title: Large osteochondral lesions of the femoral condyles: Treatment with fresh frozen and irradiated allograft using the Mega OATS technique.
abstract: BACKGROUND
  The purpose of this study was to review the clinical results of irradiated fresh frozen osteochondral allografts for large osteochondral defects of the knee using the Mega-OATS technique.
  
  
  METHODS
  Nine patients with a mean age of 32.1±6.6 (18 to 44) underwent Mega-OATS transplantation with irradiated (2.5Mrad), fresh frozen distal femur allograft. Three patients also underwent ACL-reconstruction; one patient a high tibial osteotomy. The underlying indication was osteochondrosis dissecans in four and trauma in five patients. The defect size was 25×25mm in three patients and 30×30 in six patients and the depth ranged from eight to 14mm. All OCD lesions were located on the medial femoral condyle; two of the traumatic lesions were located on the lateral femoral condyle. Clinical outcome was assessed using the Lysholm and IKDC scores. Radiographic incorporation was evaluated using serial radiographs and MR imaging at one year post surgery. All patients were reviewed at three, six, 12, and 24months following surgery.
  
  
  RESULTS
  The Lysholm (IKDC) score improved significantly (p=0.02 resp. p=0.007) within and between patients during the follow-up period from 40.9 (37) to 90.9 (87.1) at 2years. Radiographic union was observed in all patients at three months; on MR imaging at one year osseous integration was observed in eight patients. Graft subsidence with loss of the overlying cartilage was observed in one and subchondral cystic changes at the implantation side were seen in another patient.
  
  
  CONCLUSIONS
  The results of this case series suggest that irradiated osteochondral allograft provides significant medium-term clinical improvement in patients treated for large osteochondral lesions of the femoral condyles.
  
  
  METHODS
  IV, case series.
authors.affiliation: Department of Orthopaedic Surgery, Clinical Medical School, University of Queensland, Australia; Musculoskeletal Research Unit, CQ University, Rockhampton, Australia. Electronic address: ehohmann@optusnet.com.au.
authors.forename: Erik
authors.initials: E
authors.lastname: Hohmann
authors.affiliation: Department of Orthopaedic Surgery, Royal Brisbane Hospital, Herston, Australia; Department of Surgery, School of Medicine, University of Queensland, Australia.
authors.forename: Kevin
authors.initials: K
authors.lastname: Tetsworth
mesh_terms: D000328:Adult; D064591:Allografts; D016025:Bone Transplantation; D002356:Cartilage / Q000000981:diagnostic imaging / Q000637:transplantation*; D002357:Cartilage Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000601:surgery*; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D010008:Osteochondritis Dissecans / Q000000981:diagnostic imaging / Q000601:surgery*; D012189:Retrospective Studies; D014184:Transplantation, Homologous; D055815:Young Adult
keywords: Cartilage; Femoral condyles; Irradiated allograft; Mega-OATS; Osteochondral allograft transplantation; Osteochondral defect