title: Early equivalence of uncemented press-fit and Compress femoral fixation.
abstract: Bone ingrowth promises more durable biologic fixation of megaprostheses. The relative performance of different types of fixation is unknown. We compared the fixation of two forms of biologically fixed femoral components: an intramedullary uncemented press-fit stem (UCS; Group 1, 50 patients) and a Compress((R)) uncemented fixation (CPS; Group 2, 41 patients). In Group 1, the overall Kaplan-Meier prosthetic survival rates were 85% at 5 and 71% at 10 years. Most failures were long-term developments. Aseptic loosening was the primary cause of failure. Stem diameters less than 13.5 mm and a diaphyseal/stem coefficient greater than 2.5 mm were associated with decreased prosthetic survival. In Group 2, the overall rate of CPS survival was 88% at 5 years. Failure of femoral fixation or fracture during the first year was the main reason for revision. Five-year survival rates were similar between the groups and we observed no difference in the functional success of the implants. We found no failures after 1-year followup in Group 2 (CPS). Any difference in prosthetic survival can only be proven by longer-term study or a randomized trial.
  
  
  METHODS
  Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Orthopaedic Surgery Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Suite A342, New York, NY, 10021, USA.
authors.forename: German L
authors.initials: GL
authors.lastname: Farfalli
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Boland
authors.forename: Carol D
authors.initials: CD
authors.lastname: Morris
authors.forename: Edward A
authors.initials: EA
authors.lastname: Athanasian
authors.forename: John H
authors.initials: JH
authors.lastname: Healey
mesh_terms: D000293:Adolescent; D000328:Adult; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001843:Bone Cements / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000473:pathology / Q000601:surgery*; D002484:Cementation / Q000379:methods; D002648:Child; D015331:Cohort Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D023821:Limb Salvage / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011475:Prosthesis Failure; D019919:Prosthesis Implantation / Q000379:methods*; D012372:ROC Curve; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D001843:Bone Cements