Single Peg Patellar Component Fracture in Total Knee Replacement: A Case Report

Total knee arthroplasty (TKA) is considered the definitive treatment for advanced degenerative disease in the knee and involves replacing the native joint with prosthetic components. Failure mechanisms have been studied extensively due to the ubiquitous nature of these procedures. In this case report, the failure of a press-fit patellar component in a cementless TKA is investigated as a novel complication.

A 58-year-old male patient presented to an orthopedic clinic complaining of severe left knee pain with ambulation and associated varus alignment. He underwent X-ray imaging, where clear advanced osteoarthritis was visualized, with complete loss of joint space in the articulation of the medial compartment of the knee. Due to the patient's pain levels and decreased mobility, the patient elected to proceed with a TKA. The patient underwent this procedure without immediate complication until he returned 19-months post-operatively. At this time, X-rays demonstrated a failed patellar component from a shear fracture of the single peg prosthesis. A revision surgery was then completed to resolve this issue.

Based on the present reported data on TKA modes of failure, this case describes the first report of a shear fracture of the single peg prosthesis in a cementless TKA.