Contact Mechanics of Anatomic Radial Head Prosthesis: Comparison Between Native Radial Head and Anatomic Radial Head Prostheses in the Dynamic Mode.

PURPOSE

The biomechanical characteristics of anatomic radial head prostheses have not been completely investigated. We compared and analyzed the contact kinematic characteristics of the native radial head and radial head prostheses replicating the native head contour, using a real-time flexion simulation model.

METHODS

Ten fresh-frozen cadavers were used in this pilot study. A simulating dynamic motion mode from 0° to 130° of elbow flexion was applied. Radiocapitellar contact pressure and area were measured using a real-time digitized pressure sensor. Further, contact area and pressure curves were obtained during flexion, using a motion-tracking device.

RESULTS

The mean contact area, mean contact pressure, and peak contact pressure of the native radial head and radial head prosthesis were 39 mm, 0.0078 kgf/mm, 0.0123 kgf/mm, and 33 mm, 0.0093 kgf/dm, 0.0148 kgf/mm, respectively. The contact area and pressure curves were parabolic nonlinear for the radial head prosthesis and more linear for the native radial head.

CONCLUSIONS

The radial head prosthesis mimics the mechanics of the native radial head in terms of mean contact area, mean contact pressure, and peak contact pressure; however, different patterns of contact pressure and area curves during elbow flexion-extension were observed.

CLINICAL RELEVANCE

We found that the biomechanics of the anatomic radial head prostheses used in the study were similar to those of the native radial head.