A Novel Tool for Collaborative and Blinded Orthopedic Image Analysis

Can we separately measure glenoid vs. humeral lateralization and distalization in reverse shoulder arthroplasty?

BACKGROUND

Lateralization and distalization in reverse shoulder arthroplasty (RSA) can be measured on anteroposterior (AP) radiographs using 2 previously described angles: lateralization shoulder angle (LSA) and distalization shoulder angle (DSA). However, these 2 angles measure global lateralization and distalization but do not allow to differentiate how much lateralization or distalization are attributable to the glenoid and the humerus. We hypothesized that new angles could allow us to separately measure glenoid vs. humeral lateralization and distalization. A more precise understanding of independent glenoid and humeral contributions to lateralization and distalization may be beneficial in subsequent clinical research.

METHOD

Retrospective analysis of postoperative AP radiographs of 100 patients who underwent primary RSA for cuff-tear arthropathy, massive cuff tear, or glenohumeral osteoarthritis were analyzed. The new angles that we proposed use well-known bony landmarks (the acromion, glenoid, and humerus) and the most lateral point of the glenosphere, which we termed the "glenoid pivot point" (GPP). For lateralization, we used the GPP to split LSA into 2 new angles: glenoid lateralization angle (GLA) and humeral lateralization angle (HLA). For distalization, we introduced the modified distalization shoulder angle (mDSA) that can also be split into 2 new angles: glenoid distalization angle (GDA) and humeral distalization angle (HDA). Three orthopedic surgeons measured the new angles, using the online tool Tyche. Mean values with overall and individual standard deviations as well as intraclass correlation coefficients (ICCs) were calculated.

RESULTS

Because the angles form a triangle, the following equations can be made: LSA = GLA + HLA, and mDSA = GDA + HDA. All angles showed excellent inter- and intraobserver reliability (ICC = 0.92-0.97) with low means of individual standard deviations that indicate a precision of 2° for each angle.

CONCLUSION

Use of the most lateral part of the glenosphere (termed glenoid pivot point) allows us to separately measure glenoid vs. humeral lateralization and distalization. The 4 new angles (HLA, GLA, GDA, HDA) described in the present study can be used on true AP radiographs, routinely obtained after shoulder replacement, and the measured angles may be used with all types of reverse prostheses available.

Proximal humeral fractures in children - controversies in decision making

BACKGROUND

Proximal humeral fractures in children are rare and usually treated non-operatively, especially in children younger than ten. The decision between operative and non-operative treatment is mostly based on age and fracture angulation. In the current literature, diverging recommendations regarding fracture angulation that is still tolerable for non-operative treatment can be found. Besides, there is no consensus on how fracture angulation should be determined. This study aimed to determine whether leading experts in pediatric trauma surgery in Germany showed agreement concerning the measurement of fracture angulation, deciding between operative and non-operative treatment, and choosing a treatment modality.

METHODS

Twenty radiographs showing a proximal humeral fracture and the patient's age were assessed twice by twenty-two senior members of the "Section of Pediatric Traumatology of the German Association for Trauma Surgery". Experts determined the fracture angulation and chose between several operative and non-operative treatment modalities. The mean of individual standard deviations was calculated to estimate the accuracy of single measurements for fracture angulation. Besides Intra-Class Correlation and Fleiss' Kappa coefficients were determined.

RESULTS

For fracture angulation, experts showed moderate (ICC = 0.60) interobserver and excellent (ICC = 0.90) intraobserver agreement. For the treatment decision, there was fair (Kappa = 0.38) interobserver and substantial (Kappa = 0.77) intraobserver agreement. Finally, experts preferred ESIN over K-wires for operative and a Gilchrist over a Cuff/Collar for non-operative treatment.

CONCLUSIONS

Firstly, there is a need for consensus among experts on how fracture angulation in PHFs in children should be reliably determined. Our data indicate that choosing one method everybody agrees to use could be more helpful than using the most sophisticated. However, the overall importance of fracture angulation should also be critically discussed. Finally, experts should agree on treatment algorithms that could translate into guidelines to standardize the care and perform reliable outcome studies.

LEVEL OF EVIDENCE

III.

A Lightweight Browser-Based Tool for Collaborative and Blinded Image Analysis

Collaborative manual image analysis by multiple experts in different locations is an essential workflow in biomedical science. However, sharing the images and writing down results by hand or merging results from separate spreadsheets can be error-prone. Moreover, blinding and anonymization are essential to address subjectivity and bias. Here, we propose a new workflow for collaborative image analysis using a lightweight online tool named Tyche. The new workflow allows experts to access images via temporarily valid URLs and analyze them blind in a random order inside a web browser with the means to store the results in the same window. The results are then immediately computed and visible to the project master. The new workflow could be used for multi-center studies, inter- and intraobserver studies, and score validations.