Metallic ulnar head implants have been proposed not only to solve symptomatic radioulnar impingement after Darrach or Sauvé-Kapandji procedures, but also to prevent such an impingement when treating arthritic distal radioulnar joint. This article prospectively analyzes a series of ulnar head implants with special reference to bone resorption at the prosthesis collar and erosion of the sigmoid notch of the distal radius at an average follow-up of 32 months (minimum 24 months).