Objective: This study determined the effect of metallic radial head arthroplasty on radiocapitellar joint contact area.
Design: The contact area of eight intact radiocapitellar joints was assessed during simulated compressive loading. Subsequently, the same experiments were repeated after reconstruction with three different radial head implant sizes.
Background: There has been an increasing use of metal radial head implants relative to silicone implants. However, the contact characteristics with the metal reconstruction have not been determined.
Methods: A 100 N compressive load was applied to the radiocapitellar joint at three different flexion angles for the native joint and three different sizes of a metal head implant. An impression material was employed to quantify joint contact area.
Results: Following metallic radial head arthroplasty, the contact area decreased by approximately two-thirds relative to the native radiocapitellar joint (P<0.001). Smaller implant sizes resulted in slightly larger contact areas (P<0.05). In addition, contact area decreased as joint flexion angle increased (P<0.04).
Conclusions: Selection of radial head implant size is likely not a significant factor with regard to contact area mechanics of the radiocapitellar articulation.
Relevance: The effect of radial head implant size on the contact area produced with the native capitellum is not known. This study shows that the design or selection of a metallic radial head implant from the viewpoint of size is likely not an important factor with regard to minimizing joint contact stresses.