title: Coaxial extendible knee equalizes limb length in children with osteogenic sarcoma.
abstract: We assessed our ability to achieve limb length equality (LLE) in children following limb-sparing surgery for distal femur osteogenic sarcoma using coaxial extendible prostheses in 12 children, averaging 11.6 years old at the time of tumor resection (range, 5.9-15.5 years). All but one child achieved clinical limb length equality. There were 23 extensions, averaging 3.8 extensions per patient (range, 1-5), by an average 13 mm per extension and an average total extension of 49.3 mm per patient extended. Eight children underwent revision surgery after an average of 45.1 months (range, 3-115 months). Aseptic loosening occurred more frequently among children with greater femoral diameter growth. The overall prosthetic survival was 60% at 3 years and 35% at 5 years. The survival until aseptic loosening at 3 and 5 years was 85% and 45%, respectively. Press-fit components survived longer than cemented stems. None of the devices loosened. At skeletal maturity the MSTS functional scores averaged 25. Using a coaxial extendible implant, we efficiently achieved LLE in this population. Prosthetic revision was needed frequently. Younger age and longer resection percentages were associated with shorter prosthetic survival and higher revision/aseptic loosening rates. Femoral diameter growth may contribute to loosening. Early experience with this extendible implant is promising.
authors: Orthopaedic Surgery Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, affiliated with Weill Medical College of Cornell University, New York, NY 10021, USA.
authors: Alexandre
authors: A
authors: Arkader
authors: Dan C M
authors: DC
authors: Viola
authors: Carol D
authors: CD
authors: Morris
authors: Patrick J
authors: PJ
authors: Boland
authors: John H
authors: JH
authors: Healey
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005266:Femoral Neoplasms / Q000601:surgery*; D006801:Humans; D016268:Internal Fixators; D007870:Leg Length Inequality / Q000209:etiology / Q000517:prevention & control*; D023821:Limb Salvage / Q000009:adverse effects / Q000295:instrumentation*; D008297:Male; D012516:Osteosarcoma / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies