title: Surgical and Functional Outcomes in Patients Undergoing Total Knee Replacement With Patient-Specific Implants Compared With "Off-the-Shelf" Implants.
abstract: BACKGROUND
  Total knee arthroplasty (TKA) instrumentation and implant designs have been evolving, with one of the current innovations being patient-specific implants (PSIs).
  
  
  OBJECTIVE
  To evaluate whether there is a significant difference in surgical time, intraoperative blood loss, postoperative range of motion, and length of stay between PSI and conventional TKA.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  A consecutive series of 621 TKA patients, 307 with PSIs and 314 with conventional implants, was reviewed. Differences in estimated blood loss, length of stay, range of motion, and surgical time/tourniquet time between the 2 cohorts were analyzed.
  
  
  RESULTS
  Linear regression analysis demonstrated that PSI decreased estimated blood loss by 44.72 mL (P < .01), decreased length of stay by 0.39 days (P < .01), decreased postoperative range of motion by 3.90° (P < .01), and had a negligible difference on surgical and tourniquet time.
  
  
  CONCLUSIONS
  The use of PSI is associated with decreased estimated blood loss, decreased length of stay, decreased range of motion, and no discernible difference in surgical or tourniquet time, all of which are unlikely to be clinically significant.
authors.affiliation: Department of Orthopaedic Surgery, Joint Replacement Service, University of California-Irvine, Orange, California, USA.
authors.forename: Ran
authors.initials: R
authors.lastname: Schwarzkopf
authors.affiliation: Department of Orthopaedic Surgery, Joint Replacement Service, University of California-Irvine, Orange, California, USA.
authors.forename: Merrick
authors.initials: M
authors.lastname: Brodsky
authors.affiliation: Department of Orthopaedic Surgery, Joint Replacement Service, University of California-Irvine, Orange, California, USA.
authors.forename: Giancarlo A
authors.initials: GA
authors.lastname: Garcia
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Gomoll
keywords: estimated blood loss; length of stay; patient-specific implants; range of motion; surgical time; total knee arthroplasty; tourniquet time