Best-Fit Circle Missing Area Method Shows Good Accuracy and Interrater Reliability When Assessing Glenoid Bone Loss

Area of Science:

• Orthopedics
• Radiology
• Biomechanical Engineering

Background:

• Glenoid bone loss (GBL) is crucial for managing anterior shoulder instability.
• Accurate GBL measurement is essential but lacks a standardized method.

Purpose of the Study:

• To compare the accuracy and interrater reliability of three GBL measurement methods: best-fit circle missing area, ratio, and diameter.
• To determine the most reliable and accurate method for quantifying GBL.

Main Methods:

• A controlled laboratory study using 3D CT scans of 4 healthy male participants.
• Created 5 GBL models (5%-30%) on each scapula.
• Six blinded reviewers measured GBL using the missing area, ratio, and diameter methods.
• Assessed accuracy via root mean square error (RMSE) and interrater reliability using intraclass correlation coefficients (ICCs).

Main Results:

• The missing area method showed the lowest average overestimation (1%) and RMSE (3.6%), indicating superior accuracy.
• All methods demonstrated good to excellent interrater reliability (missing area: 0.89, ratio: 0.91, diameter: 0.90).
• The missing area method's accuracy advantage persisted across all reviewer experience levels (resident, fellow, attending).

Conclusions:

• The best-fit circle missing area method is the most accurate and reliable technique for measuring glenoid bone loss.
• This method's simplicity and accuracy enhance preoperative planning for shoulder instability surgeries.
• Findings are consistent regardless of the surgeon's experience level.