Patellar Tendon Rupture Following Total Knee Arthroplasty: A Case Report

Patellar tendon rupture following total knee arthroplasty (TKA) is a rare but serious complication that has the ability to result in significant functional impairment due to extensor mechanism disruption. In the early postoperative period, diagnosis may be challenging, especially if initial radiographs are unremarkable and some function is preserved. We present the case of a 60-year-old female who presented to the emergency department with right-sided knee pain following a mechanical fall approximately one month after undergoing right TKA. Initial evaluation showed intact prosthetic components, the ability to bear weight with assistance, and preserved passive range of motion, leading to discharge. Persistent pain prompted further outpatient evaluation. Magnetic resonance imaging subsequently demonstrated a complete rupture of the patellar tendon. The patient underwent surgical reconstruction with an Achilles tendon allograft and tolerated the procedure without any complications. This case highlights the potential for delayed diagnosis of patellar tendon rupture in a patient who recently underwent TKA. It also supports Achilles tendon allograft reconstruction as a viable and reliable option when primary repair is not feasible.