title: Knee reconstruction with endoprosthesis after extra-articular and intra-articular resection of osteosarcoma.
abstract: OBJECTIVE
  Extra-articular resection is necessary to obtain a wide margin for primary osteosarcomas invading the knee joint, and the limb is often reconstructed using a prosthesis. Here, outcomes of extra-articular and intra-articular procedures were compared.
  
  
  METHODS
  Between 1999 and 2012, 14 patients with osteosarcoma underwent extra-articular excision (n = 6; ages 23-65 years; mean follow-up 82.8 months) or intra-articular excision (n = 8; ages 8-58 years; mean follow-up 96.4 months). In the extra-articular group, there was one Enneking Stage IIA case and five Enneking Stage IIB cases. No local recurrences were noted in either group.
  
  
  RESULTS
  Patient outcomes were as follows (extra-articular cases vs. intra-articular cases): continuous disease-free (2 vs. 7), alive with disease (2 vs. 0) and death from disease (1 vs. 1). Average Musculoskeletal Tumor Society functional scores were 69.4% (range 63.3-83.3%) and 88.3% (range 70.0-96.7%) in the extra-articular and intra-articular groups, respectively, constituting a significant difference (P < 0.05). The 5-year oncological overall survival exceeded 80% in both groups. Amputation was necessary for one patient in the extra-articular group. The 5-year event-free prosthesis survival rates in the extra-articular and intra-articular groups were 33.3 and 75.0%, respectively (P < 0.05).
  
  
  CONCLUSIONS
  The extra-articular excision group developed more complications than the intra-articular excision group, as a result of extensive bone and muscle excision. The limb survival rates were similar in both groups. Our results suggest that extra-articular resection was a necessary and clinically acceptable procedure.
authors: Department of Orthopedic Surgery, Yodogawa Christian Hospital, Osaka ieguchi@med.osaka-cu.ac.jp.
authors: Makoto
authors: M
authors: Ieguchi
authors: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka.
authors: Manabu
authors: M
authors: Hoshi
authors: Department of Orthopedic Surgery, Osaka City General Hospital, Osaka.
authors: Masanari
authors: M
authors: Aono
authors: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka.
authors: Jun
authors: J
authors: Takada
authors: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka.
authors: Naoto
authors: N
authors: Ohebisu
authors: Department of Orthopedic Surgery, Osaka National Hospital, Osaka, Japan.
authors: Ikuo
authors: I
authors: Kudawara
authors: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka.
authors: Hiroaki
authors: H
authors: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000601:surgery*; D002648:Child; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D023821:Limb Salvage / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000601:surgery*; D016896:Treatment Outcome
keywords: knee joint; osteosarcoma; prostheses and implants