Revision Total Knee Arthroplasty in a Case of Operated Right Total Knee Arthroplasty with Implant Loosening and Pigmented Villonodular Synovitis.

Introduction: A 52-year-old male operated elsewhere with the right total knee arthroplasty 5 years ago presented with complaints of pain and swelling in his right knee and difficulty in walking. Radiographs revealed implant loosening with Anderson Orthopedic Research Institute classification type 3 bone defect in the femur and tibia. Right knee effusion was aspirated which was reddish tinged, most likely traumatic; C-reactive protein was within normal limits, and culture and sensitivity showed no growth. The aspirate was not classically bloody or chocolate colored as may be seen in pigmented villonodular synovitis (PVNS). Case Report: The diagnosis of PVNS was not established preoperatively and occult infection could not be excluded with certainty in a painful, loose total knee arthroplasty (TKA), therefore, a staged revision strategy was selected. The first stage consisted of debridement, implant removal, extensive synovectomy and placement of an antibiotic-loaded cement spacer. Histopathology subsequently confirmed PVNS. Revision TKA was performed 4 weeks later after clinical reassessment and normalization of inflammatory markers. The revision restored alignment and allowed pain-free ambulation. Conclusion: There were no surgical site complications and no symptoms pointing toward recurrence of PVNS. The SF-12 score, Hospital for Special Surgery Knee Score, Knee Society Score, and Oxford Knee Score for his right knee calculated 1 and ½ years postoperatively showed significant improvement from his pre-operative values.