Co-occurrence of Pigmented Villonodular Synovitis and Patellar Clunk Syndrome Following Total Knee Arthroplasty: A Case Report.

Pigmented villonodular synovitis (PVNS) is an uncommon hyperproliferative disease of the synovium presenting either as localized or a more aggressive diffuse form. Its occurrence following total knee arthroplasty (TKA) is rare, and its presentation alongside patellar clunk syndrome (PCS) has not been previously reported. We present a case of a 64-year-old female patient diagnosed with diffuse PVNS (D-PVNS) two and half years following TKA, co-occurring with PCS. The diagnosis was initially suspected during a diagnostic arthroscopy for PCS, after which the patient underwent arthroscopic synovectomy and scar excision. Histological analysis of the resected tissue confirmed the diagnosis, revealing inflammatory cells and hemosiderin deposits.