The Y plane is a reliable CT-based reference for glenoid component positioning in shoulder arthroplasty

Area of Science:

• Orthopedic surgery
• Anatomy
• Medical imaging

Background:

• Accurate component positioning is crucial for successful shoulder arthroplasty outcomes.
• Identifying reliable anatomic landmarks for mediolateral component placement remains a challenge.

Purpose of the Study:

• To assess the reliability of specific anatomic references for guiding mediolateral component positioning during shoulder arthroplasty.
• To compare the consistency and repeatability of different landmarks.

Main Methods:

• Computed tomography (CT) scans of 86 healthy shoulders were analyzed.
• Two surgeons independently digitized key anatomic points, including the Y-plane, glenoid center (G), and cortical convergence (CC).
• Mediolateral distances and ratios relative to humeral head size were measured and analyzed for consistency and repeatability.

Main Results:

• The Y-plane demonstrated the greatest consistency and repeatability among the evaluated landmarks.
• Distances from the glenoid center (G) to the Y-plane showed less variability (SD=2.3mm, IQR=3mm) compared to other landmarks.
• Ratios relative to humeral head size also showed superior consistency for the Y-plane.

Conclusions:

• The Y-plane is a dependable anatomic reference for glenoid component positioning in shoulder arthroplasty.
• Its consistent relationship with the glenoid center makes it suitable for preoperative planning and intraoperative guidance.
• This landmark can enhance the accuracy of mediolateral component placement, potentially improving surgical outcomes.