Interobserver and intraobserver comparison of imaging glenoid morphology, glenoid version and humeral head subluxation

Magnetic resonance imaging vs. two- and three-dimensional computed tomography scans for assessment of glenoid inclination and version

Background

Accurate glenoid component placement is crucial for anatomic (aTSA) or reverse (rTSA) total shoulder arthroplasty. Preoperative glenoid assessment in computed tomography (CT) scans with or without planning software seems to be the established method to plan implant positions. Magnetic resonance imaging (MRI) scans can also display the glenoid bone for preoperative assessment while reducing radiation exposure. Therefore, the objective of this study was to manually assess the glenoid version and inclination in 2D MRI and CT scans in cases with degenerative shoulder pathologies. The results were compared to those of an automated 3D planning software to validate the imaging modality for preoperative glenoid assessment.

Methods

MRI and CT scans of 146 patients (n = 41 aTSA; n = 105 rTSA) were included in this retrospective, single-center study. Glenoid version and inclination were measured manually according to Friedman et al and Maurer et al on CT and MRI scans by two observers. Subsequently, the results were compared to the automated measurements performed by planning software. A repeated-measures analysis of variance was performed to compare the measured angles, and the interobserver and intraobserver reliability were calculated using the intraclass correlation coefficients. The level of significance was set at P < .05.

Results

The average glenoid inclination measured in CT scans was 7.94° ± 7.33°, in MRI scans it was 8.56° ± 7.34°, and in automated planning software it was 7.87° ± 7.60°. The analysis of variance revealed significant differences in mean inclination between 2D MRI and 2D CT (P < .0005) and between MRI and automated software (P = .011). No significant difference was found between 2D CT scans and automated planning software (P = 1.000). The mean glenoid version measured in 2D CT scans was -7.94° ± 10.86°, in 2D MRI scans it was -8.04° ± 10.80°, and -8.32° ± 11.53° in the automated planning software. There was no significant difference in between measurement methods (P = .339). Interobserver reliability analysis showed no statistical differences between the two observers. All measurements had excellent intraobserver reliability.

Conclusion

Preoperative assessment of glenoid version and inclination is crucial in ensuring precise implant positioning and orientation in aTSA and rTSA. This study observed a significant level of concordance between manual and automated measuring techniques utilizing MRI and CT scans. The mean glenoid inclination exhibited a statistically significant difference of less than 1° across the assessment modalities, and no difference for glenoid version was noted. It seems to be questionable if this finding is clinically relevant. MRI may serve as a viable and safe option for assessing glenoid morphology, version, and inclination if CT scans are not available.

Good functional outcome but high rates of instability recurrence after posterior open-wedge glenoid osteotomy for the treatment of posterior shoulder instability with increased glenoid retroversion at mid-term follow-up

PURPOSE

To evaluate clinical, functional and radiological mid-term outcomes following posterior open-wedge glenoid osteotomy (POWGO) for the treatment of posterior shoulder instability (PSI) associated with increased glenoid retroversion.

METHODS

Patients who underwent POWGO for the treatment of symptomatic PSI with glenoid retroversion >10° and participated in a previous study assessing short-term outcomes were included after a minimum follow-up of 5 years. Clinical (Rowe score and physical examination) and functional outcomes (Oxford Shoulder Instability Score [OSIS] and visual analogue scale [VAS] for pain) were assessed. Preoperative versus follow-up magnetic resonance imaging (MRI) assessments were compared for changes in posterior humeral head subluxation (PHHS) and progression of osteoarthritis (shoulder osteoarthritis severity [SOAS] score).

RESULTS

Eight patients (nine shoulders) were included 92.0 months (88.0-109.5 months) post-operatively, of which seven patients (eight shoulders) underwent MRI. Shoulder function was good (Rowe score: 80.0 [76.3-91.3], OSIS: 41.0 [31.0-41.5]) and pain levels were low (VAS for pain: 3.0 [1.0-3.0]) at follow-up. Overall, the degree of PHHS did not change between preoperatively and follow-up (p > 0.05). Four shoulders demonstrated PHHS preoperatively, of which two had a centred humeral head at follow-up. Shoulder osteoarthritis progressed significantly (SOAS score: 17.0 [11.0-24.5] to 33.0 [31.0-45.0], p = 0.018). Residual PSI was evident in 75.0% of shoulders.

CONCLUSION

At mid-term follow-up, POWGO for PSI associated with increased glenoid retroversion led to good functional outcomes but failed to reliably restore posterior shoulder stability and prevent osteoarthritis progression.

LEVEL OF EVIDENCE

Level IV.

Reliability of the Walch Classification for Characterization of Primary Glenohumeral Arthritis: A Systematic Review

INTRODUCTION

The Walch classification has been widely accepted and further developed as a method to characterize glenohumeral arthritis. However, many studies have reported low and inconsistent measures of the reliability of the Walch classification. The purpose of this study was to review the literature on the reliability of the Walch classification and characterize how imaging modality and classification modifications affect reliability.

METHODS

A systematic review of publications that included reliability of the Walch classification reported through intraobserver and interobserver kappa values was conducted. A search in January 2021 and repeated in July 2023 used the terms ["Imaging" OR "radiography" OR "CT" OR "MRI"] AND ["Walch classification"] AND ["Glenoid arthritis" OR "Shoulder arthritis"]. All clinical studies from database inception to July 2023 that evaluated the Walch or modified Walch classification's intraobserver and/or interobserver reliability were included. Cadaveric studies and studies that involved subjects with previous arthroplasty, shoulder débridement, glenoid reaming, interposition arthroplasty, and latarjet or bankart procedure were excluded. Articles were categorized by imaging modality and classification modification.

RESULTS

Thirteen articles met all inclusion criteria. Three involved the evaluation of plain radiographs, 10 used CT, two used three-dimensional (3D) CT, and four used magnetic resonance imaging. Nine studies involved the original Walch classification system, five involved a simplified version, and four involved the modified Walch. Six studies examined the reliability of raters of varying experience levels with none reporting consistent differences based on experience. Overall intraobserver reliability of the Walch classifications ranged from 0.34 to 0.92, and interobserver reliability ranged from 0.132 to 0.703. No consistent trends were observed in the effect of the imaging modalities or classification modifications on reliability.

DISCUSSION

The reliability of the Walch classification remains inconsistent, despite modification and imaging advances. Consideration of the limitations of the classification system is important when using it for treatment or prognostic purposes.

Gender-specific factors influencing the glenoid version and reference values for it

BACKGROUND

Glenoid version is an important factor in the evaluation of shoulder stability and shoulder pathologies. However, there are neither established reference values nor known factors that influence the glenoid version, even though valid reference values are needed for diagnostic and orthopaedic surgery like corrective osteotomy and total or reverse shoulder arthroplasty (TSA/RSA). The aim of our population-based study was to identify factors influencing the glenoid version and to establish reference values from a large-scale population cohort.

RESULTS

Our study explored the glenoid versions in a large sample representing the general adult population. We investigated 3004 participants in the population-based Study of Health in Pomerania (SHIP). Glenoid version was measured for both shoulders via magnetic resonance imaging (MRI). Associations with the glenoid version were calculated for sex, age, body height, body weight and BMI. The reference values for glenoid version in the central European population range between -9° and 7.5°, while multiple factors are associated with the glenoid version.

CONCLUSION

To achieve a reliable interpretation prior to orthopaedic surgery, sex- and age-adjusted reference values are proposed.

Posterior Shoulder Instability but Not Anterior Shoulder Instability Is Related to Glenoid Version

Purpose

To assess and compare glenoid version in patients with anterior shoulder instability (ASI), posterior shoulder instability (PSI), and a control group.

Methods

The operative notes of all patients that had undergone arthroscopic shoulder instability repair between January 2017 and May 2022 were retrospectively reviewed. Magnetic resonance imaging scans were then analyzed, and glenoid version was measured by a single blinded observer. A P value <.05 was considered statistically significant.

Results

There were 100 patients included in the ASI group, 65 in PSI group, and 100 in the control group. The mean glenoid versions for the ASI group were -16°, -9.1°, and -9.2° for the vault version, simplified vault version, and chondrolabral version, respectively. The mean glenoid versions for the PSI group were -21°, -13.4°, and -16.6° for the vault version, simplified vault version, and chondrolabral version, respectively. The mean versions for the control group were -17.8°, -9.5°, and -9.8° for the vault version, simplified vault version and chondrolabral version, respectively. ANOVA testing and post hoc comparisons revealed the PSI group to be significantly more retroverted than both other groups P < .001. The ASI group's degree of glenoid version was not significantly different to that of the control P = .009.

Conclusion

Patients with PSI have a higher degree of retroversion in comparison to those with ASI and control. There is no significant difference in glenoid version among patients with ASI when compared with control.

Level of Evidence

Level III, retrospective comparative study.

Physiological Offset Parameters of the Adult Shoulder Joint-A MRI Study of 800 Patients

Background: Humeral offset (HO) and glenoidal offset (GO) are important morphological parameters in diagnostics and therapy for shoulder pathologies. However, physiological reference values have not yet been sufficiently determined. The aim of the present study was to establish physiological reference values for shoulder offset parameters (SOPs). Methods: MRI images of the shoulder joints of 800 patients (mean age: 50.13 years [±16.01]) were analysed retrospectively. HO, GO, lateral glenoidal humeral offset (LGHO), humeral shaft axis offset (HAO) and cortical offset (CO) were measured. SOPs were examined for associations with age, gender, side and osteoarthritis. Results: The mean HO was 26.19 (±2.70), the mean GO was 61.79 (±5.67), the mean LGHO was 54.49 (±4.69), the mean HAO was 28.17 (±2.82) and the mean CO was 16.70 (±3.08). For all SOPs, significantly higher values were measured in male shoulders. There was a significantly (p < 0.001) higher mean value for HO, GO and LGHO in right shoulders. There was a significant correlation between age and LGHO, and HAO and CO, but not between age and HO or GO. Shoulders with osteoarthritis and non-osteoarthritis did not differ in the mean value of HO, GO, LGHO and HAO, except for CO (p = 0.049). Conclusion: Reference values for SOPs in the adult shoulder joint were determined for the first time. Significant gender-specific differences were found for all measured SOPs. In addition, it was seen that for some SOPs, the joint side and the patient’s age has to be taken into account in shoulder diagnostics and surgery.

Is there a correlation between humeral osteoarthritis and glenoid morphology according to Walch?

Aims

The aim of this study was to determine whether there is a correlation between the grade of humeral osteoarthritis (OA) and the severity of glenoid morphology according to Walch. We hypothesized that there would be a correlation.

Methods

Overal, 143 shoulders in 135 patients (73 females, 62 males) undergoing shoulder arthroplasty surgery for primary glenohumeral OA were included consecutively. Mean age was 69.3 years (47 to 85). Humeral head (HH), osteophyte length (OL), and morphology (transverse decentering of the apex, transverse, or coronal asphericity) on radiographs were correlated to the glenoid morphology according to Walch (A1, A2, B1, B2, B3), glenoid retroversion, and humeral subluxation on CT images.

Results

Increased humeral OL correlated with a higher grade of glenoid morphology (A1-A2-B1-B2-B3) according to Walch (r = 0.672; p < 0.0001). It also correlated with glenoid retroversion (r = 0.707; p < 0.0001), and posterior humeral subluxation (r = 0.452; p < 0.0001). A higher humeral OL (odds ratio (OR) 1.17; 95% confidence interval (CI) 1.03 to 1.32; p = 0.013), posterior humeral subluxation (OR 1.11; 95% CI 1.01 to 1.22; p = 0.031), and glenoid retroversion (OR 1.48; 95% CI 1.30 to 1.68; p < 0.001) were independent factors for a higher glenoid morphology. More specifically, a humeral OL of ≥ 13 mm was indicative of eccentric glenoid types B2 and B3 (OR 14.20; 95% CI 5.96 to 33.85). Presence of an aspherical HH in the coronal plane was suggestive of glenoid types B2 and B3 (OR 3.34; 95% CI 1.67 to 6.68).

Conclusion

The criteria of humeral OL and HH morphology are associated with increasing glenoid retroversion, posterior humeral subluxation, and eccentric glenoid wear. Therefore, humeral radiological parameters might hint at the morphology on the glenoid side.

Cite this article: Bone Jt Open 2022;3(6):463–469.

Identification of threshold pathoanatomic metrics in primary glenohumeral osteoarthritis

BACKGROUND

An assessment of the pathoanatomic parameters of the arthritic glenohumeral joint (GHJ) has the potential to identify discriminating metrics to differentiate glenoid types in shoulders with primary glenohumeral osteoarthritis (PGHOA). The aim was to identify the morphometric differences and threshold values between glenoid types including normal and arthritic glenoids with the various types in the Walch classification. We hypothesized that there would be clear morphometric discriminators between the various glenoid types and that specific numeric threshold values would allow identification of each glenoid type.

METHODS

The computed tomography scans of 707 shoulders were analyzed: 585 obtained from shoulders with PGHOA and 122 from shoulders without glenohumeral pathology. Glenoid morphology was classified according to the Walch classification. All computed tomography scans were imported in a dedicated automatic 3D-software program that referenced measurements to the scapular body plane. Glenoid and humeral modeling was performed using the best-fit sphere method, and the root-mean-square error was calculated. The direction and orientation of the glenoid and humerus described glenohumeral relationships.

RESULTS

Among shoulders with PGHOA, 90% of the glenoids and 85% of the humeral heads were directed posteriorly in reference to the scapular body plane. Several discriminatory pathoanatomic parameters were identified: GHJ narrowing < 3 mm was a discriminatory metric for type A glenoids. Posterior humeral subluxation > 70% discriminated type B1 from normal GHJs. The root-mean-square error was a discriminatory metric to distinguish type B2 from type A, type B3, and normal GHJs. Type B3 glenoids differed from type A2 by greater retroversion (>13°) and subluxation (>71%). The type C glenoid retroversion inferior limit was 21°, whereas normal glenoids never presented with retroversion > 16°.

CONCLUSION

Pathoanatomic metrics with the identified threshold values can be used to discriminate glenoid types in shoulders with PGHOA.

Editorial Commentary: How Does Magnetic Resonance Imaging Stack up in Comparison to Computed Tomography Imaging for Measurement of Glenoid Version?

Computed tomography (CT) has been the gold standard for measuring glenoid version in patients with glenohumeral osteoarthritis or instability. However, few studies have compared measurements of glenoid version on magnetic resonance imaging (MRI) versus CT. Clinicians should feel confident in assessing glenoid version on MRI in the absence of CT imaging. In fact, MRI could be comparable to CT even in cases where the entire scapula is not visible on MRI. A 5° difference in glenoid version between imaging modalities represents a clinically significant difference.