title: Osteosarcoma following tibial plateau leveling osteotomy in dogs: 29 cases (1997-2011).
abstract: OBJECTIVE
  To determine the signalment, tibial plateau leveling osteotomy (TPLO) plate type, clinical staging information, treatment, and oncological outcome in dogs that developed osteosarcoma at the proximal aspect of the tibia following TPLO and to calculate the interval between TPLO and osteosarcoma diagnosis.
  
  
  METHODS
  Multi-institutional retrospective case series.
  
  
  METHODS
  29 dogs.
  
  
  METHODS
  Medical records from 8 participating institutions were searched for dogs that developed osteosarcoma (confirmed through cytologic or histologic evaluation) at previous TPLO sites. Signalment, TPLO details, staging tests, treatment data, and outcome information were recorded. Descriptive statistics were calculated, and disease-free intervals and survival times were evaluated by means of Kaplan-Meier analysis.
  
  
  RESULTS
  29 dogs met the inclusion criteria. The mean age was 9.2 years and mean weight was 45.1 kg (99.2 lb) at the time of osteosarcoma diagnosis. Most dogs had swelling over the proximal aspect of the tibia (17/21) and lameness of the affected limb (28/29). The mean interval between TPLO and osteosarcoma diagnosis was 5.3 years. One type of cast stainless steel TPLO plate was used in most (18) dogs; the remaining dogs had received plates of wrought stainless steel (n = 4) or unrecorded type (7). Twenty-three of 29 dogs underwent treatment for osteosarcoma. Median survival time for 10 dogs that underwent amputation of the affected limb and received ≥ 1 chemotherapeutic treatment was 313 days.
  
  
  CONCLUSIONS
  Results supported that osteosarcoma should be a differential diagnosis for dogs with a history of TPLO that later develop lameness and swelling at the previous surgical site. Oncological outcome following amputation and chemotherapy appeared to be similar to outcomes previously reported for dogs with appendicular osteosarcoma.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Selmic
authors.forename: Stewart D
authors.initials: SD
authors.lastname: Ryan
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Boston
authors.forename: Julius M
authors.initials: JM
authors.lastname: Liptak
authors.forename: William T N
authors.initials: WT
authors.lastname: Culp
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Sartor
authors.forename: Cassandra Y
authors.initials: CY
authors.lastname: Prpich
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Withrow
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery; D001859:Bone Neoplasms / Q000175:diagnosis / Q000209:etiology / Q000662:veterinary*; D004283:Dog Diseases / Q000209:etiology*; D004285:Dogs; D005260:Female; D008297:Male; D012516:Osteosarcoma / Q000150:complications / Q000662:veterinary*; D010027:Osteotomy / Q000662:veterinary*; D012189:Retrospective Studies; D013977:Tibia