title: Minimally invasive computer-navigated total hip arthroplasty, following the concept of femur first and combined anteversion: design of a blinded randomized controlled trial.
abstract: BACKGROUND
  Impingement can be a serious complication after total hip arthroplasty (THA), and is one of the major causes of postoperative pain, dislocation, aseptic loosening, and implant breakage. Minimally invasive THA and computer-navigated surgery were introduced several years ago. We have developed a novel, computer-assisted operation method for THA following the concept of "femur first"/"combined anteversion", which incorporates various aspects of performing a functional optimization of the cup position, and comprehensively addresses range of motion (ROM) as well as cup containment and alignment parameters. Hence, the purpose of this study is to assess whether the artificial joint's ROM can be improved by this computer-assisted operation method. Second, the clinical and radiological outcome will be evaluated.
  
  
  METHODS
  A registered patient- and observer-blinded randomized controlled trial will be conducted. Patients between the ages of 50 and 75 admitted for primary unilateral THA will be included. Patients will be randomly allocated to either receive minimally invasive computer-navigated "femur first" THA or the conventional minimally invasive THA procedure. Self-reported functional status and health-related quality of life (questionnaires) will be assessed both preoperatively and postoperatively. Perioperative complications will be registered. Radiographic evaluation will take place up to 6 weeks postoperatively with a computed tomography (CT) scan. Component position will be evaluated by an independent external institute on a 3D reconstruction of the femur/pelvis using image-processing software. Postoperative ROM will be calculated by an algorithm which automatically determines bony and prosthetic impingements.
  
  
  CONCLUSIONS
  In the past, computer navigation has improved the accuracy of component positioning. So far, there are only few objective data quantifying the risks and benefits of computer navigated THA. Therefore, this study has been designed to compare minimally invasive computer-navigated "femur first" THA with a conventional technique for minimally invasive THA. The results of this trial will be presented as soon as they become available.
  
  
  BACKGROUND
  DRKS00000739.
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Germany. t.renkawitz@asklepios.com
authors.forename: Tobias
authors.initials: T
authors.lastname: Renkawitz
authors.forename: Martin
authors.initials: M
authors.lastname: Haimerl
authors.forename: Lars
authors.initials: L
authors.lastname: Dohmen
authors.forename: Sabine
authors.initials: S
authors.lastname: Gneiting
authors.forename: Melanie
authors.initials: M
authors.lastname: Wegner
authors.forename: Nicole
authors.initials: N
authors.lastname: Ehret
authors.forename: Claudia
authors.initials: C
authors.lastname: Buchele
authors.forename: Mario
authors.initials: M
authors.lastname: Schubert
authors.forename: Philipp
authors.initials: P
authors.lastname: Lechler
authors.forename: Michael
authors.initials: M
authors.lastname: Woerner
authors.forename: Ernst
authors.initials: E
authors.lastname: Sendtner
authors.forename: Tibor
authors.initials: T
authors.lastname: Schuster
authors.forename: Kurt
authors.initials: K
authors.lastname: Ulm
authors.forename: Robert
authors.initials: R
authors.lastname: Springorum
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D005269:Femur / Q000502:physiology / Q000601:surgery*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D056888:Patient Positioning / Q000379:methods*; D059035:Perioperative Period; D016059:Range of Motion, Articular; D012399:Rotation; D025321:Surgery, Computer-Assisted