title: Wear debris pseudotumor following total knee arthroplasty: a case report.
abstract: BACKGROUND
  In patients who have undergone a total joint replacement, any mass occurring in or adjacent to the joint needs thorough investigation and a wear debris-induced cyst should be suspected.
  
  
  METHODS
  An 81-year-old man presented with a painful and enlarging mass at the popliteal fossa and calf of his right knee. He had had a total right knee replacement seven years previously. Plain radiographs showed narrowing of the medial compartment. Magnetic resonance imaging showed a cystic lesion at the postero-medial aspect of the knee joint mimicking popliteal cyst or soft tissue sarcoma. Fine needle aspiration was non-diagnostic. A core-needle biopsy showed metallosis. Intraoperative findings revealed massive metallosis related to extensive polyethylene wear, delamination and deformation. Revision knee and patella arthroplasty was carried out after a thorough debridement of the knee joint.
  
  
  CONCLUSIONS
  Long-term follow-up is critical for patients with total joint replacement for early detection of occult polyethylene wear and prosthesis loosening. In these cases, revision arthroplasty may provide a satisfactory knee function.
authors.affiliation: First Department of Orthopaedics, ATTIKON University General Hospital, Athens University Medical School, Athens, Greece.
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Mavrogenis
authors.forename: George N
authors.initials: GN
authors.lastname: Nomikos
authors.forename: Vasileios I
authors.initials: VI
authors.lastname: Sakellariou
authors.forename: George I
authors.initials: GI
authors.lastname: Karaliotas
authors.forename: Panayiotis
authors.initials: P
authors.lastname: Kontovazenitis
authors.forename: Panayiotis J
authors.initials: PJ
authors.lastname: Papagelopoulos