Patellar cluck syndrome is interposition of soft tissue at or hyperophied scar:

Explanation

Ans: B. Superior pole of patella and impinging on femoral component during extension Patellar Clunk Syndrome is a painful condition associated with a mechanical catching or clunking during active extension following total knee ahroplasty (TKA).The syndrome is caused by growth of interposing soft tissue usually at the superior pole of the patella.This interposed soft tissue cannot be visualized on plain radiographs.