Post-traumatic Patellofemoral Ankylosis treated with Robotic Arm Assisted Patellofemoral Arthroplasty – A Case Report

Introduction: This case report describes the procedure and 2-year outcome in a patient with bony patellofemoral ankylosis who underwent robotic arm-assisted patellofemoral arthroplasty (RA-PFA). Case Report: A 21-year-old male with Post-traumatic Patellofemoral Ankylosis with quadriceps contracture underwent RA-PFA with Quadriceps-plasty. Preoperatively, the patient had a flexion deformity of 20° with no further active flexion or extension. Passive knee extension from 20° to 0° was possible. At 2-year follow-up, he was independently ambulant with good improvement in pain and functional clinical scores. He had an improved active flexion of 0°–80° and active extension of 80°–0° with no extension lag. Conclusion: This case suggests RA-PFA may be an effective intervention to restore knee function in Post-traumatic Patellofemoral Ankylosis despite the grossly altered anatomy. Keywords: Osseous ankylosis knee, patellofemoral implant, robotic arm-assisted patellofemoral arthroplasty, quadriceps-plasty.