Trunnionosis in total hip arthroplasty with accompanying amyloidosis and calcium pyrophosphate deposition disease

Metal-on-polyethylene (MoP) is a common type of total hip arthroplasty. Trunnionosis is a rare but concerning complication of this type of implant. Trunnionosis involves wear and corrosion at the femoral component's head-neck interface and may cause a local inflammatory response referred to as an adverse reaction to metal debris (ARMD). We present a rare case of trunnionosis with concurrent calcium pyrophosphate deposition disease (CPPD) and amyloidosis in a MoP implant. ARMD can be linked to crystalline arthropathy and amyloidosis, possibly due to metal ion-induced acidosis. Clinicians should consider trunnionosis in patients with persistent post-surgical hip pain, and order metal ion tests and synovial fluid analysis to aid in the diagnosis of this condition if suspected. Timely recognition enables appropriate surgical revision.