Trunnionosis and metal wear causing metal hypersensitivity: 2 sides of the same coin?

Metal hypersensitivity (MHS) and trunnionosis are being looked at more frequently. Both entities pose a difficult concern for surgeons and patients alike. This commentary highlights the similarities and differences between the 2 conditions. When a surgeon suspects either MHS or trunnionosis, both should be considered in the differential diagnosis. Both conditions are rare and should be considered a diagnosis of exclusion. The commentary proposes an outline on how to diagnose and treat the 2 entities.