Fracture of the polyethylene tibial post in the posterior-stabilized total knee prosthesis: arthrographic and CT arthrographic diagnosis.

Fracture of the polyethylene tibial post in the posterior-stabilized total knee prosthesis is often delayed in diagnosis due to its nonspecific symptoms and the radiolucent characteristic of polyethylene on conventional radiography. Therefore, the diagnosis is always established by arthroscopy. Notwithstanding recent advances in imaging modalities, we are presently aware of only two related case reports on MRI and even no reports about arthrographic or CT-arthrographic diagnosis of fractured tibial post. We hereby report a case of a 58-year-old female patient who developed recurrent knee pain during the third year after total knee arthroplasty. The displaced polyethylene tibial post was clearly outlined by administered contrast material in the posterior knee. Under the diagnosis of fracture of the tibial post, the patient underwent isolated replacement of the broken polyethylene insert. Her knee pain significantly improved after the operation.