Measurement of Glenoid Bone Loss With 3-Dimensional Magnetic Resonance Imaging: A Matched Computed Tomography Analysis

Reliability of glenoid measurements performed using Multiplanar Reconstruction (MPR) of Magnetic Resonance (MRI) in patients with shoulder instability

PURPOSE

Measurement of glenoid bone loss in the shoulder instability can be assessed by CT or MRI multiplanar imaging and is crucial for pre-operative planning. The aim of this study is to determine the intra and interobserver reliability of glenoid deficiency measurement using MRI multiplanar reconstruction with 2D assessment in the sagittal plane (MPR MRI).

METHODS

We reviewed MRI images of 80 patients with anterior shoulder instability with Osirix software using MPR. Six observers with basic experience measured the glenoid, erosion edge length, and bone loss twice, with at least one-week interval between measurements. We calculated reliability and repeatability using the intra-class correlation coefficient (ICC) and minimal detectable change with 95% confidence (MDC95%).

RESULTS

Intra and Inter-observer ICC and MDC95% for glenoid width and height were excellent (ICC 0,89-0,96). For erosion edge length and area of the glenoid were acceptable/good (ICC 0,61-0,89). Bone loss and Pico Index were associated with acceptable/good ICC (0,63 -0,86)) but poor MDC95% (45 - 84 %). Intra-observer reliability improved with time, while inter-observer remained unchanged.

CONCLUSION

The MPR MRI measurement of the anterior glenoid lesion is very good tool for linear parameters. This method is not valid for Pico index measurement, as the area of bone loss is variable. The pace of learning is individual, therefore complex calculations based on MPR MRI are not resistant to low experience as opposed to true 3D CT.

Emerging Innovations in Preoperative Planning and Motion Analysis in Orthopedic Surgery

In recent years, preoperative planning has undergone significant advancements, with a dual focus: improving the accuracy of implant placement and enhancing the prediction of functional outcomes. These breakthroughs have been made possible through the development of advanced processing methods for 3D preoperative images. These methods not only offer novel visualization techniques but can also be seamlessly integrated into computer-aided design models. Additionally, the refinement of motion capture systems has played a pivotal role in this progress. These "markerless" systems are more straightforward to implement and facilitate easier data analysis. Simultaneously, the emergence of machine learning algorithms, utilizing artificial intelligence, has enabled the amalgamation of anatomical and functional data, leading to highly personalized preoperative plans for patients. The shift in preoperative planning from 2D towards 3D, from static to dynamic, is closely linked to technological advances, which will be described in this instructional review. Finally, the concept of 4D planning, encompassing periarticular soft tissues, will be introduced as a forward-looking development in the field of orthopedic surgery.

Editorial Commentary: Both 3-Dimensional Magnetic Resonance Imaging and Computed Tomography Are Valuable for Determination of Glenoid and Humeral Bone Loss in Patients With On- and Off-Track Shoulder Instability

Improving the modalities for advanced glenohumeral joint imaging has been an important area to address in the field of orthopaedic surgery. The current gold standard for imaging glenoid and humeral bone loss in patients with shoulder instability, 3-dimensional (3D) computed tomography (CT), provides high-quality 3D images of bones but comes with a cost of extra time, additional imaging because of the need for an additional magnetic resonance imaging (MRI) scan, and exposure to radiation. Three-dimensional MRI is a promising solution that can produce high-contrast images depicting both bony structures and soft tissues. Multiple 3D MRI sequences have been studied, with the FRACTURE (fast field echo resembling a CT using restricted echo-spacing) sequence showing high comparability of bony measurements to 3D CT scans, as well as the ability for widespread clinical use. Recent research has shown minimal differences in 3D CT and 3D MRI and has confirmed that 3D imaging does provide clinically relevant data for determination of on- and off-track instability. Finally, the gold standard for determination of bone loss is the measurement of deficiencies in the surface area of the glenoid using the best-fit circle with a diameter line measurement. This is most practical for day-to-day clinical use.

Three-Dimensional Magnetic Resonance Imaging Fast Field Echo Resembling a Computed Tomography Using Restricted Echo-Spacing Sequence Is Equivalent to 3-Dimensional Computed Tomography in Quantifying Bone Loss and Measuring Shoulder Morphology in Patients With Shoulder Dislocation

PURPOSE

To evaluate the equivalence of 3-dimensional (3D) magnetic resonance imaging (MRI) (FRACTURE [Fast field echo Resembling A CT Using Restricted Echo-spacing]) and 3D computed tomography (CT) in quantifying bone loss in patients with shoulder dislocation and measuring morphologic parameters of the shoulder.

METHODS

From July 2022 to June 2023, patients with anterior shoulder dislocation who were aged 18 years or older and underwent both MRI and CT within 1 week were included in the study. The MRI protocol included an additional FRACTURE sequence. Three-dimensional reconstructions of MRI (FRACTURE) and CT were completed by 2 independent observers using Mimics software (version 21.0) through simple threshold-based segmentation. For bone defect cases, 2 independent observers evaluated glenoid defect, percentage of glenoid defect, glenoid track, Hill-Sachs interval, and on-track/off-track. For all cases, glenoid width, glenoid height, humeral head-fitting sphere radius, critical shoulder angle, glenoid version, vault depth, and post-processing time were assessed. The paired t test was used to assess the differences between 3D CT and 3D MRI (FRACTURE). Bland-Altman plots were constructed to evaluate the consistency between 3D CT and 3D MRI (FRACTURE). Interobserver and intraobserver agreement was evaluated with the interclass correlation coefficient. The paired χ2 test and Cohen κ statistic were used for binary variables (on-track/off-track).

RESULTS

A total of 56 patients (16 with bipolar bone defect, 5 with only Hill-Sachs lesion, and 35 without bone defect) were ultimately enrolled in the study. The measurements of 21 bone defect cases showed no statistically significant differences between 3D CT and 3D MRI: glenoid defect, 4.05 ± 1.44 mm with 3D CT versus 4.16 ± 1.39 mm with 3D MRI (P = .208); percentage of glenoid defect, 16.21% ± 5.95% versus 16.61% ± 5.66% (P = .199); glenoid track, 18.02 ± 2.97 mm versus 18.08 ± 2.98 mm (P = .659); and Hill-Sachs interval, 14.29 ± 1.93 mm versus 14.35 ± 2.07 mm (P = .668). No significant difference was found between 3D CT and 3D MRI in the diagnosis of on-track/off-track (P > .999), and diagnostic agreement was perfect (κ = 1.00, P < .001). There were no statistically significant differences between the 2 examination methods in the measurements of all 56 cases, except that the post-processing time of 3D MRI was significantly longer than that of 3D CT: glenoid height, 34.56 ± 1.98 mm with 3D CT versus 34.67 ± 2.01 mm with 3D MRI (P = .139); glenoid width, 25.32 ± 1.48 mm versus 25.45 ± 1.47 mm (P = .113); humeral head-fitting sphere radius, 22.91 ± 1.70 mm versus 23.00 ± 1.76 mm (P = .211); critical shoulder angle, 33.49° ± 2.55° versus 33.57° ± 2.51° (P = .328); glenoid version, -3.25° ± 2.57° versus -3.18° ± 2.57° (P = .322); vault depth, 37.43 ± 1.68 mm versus 37.58 ± 1.75 mm (P = .164); and post-processing time, 89.66 ± 10.20 seconds versus 360.93 ± 26.76 seconds (P < .001). For all assessments, the Bland-Altman plots showed excellent consistency between the 2 examination methods, and the interclass correlation coefficients revealed excellent interobserver and intraobserver agreement.

CONCLUSIONS

Three-dimensional MRI (FRACTURE) is equivalent to 3D CT in quantifying bone loss in patients with shoulder dislocation and measuring shoulder morphologic parameters.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria (consecutive patients with consistently applied reference standard and blinding).

Accuracy and Consistency of 3-Dimensional Magnetic Resonance Imaging Is Comparable With 3-Dimensional Computed Tomography in Assessing Glenohumeral Instability: A Systematic Review

PURPOSE

To compare the accuracy of 3-dimensional (3D) magnetic resonance imaging (MRI) with that of 3D computed tomography (CT) in evaluating glenoid bone loss (GBL).

METHODS

This review aligned with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, the Cochrane Library, Embase, and Web of Science were obtained from data inception to August 28, 2023. The search term "glenoid bone loss" was extracted and analyzed via stringent inclusion and exclusion criteria. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 combined with the QUADAS-Comparative to assess the heterogeneity of included studies.

RESULTS

A total of 1,589 related studies were retrieved, and 10 studies were finally included, of which a total of 143 shoulders were evaluated. The index test in QUADAS-Comparative was low risk in 9 studies. 3D MRI measurements of GBL were primarily best-fit circles (n = 9). In both clinical and cadaveric studies, the mean percentages of GBL measured by 3D MRI were 0.38% to 2.19% and 0.25% to 6.1% when compared with 3D CT and standard reference values, respectively. Intraclass correlation coefficient agreement greater than 0.9 between GBL percentages measured by 3D CT and 3D MRI. 3D MRI also could accurately measure glenoid width, glenoid height, humeral head width, and height. 3D MRI reconstruction time was similar to that of 3D CT, which was mainly 10 to 15 minutes.

CONCLUSIONS

In both clinical and cadaveric studies, compared with 3D CT, 3D MRI is accurate and consistent in assessing glenohumeral bone, especially in measuring GBL, and the reconstruction time of 3D MRI is similar to 3D CT.

LEVEL OF EVIDENCE

Level Ⅲ, systematic review of Level Ⅱ-Ⅲ studies.

Preoperative planning with three-dimensional CT vs. three-dimensional magnetic resonance imaging does not change surgical management for shoulder instability

Background

This study aims to determine the effect of time and imaging modality (three-dimensional (3D) CT vs. 3D magnetic resonance imaging (MRI)) on the surgical procedure indicated for shoulder instability. The hypothesis is there will be no clinical difference in procedure selection between time and imaging modality.

Methods

Eleven shoulder surgeons were surveyed with the same ten shoulder instability clinical scenarios at three time points. All time points included history of present illness, musculoskeletal exam, radiographs, and standard two-dimensional MRI. To assess the effect of imaging modality, survey 1 included 3D MRI while survey 2 included a two-dimensional and 3D CT scan. To assess the effect of time, a retest was performed with survey 3 which was identical to survey 2. The outcome measured was whether surgeons made a "major" or "minor" surgical change between surveys.

Results

The average major change rate was 14.1% (standard deviation: 7.6%). The average minor change rate was 12.6% (standard deviation: 7.5%). Between survey 1 to the survey 2, the major change rate was 15.2%, compared to 13.1% when going from the second to the third survey (P = .68). The minior change rate between the first and second surveys was 12.1% and between the second to third interview was 13.1% (P = .8).

Discussion

The findings suggest that the major factor related to procedural changes was time between reviewing patient information. Furthermore, this study demonstrates that there remains significant intrasurgeon variability in selecting surgical procedures for shoulder instability. Lastly, the findings in this study suggest that 3D MRI is clinically equivalent to 3D CT in guiding shoulder instability surgical management.

Conclusion

This study demonstrates that there is significant variability in surgical procedure selection driven by time alone in shoulder instability. Surgical decision making with 3D MRI was similar to 3D CT scans and may be used by surgeons for preoperative planning.

Assessment of glenoid bone loss and other osseous shoulder pathologies comparing MR-based CT-like images with conventional CT

OBJECTIVES

To evaluate and compare the diagnostic performance of CT-like images based on a 3D T1-weighted spoiled gradient-echo sequence (T1 GRE), an ultra-short echo time sequence (UTE), and a 3D T1-weighted spoiled multi-echo gradient-echo sequence (FRACTURE) with conventional CT in patients with suspected osseous shoulder pathologies.

MATERIALS AND METHODS

Patients with suspected traumatic dislocation of the shoulder (n = 46, mean age 40 ± 14.5 years, 19 women) were prospectively recruited and received 3-T MR imaging including 3D T1 GRE, UTE, and 3D FRACTURE sequences. CT was performed in patients with acute fractures and served as standard of reference (n = 25). Agreement of morphological features between the modalities was analyzed including the glenoid bone loss, Hill-Sachs interval, glenoid track, and the anterior straight-line length. Agreement between the modalities was assessed using Bland-Altman plots, Student's t-test, and Pearson's correlation coefficient. Inter- and intrareader assessment was evaluated with weighted Cohen's κ and intraclass correlation coefficient.

RESULTS

All osseous pathologies were detected accurately on all three CT-like sequences (n = 25, κ = 1.00). No significant difference in the percentage of glenoid bone loss was found between CT (mean ± standard deviation, 20.3% ± 8.0) and CT-like MR images (FRACTURE 20.6% ± 7.9, T1 GRE 20.4% ± 7.6, UTE 20.3% ± 7.7, p > 0.05). When comparing the different measurements on CT-like images, measurements performed using the UTE images correlated best with CT.

CONCLUSION

Assessment of bony Bankart lesions and other osseous pathologies was feasible and accurate using CT-like images based on 3-T MRI compared with conventional CT. Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT.

CLINICAL RELEVANCE STATEMENT

In an acute trauma setting, CT-like images based on a T1 GRE, UTE, or FRACTURE sequence might be a useful alternative to conventional CT scan sparing associated costs as well as radiation exposure.

KEY POINTS

• No significant differences were found for the assessment of the glenoid bone loss when comparing measurements of CT-like MR images with measurements of conventional CT images. • Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT whereas the FRACTURE sequence appeared to be the most robust regarding motion artifacts. • The T1 GRE sequence had the highest resolution with high bone contrast and detailed delineation of even small fractures but was more susceptible to motion artifacts.

Characterizing the Practices of Canadian Orthopedic Surgeons in the Management of patients With Anterior Glenohumeral Instability

OBJECTIVE

To determine the practice patterns of Canadian orthopedic surgeons in the management of patients with anterior glenohumeral instability (AGHI).

DESIGN

Cross-sectional survey.

SETTING

Canada.

PATIENTS OR OTHER PARTICIPANTS

Canadian orthopedic surgeons with membership in the Canadian Orthopedic Association or Canadian Shoulder and Elbow Surgeon group who had managed at least 1 patient with AGHI in the previous year.

INTERVENTIONS

A survey including demographics and questions on the management of patients with AGHI was completed. Statistical comparisons (χ 2 ) were completed with responses stratified using the instability severity index score (ISIS) in practice, years of practice, and surgical volumes.

MAIN OUTCOME MEASURES

Summary statistics were compiled, and response frequencies were considered for consensus (75%). Case series responses were stratified on use of the ISIS in practice, years of experience, and annual procedure volumes (χ 2 , P < 0.05).

RESULTS

Eighty orthopedic surgeons responded, with consensus on areas of diagnostic workup of AGHI, nonoperative management, and operative techniques. There was no consensus on indications for soft tissue and bony augmentation or postoperative management. There was no difference in practices based on the use of ISIS, years in practice, or surgical volumes.

CONCLUSIONS

Canadian orthopedic surgeons manage AGHI consistently with consensus achieved in preoperative diagnostics and operative techniques, although debate remains as to the indications for soft tissue and bony augmentation procedures.

Effects of increased body mass index on one year outcomes following soft tissue arthroscopic shoulder instability repair

Background

The purpose of this study was to investigate the impact of high body mass index on the 1-year minimal outcome following arthroscopic shoulder stabilization.

Methods

Patients who underwent arthroscopic Bankart repair (ABR) between 2017 and 2021 were identified and assigned to 1 of 3 cohorts based on their preoperative body mass index: normal (18-25), overweight (25-30), and obese (>30). The primary outcomes assessed were postoperative shoulder instability and revision rates. The 3 groups were compared using the Patient-Reported Outcomes Measurement Information System (PROMIS) upper extremity, pain interference, pain intensity, Clinical Global Impression scores, visual analog scale pain scores, and shoulder range of motion at 1 year postoperatively.

Results

During the study period, 142 patients underwent ABR and had an average age of 35 ± 10 years. Obese patients had a higher percentage of partial rotator cuff tears (60% vs. 27%, odds ratio: 3.2 [1.1, 9.2]; P = .009), longer mean operative time (99.8 ± 40.0 vs. 75.7 ± 28.5 minutes; P < .001), and shorter time to complication (0.5 ± 0 vs. 7.0 ± 0 months; P = .038). After controlling for confounding factors, obesity was associated with a lesser improvement in upper extremity function scores (obese vs. normal: -4.9 [-9.4, -0.5]; P = .029); although this difference exists, found future studies are needed to determine the clinical significance. There were no differences in patient reported outcome measures, recurrence rate, or revision surgery rates between cohorts at any time point (P > .05).

Conclusion

Obesity is an independent risk factor for longer operative times but does not confer a higher risk of recurrent instability, revision surgery, or lower outcome scores 1 year following ABR.

Current Concepts in the Measurement of Glenohumeral Bone Loss

PURPOSE

The extent of glenohumeral bone loss seen in anterior shoulder dislocations plays a major role in guiding surgical management of these patients. The need for accurate and reliable preoperative assessment of bone loss on imaging studies is therefore of paramount importance to orthopedic surgeons. This article will focus on the tools that are available to clinicians for quantifying glenoid bone loss with a focus on emerging trends and research in order to describe current practices.

RECENT FINDINGS

Recent evidence supports the use of 3D CT as the most optimal method for quantifying bone loss on the glenoid and humerus. New trends in the use of 3D and ZTE MRI represent exciting alternatives to CT imaging, although they are not widely used and require further investigation. Contemporary thinking surrounding the glenoid track concept and the symbiotic relationship between glenoid and humeral bone loss on shoulder stability has transformed our understanding of these lesions and has inspired a new focus of study for radiologists and orthopedist alike. Although a number of different advanced imaging modalities are utilized to detect and quantify glenohumeral bone loss in practice, the current literature supports 3D CT imaging to provide the most reliable and accurate assessments. The emergence of the glenoid track concept for glenoid and humeral head bone loss has inspired a new area of study for researchers that presents exciting opportunities for the development of a deeper understanding of glenohumeral instability in the future. Ultimately, however, the heterogeneity of literature, which speaks to the diverse practices that exist across the world, limits any firm conclusions from being drawn.

Management of Shoulder Instability in Patients with Seizure Disorders

PURPOSE OF REVIEW

Patients with seizure disorders commonly suffer shoulder dislocations and subsequent instability. Due to high rates of recurrence and bone loss, management of this instability and associated pathology has proven to be more complex than that of patients without seizure disorders. The ultimate goal of this review is to outline the various treatment modalities and their respective outcomes in this complex patient population.

RECENT FINDINGS

Optimization of medical management of seizure disorders is imperative. However, despite these efforts, the incidence of post-operative seizure activity continues to be a concern. These subsequent episodes increase the risk of further instability and failure of surgical procedures. Overall, the use of soft tissue procedures has proven to result in increased recurrence of instability compared to bone-block augmenting and grafting procedures. There are a variety of bone-block procedures that have been described for anterior and posterior instability. Despite their success in decreasing further instability, they are associated with several complications that patients should be informed of. There is no consensus regarding the optimal surgical management of shoulder instability in patients with seizure activity. A multidisciplinary approach to the management of the seizure activity is paramount to the success of their treatment. Further studies are required to evaluate the optimal timing and type of surgical intervention for individualized cases.

Calculating glenoid bone loss based on glenoid height using ipsilateral three-dimensional computed tomography

PURPOSE

To investigate the relationship between glenoid width and other morphologic parameters using three-dimensional (3D) computed tomography (CT) images of native shoulders, and to create a new measurement tool to assess glenoid defects in a Canadian population with established anterior shoulder instability.

METHODS

Forty-three glenoid CT scans were analyzed for patients who underwent contralateral shoulder glenoid reconstruction for anterior shoulder instability between 2012 and 2020. Demographic data were obtained including age, gender and BMI. The subjects were excluded if they had a prior history of ipsilateral shoulder instability, shoulder fractures, or bone tumors. The following glenoid parameters were measured: width (W), height (H), anteroposterior (AP) depth, superior-inferior (SI) depth and version. The shape of the glenoid was also classified into pear, inverted comma or oval.

RESULTS

There were 35 male and 8 females with a mean age of 34.5 ± 12.9 years. The glenoid width was strongly correlated with the height (R² = 0.9) and a regression model equation was obtained: W (mm) = 2.5 + 0.7*H (mm). There was also strong correlation with gender (P < 0.001), glenoid shape (P = 0.030), AP and SI depths (P = 0.006 and P < 0.001, respectively). Male gender was associated with higher measurement values for all parameters. The most common glenoid shapes were the pear (46.5%) and oval morphotypes (39.6%) for the whole study group.

CONCLUSION

The native glenoid width can be estimated based on glenoid height using ipsilateral 3D CT. This may help with preoperative planning and surgical decision-making for patients with anterior shoulder instability and glenoid bone loss.

LEVEL OF EVIDENCE

III.

3D-MRI versus 3D-CT in the evaluation of glenoid deformity in glenohumeral arthritis using Dixon 3D FLASH sequence

OBJECTIVE

To compare MRI with 3D reconstructions and 3D-CT with respect to assessment of glenoid wear in osteoarthritic shoulders.

METHODS

3D reconstructions were generated for CT and MR (utilizing the Dixon technique) imaging performed on 29 osteoarthritic shoulders. Two reviewers independently performed glenoid morphometric measurements and evaluated glenoid erosion. Mean differences between the two modalities were calculated. Inter-observer agreement was calculated using kappa coefficient.

RESULTS

The combined mean absolute difference (bias) in glenoid version between 3D-CT and 3D-MRI was 2.7° ± 1.6° (range 0.15-7.85, P value = 0.7). The combined mean absolute difference in glenoid inclination between 3D-CT and 3D-MRI was 6.8° ± 4.1° (range 0.8°-15.75°, P value = 0.17). No significant inter-reader variation in glenoid version and inclination measurements on 3D-CT and 3D-MRI was found (P > 0.05). The inter-reader reliability for both CT and MRI was high for Walch grading of glenoid bone loss (κ = 1, κ = 0.81, respectively).

CONCLUSIONS

3D-MRI is comparable to 3D-CT with respect to axial glenoid bone loss, as measured by glenoid version. However, for coronal bone loss estimation, measured by glenoid inclination, 3D-CT remains the gold standard. Thus, 3D-MR can be used as an alternative for preoperative assessment of glenoid version in arthritic shoulders.

Comparison of computed tomography and 3D magnetic resonance imaging in evaluating glenohumeral instability bone loss

BACKGROUND

To determine whether the addition of 3-dimensional (3D) magnetic resonance imaging (MRI) to standard MRI sequences is comparable to 3D computed tomographic (CT) scan evaluation of glenoid and humeral bone loss in glenohumeral instability.

METHODS

Eighteen patients who presented with glenohumeral instability were prospectively enrolled and received both MRI and CT within 1 week of each other. The MRI included an additional sequence (volumetric interpolated breath-hold examination [VIBE]) that underwent postprocessing for reformations. The addition of a VIBE protocol, on average, is an additional 4-4.5 minutes in the scanner. CT data also underwent 3D postprocessing, and therefore each patient had 4 imaging modalities (2D CT, 2D MRI, 3D CT reformats, and 3D MRI reformats). Each sequence underwent the following measurements from 2 separate reviewers: glenoid defect, glenoid defect percentage, humeral defect, humeral defect percentage, and evaluation of glenoid track and version. Paired t tests were used to assess differences between imaging modalities and χ² for glenoid track. Intra- and interobserver reliability were evaluated. Bland-Altman tests were also performed to assess the agreement between CT and MRI. In addition, we determined the cost of each imaging modality at our institution.

RESULTS

3D MRI measurements for glenoid and humeral bone loss measurements were comparable to 3D CT (Table 1). There were no significant differences for glenoid defect size and percentage, or humeral defect size and percentage (P > .05) (Table 2). Bland-Altman analysis demonstrated strong agreement, with small measurement errors for 3D CT and 3D MRI percentage glenoid bone loss. There was also no difference in evaluation for determining on vs. off track between any of the imaging modalities. Inter- and intrarater reliability was good to excellent for all CT and MRI measurements (r ≥ 0.7).

CONCLUSION

3D MRI measurements for bone loss in glenohumeral instability through use of VIBE sequence were equivalent to 3D CT. At our institution, undergoing MRI with 3D reconstruction was 1.67 times cheaper than MRI and CT with 3D reconstructions. 3D MRI may be a useful adjuvant to standard MRI sequences to allow concurrent soft tissue and accurate assessment of glenoid and humeral bone loss in glenohumeral instability.

MRI evaluation of pediatric tibial eminence fractures: comparison between conventional and "CT-like" ultrashort echo time (UTE) images

OBJECTIVE

UTE MRI offers a radiation-free alternative to CT for bone depiction, but data on children is lacking. The purpose of this study was to determine whether UTE images improve detection and characterization of pediatric tibial eminence fractures.

METHODS

Fifteen MRIs with UTE from 12 children (10 boys, 2 girls; mean age: 12.6 ± 3.3 years) with tibial eminence fractures (2018-2020) and 15 age-matched MRIs without fractures were included. After randomization, 5 readers reviewed images without and with UTE, at least 1 month apart, and recorded the presence of fracture and preferred images. If fracture is present, radiologists also recorded fragment size, number, and displacement; surgeons assigned Meyers-McKeever grade and management. Disagreements on management were resolved through consensus review. Kappa and intra-class correlation (ICC), sensitivity, and specificity were used to compare agreement between readers and fracture detection between images without and with UTE.

RESULTS

For fracture detection, inter-reader agreement was almost perfect (κ-range: 0.91-0.93); sensitivity and specificity were equivalent between images without and with UTE (range: 95-100%). For fracture characterization, UTE improved agreement on size (ICC = 0.88 to 0.93), number (ICC = 0.52 to 0.94), displacement (ICC = 0.74 to 0.86), and grade (ICC = 0.92 to 0.93) but reduced agreement on management (κ = 0.68 to 0.61), leading to a change in consensus management in 20% (3/15). Radiologists were more likely to prefer UTE for fracture and conventional images for non-fracture cases (77% and 77%, respectively, p < 0.001).

CONCLUSION

While UTE did not improve diagnosis, it improved agreement on characterization of pediatric tibial eminence fractures, ultimately changing the preferred treatment in 20%.

Novel anterior coracoglenoid line utilizing magnetic resonance imaging (MRI) corresponds with critical glenoid bone loss

OBJECTIVE

Glenoid bone loss is estimated using a best-fit circle method and requires software tools that may not be available. Our hypothesis is that a vertical reference line drawn parallel to the long axis of the glenoid and passing through the inflection point of the coracoid and glenoid will represent a demarcation line of approximately 20% of the glenoid. Our aim is to establish a more efficient method to estimate a surgical threshold for glenoid insufficiency.

METHODS

Fifty patients with normal glenoid anatomy were randomly chosen from an orthopedic surgeon's database. Two orthopedic surgeons utilized T1-weighted sagittal MRIs and the coracoglenoid line technique to determine the percentage of bony glenoid anterior to vertical line. Two musculoskeletal radiologists measured the same 50 glenoids using the circle technique. Differences were determined using dependent t test. Reliability was compared using interclass correlation coefficient and Kappa. Validity was compared using Pearson correlation coefficient.

RESULTS

Mean surface area of the glenoid anterior to the vertical line was on average 21.69% ± 3.12%. Surface area of the glenoid using the circle method was on average 20.86% ± 2.29%. Inter-rater reliability of the circle method was 0.553 (fair). Inter-rater reliability of the vertical line technique was 0.83 (excellent). There was a linear relationship between circle and vertical line measurements, r = 0.704 (moderate to high).

CONCLUSION

The coracoglenoid line appears to represent a line of demarcation of approximately 21% of glenoid bone anterior to the coracoglenoid line. Our technique was found to be reliable, valid, and accurate.

Arthroscopic Latarjet Procedure Using FiberTape Cerclage With a Simplified Technique for Suture Passage and Coracoid Fixation

Arthroscopic Latarjet has evolved as a reproducible procedure to address significant anterior glenoid bone loss in recurrent anterior instability of the shoulder joint. While arthroscopic Bankart procedure for anterior shoulder instability has changed from metal anchors to absorbable or soft all-suture anchors to avoid metal-ware and subsequent abrasion in cases of osteolysis or backout, Latarjet procedure, until recently couple of titanium screws were used to fix the coracoid bone to the anterior glenoid. Arthroscopic techniques for Latarjet procedure of coracoid bone transfer have shown results similar to the open technique in many recent studies. We use an all-arthroscopic technique that is different and easier from the currently described technique using FiberTape cerclage loops, with 2 ultrabraid tapes fixing the coracoid bone to the prepared anteroinferior glenoid surface. The repair is completed using all-suture anchors to fix the anterior capsule over the attached coracoid, thus exteriorizing the transferred bone and preventing contact with the moving humeral head.

The Use of Multiple Imaging Studies Before Shoulder Stabilization Surgery Is Increasing

Purpose

To determine the incidence of preoperative shoulder imaging, explore the prevalence of obtaining multiple advanced imaging studies, and identify patient characteristics associated with specific imaging studies before anterior versus posterior shoulder stabilization surgery.

Methods

The PearlDiver database was queried for patients who underwent anterior or posterior shoulder stabilization surgery from 2010 to 2019. The incidence of imaging studies within a year of surgery was collected. Patient characteristics were compared between groups using one-way analysis of variance or χ² test.

Results

In total, 10,252 patients underwent anterior shoulder stabilization surgery, and 1,108 patients underwent posterior shoulder stabilization surgery. Imaging use before anterior and posterior shoulder stabilization surgery included plain radiographs (69%, 70%, respectively), magnetic resonance imaging (MRI; 43%, 33%), and computed tomography (CT; 22%, 22%). In total, 1,098 patients (11%) received MRI and CT before anterior stabilization surgery and 85 patients (8%) received MRI and CT before posterior stabilization surgery. Over time, the incidence of obtaining MRI and CT increased before anterior (z = 2.54, P = .011) and posterior (z = 2.36, P = .018) stabilization surgery.

Conclusions

This study highlights the increasing use of multiple imaging studies before shoulder stabilization surgery over recent years, including plain radiographs, MRI, and CT imaging. In total, 45% of anterior shoulder stabilization patients and 41% of posterior shoulder stabilization patients obtained more than 1 imaging study within a year of surgery, with a recent increase in patients obtaining both MR and CT scans preoperatively.

Statement of Clinical Relevance

The increasing use of multiple preoperative imaging studies observed in this study highlights an opportunity for new imaging technology to streamline and improve the preoperative workup.

Magnetic Resonance Imaging Versus Computed Tomography for Three-Dimensional Bone Imaging of Musculoskeletal Pathologies: A Review

Magnetic resonance imaging (MRI) is increasingly utilized as a radiation‐free alternative to computed tomography (CT) for the diagnosis and treatment planning of musculoskeletal pathologies. MR imaging of hard tissues such as cortical bone remains challenging due to their low proton density and short transverse relaxation times, rendering bone tissues as nonspecific low signal structures on MR images obtained from most sequences. Developments in MR image acquisition and post‐processing have opened the path for enhanced MR‐based bone visualization aiming to provide a CT‐like contrast and, as such, ease clinical interpretation. The purpose of this review is to provide an overview of studies comparing MR and CT imaging for diagnostic and treatment planning purposes in orthopedic care, with a special focus on selective bone visualization, bone segmentation, and three‐dimensional (3D) modeling. This review discusses conventional gradient‐echo derived techniques as well as dedicated short echo time acquisition techniques and post‐processing techniques, including the generation of synthetic CT, in the context of 3D and specific bone visualization. Based on the reviewed literature, it may be concluded that the recent developments in MRI‐based bone visualization are promising. MRI alone provides valuable information on both bone and soft tissues for a broad range of applications including diagnostics, 3D modeling, and treatment planning in multiple anatomical regions, including the skull, spine, shoulder, pelvis, and long bones.

Reporting of glenoid bone loss measurement in clinical studies and the need for standardization : a systematic review

AIMS

The amount of glenoid bone loss is an important factor in deciding between soft-tissue and bony reconstruction when managing anterior shoulder instability. Accurate and reproducible measurement of glenoid bone loss is therefore vital in evaluation of shoulder instability and recommending specific treatment. The aim of this systematic review is to identify the range methods and measurement techniques employed in clinical studies treating glenoid bone loss.

METHODS

A systematic review of the PubMed, MEDLINE, and Embase databases was undertaken to cover a ten-year period from February 2011 to February 2021. We identified clinical studies that incorporated bone loss assessment in the methodology as part of the decision-making in the management of patients with anterior shoulder instability. The Preferred Reporting Items for Systematic Reviews (PRISMA) were used.

RESULTS

A total of 5,430 articles were identified from the initial search, of which 82 studies met the final inclusion criteria. A variety of imaging methods were used: three studies did not specify which modality was used, and a further 13 used CT or MRI interchangeably. There was considerable heterogeneity among the studies that specified the technique used to quantify glenoid bone loss. A large proportion of the studies did not specify the technique used.

CONCLUSION

This systematic review has identified significant heterogeneity in both the imaging modality and method used to measure glenoid bone loss. The recommendation is that as a minimum for publication, authors should be required to reference the specific measurement technique used. Without this simple standardization, it is impossible to determine whether any published paper should influence clinical practice or should be dismissed. Cite this article: Bone Joint J 2022;104-B(1):12-18.

Managing Bone Loss in Shoulder Instability-Techniques and Outcomes: a Scoping Review

PURPOSE OF REVIEW

The aim of this scoping review is to provide an overview of the literature published over the past 5 years related to the management of bone loss in anterior shoulder instability.

RECENT FINDINGS

During recent years, there has been a focus on patients at high risk for failure following soft tissue anterior stabilization (Bankart repair). A growing body of evidence suggests that anterior capsulolabral repair is insufficient in the setting of subcritical glenoid bone loss with an off-track Hill Sachs lesion. In such cases, the addition of a remplissage procedure to a Bankart repair or a bone-block augmentation to the glenoid (Latarjet, for example) is often advocated to decrease the risk of recurrent instability. Recent studies have also evaluated the role of alternative bone-block procedures in comparison to the Latarjet, outcomes with arthroscopic and open techniques as well as various fixation methods and radiological outcomes (bone graft resorption, glenohumeral osteoarthritis). Advances in our understanding of subcritical glenoid bone loss and the glenoid track concept have significantly impacted clinical decision making and treatment selection. The development of arthroscopic techniques has allowed for minimally invasive and safe arthroscopic bone-block procedures as an alternative to open procedures. Further research related to free bone-block procedures will inform long-term outcomes between these procedures and the gold standard Latarjet. Additionally, high-quality evidence is lacking to identify the ideal treatment for patients with glenoid subcritical glenoid bone defect. Variability in outcome reporting suggests the need to standardize outcome measures for future instability trials.

3D MRI of the Shoulder

Magnetic resonance imaging provides a comprehensive evaluation of the shoulder including the rotator cuff muscles and tendons, glenoid labrum, long head biceps tendon, and glenohumeral and acromioclavicular joint articulations. Most institutions use two-dimensional sequences acquired in all three imaging planes to accurately evaluate the many important structures of the shoulder. Recently, the addition of three-dimensional (3D) acquisitions with 3D reconstructions has become clinically feasible and helped improve our understanding of several important pathologic conditions, allowing us to provide added value for referring clinicians. This article briefly describes techniques used in 3D imaging of the shoulder and discusses applications of these techniques including measuring glenoid bone loss in anterior glenohumeral instability. We also review the literature on routine 3D imaging for the evaluation of common shoulder abnormalities as 3D imaging will likely become more common as imaging software continues to improve.

In-Season Management of Anterior Shoulder Instability

Anterior shoulder instability commonly occurs in young and active individuals, particularly those participating in contact or collision sports. At the intercollegiate level, rates of anterior instability have been reported to be 0.12 events per 1000 athlete exposures. The treatment of in-season athletes with anterior instability presents a challenge for the team physician. The desire to return to play within the same season with nonoperative management must be weighed against the increased risk of recurrence as well as athlete and team specific demands. The purpose of this chapter is to discuss the key considerations for the management of the athlete with anterior shoulder instability that occurs within the competitive season.

Glenoid Bone Loss in Shoulder Instability: Superiority of Three-Dimensional Computed Tomography over Two-Dimensional Magnetic Resonance Imaging Using Established Methodology

Backgroud

Recent literature suggests that three-dimensional magnetic resonance imaging (3D MRI) can replace 3D computed tomography (3D CT) when evaluating glenoid bone loss in patients with shoulder instability. We aimed to examine if 2D MRI in conjunction with a validated predictive formula for assessment of glenoid height is equivalent to the gold standard 3D CT scans for patients with recurrent glenohumeral instability.

Methods

Patients with recurrent shoulder instability and available imaging were retrospectively reviewed. Glenoid height on 3D CT and 2D MRI was measured by two blinded raters. Difference and equivalence testing were performed using a paired t-test and two one-sided tests, respectively. The interclass correlation coefficient (ICC) was used to test for interrater reliability, and percent agreement between the measurements of one reviewer was used to assess intrarater reliability.

Results

Using an equivalence margin of 1 mm, 3D CT and 2D MRI were found to be different (p = 0.123). The mean glenoid height was significantly different when measured on 2D MRI (39.09 ± 2.93 mm) compared to 3D CT (38.71 ± 2.89 mm) (p = 0.032). The mean glenoid width was significantly different between 3D CT (30.13 ± 2.43 mm) and 2D MRI (27.45 ± 1.72 mm) (p < 0.001). The 3D CT measurements had better interrater agreement (ICC, 0.91) than 2D MRI measurements (ICC, 0.8). intrarater agreement was also higher on CT.

Conclusions

Measurements of glenoid height using 3D CT and 2D MRI with subsequent calculation of the glenoid width using a validated methodology were not equivalent, and 3D CT was superior. Based on the validated methods for the measurement of glenoid bone loss on advanced imaging studies, 3D CT study must be preferred over 2D MRI in order to estimate the amount of glenoid bone loss in candidates for shoulder stabilization surgery and to assist in surgical decision-making.

First-time Glenohumeral Dislocations: Current Evidence and Considerations in Clinical Decision Making

The decision to manage first-time shoulder dislocations conservatively or operatively has become increasingly complex because of conflicting literature. Although shoulder dislocations have traditionally been managed with reduction and immobilization, recent evidence has suggested high rates of subsequent recurrence. Surgical intervention is thought to better restore stability and decrease recurrence rates; however, it also has the potential for additional morbidity and financial cost. As such, recent literature has sought to better define patient risk profiles to identify optimal candidates for both conservative and operative management. The purpose of the current review is to provide a comprehensive and evidence-based assessment of the most recent literature to better delineate an appropriate treatment algorithm for this challenging clinical scenario.

Three-Dimensional Zero Echo Time Magnetic Resonance Imaging Versus 3-Dimensional Computed Tomography for Glenoid Bone Assessment

PURPOSE

To evaluate the 3-dimensional (3D) zero echo time (ZTE) magnetic resonance imaging (MRI) technique and compare it with 3D computed tomography (CT) for the assessment of the glenoid bone.

METHODS

ZTE MRI using multiple resolutions and multislice CT were performed in 6 shoulder specimens before and after creation of glenoid defects and in 10 glenohumeral instability patients. Two musculoskeletal radiologists independently generated 3D volume-rendered images of the glenoid en face. Post-processing times and glenoid widths were measured. Inter-modality and inter-rater agreement was assessed.

RESULTS

Intraclass correlation coefficients (ICCs) for inter-modality assessment showed almost perfect agreement for both readers, ranging from 0.949 to 0.991 for the ex vivo study and from 0.955 to 0.987 for the in vivo patients. Excellent interobserver agreement was found for both the ex vivo (ICCs ≥ 0.98) and in vivo (ICCs ≥ 0.92) studies. For the ex vivo study, Bland-Altman analyses for CT versus MRI showed a mean difference of 0.6 to 1 mm at 1.0-mm³ MRI resolution, 0.3 to 0.6 mm at 0.8-mm³ MRI resolution, and 0.3 to 0.6 mm at 0.6-mm³ MRI resolution for both readers. For the in vivo study, Bland-Altman analyses for CT versus MRI showed a mean difference of 0.6 to 0.8 mm at 1.0-mm³ MRI resolution, 0.5 to 0.6 mm at 0.8-mm³ MRI resolution, and 0.4 to 0.8 mm at 0.7-mm³ MRI resolution for both readers. Mean post-processing times to generate 3D images of the glenoid ranged from 32 to 46 seconds for CT and from 33 to 64 seconds for ZTE MRI.

CONCLUSIONS

Three-dimensional ZTE MRI can potentially be considered as a technique to determine glenoid width and can be readily incorporated into the clinical workflow.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria (consecutive patients with consistently applied reference standard and blinding).

Accuracy of Currently Available Methods in Quantifying Anterior Glenoid Bone Loss: Controversy Regarding Gold Standard-A Systematic Review

PURPOSE

To determine the accuracy of glenoid bone loss-measuring methods and assess the influence of the imaging modality on the accuracy of the measurement methods.

METHODS

A literature search was performed in the PubMed (MEDLINE), Embase, and Cochrane databases from 1994 to June 11, 2019. The guidelines and algorithm of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) were used. Included for analysis were articles reporting the accuracy of glenoid bone loss-measuring methods in patients with anterior shoulder instability by comparing an index test and a reference test. Furthermore, articles were included if anterior glenoid bone loss was quantified using a ruler during arthroscopy or by measurements on plain radiograph(s), computed tomography (CT) images, or magnetic resonance images in living humans. The risk of bias was determined using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.

RESULTS

Twenty-one studies were included, showing 17 different methods. Three studies reported on the accuracy of methods performed on 3-dimensional CT. Two studies determined the accuracy of glenoid bone loss-measuring methods performed on radiography by comparing them with methods performed on 3-dimensional CT. Six studies determined the accuracy of methods performed using imaging modalities with an arthroscopic method as the reference. Eight studies reported on the influence of the imaging modality on the accuracy of the methods. There was no consensus regarding the gold standard. Because of the heterogeneity of the data, a quantitative analysis was not feasible.

CONCLUSIONS

Consensus regarding the gold standard in measuring glenoid bone loss is lacking. The use of heterogeneous data and varying methods contributes to differences in the gold standard, and accuracy therefore cannot be determined.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II, III, and IV studies.

When to Abandon the Arthroscopic Bankart Repair: A Systematic Review

CONTEXT

Bone loss is a major factor in determining surgical choice in patients with anterior glenohumeral instability. Although bone loss has been described, there is no consensus on glenoid, humeral head, and bipolar bone loss limits for which arthroscopic-only management with Bankart repair can be performed.

OBJECTIVE

To provide guidelines for selecting a more complex repair or reconstruction (in lieu of arthroscopic-only Bankart repair) in the setting of glenohumeral instability based on available literature.

DATA SOURCES

An electronic search of the literature for the period from 2000 to 2019 was performed using PubMed (MEDLINE).

STUDY SELECTION

Studies were included if they quantified bone loss (humeral head or glenoid) in the setting of anterior instability treated with arthroscopic Bankart repair.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Study design, level of evidence, patient demographics, follow-up, recurrence rates, and measures of bone loss (glenoid, humeral head, bipolar).

RESULTS

A total of 14 studies met the inclusion criteria. Of these, 10 measured glenoid bone loss, 5 measured humeral head bone loss, and 2 measured "tracking" without explicit measurement of humeral head bone loss. Measurement techniques for glenoid and humeral head bone loss varied widely. Recommendations for maximum glenoid bone loss for arthroscopic repair were largely <15% of glenoid width in recent studies. Recommendations regarding humeral head loss were more variable (many authors providing only qualitative descriptions) with increasing attention on glenohumeral tracking.

CONCLUSION

It is essential that a standardized method of glenoid and humeral head bone loss measurements be performed preoperatively to assess which patients will have successful stabilization after arthroscopic Bankart repair. Glenoid bone loss should be <15%, and humeral head lesions should be "on track" if an arthroscopic-only Bankart is planned. If there is greater bone loss, adjunct or open procedures should be performed.

Influence of coracoid anatomy on the location of glenoid rim defects in anterior shoulder instability: 3D CT-scan evaluation of 51 patients

PURPOSE

Glenoid bony lesions play a role in approximately half of anterior shoulder instability cases. The purpose of this study is to see if the anatomy of the coracoid affects the location of glenoid rim defects. We hypothesized that a prominent coracoid (lower and lateral) would be more likely to cause an anterior-inferior glenoid lesion, and a less prominent coracoid more prone to cause an anterior lesion. The null hypothesis being the absence of correlation.

METHODS

Fifty-one shoulder CT-scans from a prospective database, with 3D reconstruction, were analyzed. The position of glenoid lesions was identified using the validated clock method, identifying the beginning and end time. The size of bony glenoid defects was calculated using the validated glenoid ratio method. The position of the coracoid tip was measured in three orthogonal planes.

RESULTS

Analysis included 25 right shoulders and 26 left shoulders in seven females and 41 males. The vertical position of the coracoid tip relative to the top of the glenoid was highly correlated to the location of the glenoid defect on the profile view (r = -0.625; 95% CI 0.423-0.768; p = 0.001). Thus, higher coracoids were associated with anterior lesions, while lower coracoids were associated with anterior-inferior lesions. A more laterally prominent coracoid was also correlated with anterior-inferior lesions (r = 0.433; 95% CI 0.179-0.633; p = 0.002).

CONCLUSION

This study shows that coracoid anatomy affects the location of bony Bankart defects in anterior shoulder instability. Lower and laterally prominent coracoids are associated with anterior-inferior lesions. This variation in anatomy should be considered during pre-op planning for surgeries involving bone graft.

LEVEL OF EVIDENCE

Level 4 basic science.

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.

Editorial Commentary: Methodology of Measuring Bone Loss in Recurrent Shoulder Instability Surgery: Traditional Computed Tomography Scan and Magnetic Resonance Imaging Do Not Tell the Full Story

When measuring bone loss in recurrent shoulder instability, both computed tomography (CT) scan and magnetic resonance imaging (MRI) are accurate using the circle method. However, measurement of on- versus off-track lesions can be inconsistent, and measuring Hill-Sachs lesions on MRI relative to an extrapolated rotator cuff attachment is difficult. In the end, determination of on- versus off-track treatment is quite difficult, and for this determination, differences between CT scan and MRI may be clinically imperceptible. Thus, for now, we, and we believe, other surgeons will continue to stick with the circle technique when determining individual patient treatment for recurrent shoulder instability.

Does Bone Loss Imaging Modality, Measurement Methodology, and Interobserver Reliability Alter Treatment in Glenohumeral Instability?

PURPOSE

To determine, in the context of measuring bone loss in shoulder instability, whether measurement differences between magnetic resonance imaging (MRI) and computed tomography (CT), linear-based and area-based methods, and observers altered the proposed treatment when a standardized algorithm was applied.

METHODS

This was a retrospective, comparative imaging study of preoperative patients with anterior shoulder instability with both an MRI and CT scan within 1 year of one another. On parasagittal images reoriented en face to the glenoid, 2 attending orthopaedic surgeons measured glenoid width, glenoid area, glenoid defect width, and glenoid defect area. On axial images maximal Hill-Sachs width was measured. From these, linear percent glenoid bone loss (%GBL) and area %GBL were calculated, and on-versus off-track was determined. With these results, a recommended treatment was determined by applying a standardized algorithm, in which the Latarjet procedure was selected for %GBL >20%, arthroscopic labral repair and remplissage for off-track lesions with %GBL <20%, and arthroscopic labral repair on-track shoulders with %GBL <20%.

RESULTS

In total, 53 patients with mean ± standard deviation 45 ± 83 days between scans were include with a CT linear %GBL of 23.5 ± 9.6% (range 0%-47%). CT lead to larger measurements of %GBL than MRI (linear P = .008, area P = .003), and fewer shoulders being considered on-track (33.0% vs 40.5%), which would alter treatment in 25% to 34%. Linear measurements produced larger values for %GBL (CT, P < .001; MRI, P < .001), which would alter treatment in 25%. For %GBL, inter-rater reliability was good, with intraclass correlation coefficients varying from 0.727 to 0.832 and Kappa varying from 0.57 to 0.62, but these inter-rater differences would alter treatment in 31%.

CONCLUSIONS

The significant differences in bone loss measurement between imaging modality, measurement method, and observers may lead to differences in treatment in up to 34% of cases. Linear CT measurements resulted in the most aggressive treatment recommendations.

LEVEL OF EVIDENCE

Retrospective Comparative Study: Diagnostic, Level III.

[Current concepts of diagnostic techniques and measurement methods for bone defect in patient with anterior shoulder instability]

Objective

To summarize the diagnosis and measurement methods of bone defect in anterior shoulder instability (glenoid bone defect and Hill-Sachs lesion).

Methods

The related literature on the diagnosis and measurement of the bone defect in anterior shoulder instability was reviewed and summarized.

Results

The commonly used techniques for the diagnosis of anterior glenoid bone defect and Hill-Sachs lesion of humeral head include X-ray, CT, MRI, arthroscopy, arthrography. The methods for measuring the degree of anterior glenoid bone defect include Griffith method, glenoid index method, Pico method, and best-fit circle method. The indexes for measuring the Hill-Sachs lesion include the length, width, depth, and volume. X-ray is mainly used for primary screening. Best-fit circle method on three-dimensional (3D) CT reconstruction is commonly used to measure the glenoid bone defect currently. Glenoid track theory on 3D CT reconstruction is popular in recent years. Reliability of measuring the glenoid bone defect and Hill-Sachs lesion with MRI and arthroscopy is still debatable. Arthrography is more and more used in the diagnosis of shoulder joint instability of bone defect and concomitant soft tissue injury.

Conclusion

How to improve the accuracy of evaluating glenoid bone defect and Hill-Sachs lesion before surgery still need further study.

Editorial Commentary: Measurement of Glenoid Bone Loss With Computed Tomography Scan Versus Magnetic Resonance Imaging

Glenoid bone loss remains the largest risk factor for failure after arthroscopic Bankart reconstruction, and its measurement has been called for in all cases of patients undergoing stabilization. Accurate measurements of glenoid bone loss are of the utmost importance, because just 4 mm of "subcritical" loss can separate surgical success from failure. The computed tomography scan is a standard for bone loss measurement, but patients also typically require magnetic resonance imaging for other reasons. If we can use magnetic resonance imaging to measure bone loss, we may be able to avoid radiation, cost, and inconvenience to patients while still ensuring that this critical measure is performed correctly and the proper surgical approach is applied.