Fracture of a temporary PROSTALAC knee spacer leading to mechanical symptoms after prolonged use

A 81-year-old woman with chronic periprosthetic knee infection underwent implantation of a temporary articulating PROSTALAC spacer following prosthesis removal. Over the ensuing 3 months, she developed worsening mechanical symptoms including instability, clicking, and difficulty bearing weight. Radiographs and MRI demonstrated a transverse fracture through the femoral component of the spacer with cement fragmentation and malalignment. Revision surgery with replacement of the fractured spacer led to resolution of symptoms and improved postoperative function. This case highlights the limited structural durability of polymethylmethacrylate (PMMA)-based articulating spacers during prolonged implantation and emphasizes the importance of imaging evaluation when new mechanical symptoms arise.