title: Does Microwave Ablation of the Tumor Edge Allow for Joint-sparing Surgery in Patients With Osteosarcoma of the Proximal Tibia?
abstract: BACKGROUND
  Joint-sparing surgery of a patient's native joint for osteosarcoma likely affords better function and comparable survival. However, it sometimes is challenging to resect a juxtaarticular osteosarcoma in a way that preserves the affected epiphysis because wide margins are necessary to minimize the risk of local recurrence. If there was a method to resect a tumor close to the joint and treat a potentially positive margin to prevent recurrence, it might allow salvage of a joint that otherwise might be lost.
  
  
  OBJECTIVE
  We therefore asked (1) whether joint-preserving tumor resection could be performed for juxtaarticular osteosarcoma after microwave ablation of the tumor edge under navigation without leading to local recurrences, (2) what is the resulting function, and (3) what are the complications associated with this procedure.
  
  
  METHODS
  Between 2009 and 2011, we treated 11 patients who had juxtaarticular osteosarcoma of the proximal tibia (mean age, 12 years; range, 9-16 years) with joint-preserving surgery by transepiphysis tumor resection after navigation-assisted microwave ablation of the tumor edge; they were followed a minimum of 37 months (mean, 48 months; range 37-62 months), and none was lost to followup. Patients were considered eligible for this procedure if they had a distance from the tumor edge to the articular surface between 10 to 15 mm, good chemotherapy responses, no pathologic fracture and no tumor involvement of major neurovascular structures. Allograft in combination with a vascularized fibula flap was used for segmental reconstruction. We recorded local tumor control, complications, and functional outcomes using the Musculoskeletal Tumor Society score, which ranges from 0 to 30, with higher scores indicating better function.
  
  
  RESULTS
  There were no local recurrences. Major complications included osteonecrosis of part of the epiphysis in two patients and deep infection in one. The Musculoskeletal Tumor Society score ranged from 26 to 30 with a mean of 29.
  
  
  CONCLUSIONS
  In selected patients with osteosarcoma invading the epiphysis, navigated resection facilitates performing joint-sparing surgery, and in our small series, the adjuvant microwave ablation seemed to provide adequate local tumor control. Although more experience and longer followup are needed, this approach may make it possible to salvage more native joints when performing limb salvage for osteosarcoma.
  
  
  METHODS
  Level IV, therapeutic study.
authors.affiliation: The Orthopaedic Department, Xijing Hospital Affiliated to the Fourth Military Medical University, Xi'an, 710032, People's Republic of China, ljfmmu@sina.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Hongbin
authors.initials: H
authors.lastname: Fan
authors.forename: Jun
authors.initials: J
authors.lastname: Fu
mesh_terms: D055011:Ablation Techniques; D000293:Adolescent; D001859:Bone Neoplasms / Q000601:surgery*; D002648:Child; D004838:Epiphyses; D005260:Female; D006801:Humans; D007719:Knee Joint; D008297:Male; D008872:Microwaves / Q000627:therapeutic use; D059351:Organ Sparing Treatments; D019637:Orthopedic Procedures / Q000379:methods*; D012516:Osteosarcoma / Q000601:surgery*; D013977:Tibia