HSLs-small and medium.

Clinical Relevance

Talus OCA plugs may provide a viable option for restoring congruity of the shoulder in patients with recurrent anterior glenohumeral instability and an HSL.

Humeral Head Reconstruction With Osteochondral Allograft: Bone Plug Optimization for Hill-Sachs Lesions Using CT-Based Computer Modeling Analysis

Background

Engaging Hill-Sachs lesions (HSLs) pose a significant risk for failure of surgical repair of recurrent anterior shoulder instability. Reconstruction with fresh osteochondral allograft (OCA) has been proposed as a treatment for large HSLs.

Purpose

To determine the optimal characteristics of talus OCA bone plugs in a computer-simulated HSL model.

Study Design

Descriptive laboratory study; Level of evidence, 6.

Methods

Included were 132 patients with recurrent anterior instability with visible HSLs; patients who had multidirectional instability or previous shoulder surgery were excluded. Three-dimensional computed tomography models were constructed, and a custom computer optimization algorithm was generated to maximize bone plug surface area at the most superior apex (superiorization) and minimize its position relative to the most medial margin of the HSL defect (medialization). The optimal number, diameter, medialization, and superiorization of the bone plug(s) were reported. Percentages of restored glenoid track width and conversion from off- to on-track HSLs after bone plug optimization were calculated.

Results

A total of 86 patients were included in the final analysis. Off-track lesions made up 19.7% of HSLs and, of these, the mean bone plug size was 9.9 ± 1.4 mm, with 2.2 mm ± 1.7 mm of medialization and 3.3 mm ± 2.9 mm of superiorization. The optimization identified 21% of HSLs requiring 1 bone plug, 65% requiring 2 plugs, and 14% requiring 3 plugs, with a mean overall coverage of 60%. The mean width of the restored HSLs was 68%, and all off-track HSLs (n = 17) were restored to on-track. A Jenks natural-breaks analysis calculated 3 ideal bone plug diameters of 8 mm (small), 10.4 mm (medium), and 12 mm (large) in order to convert this group of HSLs to on-track.

Conclusion

Using a custom computer algorithm, we have demonstrated the optimal talus OCA bone plug diameters for reconstructing HSLs to successfully restore the HSL track and, on average, 60% of the HSL surface area and 68% of the HSL width.

Clinical Relevance

Reconstructing HSLs with talus OCA is a promising treatment option with excellent fit and restoration of HSLs. This study will help guide surgeons to optimize OCA bone plugs from the humeral head, femoral head, and talus for varying sizes of HSLs.

Glenoid Track Assessment at Imaging in Anterior Shoulder Instability: Rationale and Step-by-Step Guide

Anterior shoulder dislocation is the most common form of joint instability in humans, usually resulting in soft-tissue injury to the glenohumeral capsuloligamentous and labral structures. Bipolar bone lesions in the form of fractures of the anterior glenoid rim and posterolateral humeral head are often associated with anterior shoulder dislocation and can be a cause or result of recurrent dislocations. Glenoid track assessment is an evolving concept that incorporates the pathomechanics of anterior shoulder instability into its management. Currently widely endorsed by orthopedic surgeons, this concept has ramifications for prognostication, treatment planning, and outcome assessment of anterior shoulder dislocation. The glenoid track is the contact zone between the humeral head and glenoid during shoulder motion from the neutral position to abduction and external rotation. Two key determinants of on-track or off-track status of a Hill-Sachs lesion (HSL) are the glenoid track width (GTW) and Hill-Sachs interval (HSI). If the GTW is less than the HSI, an HSL is off track. If the GTW is greater than the HSI, an HSL is on track. The authors focus on the rationale behind the glenoid track concept and explain stepwise assessment of the glenoid track at CT or MRI. Off-track to on-track conversion is a primary goal in stabilizing the shoulder with anterior instability. The key role that imaging plays in glenoid track assessment warrants radiologists' recognition of this concept along with its challenges and pitfalls and the production of relevant and actionable radiology reports for orthopedic surgeons-to the ultimate benefit of patients. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Management of off-track Hill-Sachs lesions in anterior glenohumeral instability

Bone loss has been identified as a risk factor for recurrent shoulder dislocations or failure after soft tissue repair. Although the range for "critical" bone loss is yet to be determined, glenoid and humeral bone defects should not be regarded as independent problems, but the interaction between them during shoulder motion should be evaluated as suggested by the glenoid track concept. The glenoid track concept is now widely accepted and considered essential for making decisions about surgery. Soft-tissue procedures usually work well in patients with on-track Hill-Sachs lesions but in off-track lesions do not. In this situation additional procedures should be performed.Different surgical options have been described to address off-track Hill-Sachs lesions, most commonly remplissage, Latarjet or free bone block procedures. Coracoid graft and free bone grafts convert the off-track Hill-Sachs lesion into on-track by lengthening the glenoid-track, whereas remplissage fill-in the humeral lesion so that it does not engage. In the setting of a Hill-Sachs lesion with little or no glenoid bone loss, remplissage has demonstrated satisfactory outcomes with a low complications and recurrence rate. Favorable results have been reported with glenoid bone grafting when managing isolated Hill-Sachs or bipolar lesions. Studies analyzing Latarjet and Eden-Hybinette procedures show that both procedures are safe and effective in the management of anterior glenohumeral instability. Attention should be paid to those patients with large bone defects not amenable to be restored with an isolated Latarjet that may be better addressed with an Eden-Hybinnete or adding a remplissage to the Latarjet procedure.

[Chronic posttraumatic shoulder instability]

Chronic posttraumatic shoulder instability is characterized by trauma-associated, recurrent dislocations. Surgical treatment is indicated in most cases but it remains controversial how risk factors should be weighted to decide between arthroscopic Bankart repair (ABR), Latarjet or alternative procedures. Known risk factors for recurrence are patient age, hyperlaxity, sports profile and bone loss. Surgical techniques are discussed in detail. The ABR leads to high patient satisfaction and return to sports; however, in association with risk factors, recurrent dislocations are seen even several years later. Latarjet or bone block procedures lead to high patient satisfaction, sustainable stability as a revision procedure, but can also be primarily indicated for chronic instability depending on risk factors. Early complications are more frequent but of a minor nature in most cases. All techniques are known for a serious learning curve. If performed well, they do not seem to increase the risk of arthritis, which is most affected by the number of lifetime dislocations and higher energy trauma.

Arthroscopic Hill-Sachs Filling Technique Using an Absorbable Interference Screw

We present an arthroscopic technique used to treat traumatic shoulder instability in the patient with a Hill-Sachs lesion, especially an off-track lesion. The incidence of this bony defect is approximately 40% to 90% of all anterior shoulder instability cases-and up to 100% in patients with recurrent anterior instability. Incorrect management of this humeral bone defect can lead to treatment failure, and it is essential to define characteristics such as the lesion's location, depth, width, and orientation. Many arthroscopic and open procedures have been described for the surgical management of the Hill-Sachs lesion. Using arthroscopy for the surgical treatment of shoulder instability offers numerous advantages. We describe an arthroscopic technique that consists of filling the Hill-Sachs lesion with absorbable interference screws made out of an advanced biocomposite material. After repair of the Hill-Sachs lesion, the Bankart lesion is repaired. As these screws are resorbed by bone tissue over several months, the bony anatomy is restored.

A Case Series of Whether Arthroscopic Bankart Repair Following Primary Traumatic Anterior Shoulder Dislocation Versus Recurrent Dislocation in Soldiers Has Any Effect on the Postoperative Recurrence Rate

Background

Anterior traumatic shoulder dislocation is very common among soldiers or any young population following injury, which is invariably treated by closed reduction. The dislocation when treated nonsurgically has a 71% high rate of recurrence. There is not much data available on the rate of recurrence when primary dislocation (first time) was treated by arthroscopic Bankart repair and in those who have recurrent (multiple) dislocations before surgery.

Aim

This study aims to report the postoperative recurrence rate in soldiers with first-time dislocation versus those with recurrent dislocations before surgery.

Study design

The present study is a level IV case series treatment study.

Methods

In this prospective study, 143 soldiers were included, of which 82 patients had first-time dislocation (F group) and 61 patients had recurrent dislocation before surgery (R group). The patients were evaluated and followed up for over three years. Nonabsorbable PEEK suture anchors (Chetan Meditech, India) were used for arthroscopic Bankart repair. The recurrence rates, Rowe scores, visual analog scale (VAS) scores, subjective shoulder values (SSVs), and satisfaction were compared. We also used the Simple Shoulder Test (SST) score for evaluation. The scores were recorded preoperatively and at three-year follow-up. The range of motion, postoperative function, recurrence rates, and return to pre-injury state was evaluated.

Results

A total of 143 patients were included, providing 97.3% follow-up at an average of 36 months. The postoperative recurrence rate was 19.7% in the F group and 58.3% in the R group (P < 0.001). The odds of postoperative recurrence were five times higher in the recurrent dislocation group (odds ratio (OR): 5.23).

Conclusion

Patients who underwent repair after first-time dislocation show a lower postoperative recurrence rate as compared with those who had multiple dislocations before surgery. It is prudent to advise early repair even after the first dislocation especially in young active soldiers to reduce the risk of postoperative recurrence.

Remplissage for Anterior Shoulder Instability: History, Indications, and Outcomes

Remplissage is a nonanatomic capsulotenodesis of the infraspinatus tendon used to fill engaging or "off-track" Hill-Sachs lesions in patients at high risk of recurrent instability with isolated Bankart repair. Indications for remplissage are expanding, as the importance of subcritical bone loss and the glenoid track on patient outcomes and recurrence rates continues to be investigated. Remplissage is also suggested in patients at high risk of recurrent instability following isolated anterior labral repair, such as collision and contact athletes with Hill-Sachs lesions that have not reached the threshold of "off track." Multiple arthroscopic remplissage techniques exist including, more recently, knotless techniques.

Evaluating Bone Loss in Anterior Shoulder Instability

Anterior shoulder instability is a common orthopaedic condition that often involves damage to the bony architecture of the glenohumeral joint in addition to the capsulolabral complex. Patients with recurrent shoulder dislocations are at increased risk for glenohumeral bone loss, as each instability event leads to the accumulation of additional glenoid and/or humeral head bone defects. Depending on the degree of bone loss, successful treatment may need to address bony lesions in addition to injured soft-tissue structures. As such, a thorough understanding of methods for evaluating bone loss preoperatively, in terms of location, size, and significance, is essential. Although numerous imaging modalities can be used, three-dimensional imaging has proven particularly useful and is now an integral component of preoperative planning.

Normal Humeral Head Ossification in Pediatric and Adolescent Shoulders Can Mimic Hill-Sachs Lesions: A Magnetic Resonance Imaging-based Study

BACKGROUND

The sequential maturation of the humeral head (HH) as viewed on magnetic resonance imaging (MRI) has not been described to date. Proper assessment may be complicated by the presence of physeal tissue in pediatric patients. Past studies suggest that skeletally immature patients may also have a higher risk of a false-positive diagnosis of Hill-Sachs lesion on MRI. The purpose of this study was to define pediatric HH developmental patterns using MRI and to investigate for any associations with findings of known false-positive Hill-Sachs.

METHODS

Picture Archiving and Communication System (PACS) records at an urban academic tertiary care musculoskeletal facility from 2014 to 2020 were queried for shoulder MRI in patients aged 0 to 15 years. Patients were excluded if they had a history of glenohumeral instability, fracture, growth arrest, brachial plexus injury, surgery, or infection. All images were independently evaluated by a musculoskeletal fellowship-trained radiologist. Each HH was staged based on skeletal maturity.

RESULTS

For both sexes, HHs matured in a predictable manner with increasing chronological age associated with a higher ossification stage. False Hill-Sachs lesions were observed in girls aged 4 to 7 and boys aged 5 to 14, exclusively during stage I to II ossification.

CONCLUSIONS

False Hill-Sachs lesions were visualized on MRI in stage I to II proximal humerus ossification. Due to differential timing of skeletal maturation, males present with false Hill-Sachs lesions at a later age than females on average. When interpreting shoulder MRI for glenohumeral instability, clinicians should be cautious of false Hill-Sachs lesions, especially in younger patients with distinct greater tuberosity and HH ossification centers (stage I to II ossification).

LEVEL OF EVIDENCE

Level III.

Editorial Commentary: A Consensus of Experts Complements the Clinical Evidence on Diagnosis and Treatment of Anterior Glenohumeral Instability

The current diagnostic and treatment strategies for anterior glenohumeral instability have been refined by high-quality clinical and basic science studies, but many controversies remain. These include the bone loss threshold for arthroscopic Bankart repair and the influence of other clinical factors on this decision, the optimal bracing position following anterior glenohumeral dislocation, and the optimal coracoid graft orientation during the Latarjet procedure. Randomized clinical trials often present conflicting results, and many of these are small-sample and fragile studies. Obtaining an expert consensus on the topic, by means of the Delphi method, is an attractive alternative to such clinical trials. Several studies employing variations of the Delphi method have addressed the diagnosis and treatment of anterior glenohumeral instability. These have stressed the importance of a meticulous technique during arthroscopic Bankart repair and of recognition of glenoid and humeral bone loss and treating this appropriately. These studies have also helped identify areas where consensus is modest or lacking to motivate additional clinical research study.

Arthroscopic remplissage is safe and effective: clinical and magnetic resonance results at a minimum 3 years of follow-up

BACKGROUND

Large Hill-Sachs lesions are considered a risk factor for recurrence of instability after arthroscopic Bankart repair alone. The aim of this study was to demonstrate that remplissage is a safe procedure that effectively reduces the risk of recurrent dislocations without causing fatty degeneration of the infraspinatus at medium-term follow-up.

METHODS

Patients who underwent arthroscopic Bankart repair and remplissage with a minimum 3 years of follow-up were included. Constant-Murley (CMS), American Shoulder and Elbow Surgeons (ASES), and Walch-Duplay scores were evaluated. Magnetic resonance imaging (MRI) was performed to detect the appearance of fatty infiltration inside the infraspinatus muscle, the percentage of the Hill-Sachs lesion filled by the tendon and its integration, and the onset of rotator cuff tears.

RESULTS

Thirteen patients (14 shoulders) with a mean follow-up of 55.93 (± 18.16) months were enrolled. The Walch-Duplay score was 95.00 [87.25-100.00], with a return to sport rate of 100%. Both the CMS and the ASES indicated excellent results. The affected shoulders showed a statistically significant reduction in active external rotation both with the arm at the side (ER1) and with the arm at 90° of abduction (ER2) (p = 0.0005 and p = 0.0010, respectively). A reduction in infraspinatus isometric strength was found for both ER1 and ER2, but this reduction was only statistically relevant in ER2 (p = 0.0342). There was a traumatic recurrence of instability in two cases (14.28%). MRI evaluation demonstrated an absence of adipose infiltration in 50% of cases and only a minimal amount in the remaining 50%. In 12 cases (85.72%), the capsulotenodesis completely filled the lesion and good tendon-bone integration was observed.

CONCLUSION

Arthroscopic remplissage provided successful clinical outcomes without fatty infiltration of the infraspinatus and with good healing of the tissues. The low risk of recurrence was associated with an objective limitation on active external rotation, but this did not influence the patients' daily or sports activities.

LEVEL OF EVIDENCE

Cohort study, level of evidence 3.

With the exception of the Hill-Sachs interval, CT and MRI show no significant differences in the diagnostic value of the HSL measurement regardless of the measurement technique

PURPOSE

The aim of the current study was to compare the diagnostic precision and reliability of different methods in measuring Hill-Sachs lesions (HSLs) using MRI and CT.

METHODS

A total of 80 consecutive patients with a history of anterior shoulder instability were retrospectively included. The preoperative CT and MRI scans of the affected shoulders were analysed. To investigate the ability of the Franceschi grading, Calandra classification, Richards, Hall, and Rowe grading scale, Flatow percentage and "glenoid track" assessment according to Di Giacomo et al. to quantify the extent of humeral bone loss, the results of each measurement method obtained with MRI were compared with those achieved with CT. In addition, the intra- and inter-rater reliabilities of each measurement method using CT and MRI were calculated and compared.

RESULTS

A significant difference was found between CT and MRI in the determination of the Hill-Sachs interval (HSI) (p = 0.016), but not between the results of any of the other measurement techniques. With the exceptions of the Franceschi grade and Calandra classification, all measurement methods showed good or excellent intra- and inter-rater reliabilities for both MRI and CT.

CONCLUSIONS

While the determination of the HSI with MRI was more accurate, all other analysed techniques for measuring the amount of humeral bone loss showed similar diagnostic precision. With regard to the intra- and inter-rater reliabilities, all measurement techniques analysed, with the exception of the Franceschi and Calandra classifications, provided good to very good reliabilities with both CT and MRI.

LEVEL OF EVIDENCE

III.

Editorial Commentary: It Is Not the Size, But the Location of Hill-Sachs Lesion That Matters

The risk of a Hill-Sachs lesion (HSL) to engage the anterior glenoid rim depends on the location of the medial margin of the HSL relative to the anterior rim of the glenoid. The same-sized HSL can be engaging or nonengaging depending upon the size of the glenoid. In order to assess these bony lesions (bipolar lesion) together, the glenoid track concept has been introduced: an on-track lesion (stable) and an off-track lesion (unstable). Three-dimensional computed tomography (3D-CT) confirms that more medialized HSLs have larger volume, greater width, more surface area loss, and higher lesion angles (HS angle), and are more inferior in the humeral head. We know that medialization of the HSL is a definitive risk factor to make it off track, whereas the volume, surface area, and width are all subordinate risk factors dependent on the medialization. On the other hand, while we know very little about the orientation of the HSL, recent research shows a significant association between the medialization and orientation of the HSL. However, we do not know whether the orientation is an independent risk factor or dependent on the medialization. There are two things I emphasize when I look at a HSL: 1) do not look at the HSL alone, but look at the glenoid as well, and 2) the risk of the HSL depends on the location of the medial margin of the HSL relative to the glenoid, not on the volume, depth, or length.

Arthroscopic bone block metal-free fixation for anterior shoulder instability. Short-term functional and radiological outcomes

INTRODUCTION

Anterior glenohumeral bone loss reconstruction reduces failure rates after soft tissue surgery in patients with large glenoid bone defects. Multiple bone block techniques have been described, most with metal hardware fixation. The objective of this study is to evaluate the safety, as well as the short-term functional and radiological results of an arthroscopic bone block metal-free fixation or bone block cerclage.

MATERIAL AND METHODS

Retrospective study of patients with glenohumeral instability and>15% glenoid bone loss operated during 2019 with follow-up of at least 12 months. Radiography and computerized tomography studies were performed. Functional outcomes were evaluated before and after surgery with the Western Ontario Shoulder Instability Index and Rowe score.

RESULTS

A total of 21 patients with a median age of 30.6 (SD 7.1) were included. All showed radiographic consolidation at 3 months follow-up. A percentage of 90.4 of bone grafts presented osteolysis at peripherical areas and 95.2% revealed consolidation in the areas with contact to the glenoid. The median glenoid estimated surface went from 79.3% before surgery to 98.4% at 12 months. Functional scores were statically significant (P<.001) for Western Ontario Shoulder Instability Index (35.6-86.9) and Rowe score (25.2 to 96.4). No serious complications were reported.

CONCLUSION

The bone block cerclage is a safe, metal-free technique that achieves total consolidation of the bone graft and favorable functional and radiological outcomes at 12 months follow-up.

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.

Shoulder: Instability

Glenohumeral instability is the inability to keep the humeral head centered in the glenoid fossa. Glenohumeral instability can be classified according to etiology and direction of instability. The glenoid labrum, the glenohumeral ligaments, and the bony structures contribute to the stability glenohumeral joint and need to be addressed with imaging. One of the difficulties with accurately diagnosing labral tears on MR imaging is the normal labral variants, which can sometimes appear similar to tears. The location and extent of a Hill-Sachs lesion and glenoid rim defects need to be related to recognize engaging Hill-Sachs lesions or off-track situations. There are several types of labral tears that are not associated with a prior dislocation. SLAP tears are one of the more common tears of the labrum and can sometimes be difficult to distinguish from a normal variant superior sublabral recess. Labral tears in overhead thrower occur in the posterosuperior labrum, adjacent to the posterior rotator cuff tears in these athletes. Tears in the posterosuperior labrum are also associated with spinoglenoid notch paralabral cysts, which can be painful and cause external rotation weakness.

Factors related to large bone defects of bipolar lesions and a high number of instability episodes with anterior glenohumeral instability

Background

Significant bone defects are associated with poor clinical results after surgical stabilization in cases of glenohumeral instability. Although multiple factors are thought to adversely affect enlargement of bipolar bone loss and increased shoulder instability, these factors have not been sufficiently evaluated. The purpose of this study was to identify the factors related to greater bone defects and a higher number of instability episodes in patients with glenohumeral instability.

Methods

A total of 120 consecutive patients with symptomatic unilateral instability of the glenohumeral joint were retrospectively reviewed. Three-dimensional surface-rendered/registered models of bilateral glenoids and proximal humeri from computed tomography data were matched by software, and the volumes of bone defects identified in the glenoid and humeral head were assessed. After relationships between objective variables and explanatory variables were evaluated using bivariate analyses, factors related to large bone defects in the glenoid and humeral head and a high number of total instability episodes and self-irreducible dislocations greater than the respective 75th percentiles were evaluated using logistic regression analyses with significant variables on bivariate analyses.

Results

Larger humeral head defects (P < .001) and a higher number of total instability episodes (P = .032) were found to be factors related to large glenoid defects. On the other hand, male sex (P = .014), larger glenoid defects (P = .015), and larger number of self-irreducible dislocations (P = .027) were related to large humeral head bone defects. An increased number of total instability episodes was related to longer symptom duration (P = .001) and larger glenoid defects (P = .002), and an increased number of self-irreducible dislocations was related to larger humeral head defects (P = .007).

Conclusions

Whereas this study showed that bipolar lesions affect the amount of bone defects reciprocally, factors related to greater bone defects differed between the glenoid and the humeral head. Glenoid defects were related to the number of total instability episodes, whereas humeral head defects were related to the number of self-irreducible dislocations.

Long-term results of arthroscopic Bankart repairs for anterior instability of the shoulder in patients aged thirty years or older

INTRODUCTION

Bankart repair is a popular treatment for anterior shoulder instability. However, long-term failure rates of arthroscopic Bankart repair remain higher than Latarjet procedures. The purpose of this study was to report long-term results of arthroscopic Bankart repair in patients greater than 30 years old and analyze risk factors of failure following arthroscopic Bankart repair that are independent of younger age.

MATERIALS AND METHODS

Between January 1999 and December 2003, 41 patients aged 30 years or older treated with arthroscopic Bankart repair for anterior shoulder instability were evaluated. Outcome measures included pain (VAS), range of motion, post-operative Walch-Duplay, WOSII scores, complications, failure rate, and risk factors of failure. Failure was defined as recurrent dislocation or subluxation.

RESULTS

At a mean 12-year follow-up (range; 10-15 years), the failure rate of arthroscopic Bankart repair in patients aged 30 years and older was 37%. The mean post-operative Walch-Duplay score was significantly higher in patients who had no recurrence compared to those who had had recurrence of instability (100 versus 90, p=0.02). An ISIS score≥3 (p=0.02), a glenoid bone lesion (p=0.06), and a Hill-Sachs lesion>15% defect (p=0.001) were risk factors for recurrent instability. When considering a modified ISIS score that accounted for bony defects on the glenoid and humeral side, patients with an ISIS score <3 + no glenoid lesion + Hill-Sachs ≤ 15% had a recurrence rate of 0%.

CONCLUSION

The failure rate of arthroscopic Bankart repairs in patients over 30 was higher than previously reported. Specifically, patients with an ISIS >3 and bony glenoid defects and/or Hill-Sachs lesions > 15% may be at higher risk for recurrent instability following an isolated arthroscopic Bankart repair. Alternative stabilization techniques may need to be considered for this subset of patients.

Measuring Bone Loss in the Unstable Shoulder: Understanding and Applying the Track Concept

An interesting international debate has been developed over the past 10 years (the last decade) surrounding the surgical procedure for recurrent anteroinferior instability and a definitive consensus is lacking on the factors which favor one technique over another, especially when bone loss is present (soft tissue vs. bone block). Glenoid bone loss is commonly observed in the shoulder with anterior instability, and it is difficult to evaluate the shape of the glenoid using plain radiograph, therefore, computed tomography or intraoperative observation is recommended for accurate assessment of glenoid bone loss and Hill-Sachs lesion. When we consider the bony defect of the glenoid as a risk factor for surgical failure, it is crucial to take into consideration the features of a concomitant Hill-Sachs lesion. However, all the previous reports focusing on the size of the Hill-Sachs lesion or on the glenoid bone loss in isolation, overlook the interaction of the 2 lesions through the arc of range of motion and how this may influence instability. The glenoid track is the first model to determine, in a dynamic way, how bone loss on both sides of the joint can lead to instability. The glenoid track is a zone of contact created by the glenoid on the humeral articular surface when the arm is moved along the end-range of motion (abduction and external rotation). The use of the glenoid track concept can potentially help guide surgical decision-making.

Does an "Off-Track" Hill-Sachs Lesion That Is Misclassified as "Non-Engaging" Affect Outcomes From Bankart Repair Alone Compared With Bankart Repair Combined With Remplissage?

PURPOSE

To determine how intraoperative assessment (engagement test) may affect recurrent dislocation rate and to compare the clinical outcomes, recurrence rates, and presence of on-/off-track conditions between cases that received arthroscopic Bankart repair alone (nonengaged Hill-Sachs lesion) and Bankart repair with remplissage (engaged Hill-Sachs lesion).

METHODS

We retrospectively reviewed 213 patients who underwent arthroscopic Bankart repair alone (186 patients with nonengaging lesions, group A) or with remplissage (27 patients with engaging lesion, group B) for recurrent anterior shoulder instability with <25% glenoid bone defect. The presence of an engaging Hill-Sachs lesion was determined during arthroscopic evaluation. On-track or off-track lesions were assessed retrospectively from preoperative 3-dimensional (3D) computed tomography (CT).

RESULTS

Mean glenoid bone defect was 13.7% in group A and 20.7% in group B (P < .001). Off-track lesions were identified in 8.1% (15/186) and 100% (27/27) in group B. At the final follow-up (minimum 2 years; mean follow-up periods after surgery of 50.1 months in group A and 47.7 months in group B), there were no significant differences in shoulder functional scores and recurrence rates between groups, despite improvement after surgery. In the off-track lesion (group A-1: nonengaging but off-track lesion), recurrence instability occurred in 9 patients (60%, 9/15). Also, comparing group A-1 and group B, we noted significant differences in shoulder functional scores and recurrence rates (P < .001).

CONCLUSION

Of 186 patients, 8.1% with nonengaging Hill-Sachs lesions during direct arthroscopic examination under anesthesia actually demonstrated off-track lesions on preoperative 3D CT scans retrospectively, with 60% experiencing recurrent instability. Intraoperative manual assessment for Hill-Sachs engagement was inferior to 3D CT scan in establishing the presence of off-track defects.

LEVEL OF EVIDENCE

III, retrospective comparative study.

Determining On-/Off-track Lesions in Glenohumeral Dislocation Using Multiplanar Reconstruction Computed Tomography Is Easier and More Reproducible Than Using 3-dimensional Computed Tomography

BACKGROUND

The glenoid track is a useful tool to predict engagement and therefore the risk of recurrence of dislocation in the presence of Hill-Sachs and/or bony Bankart lesions. To assess the glenoid track preoperatively, only methods using 3-dimensional reconstruction (3DR) have been described, but these lack a standardized, reliable, and easy description.

PURPOSE/HYPOTHESIS

The purpose was to evaluate a new method for determining the glenoid track using computed tomography (CT) scan with multiplanar reconstruction (MPR) in comparison with using 3DR images. Our hypothesis was that the MPR method would be easier to standardize and more reproducible.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

A total of 52 patients whose arthro-CT scan revealed a Hill-Sachs lesion, whether in combination with a bony Bankart lesion or not, were included. Digital Imaging and Communications in Medicine data from the 52 CT scans were all analyzed using open source image analysis software. Glenoid width, with or without associated bony defect, and the Hill-Sachs interval (HSI) were measured on MPR as well as on 3DR images. All measurements obtained using both methods were directly compared and evaluated for intra- and interobserver reliability.

RESULTS

In absolute values, only small differences were seen between the MPR and 3DR methods, amounting to a maximal difference of 0.07 cm for the HSI and 0.04 cm for the glenoid width. For glenoid measurements, both methods were similar. For humeral measurements, the MPR method demonstrated higher inter- and intraobserver reliability than did the 3DR method.

CONCLUSION

The newly described MPR method for the assessment of the glenoid track and HSI is at least as accurate as the published 3DR method, with better intra- and interobserver reliability. Because MPRs are also easier to obtain, this method could be recommended in daily practice.

Clinical and radiological examination of bony-mediated shoulder instability

The coexistence of glenoid and humeral head bone defects may increase the risk of recurrence of instability after soft tissue repair.

Revealed factors in medical history such as male gender, younger age of dislocation, an increasing number of dislocations, contact sports, and manual work or epilepsy may increase the recurrence rate of instability.

In physical examination, positive bony apprehension test, catching and crepitations in shoulder movement may suggest osseous deficiency.

Anteroposterior and axial views allow for the detection of particular bony lesions in patients with recurrent anterior shoulder instability.

Computed Tomography (CT) with multiplanar reconstruction (MPR) and various types of 3D rendering in 2D (quasi-3D-CT) and 3D (true-3D-CT) space allows not only detection of glenoid and humeral bone defects but most of all their quantification and relations (engaging/not-engaging and on-track/off-track) in the context of bipolar lesion.

Magnetic resonance imaging (MRI) is increasingly developing and can provide an equally accurate measurement tool for bone assessment, avoiding radiation exposure for the patient.

Cite this article: EFORT Open Rev 2020;5:815-827. DOI: 10.1302/2058-5241.5.200049

Arthroscopic Bankart repair with remplissage versus Latarjet procedure for management of engaging Hill-Sachs lesions with subcritical glenoid bone loss in traumatic anterior shoulder instability: a systematic review and meta-analysis

BACKGROUND

A large engaging Hill-Sachs lesion (HSL) with subcritical glenoid bone loss (GBL) is approached through either increasing the glenoid arc by the Latarjet procedure or converting the HSL to an extra-articular defect by arthroscopic Bankart repair with remplissage (BRR). Until now, there has been no evidence-based consensus about which of these 2 most appropriate procedures is the better surgical choice. The purpose of this study was to analyze the current literature comparing results of BRR vs. the Latarjet procedure in the treatment of engaging HSLs with subcritical GBL.

METHODS

A comprehensive review of the PubMed and Cochrane databases was completed for studies that compared the clinical outcomes and complications of BRR vs. the Latarjet procedure with minimum follow-up of 2 years. The outcome measures analyzed included postoperative Rowe score, visual analog scale pain score, postoperative range of motion (ROM), and rates of recurrent instability and other complications.

RESULTS

Overall, 4 articles (level III evidence in 3 and level II in 1) were included from an initial 804 abstracts. The study population consisted of a total of 379 patients, of whom 194 underwent BRR and 185 underwent the Latarjet procedure. There were no unacceptable differences in baseline characteristics between the 2 groups. For the rate of recurrent instability, both groups had comparable risk ratios (RRs) (N = 379; RR, 0.72; 95% confidence interval [CI], 0.37-1.41). The risk of other complications was significantly increased with the Latarjet procedure (by about 7 times) relative to the the BRR procedure (N = 379; RR, 7.37; 95% CI, 2-27). Both groups had comparable postoperative Rowe scores (n = 190; mean difference [MD], -0.9; 95% CI, -3.45 to 1.7) and visual analog scale pain scores (n = 347; MD, -0.2; 95% CI, -0.6 to 0.2). Moreover, both groups had comparable postoperative external rotation ROM (MD, -1.7°; 95% CI, -9.4° to 6°) and internal rotation ROM (MD, 1.95°; 95% CI, -5.35° to 9.25°). There was substantial heterogeneity in the effect of both procedures on postoperative pain and ROM (external rotation and internal rotation).

CONCLUSION

Both the BRR and Latarjet procedures are effective for the management of engaging HSLs with subcritical GBL and give comparable clinical outcomes. However, given the fewer overall postoperative complications, remplissage may be safer. The results of the included studies were adequately consistent for most analyzed outcomes. However, for the intervention effect on postoperative pain and ROM, there was a small body of evidence, limiting the strength of the reported conclusions.

Mechanism and patterns of bone loss in patients with anterior shoulder dislocation

BACKGROUND

Bony defects are common injuries associated with anterior shoulder dislocation. It is generally thought that these bony defects are created at the time of dislocation. However, there have been no biomechanical reports demonstrating the exact time point when these lesions occur. The purpose of this study was to clarify when, how, and which types of bony defects were created during experimental dislocation in cadaveric shoulders.

METHODS

Fifteen fresh-frozen cadaveric shoulders (mean age at the time of death, 79 years) were fixed in a custom testing machine. First, the glenohumeral joint was inspected by arthroscopy. Then, the arm was held at 60° of abduction and maximum external rotation and was manually extended horizontally under fluoroscopy until an anterior dislocation occurred. Next, a force of 800 N was applied to a Kirschner wire inserted in the humeral head in the direction of the pectoralis major with use of an air cylinder. We waited until the arm came to equilibrium under this condition. Finally, the glenohumeral joint was arthroscopically examined. We further performed x-ray micro-computed tomography and histologic examination in 1 shoulder with a bipolar lesion.

RESULTS

After the anterior dislocation, a Bankart lesion was created in 9 of 15 shoulders and a fragment-type glenoid defect (avulsion fracture) was created in 4. A Hill-Sachs lesion, on the other hand, was not observed after the dislocation. The equilibrium arm position was 40° ± 17° in flexion, 45° ± 22° in abduction, and 27° ± 19° in external rotation. In this arm position, newly created lesions were Hill-Sachs lesions in 6 shoulders and erosion-type glenoid defects (compression fracture) in 7. Micro-computed tomography, performed in a single specimen, showed a flattened anterior glenoid rim with collapse of trabecular bone. Histologic analysis of nondecalcified sections using hematoxylin-eosin staining indicated that the anterior rim of the glenoid was compressed and flattened. The cortex of the anterior glenoid rim could be clearly observed.

CONCLUSION

The fragment-type glenoid defect (avulsion fracture) was observed at the time of dislocation, whereas the erosion-type defect (compression fracture) was observed when the arm came to equilibrium in the midrange of motion. Hill-Sachs lesions were created not at the time of dislocation but after the arm came to equilibrium.

Effects of Glenoid and Humeral Bone Defects on Recurrent Anterior Instability of the Shoulder

For proper treatment of recurrent anterior instability of the shoulder with a bone defect, the defect size should be assessed preoperatively with three-dimensional computed tomography or magnetic resonance imaging. In general, the risk of postoperative recurrence of instability is estimated on the basis of preoperative imaging of bipolar bone defects: more than 20%–25% glenoid bone loss and off-track Hill-Sachs lesions have been considered risk factors for recurrence. In patients with a glenoid bone defect more than 20%–25%, a bone graft procedure, such as the Latarjet procedure, is preferred regardless of the glenoid track concept, because compared with arthroscopic stabilization procedure, it provides greater postoperative stability. For patients with a borderline glenoid bone defect (around 20%), surgeons should discuss surgical options with the patients, considering their demand and physical activity level. In addition, the surgeon should take care to prevent postoperative instability and long-term complications. Arthroscopic soft-tissue reconstruction including labral repair and capsular plication combined with the additional remplissage procedure is an anatomical procedure and could be considered as one of the primary treatment methods for patients with glenoid bone defects around 20%. Therefore, treatment strategies for recurrent anterior shoulder instability combined with bone defects should be determined more flexibly on the basis of the patient's individual condition.

Anterior Instability: What to Look for

Most first-time anterior glenohumeral dislocations occur as the result of trauma. Many patients suffer recurrent episodes of anterior shoulder instability (ASI). The anatomy and biomechanics of ASI is addressed, as is the pathophysiology of capsulolabral injury. The roles of imaging modalities are described, including computed tomography (CT) and MR imaging with the additional value of arthrography and specialized imaging positions. Advances in 3D CT and MR imaging particularly with respect to the quantification of humeral and glenoid bone loss is discussed. The concepts of engaging and nonengaging lesions as well as on-track and off-track lesions are examined.

A retrospective cohort analysis of arthroscopic Bankart repair with or without remplissage in patients with off-track Hill-Sachs lesion evaluated for functional outcomes, recurrent instability, and range of motion

BACKGROUND

Lone Bankart repair is associated with high rates of recurrence, especially in off-track Hill-Sachs (HS) lesion. The objective of the study was to assess the impact of remplissage in off-track HS lesion influencing the rate of redislocation and range of motion (ROM) of the shoulder.

MATERIAL AND METHOD

We retrospectively reviewed 136 patients for arthroscopic Bankart repair without remplissage (group 1, n = 77) or with remplissage (group 2, n =59) for recurrent anterior dislocation of the shoulder with glenoid bone loss of <25%. Further subgroups of on- and off-track HS lesion were based on computed tomographic assessment. At a minimum follow-up of 2 years; patients were evaluated for functional scores (Rowe, Constant-Murley, Western Ontario Shoulder Instability Index), redislocations, and ROM.

RESULTS

At a mean follow-up of 54 and 44 months in group 1 and 2, respectively, there was no difference in postoperative functional scores. There were significantly more dislocations in patients with Bankart repair with off-track lesion than in patients with Bankart repair with on-track lesion (P = .02). There were significantly fewer redislocations in patients with off-track lesion who underwent Bankart repair and remplissage than in those who did not undergo remplissage (P = .0007). Compared with group 1 patients, those in group 2 revealed a statistically significant loss of ROM.

CONCLUSIONS

Although a nonremplissaged off-track HS lesion remains an important risk factor for recurrent instability, remplissage also results in significant loss of shoulder ROM compared with those who do not undergo remplissage.

Peripheral-Track and Central-Track Hill-Sachs Lesions: A New Concept of Assessing an On-Track Lesion

BACKGROUND

It has been demonstrated biomechanically that 25% is a critical size defect of the glenoid. However, a recent clinical study reported that a bone loss between 13.5% and 20% (subcritical bone loss) led to impairment of quality of life but not a recurrence of instability.

PURPOSE

To clarify whether a subcritical bone loss exists in assessing a Hill-Sachs lesion via a disease-specific quality of life questionnaire.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Fifty patients (mean age, 27 years) with <25% glenoid defect who were treated with arthroscopic Bankart repair for recurrent anterior dislocation were assessed at a mean follow-up of 28 months. All had an on-track Hill-Sachs lesion. The Western Ontario Shoulder Instability Index (WOSI) and Rowe scores were used for the clinical evaluation. The Hill-Sachs interval was measured on 3-dimensional computed tomography images and divided by the glenoid track width, defined as the Hill-Sachs occupancy (in percentages). The glenoid track was divided into 4 zones based on the percentage of the Hill-Sachs occupancy: zone 1, <25%; zone 2, 25% to <50%; zone 3, 50% to <75%; and zone 4, ≥75%.

RESULTS

The recurrence rate was 6% (3 of 50 shoulders). The Rowe score significantly improved from 45.2 ± 4.7 (mean ± SD) preoperatively to 92.3 ± 6.5 at the final follow-up (P < .05). The WOSI score also significantly increased from 46.6% ± 19.3% preoperatively to 72.3% ± 21.0% at the final follow-up (P < .001). The WOSI score of patients in zone 4 (peripheral-track lesion) (n = 10) was significantly lower than those in the other zones (central-track lesion) (P = .0379). Of the 10 patients with the peripheral-track lesion, 5 had a <40% WOSI score, similar to the preoperative WOSI score (46.6%).

CONCLUSION

Patients with on-track lesions can be divided into 2 subgroups: those with the Hill-Sachs occupancy ≥75% (peripheral-track lesion) showed significantly worse WOSI score without recurrent instability events than those with the Hill-Sacks occupancy <75% (central-track lesion).

Off-track Hill-Sachs lesions do not increase postoperative recurrent instability after arthroscopic Bankart repair with selective Remplissage procedure

PURPOSE

This study aimed to compare clinical outcomes and recurrence rates after arthroscopic Bankart repair with selective Remplissage procedure, between patients with off-track and on-track Hill-Sachs lesions.

METHODS

Patients who underwent arthroscopic Bankart repair with selective Remplissage procedure for recurrent anterior shoulder instability and were followed up for at least 2 years were included. Patients with a glenoid defect greater than 25% were excluded. According to the glenoid track concept, patients were divided into group I (off-track lesions) and group II (on-track lesions). After Bankart repair, an additional Remplissage procedure was performed selectively in patients who sustained engagement of the humeral head. The clinical outcomes and recurrence rates were evaluated.

RESULTS

A total of 193 patients (23 in group I and 170 in group II) were enrolled. No significant differences were found in clinical outcomes (n.s.) or recurrence rates (n.s.) between the two groups, despite larger glenoid defects in group I (group I:17.1 ± 6.1%, and group II:13.0 ± 6.4%, P = 0.003). In all patients, the incidence of off-track lesions was not significantly different according to the occurrence of postoperative recurrence (n.s.), whereas the glenoid defect size showed a significant difference (with recurrence: 17.9 ± 3.9%, and without recurrence: 13.2 ± 6.5%, P = 0.002).

CONCLUSIONS

The presence of an off-track lesion did not alter the clinical outcomes and recurrence rates after arthroscopic Bankart repair with selective Remplissage procedure. The glenoid defect size rather than the presence of an off-track lesion can more reliably predict postoperative recurrence. Arthroscopic Bankart repair with selective Remplissage procedure is considered one surgical option for the treatment of off-track lesions.

LEVEL OF EVIDENCE

III.

Changes of Bipolar Bone Defect Size After Arthroscopic Bankart Repair for Traumatic Anterior Shoulder Instability: Evaluation Using a Scoring System and Influence on Postoperative Recurrence

Background

The combination of a glenoid defect and a Hill-Sachs lesion in shoulders with traumatic anterior instability has been termed bipolar bone loss, and the preoperative size of these lesions has been reported to influence postoperative recurrence of instability after arthroscopic Bankart repair.

Purpose

To investigate the influence of postoperative bipolar bone defect size on postoperative recurrence of instability.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 64 male collision/contact athletes (69 shoulders) were evaluated for a minimum of 2 years after surgery, and the pre- and postoperative sizes of both lesions (glenoid defect and Hill-Sachs) were evaluated retrospectively with 3-dimensional computed tomography. The sports played by the athletes included rugby (n = 28 shoulders), American football (n = 24 shoulders), and other collision/contact sports (n = 17 shoulders). Glenoid defects and Hill-Sachs lesions were classified into 5 size categories and assigned scores from 0 (no defect) to 4 (very large defect). Patients were then classified according to the total score (sum of the scores for both lesions). The influence of pre- and postoperative bipolar bone defect sizes on recurrence of instability was investigated by using the total scores for bipolar bone defects. The influence of postoperative glenoid morphology (normal preoperative glenoid, preoperative glenoid erosion, bone union after arthroscopic bony Bankart repair [ABBR], or nonunion after ABBR) was also investigated, as well as changes in shoulders with a preoperative off-track Hill-Sachs lesion.

Results

Of 69 shoulders, 15 (21.7%) developed recurrent instability after surgery. The postoperative recurrence rate was 0% in shoulders with a total score ≤1, while the recurrence rate was consistently higher in shoulders with a total score ≥2 at both pre- and postoperative evaluation (mean, 28.8% and 32.6%, respectively). Postoperative recurrence was uncommon when there was a normal preoperative glenoid or bone union after ABBR, while it was frequent in shoulders with preoperative glenoid erosion or shoulders with nonunion after ABBR and a total score ≥2. An off-track lesion was recognized in 9 shoulders preoperatively. It was transformed to on-track lesions in 4 of the 5 shoulders showing bone union after ABBR, and there was no recurrence in the 5 shoulders with bone union. In contrast, postoperative recurrence of instability occurred in 3 of the 4 shoulders without bone union.

Conclusion

Postoperative recurrence was influenced by the pre- and postoperative size of bipolar bone defects. Recurrence was uncommon if bone union was achieved after ABBR, even if there had been an off-track lesion preoperatively.

Management of Recurrent Anterior Shoulder Instability With Bipolar Bone Loss: A Systematic Review to Assess Critical Bone Loss Amounts

BACKGROUND

There is increasing evidence to suggest that the amount of glenoid bone loss to indicate bone block procedures may be lower than previously thought, particularly in the presence of a Hill-Sachs defect.

PURPOSE

To better establish treatment recommendations for anterior shoulder instability among patients with bipolar bone lesions.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

A systematic review of the literature was performed with PubMed, EMBASE, Cochrane Library, and Scopus databases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Studies evaluating outcomes of operative management in anterior shoulder instability that also reported glenoid bone loss in the presence of Hill-Sachs defects were included. Recurrence rates, glenoid bone loss, and humeral bone loss were pooled and analyzed with forest plots stratified by surgical procedure. Methods of quantification were analyzed for each article qualitatively.

RESULTS

Thirteen articles were included in the final analysis, with a total of 778 patients. The mean ± SD age was 24.9 ± 8.6 years. The mean follow-up was 30.1 months (range, 11-240 months). Only 13 of 408 (3.2%) reviewed bipolar bone loss articles quantified humeral and/or glenoid bone loss. Latarjet procedures had the greatest glenoid bone loss (21.7%; 95% CI, 14.8%-28.6%), followed by Bankart repairs (13.1%; 95% CI, 9.0%-17.2%), and remplissage (11.7%; 95% CI, 5.5%-18.0%). Humeral bone loss was primarily reported as percentage bone loss (22.2%; 95% CI, 13.1%-31.3% in Bankart repairs and 31.7%; 95% CI, 21.6%-41.1% in Latarjet) or as volumetric defects (439.1 mm³; 95% CI, 336.3-541.9 mm³ in Bankart repairs and 366.0 mm³; 95% CI, 258.4-475.4 mm³ in remplissage). Recurrence rates were as follows: Bankart repairs, 19.5% (95% CI, 14.5%-25.8%); remplissage, 4.4% (95% CI, 1.3%-14.0%); and Latarjet, 8.7% (95% CI, 5.0%-14.7%). Bankart repairs were associated with significantly greater recurrence of instability in included articles (P = .013).

CONCLUSION

There exists a need for universal and consistent preoperative measurement of humeral-sided bone loss. The presence of concomitant Hill-Sachs defects with glenoid pathology should warrant more aggressive operative management through use of bone block procedures. Previously established values of critical glenoid bone loss are not equally relevant in the presence of bipolar bone loss.

Factors Related to Patient Dissatisfaction Versus Objective Failure After Arthroscopic Shoulder Stabilization for Instability

BACKGROUND

After arthroscopic stabilization procedures for recurrent anterior shoulder instability, patients are not always satisfied with their shoulder, even when the operation successfully restored stability. The aim of this study was to evaluate the factors associated with subjective patient dissatisfaction after arthroscopic stabilization procedures for recurrent anterior shoulder instability and to compare these factors with those associated with objective surgical failure.

METHODS

A total of 195 patients who underwent an arthroscopic stabilization procedure for recurrent anterior shoulder instability were included in this study. At the 2-year postoperative visit, subjective patient dissatisfaction was assessed with a 15-point scale. Objective surgical failure was defined as postoperative dislocation or subluxation events requiring revision surgery. Several factors, including age at the first dislocation, age at the time of the operation, presence of an off-track Hill-Sachs lesion, width of the Hill-Sachs lesion, size of the glenoid bone defect, and number of instability events, were recorded. Multivariable linear regression analysis and multivariable logistic regression analysis were performed using a backward stepwise procedure as the variable selection method.

RESULTS

Fifteen patients (7.7%) had recurrent instability requiring revision surgery. In the group of 180 patients without surgical failure, the width of the Hill-Sachs lesion (regression coefficient: 0.052, p = 0.011) and number of instability events (regression coefficient: 0.103, p = 0.029) were positively correlated with subjective patient dissatisfaction, whereas concomitant repair of a SLAP (superior labrum anterior-posterior) lesion showed negative correlation (regression coefficient: -0.926, p = 0.004). In the total cohort of patients, objective surgical failure was correlated with the age at the time of the operation (odds ratio [OR]: 0.851, p = 0.042), size of the glenoid bone defect (OR: 1.172, p < 0.001), and number of instability events (OR: 1.147, p = 0.048). Other variables, including an off-track Hill-Sachs lesion or a concomitant remplissage procedure, were not correlated with subjective patient dissatisfaction or objective surgical failure.

CONCLUSIONS

Factors related to subjective patient dissatisfaction differed from those related to objective surgical failure. For a better understanding of the clinical outcomes after surgery, surgeons should assess the factors that correlate with subjective patient dissatisfaction and objective surgical failure.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

[Recurrent instability and instability arthropathy]

Capsulolabral reconstruction (Bankart repair) is recommended as the first line treatment in young and functionally demanding active patients with anteroinferior shoulder instability, due to the high tendency to recurrent dislocation. This has become established both for arthroscopic and open primary shoulder stabilization with good clinical outcome; nevertheless, recurrence of dislocation is reported in up to 25% of patients. Risk factors for failed surgery are patient (e.g. young age, male gender and contact sports) and surgery (e.g. primarily underestimated glenoid bone loss, Hill-Sachs lesion, non-treatment of bipolar defects or malpositioned anchors) related. In the management of recurrent instability, it is necessary to carry out a thorough clinical investigation in addition to extended diagnostics with X‑ray and computed tomography. A second Bankart repair is only indicated in patients with low demands and without any glenoid bone loss. In the majority of patients, bony augmentation of the glenoid is necessary and realized by coracoid or iliac crest bone block transfer. The Latarjet procedure is biomechanically advantageous due to the additional sling effect of the conjoined tendons and both techniques show good clinical outcomes and a low recurrence rate. Furthermore, engaging Hill-Sachs lesions also require additional treatment. Remplissage of the infraspinatus muscle, iliac crest bone block transfer and partial joint replacement are viable options. A final consensus for treatment of Hill-Sachs lesions has yet to be defined. Dislocation arthropathy is an underestimated complication as a result of frequent recurrent dislocations. After development of dislocation arthropathy, patients reported a painful restriction of range of motion rather than instability. Arthroscopic arthrolysis and comprehensive arthroscopic management (CAM procedure) are possible joint-preserving treatment options.

In Vivo Glenoid Track Width Can Be Better Predicted With the Use of Shoulder Horizontal Extension Angle

BACKGROUND

The glenoid track concept has been widely used to assess the risk of instability caused by a bipolar lesion. The mean glenoid track width is reported to be 83% of the glenoid width. However, this width seems to be affected by the range of motion of the shoulder. By clarifying the relationship between the range of shoulder motion and the glenoid track width, a more precise determination of the glenoid track width for each individual could be possible.

PURPOSE

To determine the relationship between the glenoid track width and the range of motion of healthy volunteers.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Magnetic resonance imaging was taken in 41 shoulders of 21 healthy volunteers (mean age, 32 years) with the arm in maximum horizontal extension, with the arm kept in 90° of abduction and 90° of external rotation. Three-dimensional surface bone models of the glenoid and the humerus were created with image analysis software. The distance from the anterior rim of the glenoid to the medial margin of the footprint of the rotator cuff tendon was defined as the glenoid track width. Active and passive ranges of shoulder motion were measured in the supine and sitting positions. The correlations between the glenoid track width and the ranges of shoulder motion were investigated with Pearson correlation coefficients. Intra- and interobserver reliabilities based on the intraclass correlation coefficient were also analyzed to assess the reliability of the glenoid track measurement.

RESULTS

The intra- and interobserver reliabilities for the glenoid track measurement were excellent (0.988 and 0.988, respectively). Among all the measurements, the glenoid track width and the active range of motion in horizontal extension in the sitting position showed the greatest correlation coefficient ( r = -0.623, P < .0001). A correlation between the glenoid track width and this angle was expressed as Y = -0.49 X + 90, where X is the horizontal extension angle (degrees) and Y is the glenoid track width (percentage of glenoid width).

CONCLUSION

The present data demonstrate that the greater the horizontal extension angle in abduction and external rotation, the smaller the glenoid track width. An individualized glenoid track width can be obtained by measuring the active horizontal extension angle with the arm in abduction and external rotation in the sitting position.

CLINICAL RELEVANCE

An individualized glenoid track width enables selection of a more precise surgical option by the on-track/off-track concept.