Imaging Modalities for the Glenoid Track in Recurrent Shoulder Instability: A Systematic Review

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.

How does dynamic arthroscopic tracking compare with radiologic glenoid track for identification of on- and off-track lesions in anterior shoulder instability?

BACKGROUND

Current treatment paradigms for anterior shoulder instability are based on radiologic measurements of glenohumeral bone defects, and mathematical calculation of the glenoid track (GT) is used to classify lesions into on-track and off-track morphology. However, radiologic measurements have shown high variability, and GT widths under dynamic conditions have been reported to be significantly smaller than those under static radiologic conditions. The purpose of this study was to assess the reliability, reproducibility, and diagnostic validity of dynamic arthroscopic standardized tracking (DAST) in comparison to the gold-standard radiologic track measurement method for the identification of on- and off-track bony lesions in patients with anteroinferior shoulder instability.

METHODS

Between January 2018 and August 2022, 114 patients with traumatic anterior shoulder instability were evaluated using 3-T magnetic resonance imaging or computed tomography scans; glenoid bone loss, Hill-Sachs interval, GT, and Hill-Sachs occupancy ratio (HSO) were measured, and defects were classified as on-track or off-track defects and peripheral-track defects (based on HSO percentage) by 2 independent researchers. During arthroscopy, a standardized method (DAST method) was used by 2 independent observers to classify defects into on-track defects (central and peripheral) and off-track defects. Interobserver reliability of the DAST and radiologic methods was calculated using the κ statistic and reported as percentage agreement. Diagnostic validity (sensitivity, specificity, positive predictive value, and negative predictive value) of the DAST method was calculated using the radiologic track (HSO percentage) as the gold standard.

RESULTS

The radiologically measured mean glenoid bone loss percentage, Hill-Sachs interval, and HSO in off-track lesions were lower with the arthroscopic method (DAST) as compared with the radiologic method. The DAST method showed nearly perfect agreement between the 2 observers for the on-track/off-track classification (κ = 0.96, P < .001) and the on-track central or peripheral /off-track classification (κ = 0.88, P < .001). The radiologic method showed greater interobserver variability (κ = 0.31 and κ = 0.24, respectively) with only fair agreement for both classifications. Inter-method agreement varied between 71% and 79% (95% confidence interval, 62%-86%) between the 2 observers, and reliability was assessed as slight (κ = 0.16) to fair (κ = 0.38). Overall, for identification of an off-track lesion, the DAST method showed maximum specificity (81% and 78%) when radiologic peripheral-track lesions (HSO percentage of 75%-100%) were considered off-track and showed maximum sensitivity when arthroscopic peripheral-track lesions were classified as off-track.

CONCLUSION

Although inter-method agreement was low, a standardized arthroscopic tracking method (DAST method) showed superior interobserver agreement and reliability for lesion classification in comparison to the radiologic track method. Incorporating DAST into current algorithms may help reduce variability in surgical decision making.

Onlay Dynamic Anterior Stabilization With Biceps Transfer for the Treatment of Anterior Glenohumeral Instability Produces Good Clinical Outcomes and Successful Healing at a Minimum 1 Year of Follow-Up

Purpose

To report the results of the onlay dynamic anterior stabilization (DAS) using the long head of biceps (LHB) and the double double-pulley technique for the treatment of anterior glenohumeral instability (AGI) with ≤20% glenoid bone loss (GBL).

Methods

From September 2018 to December 2021, patients with AGI and ≤20% GBL were enrolled in a prospective study on DAS and followed for a minimum of 1 year. The primary outcomes were Western Ontario Shoulder Instability Index, Rowe score, range of motion, and strength. The secondary outcomes were ability to return to play (RTP), RTP at same level, lack of recurrence of instability, successful LHB healing, and lack of complications. Magnetic resonance imaging was used to measure GBL, Hill-Sachs interval, glenoid track, and assess LHB integrity.

Results

Eighteen consecutive patients underwent DAS. Fifteen patients had a minimum follow-up of 12 months (mean, 23.93 ± 13.67 months). In total, 12 were male and 3 female patients; 73.3% practiced recreational sports; mean age at surgery was 23.40 ± 6.53 years; mean number of dislocation episodes were 10.13 ± 8.42; mean GBL was 8.21 ± 7.39% (range, 0-20.24%); mean Hill-Sachs interval was 15.00 ± 2.96 mm; and mean glenoid track was 18.87 ± 2.57mm. The mean improvement in the Western Ontario Shoulder Instability Index and Rowe score (959.27 ± 386.70 and 74.00 ± 22.22 points) was significant (P < .001 and P < .001) and more than 6 times greater than the minimum clinically important difference. The mean improvement in active elevation, abduction, and external and internal rotation (23.00 ± 27.76°, 33.33 ± 43.78°, 8.33 ± 13.58°, and 0.73 ± 1.28 points) was significant (P = .006, P = .011, P = .032, and P = .044). RTP rate was 93.33%. RTP at same level was 60.00%. One patient with hyperlaxity had a redislocation (6.7% recurrence). No complications were reported. Each magnetic resonance imaging scan showed successful LHB healing to the anterior glenoid.

Conclusions

At a minimum of 1-year follow-up, DAS produces significant and clinically important improvements in shoulder function, successful LHB healing, and is safe for the treatment of AGI with ≤20% GBL without severe hyperlaxity.

Level of Evidence

IV, therapeutic case series.

Contrast solution properties and scan parameters influence the apparent diffusivity of computed tomography contrast agents in articular cartilage

The inability to detect early degenerative changes to the articular cartilage surface that commonly precede bulk osteoarthritic degradation is an obstacle to early disease detection for research or clinical diagnosis. Leveraging a known artefact that blurs tissue boundaries in clinical arthrograms, contrast agent (CA) diffusivity can be derived from computed tomography arthrography (CTa) scans. We combined experimental and computational approaches to study protocol variations that may alter the CTa-derived apparent diffusivity. In experimental studies on bovine cartilage explants, we examined how CA dilution and transport direction (absorption versus desorption) influence the apparent diffusivity of untreated and enzymatically digested cartilage. Using multiphysics simulations, we examined mechanisms underlying experimental observations and the effects of image resolution, scan interval and early scan termination. The apparent diffusivity during absorption decreased with increasing CA concentration by an amount similar to the increase induced by tissue digestion. Models indicated that osmotically-induced fluid efflux strongly contributed to the concentration effect. Simulated changes to spatial resolution, scan spacing and total scan time all influenced the apparent diffusivity, indicating the importance of consistent protocols. With careful control of imaging protocols and interpretations guided by transport models, CTa-derived diffusivity offers promise as a biomarker for early degenerative changes.

Magnetic resonance arthrography in patients with multidirectional instability: could inferior capsulsar width be considered the cornerstone in the diagnosis of non-traumatic shoulder instability?

OBJECTIVES

To provide quantitative anatomical parameters in patients with and without non-traumatic multidirectional instability using MR arthrography (MR-a).

MATERIALS AND METHODS

One hundred and seventy-six MR-a performed from January 2020 to March 2021 were retrospectively evaluated. Patients were divided according to the presence of clinically diagnosed multidirectional shoulder instability (MDI). Each MR-a was performed immediately after intra-articular injection of 20 ml of gadolinium using the anterior approach. The width of the axillary recess, the width of the rotator interval, and the circumference of the glenoid were measured by three independent radiologists, choosing the average value of the measurements. The difference between the mean values of each of the three parameters between the two study groups was then assessed.

RESULTS

Thirty-seven patients were included in the study (20 in the MDI group, 17 in the control group). The mean axillary recess width in the MDI group was significantly greater than in the control group (t(33) = 3.15, p = .003); rotator interval width and glenoid circumference measurements were not significantly different (t(35) = 1.75, p = .08 and t(30) = 0,51, p = .6, respectively).

CONCLUSIONS

Inferior capsular redundancy may be an important predisposing factor in MDI, while glenoid circumference is not related to MDI. The relationship between the width of the rotator interval and shoulder instability remains debated.