title: Comparison of two methods of reconstruction for primary malignant tumors at the knee: a sequential cohort study.
abstract: OBJECTIVE
  The purpose of this study was to compare the complications and functional outcome associated with the use of an irradiated allograft-implant composite or a bone-ingrowth modular tumor prosthesis for replacement of the knee joint after resection of a bone sarcoma from the distal femur or proximal tibia.
  
  
  METHODS
  Eleven patients initially received an allograft reconstruction, followed by 64 treated with a tumor prosthesis. The primary analysis concerned reconstructive failure, defined by the requirement for removal of the original construct. Functional outcome was assessed by using the 1987 Musculoskeletal Tumor Society rating system.
  
  
  RESULTS
  Reconstructive failure occurred in 6 of 11 (55%) allograft constructs compared with 10 of 64 (16%) tumor prostheses (P = 0.009). Failures were due to infection (2 of 11 allografts versus 4 of 64 prostheses; P = 0.2) or mechanical complications (4 of 11 allograft fractures versus 5 of 64 broken prosthetic stems and 1 aseptically loose prosthesis; P = 0.03). The limb salvage rate was 95% (61 of 64) for patients with a tumor prosthesis compared with 64% (7 of 11) for those with an allograft (P = 0.007). Patients with a tumor prosthesis had a better functional outcome with a mean score of 75% compared with 57% for those with an allograft reconstruction (P = 0.006).
  
  
  CONCLUSIONS
  This comparative study suggests that limb salvage surgery at the knee has a better and more predictable outcome with a tumor prosthesis than with an allograft-implant reconstruction.
authors.affiliation: University Musculoskeletal Oncology Unit, Mount Sinai Hospital, and the Department of Surgery, University of Toronto, Toronto, Canada. wunder@mshri.on.ca
authors.forename: J S
authors.initials: JS
authors.lastname: Wunder
authors.forename: K
authors.initials: K
authors.lastname: Leitch
authors.forename: A M
authors.initials: AM
authors.lastname: Griffin
authors.forename: A M
authors.initials: AM
authors.lastname: Davis
authors.forename: R S
authors.initials: RS
authors.lastname: Bell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001859:Bone Neoplasms / Q000601:surgery*; D016025:Bone Transplantation; D015331:Cohort Studies; D005260:Female; D005266:Femoral Neoplasms / Q000601:surgery; D005269:Femur / Q000601:surgery; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D019651:Plastic Surgery Procedures / Q000379:methods*; D012509:Sarcoma / Q000601:surgery*; D013977:Tibia / Q000601:surgery; D019172:Transplantation Conditioning; D014184:Transplantation, Homologous; D016896:Treatment Outcome