Anatomical Features of the Proximal End of the Radius and Its Implications for Implant Design

Purpose: The proximal radio-ulnar joint allows supination and pronation of the forearm and the humeroradial joint allows flexion and extension movements at the elbow joint. Although the proximal end of the radius is less common than other fractures, it is more common nowadays due to the prolongation of life expectancy, increased incidence of osteoporosis. There have been reports in the literature that success has not been achieved due to the lack of anatomical fit of the prosthesis. Knowledge of the morphometric features of the proximal end of the radius is important for the design of anatomically and biomechanically appropriate prostheses.

Methods: In this study, measurements of head and neck of radius, and radial tuberosity were measured in 80 dry radii. Parameters important for prosthesis design were analysed and their correlations examined.

Results: The shapes of radial head was found 36% oval and 64% circular. The mean heights of the radial head at anterior, posterior, medial, and lateral sides were 8.52 ± 1.32 mm, 9.02 ± 1.23 mm, 9.20 ± 1.59 mm, 8.05 ± 1.13 mm, respectively. The mean depth of articular facet were 1.85 ± 0.37 mm. It was determined that there was no high correlation between the parameters affecting the prosthesis design.

Conclusions: Morphological and morphometric features of the proximal radius are important for prosthesis design and implantation. The ideal radial head prosthesis design is challenging due to numerous parameters, wide ranges and low correlation, although modular designs facilitate compatibility. The widespread use of 3D printing technologies is expected to reduce the potential complications associated with prosthesis applications.