Quantitative measurements of the coronoid in healthy adult patients.

Purpose: We investigated the hypothesis that a quantitative 3-dimensional computed tomography (CT) modeling technique that can measure size, shape, and proximal articular surface area can be used to develop formulas that could predict the volume and proximal surface area of the intact coronoid based on anatomical and demographic data available in patients with fracture of the coronoid process.

Methods: We used a consecutive series of 50 CT scans with a slice thickness of 1.25 mm or less obtained in patients with fracture of the distal humerus, but no injury to the coronoid, to create 3-dimensional models. The volume and articular surface area of the coronoid were measured, and predictive formulas were based on anatomical measurements. We calculated gender using multiple linear regression.

Results: There were significant correlations between total coronoid volume and coronoid articular surface area for coronoid width, radial neck diameter, radial head diameter, height, weight, and gender. Multiple linear regression modeling with the factors radial head diameter, radial neck diameter, coronoid width, height, weight, and gender resulted in formulas that could account for 71.8% of the variation in coronoid volume and 66.2% of the variation in coronoid articular surface area. The average relative percent difference was 1.32% for the coronoid volume and 0.68% for the coronoid articular surface area.

Conclusions: The volume and articular surface area of the coronoid can be estimated based on anatomical measurements and gender. This may lead to better estimates of lost fragments when modeling the fractured coronoid and CT scan of the opposite limb is not available.