title: Medium to long-term results after reconstruction of bone defects at the knee with tumor endoprostheses.
abstract: OBJECTIVE
  Limb salvage and reconstruction with tumor endoprostheses is considered as therapeutic standard in the treatment of bone defects at the knee. Few studies report long-term results so far.
  
  
  METHODS
  Seventy-seven patients who had a cementless or cemented MUTARS endoprosthesis implanted were followed-up for a mean period of 46 months (3-128 months). The defects were due to primary tumor lesions in 69 cases or metastases in 8 cases. The distal femur (n = 49) or the proximal tibia (n = 28) was reconstructed predominantly with cementless implants (femur: 69%, tibia: 92%). The resection of the tumor was intraarticular in 46 and extraarticular in 31 patients.
  
  
  RESULTS
  After 10 years probability of limb salvage was 92% with a recurrence rate of 3%. Complications were frequent with a revision rate of 58% and lead to a cumulative probability of survival of the initially implanted prosthesis of 57% after 5 years. Locking mechanism failure (n = 15) and aseptic loosening (n = 13) were the most frequent failure modes.
  
  
  CONCLUSIONS
  Regardless of achieving a low recurrence rate and satisfactory functional results, we found a high complication rate after implantation of a megaprosthesis. This was particularly evident for extraarticular resections and cemented fixation, which should be avoided when possible.
authors.affiliation: Department of Orthopaedics, University of Heidelberg, 69118 Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kinkel
authors.forename: B
authors.initials: B
authors.lastname: Lehner
authors.forename: J A
authors.initials: JA
authors.lastname: Kleinhans
authors.forename: E
authors.initials: E
authors.lastname: Jakubowitz
authors.forename: V
authors.initials: V
authors.lastname: Ewerbeck
authors.forename: C
authors.initials: C
authors.lastname: Heisel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000601:surgery*; D002648:Child; D005260:Female; D005269:Femur; D006801:Humans; D007717:Knee / Q000601:surgery*; D007720:Knee Prosthesis; D023821:Limb Salvage; D008297:Male; D008875:Middle Aged; D013977:Tibia; D013997:Time Factors; D016896:Treatment Outcome