How to measure a Hill-Sachs lesion: a systematic review

Functional Anatomy and Biomechanics of Shoulder Instability

The glenohumeral joint is the least congruent and least constrained joint with a complex relationship of static and dynamic stabilizers to balance its native mobility with functional stability. In the young athlete, anterior shoulder instability is multifactorial and can be a challenge to treat, requiring a patient-specific treatment approach. Surgical decision-making must consider patient-specific factors such as age, sport activity and level, underlying ligamentous laxity, and goals for return to activity, in addition to careful scrutiny of the underlying pathology to include humeral and glenoid bone loss and surrounding scapular bone morphology.

Osteochondral allografts for the treatment of shoulder instability

Aims

To systematically review the predominant complication rates and changes to patient-reported outcome measures (PROMs) following osteochondral allograft (OCA) transplantation for shoulder instability.

Methods

This systematic review, following PRISMA guidelines and registered in PROSPERO, involved a comprehensive literature search using PubMed, Embase, Web of Science, and Scopus. Key search terms included "allograft", "shoulder", "humerus", and "glenoid". The review encompassed 37 studies with 456 patients, focusing on primary outcomes like failure rates and secondary outcomes such as PROMs and functional test results.

Results

A meta-analysis of primary outcomes across 17 studies revealed a dislocation rate of 5.1% and an increase in reoperation rates from 9.3% to 13.7% post-publication bias adjustment. There was also a noted rise in conversion to total shoulder arthroplasty and incidence of osteoarthritis/osteonecrosis over longer follow-up periods. Patient-reported outcomes and functional tests generally showed improvement, albeit with notable variability across studies. A concerning observation was the consistent presence of allograft resorption, with rates ranging from 33% to 80%. Comparative studies highlighted similar efficacy between distal tibial allografts and Latarjet procedures in most respects, with some differences in specific tests.

Conclusion

OCA transplantation presents a promising treatment option for shoulder instability, effectively addressing both glenoid and humeral head defects with favourable patient-reported outcomes. These findings advocate for the inclusion of OCA transplantation in treatment protocols for shoulder instability, while also emphasizing the need for further high-quality, long-term research to better understand the procedure's efficacy profile.

Creating a Three-Dimensional Reconstruction of the Glenohumeral Joint From Magnetic Resonance Imaging to Assist in Surgical Decision-Making

Understanding the anatomical structure of a patient's shoulder joint is essential in surgical decision-making, especially regarding glenohumeral bone loss. The use of various imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT), bring certain advantages and disadvantages in assessing joint structure. Before a surgical procedure, bone loss can be observed and measured using these imaging techniques in both 2-dimensional and 3-dimensional (3D) views. The ability to visualize the shoulder joint in a 3D manner, as commonly done with CT scans, is helpful in assessing bone loss; however, CT involves exposure to radiation, additional time, and greater costs. The process of obtaining a 3D view of the shoulder joint from an MRI, although less common, can be completed effectively to assess bone loss while also solving some issues surrounding CT scans. By loading MRI datasets into an image-reformation program, such as 3D Slicer, the anatomical structures can be segmented to create realistic 3D models of the shoulder joint. Surgical direction can be determined after bone loss measurements and structural assessment of these models, without the need for CT scans. This technique can also be applied to other skeletal joints, in addition to the shoulder.

The Global Track Concept for Assessment of Engaging Hill-Sachs Defects in Anterior Shoulder Instability

BACKGROUND

The glenoid track concept is used to determine preoperatively whether a Hill-Sachs defect is engaging or not. Currently, the glenoid track concept relies on measurements of bony structures as well as on the confines and elasticity of the rotator cuff as a reference point, which varies extensively among individuals and therefore limits the reliability and accuracy of this concept.

PURPOSE

To evaluate the reliability of the global track concept, which determines the angular distance of the Hill-Sachs defect from the center of the articular surface of the humeral head as a new reference point with the help of an automated image analysis software and 3-dimensional analysis of the humeral head.

STUDY DESIGN

Controlled laboratory study.

METHODS

Computed tomography scans of 100 patients treated for anterior shoulder instability with different sizes of Hill-Sachs defects were evaluated manually by 2 orthopaedic surgeons independently using the software OsiriX as well as automatically by using a dedicated prototype software (ImFusion). Obtained manual and automated measurements included the Hill-Sachs length, Hill-Sachs width, and Hill-Sachs depth of the defect; the Hill-Sachs interval (HSI); and the glenoid width for the glenoid track concept, as well as the angular distance of the Hill-Sachs defect from the center of the articular surface of the humeral head (global track concept). The reliability of the different measurement techniques was compared by calculating intraclass correlation coefficients (ICCs).

RESULTS

There was a significant difference for all obtained parameters comparing manual and automatic measurements. For manually obtained parameters, measurements referring to bony boundaries (glenoid width, Hill-Sachs length, and Hill-Sachs width) showed good to excellent agreement (ICC, 0.86, 0.82, and 0.62, respectively), while measurements referring to soft tissue boundaries (HSI and glenoid track; ICC, 0.56 and 0.53, respectively) or not directly identifiable reference points (center of articular surface and global track) only showed fair reliability (ICC middle excursion, 0.42). When the same parameters were measured with the help of an automated software, good reliability for the glenoid track concept and excellent reliability for the global track concept in the middle excursion were achieved.

CONCLUSION

The present study showed that the more complex global track measurements of humeral defects are more reliable than the current standard HSI and glenoid track measurements. However, this is only true when automated software is used to perform the measurements.

CLINICAL RELEVANCE

Future studies using the new proposed method in combination with an automated software need to be conducted to determine critical threshold values for defects prone to engagement.

Reconsidering "Critical" Bone Loss in Shoulder Instability: 17-Year Follow-Up Study following Arthroscopic Bankart Repair

Background

Glenoid bone loss is a risk factor leading to the failure of arthroscopic Bankart repair. While 20-25% glenoid bone loss has long been considered the level to necessitate bony augmentation, recent studies indicate that 13.5% has a "subcritical" glenoid bone loss level, which is associated with decreased short- and medium-term functional scores. Few researchers worked on the long-term effect of "subcritical" or even less severe degrees of glenoid bone loss on redislocation rates and functional outcomes after arthroscopic Bankart repair. This study aimed to evaluate the effect of subcritical or less severe glenoid bone loss on redislocation rates and function after arthroscopic Bankart repair.

Methods

A patient cohort who had undergone computed tomography (CT) of glenoid bone loss and arthroscopic Bankart repair over 15 years ago was reviewed. Western Ontario Shoulder Instability (WOSI) score, Single Assessment Numeric Evaluation (SANE) score, redislocation after operation, mechanism of recurrence, and revision details were reviewed.

Results

Seventy-five patients were reassessed 17.6 ± 1.9 years following initial surgery. The age at enrolment was 26.8 ± 8.3 years. Twenty-two (29%) patients of the 75 patients had a redislocation on long-term follow-up, though this was not related to glenoid bone loss severity. The impaired functional score was found in patients with initial glenoid bone loss of 7% or more on long-term follow-up: WOSI (physical symptoms): 0.98 ± 2.00 vs 2.25 ± 4.01, p=0.04 and WOSI (total): 0.79 ± 1.43 vs 1.88 ± 3.56, p=0.04.

Conclusions

At a mean of 17.5 years following arthroscopic Bankart repair, redislocation occurs in over a quarter of 75 patients, and they are not related to initial glenoid bone loss severity. Impaired functional outcome is apparent in patients with initial glenoid bone loss of >7%, though this impairment does not seem sufficiently severe to warrant an alternative treatment approach.

Native Glenoid Depth and Hill-Sachs Lesion Morphology in Traumatic Anterior Shoulder Instability

BACKGROUND

Although Hill-Sachs lesions (HSLs) are assumed to be influenced by glenoid characteristics in the context of bipolar bone loss, little is known about how glenoid concavity influences HSL morphology.

PURPOSE

To investigate the relationship between the native glenoid depth and HSL morphological characteristics.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Computed tomography images of bilateral shoulders from 151 consecutive patients with traumatic unilateral anterior shoulder instability were retrospectively reviewed. Patients were categorized into flat (<1 mm), moderate (1-2 mm), and deep (>2 mm) groups based on the native glenoid depth measured from the contralateral unaffected shoulder. The HSL morphological characteristics included size (depth, width, length, and volume), location (medial, superior, and inferior extent), and orientation (rim and center angle). The glenoid characteristics included diameter, depth, version, and bone loss. The patient, glenoid, and HSL morphological characteristics were compared among the 3 depth groups. Subsequently, the independent predictors of some critical HSL morphological characteristics were determined using multivariate stepwise regression.

RESULTS

After exclusion of 55 patients, a total of 96 patients were enrolled and classified into the flat group (n = 31), moderate group (n = 35), and deep group (n = 30). Compared with those in the flat group, patients in the deep group were more likely to have dislocation (38.7% vs 93.3%; P = .009) at the primary instability and had a significantly larger number of dislocations (1.1 ± 1.0 vs 2.2 ± 1.8; P = .010); moreover, patients in the deep group had significantly deeper, wider, larger volume, more medialized HSLs and higher incidences of off-track HSLs (all P≤ .025). No significant differences were detected among the 3 groups in HSL length, vertical position, and orientation (all P≥ .064). After adjustment for various radiological and patient factors in the multivariate regression model, native glenoid depth remained the strongest independent predictor for HSL depth (β = 0.346; P < .001), width (β = 0.262; P = .009), volume (β = 0.331; P = .001), and medialization (β = -0.297; P = .003).

CONCLUSION

The current study sheds light on the association between native glenoid depth and the morphology of HSLs in traumatic anterior shoulder instability. Native glenoid depth was independently and positively associated with HSL depth, width, volume, and medialization. Patients with deeper native glenoids were more likely to have off-track HSLs and thus require more attention in the process of diagnosis and treatment.

Variability in quantifying the Hill-Sachs lesion: A scoping review

Background

Currently, is there no consensus on a widely accepted measurement technique for calculating the Hill-Sachs lesion (HSL). The purpose of this review is to provide an overview of the techniques and imaging modalities to assess the HSL pre-operatively.

Methods

Four online databases (PubMed, Embase, MEDLINE, and COCHRANE) were searched for literature on the various modalities and measurement techniques used for quantifying HSLs, from data inception to 20 November 2021. The Methodological Index for Non-Randomized Studies tool was used to assess study quality.

Results

Forty-five studies encompassing 3413 patients were included in this review. MRA and MRI showed the highest sensitivity, specificity, and accuracy values. Intrarater and interrater agreement was shown to be the highest amongst MRA. The most common reference tests for measuring the HSL were arthroscopy, radiography, arthro-CT, and surgical techniques.

Conclusion

MRA and MRI are reliable imaging modalities with good test diagnostic properties for assessment of HSLs. There is a wide variety of measurement techniques and imaging modalities for HSL assessment, however a lack of comparative studies exists. Thus, it is not possible to comment on the superiority of one technique over another. Future studies comparing imaging modalities and measurement techniques are needed that incorporate a cost-benefit analysis.

Factors affecting a patient's experience following the open Latarjet procedure to treat recurrent anterior shoulder instability

The open Latarjet procedure is a widely used treatment for recurrent anterior instability of the shoulder. Although satisfactory outcomes are reported, factors which influence a patient's experience are poorly quantified. The aim of this study was to evaluate the effect of a range of demographic factors and measures of the severity of instability on patient-reported outcome measures in patients who underwent an open Latarjet procedure at a minimum follow-up of two years. A total of 350 patients with anterior instability of the shoulder who underwent an open Latarjet procedure between 2005 and 2018 were reviewed prospectively, with the collection of demographic and psychosocial data, preoperative CT, and complications during follow-up of two years. The primary outcome measure was the Western Ontario Shoulder Instability Index (WOSI), assessed preoperatively, at two years postoperatively, and at mid-term follow-up at a mean of 50.6 months (SD 24.8) postoperatively. The secondary outcome measure was the abbreviated version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) score. The influence of the demographic details of the patients, measurements of the severity of instability, and the complications of surgery were assessed in a multivariate analysis. The mean age of the patients was 25.5 years (22 to 32) and 27 (7.7%) were female. The median time to surgery after injury was 19 months (interquartile range (IQR) 13 to 39). Seven patients developed clinically significant complications requiring further intervention within two years of surgery. The median percentage WOSI deficiency was 8.0% (IQR 4 to 20) and median QuickDASH was 3.0 (IQR 0 to 9) at mid-term assessment. A minority of patients reported a poorer experience, and 22 (6.3%) had a > 50% deficiency in WOSI score. Multivariate analysis revealed that consumption of ≥ 20 units of alcohol/week, a pre-existing affective disorder or epilepsy, medicolegal litigation, increasing time to surgery, and residing in a more socioeconomically deprived area were independently predictive of a poorer WOSI score. Although most patients treated by an open Latarjet procedure have excellent outcomes at mid-term follow-up, a minority have poorer outcomes, which are mainly predictable from pre-existing demographic factors, rather than measures of the severity of instability.

Recurrence in traumatic anterior shoulder dislocations increases the prevalence of Hill-Sachs and Bankart lesions: a systematic review and meta-analysis

PURPOSE

The extent of shoulder instability and the indication for surgery may be determined by the prevalence or size of associated lesions. However, a varying prevalence is reported and the actual values are therefore unclear. In addition, it is unclear whether these lesions are present after the first dislocation and whether or not these lesions increase in size after recurrence. The aim of this systematic review was (1) to determine the prevalence of lesions associated with traumatic anterior shoulder dislocations, (2) to determine if the prevalence is higher following recurrent dislocations compared to first-time dislocations and (3) to determine if the prevalence is higher following complete dislocations compared to subluxations.

METHODS

PubMed, EMBASE, Cochrane and Web of Science were searched. Studies examining shoulders after traumatic anterior dislocations during arthroscopy or with MRI/MRA or CT published after 1999 were included. A total of 22 studies (1920 shoulders) were included.

RESULTS

The proportion of Hill-Sachs and Bankart lesions was higher in recurrent dislocations (85%; 66%) compared to first-time dislocations (71%; 59%) and this was statistically significant (P < 0.01; P = 0.05). No significant difference between recurrent and first-time dislocations was observed for SLAP lesions, rotator-cuff tears, bony Bankart lesions, HAGL lesions and ALPSA lesions. The proportion of Hill-Sachs lesions was significantly higher in complete dislocations (82%) compared to subluxations (54%; P < 0.01).

CONCLUSION

Higher proportions of Hill-Sachs and Bankart were observed in recurrent dislocations compared to first-time dislocations. No difference was observed for bony Bankart, HAGL, SLAP, rotator-cuff tear and ALPSA. Especially when a Hill-Sachs or Bankart is present after first-time dislocation, early surgical stabilization may need to be considered as other lesions may not be expected after recurrence and to limit lesion growth. However, results should be interpreted with caution due to substantial heterogeneity and large variance.

LEVEL OF EVIDENCE

IV.

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.

Glenoid track measurement using magnetic resonance imaging arthrography is predictive of recurrent instability following arthroscopic shoulder stabilisation

PURPOSE

The primary aim of this study was to investigate medium-term survivorship following arthroscopic Bankart repair (ABR) for anterior glenohumeral instability. The secondary aim was to determine whether the pre-operative magnetic resonance (MR) arthrography glenoid track measurement predicted recurrent instability following ABR.

METHODS

Over a 9-year period (2008-2017), 215 patients underwent ABR. Median age was 26 years (IQR 22-32.5; range 14-77). There were 173 males (81%). 175 patients (81%) had available pre-operative MR arthrography, which was used to determine the presence of "off-track" bone loss. Retrospective analysis was undertaken to determine recurrence of instability at a median follow-up of 76 months (range 21-125 months). Survivorship analysis was undertaken using Kaplan-Meier methodology: the endpoints examined were repeat dislocation, revision stabilisation, and symptomatic instability.

RESULTS

56 patients (26%) presented with further instability, including 29 patients with recurrent dislocation and 15 patients required revision stabilisation. Cumulative incidence of instability was 10% at 1 year, 27% at 5 years and 28% at 7 years. No significant difference in instability was seen between men and women 7 years after stabilisation (19% vs 17%; p = 0.87). Age at time of surgery did not predict recurrence. "Off-track" lesions were identified in 29 patients (16.1%). The incidence of redislocation was significantly higher in these patients (24% vs 3%; p = 0.01; relative risk 7.2; 95% CI 2.45-20.5; p = 0.001). Recurrent instability without frank redislocation was also significantly higher in this group (60% vs 18%; RR 3.33, 95% CI 2.02-5.20; p < 0.0001).

CONCLUSIONS

This study has reported a significant rate of recurrent instability in longer-term follow-up after ABR. It has also identified pre-operative MR arthrography as an important predictor of recurrent instability, which may be used to risk stratify patients with anterior instability in a typical UK population.

LEVEL OF EVIDENCE

III (cohort study).

Evaluation and Management of Glenohumeral Instability With Associated Bone Loss: An Expert Consensus Statement Using the Modified Delphi Technique

PURPOSE

To establish an international expert consensus, using the modified Delphi technique, on the evaluation and management of glenohumeral instability with associated bone loss.

METHODS

A working group of 6 individuals generated a list of statements related to history and physical examination, imaging and specialized diagnostic tests, bone loss quantification and classification, treatment outcomes and complications, and rehabilitation for the management of glenohumeral instability associated with bone loss to form the basis of an initial survey for rating by a group of experts. The expert group (composed of 22 high-volume glenohumeral instability experts) was surveyed on 3 occasions to establish a consensus on the statements. Items with over 70% agreement and less than 10% disagreement achieved consensus.

RESULTS

After a total of 3 rounds, 31 statements achieved consensus. Eighty-six percent of the experts agreed that a history of multiple dislocations and failed soft-tissue surgery should raise suspicion about the possibility of an associated bone deficit. Ninety-five percent of the experts agreed that 3-dimensional (3D) computed tomography (CT) is the most accurate diagnostic method to evaluate and quantify bone loss. Eighty-six percent of the experts agreed that any of the available methods to measure glenoid bone deficiency is adequate; however, 91% of the experts thought that an en face view of the glenoid using 3D CT provides the most accurate method. Ninety-five percent of the experts agreed that Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Ninety percent of the experts agreed that in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed and any of the available options is valid. There was no consensus among experts on how Hill-Sachs injuries should be managed or on how postoperative rehabilitation should be carried out.

CONCLUSIONS

The essential statements on which the experts reached consensus included the following: A history of multiple dislocations and failed soft-tissue surgery should make surgeons consider the possibility of an associated bone deficit. Three-dimensional CT is the most accurate diagnostic method to evaluate and quantify bone loss. Although any of the available methods to measure glenoid bone deficiency is adequate, an en face view of the glenoid using 3D CT provides the most accurate method. Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Finally, in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed.

LEVEL OF EVIDENCE

Level V, consensus statement.

Contemporary imaging of the pediatric shoulder: pearls and pitfalls

In skeletally immature patients, the presence of growth plates and articular cartilage of the shoulder can create a predisposition for unique injuries not observed in adults. Furthermore, increasing participation in sports by children and adolescents appears to be leading to a corresponding increase in the number of sports-related injuries. The importance of radiologists being familiar with pediatric shoulder imaging and its associated injuries is therefore growing. In this article, we review the normal development and maturation pattern of ossification centers of the shoulder from the early gestational period through adolescence. Brachial plexus birth palsy, physeal injuries, shoulder dislocation, and internal impingement are discussed within the context of the child's age and the mechanism of injury to guide radiologists to a correct diagnosis.

Imaging of shoulder instability

The shoulder enjoys the widest range of motion of all the joints in the human body, therefore requires a delicate balance between stability and motility. The glenohumeral joint is inclined to fall into two main instability categories: macro and micro. Macroinstability can be traumatic or atraumatic, with anterior or posterior dislocation of the humeral head. Microinstability falls within the broader section of acquired instability in overstressed shoulder caused by repeated joint stress. Anterior traumatic instability is the most frequent entity and a relatively common injury in young and athletic population. While shoulder instability is a clinical diagnosis, imaging impacts the patient management by detailing the extent of injury, such as capsulo-labral-ligamentous tears, fracture, and/or dislocation, describing the predisposing anatomic conditions and guide the therapetic choice. The aim of this comprehensive review is to cover the imaging findings of shoulder instability by different imaging techniques.

Reliability of humeral head measurements performed using two- and three-dimensional computed tomography in patients with shoulder instability

Purpose

The aim of the study was to compare two measurement methods of humeral head defects in patients with shoulder instability. Intra- and inter-observer reliability of humeral head parameters were performed with the use of 2D and 3D computed tomography.

Methods

The study group was composed of one hundred humeral heads measured with the use of preoperative 2D and 3D computed tomography by three independent observers (two experienced and one inexperienced). All observers repeated measurements after 1 week. The intra-class correlation coefficient (ICC) and the minimal detectable change with 95% confidence (MDC₉₅%) were used for statistical analysis of diagnostic agreement.

Results

For 3D inter-observer reliability, ICC values were “excellent” for all parameters and MDC₉₅% values were “excellent” or “reasonable.” All intra-observer ICC and MDC₉₅% values for 3D were “excellent” for experienced and inexperienced observers. For 2D-CT, ICC values were usually “good” or “moderate” with MDC₉₅% values higher than 10 or 30%.

Conclusions

Three-dimensional CT measurements are more reliable than 2D for humeral head and Hill-Sachs lesion assessment. This study showed that 2D measurements, even performed by experienced observers (orthopaedic surgeons), are burdened with errors. The 3D reconstruction decreased the risk of error by eliminating inaccuracy in setting the plane of the measurements.

Management of bone loss in recurrent traumatic anterior shoulder instability: a survey of North American surgeons

Background

Management of bone loss in recurrent traumatic anterior shoulder instability remains a topic of debate and controversy in the orthopedic community. The purpose of this study was to survey members of 4 North American orthopedic surgeon associations to assess management trends for bone loss in recurrent anterior shoulder instability.

Methods

An online survey was distributed to all members of the American Shoulder and Elbow Surgeons, American Orthopaedic Society for Sports Medicine, and Canadian Orthopaedic Association and to fellow members of the Arthroscopy Association of North America. The survey comprised 3 sections assessing the demographic characteristics of survey respondents, the influence of prognostic factors on surgical decision making, and the operative management of 12 clinical case scenarios of varying bone loss that may be encountered in clinical practice.

Results

A total of 150 survey responses were returned. The age of the patient and quantity of bone loss were consistently considered important prognostic criteria. However, little consensus was reached for critical thresholds of bone loss and how this affected the timing (ie, primary or revision surgery) and type of bony augmentation procedure to be performed once a critical threshold was reached, especially in the context of critical humeral and bipolar bone loss.

Conclusions

Consistent trends were found for the management of recurrent anterior shoulder instability in cases in which no bone loss existed and when isolated critical glenoid bone loss was present. However, inconsistencies were observed when isolated critical humeral bone loss and bipolar bone loss were present.

How to handle minor and major bone loss in the shoulder? Current concepts

Anterior shoulder instability is a significant problem in orthopaedic surgery. It carries a heavy burden on quality of life, especially in young, active patients. Surgical treatment is therefore often carried out in this population. Several strategies can effectively address this issue. Yet, the consensus is lacking on the parameters which favour one technique over another, especially when bone loss is present. This is because of the complex, dynamic interplay between bone loss on the humeral side (ie, Hill-Sachs lesion) and glenoid bone loss, which is a common occurrence and defined as ‘bipolar’. There is an ongoing debate over the percentage of glenoid bone loss warranting bone block procedures: 13.5–15% is an indicator for such procedures (ie, Latarjet), although this value is still considered controversial and not uniformly accepted. A multitude of other factors (ie, age, sex, level of activity and so on) come into play alongside bipolar bone loss and the weight of each factor has yet to be fully elucidated. Also, refining the algorithm for the right procedure in the right patients will reduce the number of side effects stemming from initial, suboptimal treatment choice. Knowing how to manage previous surgical treatment failure is also key for the treating orthopaedic surgeon, who must be able to address the root cause of failure and react accordingly and effectively. This paper analyses key factors in treatment choice, the current stance of the literature on varying degrees of bone loss and choices on surgical treatment failure, lack of evidence and need for future research.