title: Tibial Growth Disturbance Following Distal Femoral Resection and Expandable Endoprosthetic Reconstruction.
abstract: BACKGROUND
  In growing children, an expandable endoprosthesis is commonly used after distal femoral resection to compensate for loss of the distal femoral physis. Our hypothesis was that such prostheses can affect proximal tibial growth, which would contribute to an overall leg-length discrepancy and cause angular deformity.
  
  
  METHODS
  Twenty-three skeletally immature patients underwent the placement of a distal femoral expandable endoprosthesis between 1994 and 2012. Tibial length, femoral length, and mechanical axis were measured radiographically to determine the growth rate.
  
  
  RESULTS
  No patient had radiographic evidence of injury to the proximal tibial physis at the time of surgery other than insertion of the tibial stem. Fifteen (65%) of the patients experienced less proximal tibial growth in the operative compared with the contralateral limb. In ten (43%) of the patients, the discrepancy progressively worsened, whereas in five (22%) of the patients, the discrepancy stabilized. Seven patients did not develop tibial length discrepancy, and one patient had overgrowth of the tibia. For the ten patients with progressive shortening, the proximal tibial physis grew an average of 4.0 mm less per year in the operative limb. Five (22%) of the patients had ≥ 20 mm of tibial length discrepancy at last follow-up. Three of these patients underwent contralateral tibial epiphysiodesis. Three patients required corrective surgery for angular deformity.
  
  
  CONCLUSIONS
  The tibial growth plate may not resume normal growth after implantation of a distal femoral prosthesis. Physeal bar resection, prosthesis revision, and contralateral tibial epiphysiodesis may be needed to address tibial growth abnormalities.
authors.affiliation: CHU de Québec, Pavillon Hôtel Dieu, 11 Côte du palais, Québec G1R2J6, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Arteau
authors.affiliation: Department of Orthopaedic Oncology, MD Anderson Cancer Center, Unit 1448, P.O. Box 301402, Houston, Texas 77230. E-mail address for P.P. Lin: plin@mdanderson.org.
authors.forename: Valerae O
authors.initials: VO
authors.lastname: Lewis
authors.affiliation: Department of Orthopaedic Oncology, MD Anderson Cancer Center, Unit 1448, P.O. Box 301402, Houston, Texas 77230. E-mail address for P.P. Lin: plin@mdanderson.org.
authors.forename: Bryan S
authors.initials: BS
authors.lastname: Moon
authors.affiliation: Department of Orthopaedic Oncology, MD Anderson Cancer Center, Unit 1448, P.O. Box 301402, Houston, Texas 77230. E-mail address for P.P. Lin: plin@mdanderson.org.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Satcher
authors.affiliation: Department of Orthopaedic Oncology, MD Anderson Cancer Center, Unit 1448, P.O. Box 301402, Houston, Texas 77230. E-mail address for P.P. Lin: plin@mdanderson.org.
authors.forename: Justin E
authors.initials: JE
authors.lastname: Bird
authors.affiliation: Department of Orthopaedic Oncology, MD Anderson Cancer Center, Unit 1448, P.O. Box 301402, Houston, Texas 77230. E-mail address for P.P. Lin: plin@mdanderson.org.
authors.forename: Patrick P
authors.initials: PP
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D002648:Child; D004838:Epiphyses / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D005266:Femoral Neoplasms / Q000601:surgery; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007870:Leg Length Inequality / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D023821:Limb Salvage / Q000295:instrumentation / Q000379:methods; D008297:Male; D012516:Osteosarcoma / Q000601:surgery; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D019919:Prosthesis Implantation / Q000295:instrumentation / Q000379:methods; D011859:Radiography; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000254:growth & development*; D016896:Treatment Outcome