title: Case report: Fibroxanthoma: a complication of a biodegradable screw.
abstract: BACKGROUND
  Biodegradable interference screws in anterior cruciate ligament (ACL) reconstruction have gained popularity because of their similar or superior fixation strength in comparison to metallic interference screws and because they do not cause imaging artifacts and do not need to be removed.
  
  
  METHODS
  We report the case of a 23-year-old man who presented with slowly progressive firm swelling of 2 months' duration at the site of the tibial tunnel 3 years after ACL reconstruction using a biodegradable interference screw. After curettage and débridement, the material was sent for histopathologic examination, which was reported as a fibroxanthoma.
  
  
  METHODS
  Reported complications are osteolysis around the screw, allergic reaction, sterile abscess formation, ganglion cyst formation, and intraarticular migration. A fibroxanthoma consists of fibroblasts and mononuclear or multinucleated cells with large lipid-filled histiocytes (foam cells). The cells are negative for S-100 and keratin and positive for anti-human macrophage marker HAM-56.
  
  
  CONCLUSIONS
  Use of biodegradable screws is associated with high healing rates and low complication rates; however, awareness of their potential complications may help in early recognition and prevention of associated morbidity.
authors: The University Department of Orthopaedic Surgery, College of Medicine, King Faisal University, Dammam, Saudi Arabia. drsadat@hotmail.com
authors: Mir
authors: M
authors: Sadat-Ali
authors: Quamar
authors: Q
authors: Azzam
authors: Mohammed
authors: M
authors: Bluwi
authors: Abdallah S
authors: AS
authors: Al-Umran
mesh_terms: D020341:Absorbable Implants / Q000009:adverse effects*; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000911:Antibodies, Monoclonal / Q000032:analysis; D001859:Bone Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D001863:Bone Screws / Q000009:adverse effects*; D003475:Curettage; D003646:Debridement; D006644:Histiocytes / Q000737:chemistry / Q000473:pathology; D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008264:Macrophages / Q000737:chemistry / Q000473:pathology; D008297:Male; D011475:Prosthesis Failure; D013977:Tibia / Q000473:pathology* / Q000601:surgery
chemical_list: D000911:Antibodies, Monoclonal; C096893:HAM-56 antibody