536 - Particle Predicament: Mild Knee Pain after Total Knee Arthroplasty

Case Diagnosis: Particle disease

Case Description: A 58-year-old female with a past surgical history of right total knee arthroplasty (TKA) presented to clinic for right knee pain. She reported one year of mild right knee pain that was worse with prolonged sitting and associated with clicking upon standing. She had a TKA four years ago without any complications on post-surgical follow ups. The patient was then lost to follow up one year later. On examination, there was pain on palpation over the patellar facets. Right knee x-ray showed a new large lucency about the superior aspect of the femoral component suspicious for particle disease. The patient was referred to orthopedics for revision surgery. A CT scan with contrast confirmed extensive periprosthetic osteolysis involving the femoral and tibial component.

Discussions: Infection, instability, and aseptic loosening are the most common causes of TKR failure. The average time to revision surgery due to late aseptic loosening is 8.1 years and can be caused by a silent joint infection, cumulative mechanical stress, and particle disease. Particle disease is the process of aggressive bone osteolysis due to a chronic inflammatory response from the release of microscopic periprosthetic particles, thought to be more common in older polyethylene inserts. In many cases particle disease can present insidiously without symptoms. This case highlights a patient with minor knee complaints presenting with severe particle disease requiring revision at 4 years post-TKA in an otherwise well-functioning modern TKA.

Conclusions: Particle disease can commonly present as minor complaints or even asymptomatically. In patients presenting with knee pain and a history of TKA, particle disease is important to keep in the differential and can easily be screened for with x-ray imaging.