Late posterior interosseous nerve palsy associated with loosening of radial head implant

Radial head arthroplasty with metallic prosthesis is a safe and effective treatment for comminuted fractures of the radial head, especially in the setting of concomitant elbow instability. Injury to the posterior interosseous nerve (PIN) is a known risk associated with surgical treatment of radial head fractures. Transient PIN neurapraxia has been reported in radial head arthroplasty, occurring postoperatively and improving over time. We report a patient who had full PIN function after radial head arthroplasty, but a late PIN palsy subsequently developed associated with implant loosening and formation of a subperiosteal cyst. To our knowledge, this complication has not previously been reported. This patient was notified of the use of these data and its submission for publication.