Last updated May 19 2025
Description
The Anatomic Total Shoulder Arthroplasty procedure enables the calculation of anatomical bone dimensions through the analysis of shoulder CT images. This technique involves performing a shoulder resection, followed by the automatic insertion of shoulder templates. Anatomic shoulder joint replacement is recommended for patients experiencing pain and dysfunction caused by non-inflammatory degenerative joint diseases, which may include osteoarthritis, avascular necrosis of the humeral head and/or glenoid, and post-traumatic arthritis. It is also indicated for those with rheumatoid arthritis and other inflammatory arthritides, as well as for the correction of functional deformities such as fracture malunion, humeral head fractures, and revisions of prior surgical devices, provided that adequate bone stock is available.
Requirements
This procedure is available for CT scan only with a mandatory shoulder bones representation (scapula with glenoid, and humerus).
Measurements
The measurements made by the procedure are displayed in the image:- Glenoid Inclination (GI): The angle formed between the normal line of the glenoid face plane and the mediolateral axis, as measured in the coronal plane;
- Glenoid Version (GV): The angle formed between the perpendicular line of the glenoid face plane and the mediolateral axis, as assessed in the axial plane;
- Glenoid Reaming Depth (GRD): The measurement of how deep the glenoid surface has been reamed;
- Glenoid Implant Coverage (GIC): The proportion of the glenoid surface that is encompassed by the glenoid template;
- Humeral Head Subluxation (HHS): The proportion of the humeral head's volume that is located posterior to the coronal scapular plane;
- Humeral Head Diameter (HHD): The diameter of the optimal sphere that most accurately encompasses the majority of the humeral head bone;
- Neck Shaft Angle (NSA): The angle formed between a line perpendicular to the Humeral Neck Plane and the humeral axis;
- Humeral Implant Inclination (HII): The angle formed between the perpendicular line of the implant head base plane and the axis of the humeral stem in the coronal plane of the humerus;
- Humeral Implant Version (HIV): The angle formed between the perpendicular line of the implant head base plane and the mediolateral axis in the humeral axial plane;
- Anteroposterior Humeral Implant Shift (apHIS): The measurement of the distance from the center of the implant shell base to the center of the resection along the anteroposterior axis;
- Superoinferior Humeral Implant Shift (siHIS): The measurement taken from the center of the implant shell base to the center of the resection along the superior-inferior axis of the resection plane;
- Anteroposterior Humeral Stem Tilt (apHST): The angle formed between the axis of the implant stem and the axis of the humerus in the sagittal plane of the humerus;
- Mediolateral Humerus Stem Tilt (mlHST): The angle formed between the axis of the implant stem and the axis of the humerus in the coronal plane of the humerus.
How to perform
Pre-op stage
- Validate landmarks and consult measurements
Upon creating the case and uploading the image, the system will automatically place all relevant landmarks, allowing you to view the pre-operative values of each measurement.
If necessary, you can refine the position of these landmarks. Simply click on "Edit landmarks," make the required adjustments, and then save your changes by selecting "Save." The measurements will be updated accordingly, enabling you to continue to the next step by clicking “Approve.”
To reposition the landmarks, simply hover your cursor over the desired landmark and use the left mouse button to adjust each handle to the most appropriate location.
Plan stage
- Template selection and positioning
Upon the approval of the procedure, you will proceed to the templating stage. Here, you can select the manufacturer of your choice. If only one manufacturer is available, it will be automatically selected for you.
During the template configuration phase, you have the flexibility to adjust the properties of the selected template(s) and reposition them as needed.
To finalize the plan, it is essential to click on "Approve plan" and confirm the action in the dialog box that appears.
Export stage
The final stage of the planning process involves the Export step. At this point, you can download a comprehensive PDF report that encapsulates all the planning information, ensuring you have a thorough record of the procedures and measurements taken.
