title: Biological reconstruction after excision of juxta-articular osteosarcoma around the knee: a new classification system.
abstract: BACKGROUND
  A new classification system for juxta-articular osteosarcoma around the knee joint was developed to allow biological reconstructions using distraction osteogenesis or frozen autograft containing tumors treated with liquid nitrogen. Type I: Tumor has metaphyseal extension to a maximum of 2 cm from the epiphyseal cartilage plate. Type II: Tumor extends to at least half the circumference of the epiphyseal cartilage plate. Type III: Extension to the whole circumference of the epiphyseal cartilage plate. Type IV: Tumor extends to part of the epiphysis through any point of the epiphyseal cartilage plate 10 mm from the joint line. Type V: Tumor extends to half or less of the epiphysis. Type VI: Extension of the tumor to more than half of the epiphysis.
  
  
  METHODS
  Twenty patients with juxta-articular osteosarcoma around the knee joint were treated according to this classification system. The cohort comprised 12 males and 8 females with a mean age of 20 years. The tumors were located in the femur in 12 patients and in the tibia in 8 patients.
  
  
  RESULTS
  The tumors were Type II in 1 patient, Type III in 8 patients, Type IV in 2 patients, Type V in 3 patients and Type VI in 6 patients. Reconstruction after tumor excision was performed using distraction osteogenesis in 13 patients and using frozen autografts in 7 patients. The mean follow-up in the series was 54 months, ranging from 5 to 103 months.
  
  
  CONCLUSIONS
  The classification system may act as a guide to appropriate decision-making in cases of juxta-articular osteosarcoma around the knee joint. Biological reconstruction, using distraction osteogenesis or frozen autografts, may yield good functional results without leading to an increase in the incidence of local recurrence.
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, Japan. tsuchi@med.kanazawa-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: Abdel-Wanis
authors.forename: Katsuro
authors.initials: K
authors.lastname: Tomita
mesh_terms: D000293:Adolescent; D000328:Adult; D001174:Arthrodesis / Q000379:methods; D001859:Bone Neoplasms / Q000145:classification* / Q000601:surgery*; D016025:Bone Transplantation / Q000379:methods; D002648:Child; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000601:surgery*; D008297:Male; D012516:Osteosarcoma / Q000145:classification* / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods; D014182:Transplantation, Autologous