A Case Report of Broken Kotz Modular System due to Metal Fatigue

We report a case of broken Kotz modular system due to metal fatigue. A 25 year-old woman suffered left knee dislocation 9 years after total knee arthroplasty with Kotz modular femur and tibia reconstruction (KMFTR) system for osteosarcoma of the left proximal tibia. Roentgenograms showed breakage of the housing part in the proximal tibial component. At revision surgery of the component, bearing bushes had worn off and the housing part had severed into several blocks. Electromicroscopic studies showed many irregular cracks in the severed anterior face. These findings demonstrated that breakage in the housing part of the prosthesis was due to metal fatigue.